| NO. |
Title |
Presented at
&
Date |
Author |
Project Team / Research Division |
| Abstract |
10986
|
Poro-mechanical/chemical coupling analysis of borehole
instability in heterogeneous shale
|
3rd Biot Conference on Poromechanics
2005/5/25 |
Koji Yamamoto, Teruyuki Koyama(Japan Oil, Gas and Metals
National Corporation), Younane Abousleiman(The University
of Oklahoma)
|
Petroleum Engineering Research Team
|
| [Abstract] This paper describes a process to tackle with wellbore
stability problems occurring in a shale formation of an
oil field. In the formation, conventional homogeneous,
linear elastic, and isotropic model could not explain
the phenomena occurred. Instead, fluid-solid coupling
ideas are fully utilized not only to explain the phenomena,
but also determine the mud weight window quantitatively.
Also, chemical effects of the drilling fluid are considered
to reduce the drilling troubles. Phenomenological and
numerical models and used techniques are discussed along
with the schematic flow of the study. |
|
|
10981
|
Hydrogen Production with Steam Reformign of Dimethyl
Ether
|
10th Japan-Korea Symposium on Catalysis
2005/5/12 |
Kaoru Takeishi(Shizuoka University)
|
Research Project Team on Emerging Gas Technologies
|
| [Abstract] Steam reforming of methanol and gasoline are actively
researched as hydrogen supply methods for fuel cells of
vehicles, and so on. However, these materials have problems
such as the infrastructure, toxicity, difficulty of reforming,
and so forth. Dimethyl ether (DME) is expected as one
of clean fuels, and DME is one of substitutes of diesel
fuels and LPG. Infrastructures of LPG will be able to
use for DME. Therefore, we have been studying on DME steam
reforming for hydrogen production. Copper alumina catalysts
prepared by a sol-gel method produced large quantities
of H2 and CO2 with DME steam reforming at 300 ℃. Other
metal alumina catalysts prepared by the sol-gel method
produced H2 and CO2, but also produced large quantities
of CO. Our studies showed that copper is the best metal
for the production of H2 while producing less CO. Γ-alumina
for DME hydrolysis into methanol, and copper for methanol
steam reforming to H2 and CO2 coexist on the surfaces
of catalysts prepared by the sol-gel method, and the catalysts
produce more H2 from DME than impregnation catalysts,
mixed catalysts, and so on. We have developed a great
potential for H2 supply from DME. |
|
|
10973
|
Scientific Results of the METI 2004 Nankai Trough Gas
Hydrate Drilling and Testing Project
|
AAPG Hedberg Conference
2004/9/13 |
Yoshihiro Tsuji(Japan Oil, Gas and Metals National Corporation)
|
Methane Hydrate Research Project Team
|
[Abstract] The Nankai Trough is a depression
between the Philippine Sea Plate to the southeast and
the Eurasian Plate to the northwest, extending along central
Honshu to Shikoku in the south and to the east of Kyushu.
From late 1999 to early 2000, MITI Nankai Trough wells
for research on methane hydrate in resource potential
evaluation point of view were drilled off central Honshu
at the water depth of 945m.
A total of six wells, that is, two pilot holes, the main
hole and three post survey wells, were drilled within
a 100m radius of the main hole. Those wells clarified
the occurrence of methane hydrate at the drilling site
by wireline logging, LWD and/or coring. Four zones displaying
spikes of high methane-hydrate concentration were identified
based on the log responses (high resistivity, high sonic
velocity, combinable magnetic resonance and porosity).
FMI (Formation Micro Images) tool suggested the zones
are sand rich intervals of turbidite fan deposits. The
methane hydrate occurrence to fill pore spaces among grains,
an advantage for resource point of view, was visually
confirmed by cores from two wells.
Although the MITI Nankai Trough wells revealed the existence
of methane hydrates in the pores of turbiditic sands,
there remain many issues to be clarified regarding the
occurrence of hydrates in the deep sea off Central Japan,
including the volume and the relationship with the BSR
distribution.
To collect data and information to be used in the evaluation
of the resource potential of methane hydrate, a multi-well
drilling campaign METI Tokai-oki to Kumano-nada was planned
and carried out. Took the lead in the drilling, 2D and
3D seismic surveys targeted in the BSRs were accomplished
and BSR distribution had been Tsuji 2 carefully examined
and interpreted. A total of 16 drill sites at water depths
of 700 to 2000 m were selected from distribution and characters
of BSRs (Fig. 1). The sites were located not only with
BSRs, but also without them. Some are with double BSRs
and others are with high sonic velocity intervals predicted
by velocity analysis.
The campaign was carried out in early 2004 applying JOIDES
Resolution, which has enough experience in the drilling
of methane hydrate in the ODP cruises. LWD (Logging While
Drilling) wells were drilled at all of the sites, and
two WL (Wireline Logging) wells, two full coring wells,
and wells for spot coring of methane hydrate were drilled
after the evaluation of LWD results. Methane hydrate existence
was confirmed by LWD, WL and/or cores in most of the wells
with BSRs. It is suggested that the occurrences of the
methane hydrate are both in pore space filling in sandstone
and layered or nodular form in mudstone.
The logging data as well as the core data will be evaluated
and related to the 3D seismic data. The occurrences of
methane hydrate and sonic velocity and seismic attributes
will be compared and the study is planned to provide a
methodology estimating the volume of the methane hydrate
for the evaluation of resource potential.
The drilling campaign was carried out by the effort of
many geologists, geophysicists, drilling engineers and
many people related to the project. Especially Takatoshi
Namikawa, Tetsuya Fujii, Koji Ochiai, Masao Hayashi, Masaru
Nakamizu, Shoshiro Shimizu, Nobutaka Oikawa, Jun Matsushima,
Tetsuo Saeki, Toshiharu Okui and Ryuta Kitamura and Masayuki
Kawasaki of JOGMEC and Tomonori Mori and Takashi Sugiura
of METI played important roles in preparation and operation.
Japan Petroleum Exploration Co., Ltd. and Teikoku Oil
Co. Ltd. jointly worked as the operating company. Discussion
in MH21 consortium of Japan Methane Hydrate Exploitation
Program helped the planning. Without JOIDES Resolution,
we could not obtain the fruitful results. METI and JOGMEC
approved the presentation of this paper. |
|
|
10967-9
|
Appendix: A Bibliographic Guide to Fault Traps, Fault
Seals and Fault-Related Fluid Flow in Sedimentary Basins
|
AAPG Memoir 85 "Faults, Fluid Flow, and Petroleum
Traps"
2005 |
Rasoul Sorkhabi(Japan Oil, Gas and Metals National Corporation)
|
Geology & Geophysics Research Team
|
[Abstract] The following bibliography is
a list by subject of selected journal articles and books
on the role of faults in fluid flow migration and entrapment
in sedimentary basins. It is a bibliographic guide for
further reading and research; it is not an exhaustive
bibliography. In selecting references the following criteria
were considered:
1. References on fault traps, fault sealing, and fault-related
fluid flow in sedimentary basins (not igneous or metamorphic
terrains)
2. Full articles (not abstracts) published in English-language
mainstream journals so that the references have an international
accessibility
3. Under each category where a book or a special journal
issue has been referenced, individual papers from that
volume have not been listed for the sake of space.
4. For some categories specified with (*), only book volumes
and journal special issues are given because of the broad
scope of these topics.
5. The bibliography is up to March 2003 (including AAPG
Bulletinfs thematic issue on Fault Seals).
The bibliographic guide has been arranged as follows:
(1) Fault Trap Structures
1.1. Faults and the Classification of Traps
1.2. Structural Styles & Closure of Fault Traps
1.3. Normal Faults, Extensional Basins, and Passive Margins
1.4. Reverse Faults, Compressional Basins, and Active
Margins
1.5. Strike-Slip Faults and Wrench Basins
1.6. Faults of Salt Tectonics
1.7. Faults of Inversion Tectonics and Inverted Basins
1.8. Subsurface Mapping of Faults
1.9. Faults on Seismic Images
1.10. Construction of Fault Surface Geometry and Fault
Juxtaposition
(2) Fault Sealing Processes
2.1. Sealing Mechanisms: General Aspects
2.2. Fault Rocks and Fault Sealing Processes: General
Aspects
2.3. Cataclastic Rocks
2.4. Shale Smear in Clastic Sequences
2.5. Deformation Bands in Porous Sandstone
2.6. Pressure Solution Seals
2.7. Mineral Veins and Crack Seals Associated with Faulting
2.7. Fault-related Diagenesis and Fluid-Rock Interactions
in Fault Zones
(3) Fault-Related Fluid Flow
3.1. Fluid Flow in Rocks
3.2. Fault-Related Fluid Flow: Field Studies
3.3. Fluid Flow and Natural Seismicity
3.4. Fluid Flow and Induced Seismicity in Petroleum Basins
3.5. Structural Controls on Petroleum Seepage
(4) Petrophysical Properties of Faults
4.1. Empirical Measurements
4.2. Experimental Measurements
4.3. Numerical Simulation
(5) Analysis of Fault Stress, Stability and Failure
5.1. Rock Mechanics, Rock Stress, and Fault Mechanics
5.2. Borehole Technologies for Fault Stress Measurements
5.3. Field Studies |
|
|
10967-8
|
Geochemical Signatures of Fluid Flow in Thrust Sheets:
Fluid-Inclusion and Stable Isotope Studies of Calcite
Veins in Western Wyoming
|
AAPG Memoir 85 "Faults, Fluid Flow, and Petroleum
Traps"
2005 |
Rasoul Sorkhabi(Japan Oil, Gas and Metals National Corporation)
|
Geology & Geophysics Research Team
|
| [Abstract] The fold-and-thrust belt of western Wyoming consists
of a series of thrust sheets formed in the Cretaceous-Paleocene
during the Sevier-Laramide orogenies. The stratigraphic
succession ranges from the Cambrian through the Eocene,
and the thrust packages have been transported for several
kilometers in a thin-skinned (basement-detached) tectonic
regime. The major thrust faults in the region are east
verging, and become younger from the west toward the east
with a decrease in displacement amount but an increase
in thrust velocity. The thrust zones are associated with
mineral veins of various styles, including those in fractured
limestones, conjugate veins, en echelon veins, and fracture-fills
of fault breccias. Calcite veins provide geochemical signatures
of fluid flow in the thrust zones. Fluid inclusion data
from the calcite veins demonstrate the flow of not only
various generations of brine but also liquid hydrocarbons.
Aqueous inclusions yield homogenization temperatures (minimum
inclusion temperatures) of three populations: 110-125
℃, 130-140 ℃, and 158-163 ℃ with brines of various salinities,
indicative of both freshwater and highly saline water.
Petroleum inclusions record relatively lower homogenization
temperatures (>100 ℃) compared to brines. Stable isotope
analyses of host limestone rocks and calcite veins clearly
indicate meteoric water flushing through thrust zones,
thus altering the oxygen chemistry of host rock. δ13C
values for host limestone rocks and calcite veins were
found to be very similar indicating the precipitation
of the same carbonaceous matter from host rock in the
vein. In contrast, δ18O values are quite different for
host limestone rocks and calcite veins indicating distinct
origin and heterogeneous nature of brines. Micro-permeability
measurements of calcite veins in a fault breccia as well
as a calcite-cemented sandstone yielded similar range
of gas permeability between host rock fragments and calcite
veins. |
|
|
10967-7
|
Fault Zone Architecture and Permeability Distribution
in the Neogene Clastics of Northern Sarawak (Miri Airport
Road Outcrop), Malaysia
|
AAPG Memoir 85 "Faults, Fluid Flow, and Petroleum
Traps"
2005 |
Rasoul Sorkhabi, Shutaro Hasegawa(Japan Oil, Gas and
Metals National Corporation)
|
Geology & Geophysics Research Team
|
| [Abstract] The Miri Airport Road outcrop in Miri, Sarawak, has
exposed a weakly-consolidate sandstone-mudstone sequence
of Miocene age in the form of a gentle anticline cut by
a series of normal faults. An outcrop study of the normal
faults shows that fault zones in porous sandstones are
characterized by a combination of shale smear and anastomosing
deformation bands. The continuity of shale smear on fault
offset was observed as having a "shale smear factor" (fault
throw divided by shale layer thickness) of at least 5.
Deformation bands occur as solitary planar structures
in host sandstone away from fault zone but increase remarkably
in density and linkage toward fault slip plane, possibly
indicating that the faulting evolves from individual bands
to a high strain zone characterized by anastomosing deformation
bands and culminating in fault slip plane. Gas permeability
measurements show that individual deformation bands have
an order of magnitude lower permeability than the nearby
sandstone matrix, and that the permeability of fault zone
defined by anastomosing deformation bands is the lowest
across a fault traverse. It was found that sandstone matrix
in the fault zone has lower permeability than individual
deformation bands outside the fault zone indicating that
fault zone as a whole undergoes tectonic compaction and
porosity collapse. The development of major normal faults
was also accompanied by reactivation of bedding-perpendicular
joints as small-displacement simple-shear faults in between
the major faults. |
|
|
10967-6
|
Development of Synthetic Layer Dip Adjacent to Normal
Faults
|
AAPG Memoir 85 "Faults, Fluid Flow, and Petroleum
Traps"
2005 |
David A. Ferrill(Center for Nuclear Waste Regulatory
Analyses, Southwest Research Institute), Alan P. Morris(University
of Texas), Darrell W. Sims, Deborah J. Waiting(Center
for Nuclear Waste Regulatory Analyses, Southwest Research
Institute), Shutaro Hasegawa(Japan Oil, Gas and Metals
National Corporation)
|
Geology & Geophysics Research Team
|
| [Abstract] Field analyses of normal faulting illustrate that synthetic
layer dip associated with normal faults is a common feature
of extensional fault systems. These synthetic dip panels
are developed where layers on upthrown, downthrown, or
both sides of a normal fault dip toward the downthrown
side of the fault. Synthetic dip panels adjacent to normal
faults should be expected at some scale in all normal
fault systems. In addition to faults developed in strata
with a regional dip, five fault-related mechanisms for
the development of synthetic dip are: faulted monocline
(fault tip-line folding), antilistric fault bend, distributed
shear, shear in relay zone of vertically and/or laterally
segmented faults, and fault block impingement and lateral
contraction. Development of synthetic dip accommodates
a component of throw by tilting or folding, thereby reducing
the offset of true displacement on the related normal
faults. Fault block deformation is strongly dependent
on the mechanisms that produce synthetic dip panels, and
may influence fault zone and block permeability. Depending
on stratigraphic and structural relationships, synthetic
dip panels can produce downthrown closure for hydrocarbon
trapping, provide fluid migration and/or production communication
pathways across faults, or produce barriers to fluid communication
across faults |
|
|
10967-5
|
Analogue Models of Faults Associated with Salt Doming
and Wrenching: Application to offshore UAE
|
AAPG Memoir 85 "Faults, Fluid Flow, and Petroleum
Traps"
2005 |
Yasuhiro Yamada(JAPEX Research Center), Hitoshi Okamura(Japan
Oil, Gas and Metals National Corporation), Yoshihiko Tamura(JODCO),
Futoshi Tsuneyama(Japan Oil, Gas and Metals National Corporation)
|
Geology & Geophysics Research Team
|
[Abstract] Regional stress has a significant
impact on fault development during the formation of salt
dome structures. In order to examine such effects of wrenching,
we conducted a series of analogue experiments of up-doming
using dry granular materials and observed the deformation
on the top free surface. The experiments included three
deformation styles: 1) up-doming followed by wrenching,
2) simultaneous up-doming and wrenching, and 3) wrenching
followed by up-doming. In the first series of the experiments,
the faults produced by simple up-doming were overprinted
by two strike slip fault systems generated by the subsequent
wrenching. The second series of experiments with the configuration
of simultaneous up-doming and wrenching generated normal
faults in a direction perpendicular to relative extension
by the wrench. In the third series of experiments, the
Riedel and anti-Riedel shear faults formed by wrenching
were deformed by the subsequent up-doming, and were overprinted
by the faults related to the up-doming.
These experimental results are applied to the fault systems
observed above dome structures in the UAE region, where
extensive faults in the northwest-southeast direction
have developed. By analogy, these faults were probably
formed during an up-doming and simultaneous wrenching.
The direction of simple shear inferred from a comparison
of real faults and experimental results suggests that
dextral wrenching caused by the Oman Stress regime during
the Late Cretaceous affected the region at the time of
the up-doming. |
|
|
| 10967-4 |
Extensional Fault System Evolution and Reservoir Connectivity |
AAPG Memoir 85 "Faults, Fluid Flow, and Petroleum
Traps"
2005 |
Darrell W. Sims(Center for Nuclear Waste Regulatory
Analyses, Southwest Research Institute), Alan P. Morris(University
of Texas), David A. Ferrill(Center for Nuclear Waste Regulatory
Analyses, Southwest Research Institute), Rasoul Sorkhabi(Japan
Oil, Gas and Metals National Corporation) |
Geology & Geophysics Research Team |
| [Abstract] Sandbox analog modeling experiments provide new insights
into the effects of fault geometry on reservoir connectivity.
During progressive distributed extension, three phases
of fault system evolution are apparent. In Phase I, geometrically
simple faults nucleate rapidly at a large number of sites
throughout the deforming region. This is followed by Phase
II in which faults link and increase in trace length.
Phase III is characterized by a quasi steady-state nucleation
and linkage of faults. Reservoir connectivity has many
components; here we focus on fault-controlled connectivity,
which can be viewed from two complementary perspectives:
rock mass connectivity (continuity of rock between and
around faults), and fault network connectivity. Which
of these perspectives is adopted depends upon whether
faults cutting the reservoir act as barriers to flow (e.g.,
in highly porous sandstone reservoirs) or conduits for
flow (e.g., in fractured carbonate reservoirs). We use
two measures of fault-controlled connectivity: (i) a fault
density measure derived from the number of intersections
between faults and potential flowpaths, and (ii) the ratio
of number of fault tips to number of faults. Taken together,
these characteristics convey both the short-term transmissivity
characteristics and the ultimate leakiness of the reservoir. |
|
|
| 10967-3 |
Fault Seal Analysis Applied to the Erawan Gas-Condensate
Field in the Gulf of Thailand |
AAPG Memoir 85 "Faults, Fluid Flow, and Petroleum
Traps"
2005 |
Tokio Kachi, Hideki Yamada, Kiyoshi Yasuhara(Mitsui
Oil Exploration Company), Masamichi Fujimoto, Shutaro
Hasegawa, Shoji Iwanaga, Rasoul Sorkhabi(Japan Oil, Gas
and Metals National Corporation) |
Geology & Geophysics Research Team |
| [Abstract] The Erawan field in the Gulf of Thailand is characterized
by a series of east- and west-dipping normal faults displacing
the Miocene clastic reservoirs. The fault seal capacity
of these faults was assessed using sand-shale juxtaposition
diagrams, clay smear parameters, and fault seal failure
probability (based on in-situ stress conditions). For
this study, five east-dipping faults in the Erawan North
Platform area were selected (faults E-16, E-17, E-18,
E-20, and E-27). Several deviated wells have been drilled
through the footwall blocks of these faults. Low values
of Shale Smear Factor (SSF<6) and high values of Clay
Content Ratio (CCR>30%) of four of the faults suggest
that fault seal along their planes. In contrast to these
four faults, fault E-27 appears to act as an across-fault
conduit for some intervals and seal in others. Intervals
without trapped hydrocarbons have higher SSF values suggesting
that the fault leaks locally. These five faults trap 15
gas pay zones. Eight of the pay zones have sand-shale
juxtaposition across the faults which may explain 8 of
the 15 accumulations. Clay smear parameters can account
for all 15 accumulations. Fault seal failure probability
(FSFP) was derived fro one of these faults (E-16) by integrating
the CCR values and the probability of fault slip tendency
and fault dilation tendency under the current stress regime
in the Erawan field. Low FSFP values indicate that the
fault seals do not appear to have been breached given
the in-situ stress field acting upon the normal fault. |
|
|
| 10967-2 |
Fault Seal Analysis in the Temana Field, Offshore Sarawak,
Malaysia |
AAPG Memoir 85 "Faults, Fluid Flow, and Petroleum
Traps"
2005 |
Shutaro Hasegawa, Rasoul Sorkhabi, Shoji Iwanaga, Naofumi
Sakuyama(Japan Oil, Gas and Metals National Corporation),
Othman Ali Mahmud(PETRONAS) |
Geology & Geophysics Research Team |
| [Abstract] The Temana field is located on a structural high in
the Balingian province, offshore Sarawak, Malaysia. Fault
sealing assessment of a normal fault in the Tertiary clastic
rocks of the Temana field was carried out using the shale
smear parameters. Shale Smear Factor (SSF) values of <6
and Clay Content Ratio (CCR) of >30% on the fault surface
indicate across-fault sealing of the reservoir rocks.
The fault sealing appears to be efficient enough to support
the hydrocarbon columns filled up to the structural spillpoints
of reservoirs. Fault rock permeability calculated from
the available calibrations of clay content-permeability
relationship show lower permeabilities of <0.3 mD.
Taking the Temana fault as a case in point, new approaches
on the estimation of hydrocarbon column height from across-fault
pressure differences, and fault rock permeability probability
(based on integration of clay content, fault displacement
and depth factors) are discussed. |
|
|
| 10967-1 |
The Place of Faults in Petroleum Traps |
AAPG Memoir 85 "Faults, Fluid Flow, and Petroleum
Traps"
2005 |
Rasoul Sorkhabi, Yoshihiro Tsuji(Japan Oil, Gas and
Metals National Corporation) |
Geology & Geophysics Research Team |
| [Abstract] Ever since Frederick Clapp included
fault structures as significant petroleum traps in the
1910s, the myriad role of faults in petroleum migration
and accumulation in sedimentary basins has drawn increasing
attention. Fault analyses in petroleum traps have grown
along two distinct and successive lines of thought: (1)
fault closures, and (2) fault-rock seals. Through most
of the last century, geometric closure of fault traps
and reservoir-seal juxtaposition by faults were the focus
of research and industrial application; as structural
geology developed quantitative methods for geometric and
kinematic analyses of sedimentary basins, and plate tectonics
offered a unified tool to correlate faults and basins
on the basis of the nature of plate boundaries as stress
engines. Over the last two decades, compartmentalization
of reservoirs by fault seals has been intensively investigated
as 3D seismic images better resolve fault structures.
Geometric characterization of fault architecture, identification
of various sealing processes in fault zones, and quantitative
appraisal of petrophysical properties of fault rocks have
been significant advances of the recent decades. |
|
|
| 10965 |
Mapping a fracture network using wide-azimuthal Ocean
Bottom Cable seismic data |
The Leading Edge
2005/1 |
Mu Luo, Isao Takahashi, Mamoru Takanashi(Japan Oil,
Gas and Metals National Corporation), Yoshihiko Tamura(Japan
Oil Development Co., Ltd. ) |
Research Project Team on Carbonate Reservoir |
| [Abstract] For enhanced oil and gas production from fractured reservoirs,
there is an increasing need to image fracture systems
through the study of wide-azimuthal surface P-wave seismic
data. There is an established understanding that reservoir
complexity could be diagnosed through seismic anisotropy
studies. One of the technical challenges remaining is
to maximally exploit seismic attribute sensitivities to
improve the mapping of the spatial distribution of subsurface
fractures. In the paper, we present a case study of mapping
a possible fracture network using wide-azimuthal Ocean
Bottom Cable (OBC) seismic data recorded over a Middle
East offshore production field. Results shown in the paper
demonstrate the potential for obtaining detailed fracture
information through seismic studies. |
|
|
| 10964 |
Subsurface occurrence and distribution of natural gas
hydrate at the Mallik site: Implications for the future
energy potential in the Nankai Trough |
ICDP Conference (International Continental Drilling
Program Conference)
2005/3/29 |
Takashi Uchida(JAPEX Research Center) |
Methane Hydrate Research Project Team |
[Abstract] Gas hydrates are ice-like clathrate solids made of water
molecules containing various gas molecules in their cages.
The geological evaluations have suggested worldwide methane
contents in gas hydrate beneath deep sea floors as well
as permafrost-related zones to about twice the total resources
of conventional and unconventional hydrocarbon. Occurrences
of subsurface gas hydrate in deep marine and permafrost-associated
environments are in the pressure-temperature stability
field typically around 10℃, or 10 MPa. Scientific and
economic interests have been increasing in gas hydrate,
and new research appraisals on gas hydrate are presented
relevant to a new energy resource, climate, and geohazard
research as a potential greenhouse gas.
In 2002 Mallik wells were drilled in the Canadian Arctic
with support from the Mallik Gas Hydrate Production Research
Well Program, and a substantially expanded science program
was enabled through the ICDP. The scientific results clarified
the characteristics of gas hydrate-dominant layers at
depths from 890 to 1110 m beneath the permafrost zone.
Continuous downhole well log data, anomalies of chloride
contents in pore waters, core temperature depression due
to endothermic decomposition of gas hydrate as well as
visible gas hydrates have confirmed the highly saturated
pore-space hydrate as intergranular pore filling within
sandy layers. It should be remarked that their saturations
in pore volume are evaluated up to 80%, and that muddy
sediments scarcely contain gas hydrate.
The Nankai Trough runs along the Japanese Island, where
forearc basins and accretionary prisms developed extensively
and BSRs (bottom simulating reflectors) have been recognized
widely. The multiple wells drilled by the Japanese government
METI in 2000 and 2004 also revealed the presence of pore-space
hydrate filling intergranular pore of sandy layers. It
is suggested that the distribution of a porous and coarser-grained
sandy sediments is one of the most important factors to
control the occurrence of gas hydrates, as well as physicochemical
conditions.
There are many similar features in appearance and characteristics
of gas hydrate between the Mallik and Nankai Trough areas
with observations of well-interconnected and highly saturated
pore-space hydrate. A key goal for the Japanese scientists
in the Mallik programs is to undertake scientific and
engineering studies in the known terrestrial gas hydrate
occurrence and apply those results to the major research
program on gas hydrate on the relevance to the future
production testing in the Nankai Trough. |
|
|
| 10960 |
Pore Space Reconstruction using Multiple-Point Statistic |
Journal of Petroleum Science and Engineering
2005/2/15 |
Hiroshi Okabe(Japan Oil, Gas and Metals National Corporation,
Imperial College London), Martin J. Blunt(Imperial College
London) |
Petroleum Engineering Research Team |
| [Abstract] The reconstruction of porous media is of great interest
in a wide variety of fields, including earth science and
engineering, biology, and medicine. To predict multiphase
flow through geologically realistic porous media it is
necessary to have a three dimensional (3D) representation
of the pore space. Multiple-point statistics were used,
based on two-dimensional (2D) thin sections as training
images, to generate 3D pore space representations. The
method was borrowed from geostatistical techniques that
use pixel-based representations to reproduce large-scale
patterns. Thin-section images can provide multiple-point
statistics, which describe the statistical relation between
multiple spatial locations. Assuming that the medium is
isotropic, a 3D image can be generated that preserves
typical patterns of the void space seen in the thin sections.
The method is tested on Fontainebleau and Berea sandstones
for which 3D images from micro-CT scanning are available.
The use of multiple-point statistics predicts long-range
connectivity of the structures (measured by local percolation
probability) better than standard two-point statistics
methods. The selection of multiple-point statistics is
a key issue and is discussed in detail. |
|
|
| 10956 |
Good design and operation of MEOR field test based on
the biotechnological approaches |
13th International Oil, Gas and Petrochemical Congress
2005/1/26 |
Kazuhiro Fujiwara(CHUGAI TECHNOS Co.), Kenji Ono, Nintoku
Yazawa(Japan Oil, Gas and Metals National Corporation),
Heiji Enomoto(Tohoku University), Cheng Xie Hong(Jilin
Oilfield Company, China) |
Petroleum Engineering Research Team |
[Abstract] Through an international collaborative research program
between Technology and Research Center of Japan Oil, Gas
and Metals Corporation (JOGMEC) and PetroChina Jilin Oilfield
Company, the effectiveness of biotechnological approaches
for MEOR was ascertained. The objectives of this research
were twofold: the collection of valuable data proving
MEORfs effects, and the development of fundamental technologies
for collection of microbial data and for technical breakthrough
in MEOR.
Firstly, we developed a biotechnological tool, that is,
PCR-RFLP method to estimate the behavior of microbes which
had an ability to propagate using molasses in the reservoir
and could struggle for existence with the target microbe.
Consequently, scientific knowledge of the microbes inhabiting
in the reservoir rock and materials relating to the MEOR
process such as ground water, molasses, and reservoir
brine were collected through both laboratory cultivation
tests and molasses injection tests in the field.
Secondly, a microbe CJF-002 to be injected in the reservoir
which had an ability to produce insoluble polymer was
screened to plug highly permeable paths. In addition,
the combinational method with Direct-PCR was also developed
for monitoring the target microbe(s) among many others.
Finally, continuous injection tests with CJF-002 were
conducted to demonstrate the fundamental breakthroughs
in MEOR technology and the real state of MEOR as well.
As conclusions, it was demonstrated that biotechnological
approaches can contribute to promote the prevalence of
MEOR. |
|
|
| 10955 |
Modeling and EOR Performance Predictions of a Fractured
Carbonate Reservoir |
13th International Oil, Gas and Petrochemical Congress
2005/1/26 |
Kenji Ono, Yoshihiro Tsuji(Japan Oil, Gas and Metals
National Corporation), Maghsood Abbaszadeh(Innovative
Petrotech Solutions Inc.), David H. Zamora Guerrero(PEMEX) |
Petroleum Engineering Research Team |
| [Abstract] A joint study was conducted by PEMEX and JOGMEC (former
JNOC) to develop integrated technologies for evaluating
and revitalizing a compartmentalized naturally fractured
carbonate reservoir. A new stratigraphic layering has
been established based on enhanced log responses obtained
from waveform frequency analysis combined with core/thin
section observations. Faults and fractures are found to
have major impacts on reservoir properties; thus a comprehensive
effort is made to characterize them. The lineament analysis
on topographic contours and aerial photographs, and structural
maps indicate NW-SE trend of faults/fractures in the region.
Statistical data on fracture spacing and occurrences are
obtained from image logs and outcrop data. Fractal analysis
was applied to obtain areal fracture density and fracture
distribution patterns in the field. The pressure performance
as well as salinity of produced water differ among blocks
in the field. The dynamic data interpretation suggests
possible barriers in the orthogonal direction to the major
trend. The double porosity phenomena and/or the presence
of conductive faults were suggested for some wells from
well test analyses. A 3D geological model for flow simulation
was constructed, and the simulation model was calibrated
to reservoir production data by history matching. Several
EOR gas injection cases were studied to provide guidelines
for subsequent field development scenarios. |
|
|
| 10954 |
MEOR/MIOR Field Applications - Biotechnological Know-How
is Key to the Success |
13th International Oil, Gas and Petrochemical Congress
2005/1/26 |
Kenji Ono(Japan Oil, Gas and Metals National Corporation),
Kazuhiro Fujiwara(CHUGAI TECHNOS Co.), Heiji Enomoto(Tohoku
University), Cheng Xie Hong(Jilin Oilfield Company, China) |
Petroleum Engineering Research Team |
| [Abstract] Several different microbes have been applied to a shallow
sandstone reservoir in collaboration with Jilin Oilfield
Company. The reservoir has been waterflooded for more
than 20 years and watercut was 80-90%. TRC-322, Enterobacter,
and some other microbes, which produce CO2, acid and soluble
polymer, were firstly applied to the production wells.
Microbes and nutrients were continuously injected after
the huff-n-puff operation. Some sixty percent of the wells
showed increase in oil cut, effectiveness, however, was
relatively limited. A different Enterobacter, CJF-002
produces insoluble polymer was searched and identified
in the oilfield. Different approaches, a huff-n-puff at
production wells and a microbial treatment at injection
wells was adopted. The water cut in production wells were
dramatically reduced shortly after the microbial treatment
at injection wells. Oil production in the test area increased
by more than double in volume and effect of plugging high
permeable zones was continued longer than half a year.
During these treatments, monitoring and evaluating properly
the in-situ growth of the target microbes by CFU + PCR
method and the metabolic activities by HPLC are quite
important to identify and evaluate the mechanism of the
microbial process. Process modification and adjustment
to the particular environment based on the biotechnological
know-how is key to the successful field applications of
MIOR/MEOR. |
|
|
| 10952 |
Hydrogen production with steam reforming of dimethy
ether |
1st International Fuel Cell Expo 2005, Academic Forum
2005/1/19 |
Takeishi Kaoru(Shizuoka University) |
Research Project Team on Emerging Gas Technologies |
[Abstract] Dimethyl ether (DME) is expected as one of clean fuels,
and DME is one of substitutes of diesel fuel and LPG.
Infrastructures of LPG will be able to use for DME infrastructures.
We studied the hydrogen production with steam reforming
of DME, for fuel cells.
Large quantities of H2 and CO2 were produced from DME
and water using alumina catalysts prepared by a sol-gel
method, especially copper alumina catalysts. Other metal
alumina catalysts prepared by the sol-gel method produced
H2 and CO2, but also produced large quantities of carbon
monoxide. Our studies showed that copper is the best metal
for the production of H2 while producing less CO. Á-Alumina
for DME hydrolysis into methanol, and active metals such
as copper for methanol steam reforming to H2 and CO2 are
mixed and distributed closely on the surfaces of catalysts
prepared by the sol-gel method. Therefore, sol-gel catalysts
produce H2 and CO2 well from DME. |
|
|
| 10948 |
Prediction of Permeability for Porous Media Reconstructed
using Multiple-Point Statistics |
Physical Review E
2004/12/23 |
Hiroshi Okabe(Japan Oil, Gas and Metals National Corporation, Imperial
College London), Martin J. Blunt(Imperial College London) |
Petroleum Engineering Research Team |
| [Abstract] To predict multiphase flow through geologically realistic
porous media, it is necessary to have a three-dimensional
(3D) representation of the pore space. We use multiple-point
statistics based on two-dimensional (2D) thin-sections
as training images to generate geologically realistic
3D pore space representations. Thin-section images can
provide multiple-point statistics, which describe the
statistical relation between multiple spatial locations
and use the probability of occurrence of particular patterns.
Assuming that the medium is isotropic, a 3D image can
be generated that preserves typical patterns of the void
space seen in the thin-sections. The method is tested
on Berea sandstone for which a 3D image from micro-CT
scanning is available and shows that the use of multiple-point
statistics allows the long-range connectivity of the structure
to be preserved, in contrast to two-point statistics methods
that tend to underestimate the connectivity. Furthermore,
a high-resolution 2D thin-section image of a carbonate
reservoir rock is used to reconstruct 3D structures by
the proposed method. The permeabilities of the statistical
images are computed using the lattice-Boltzmann method
(LBM). The results are similar to the measured values,
to the permeability directly computed on the micro-CT
image for Berea and to predictions using analysis of the
2D images and the effective medium approximation. |
|
|
| 10946 |
Concentration of Natural Gas Hydrate Beneath the Permafrost
Zone: Implications for Geochemical and Hydrologic Investigations |
AGU (American Geophysical Union)
2004/12/13 |
Amane Waseda(Japan Petroleum Exploration Co., Ltd.),
Takatoshi Namikawa(Japan Oil, Gas and Metals National
Corporation) |
Methane Hydrate Research Project Team |
| [Abstract] Gas hydrates are ice-like solids that have cages made
of water molecules containing various gas molecules. The
geological evaluations have suggested the worldwide methane
content of gas hydrate beneath deep sea floors along continental
margins as well as permafrost-related zones to about twice
the total reserves of conventional and unconventional
hydrocarbon. Scientific and economic interests are increasing
in gas hydrate as a new energy resource and a potential
greenhouse gas. In 1998 and 2002 Mallik wells were drilled
in the Canadian Arctic that clarified the characteristics
of gas hydrate-dominant layers at depths from 890 to 1110
m beneath the permafrost zone. Continuous downhole well
log data, anomalies of chloride contents in extracted
pore waters, core temperature depression, core observations
as well as visible gas hydrates have confirmed the presence
of highly saturated pore-space hydrate as intergranular
pore filling within sandy layers, whose saturations are
higher than 70 % in pore volume. Muddy sediments which
separate the main gas hydrate-bearing layers scarcely
contain gas hydrate. The Nankai Trough runs along the
Japanese Island, where forearc basins and accretionary
prisms developed extensively and BSRs (bottom simulating
reflectors) have been recognized widely. The METI Nankai
Trough wells in 2000 also revealed the presence of pore-space
hydrate filling intergranular pore of sandy layers. It
is remarked that there are many similar features in appearance
and characteristics between the Mallik and Nankai Trough
areas with observations of well-interconnected and highly
saturated pore-space hydrate. It is necessary for evaluating
subsurface fluid flow behaviors to know both porosity
and permeability of gas hydrate-bearing sandy sediments,
and measurements of water permeability for them indicate
that highly saturated sands may have permeability of a
few milli-darcies. Subsequent analyses in sedimentology
and geochemistry performed on gas hydrate-bearing sands
revealed important geologic and sedimentologic controls
on the formation and concentration of gas hydrate. It
is suggested that the distribution of a porous and coarser-grained
sandy sediments is one of the most important factors to
control the occurrence of gas hydrates, as well as physicochemical
conditions. |
|
|
| 10944 |
Multidisciplinary Approach for Borehole Instability
Problems in a Shale formation |
3rd Asian Rock Mechanics Symposium
2004/11/29 |
Koji Yamamoto(Japan Oil, Gas and Metals National Corporation) |
Petroleum Engineering Research Team |
| [Abstract] Shale instability problem during drilling operation
are complex phenomena that involve many mechanical, chemical,
and operational factors. In a collaborative study on this
costly problem for the oil industry, integrated researches
of various scale of instability mechanism were carried
out to determine the nature of shale instability problems
in deep petroleum wells. In this paper, an example of
shale trouble and our approach for it are presented. The
characteristic nature of shale such as chemical activity,
anisotropy, fissured nature fully considered. The approach
to the problem and modeling concepts are described. The
results suggest the limitation of conventional elastic
approaches. |
|
|
| 10943 |
Estimation of sonic attenuation properties of methane
hydrate-bearing sediments from the Nankai Trough exploratory
well off Tokai, central Japan |
The 7th SEGJ International Symposium
2004/11/26 |
Jun Matsushima(Japan Oil, Gas and Metals National Corporation) |
Methane Hydrate Research Project Team |
| [Abstract] Full waveform logs from the Nankai Trough exploratory
well off central Japan are used to estimate both compressional
and shear attenuation in methane hydrate (MH) bearing
sediments. Attenuation estimation is based on a median
frequency shift to the amplitude spectrum of the recorded
waveforms. This paper is concerned with the estimation
of attenuation at sonic frequencies 10-20 kHz for compressional
waves and 500-1500 Hz for shear waves. The high attenuation
of the compressional waveforms and high attenuation of
the shear waveforms correlate well with the presence of
methane hydrate inferred from the resistivity log. On
the other hand, we observed the high attenuation of the
compressional waveforms and low attenuation of the shear
waveforms below the methane hydrate stability zone. This
can be explained by the presence of partially gas-saturated
sediments. The shear attenuation may therefore be directly
related to MH because the compressional attenuation is
strongly affected by the presence of gas. The ratio of
compressional to shear attenuation is found to be a more
sensitive indicator of the presence of gas than is the
corresponding velocity ratio. We concluded that sonic
attenuation from both monopole and dipole waveforms should
give new insight to characterize methane hydrate bearing
sediments and gas-saturated sediments. |
|
|
| 10945 |
Phylogenic analysis of Methanogens in the gas wells |
Japanese Society of Microbial Ecology
2004/11/21-23 |
Hanako Mochimaru(National Institute of Advanced Industrial
Science and Technology, AISTEUniversity of Tsukuba), Hiroyuki
Imachi(Nagaoka University of Technology), Yuji Sekiguchi(National
Institute of Advanced Industrial Science and Technology,
AIST), Aya Amaishi(Taisei Corporation), Toshihiro Hoaki(Taisei
Corporation), Hiroo Uchiyama(University of Tsukuba), Yoichi
Kamagata(National Institute of Advanced Industrial Science
and Technology, AIST) |
Methane Hydrate Research Project Team |
| [Abstract] We studied diversity of methanogens in the subsurface
ecosystems in Niigata and Mobara natural gas fields to
figure out the relation between methanogenic populations
and methane production. Our studies indicate that there
are a number of methanogenic species in the samples based
on molecular analysis. We will show these data and the
traits of methanogens isolated from these ecosystems. |
|
|
| 10938 |
Application of Genetic Algorithm to history matching
for core flooding |
2004 SPE Asia Pacific Oil & Gas Conference and Exhibition
(APOGCE)
2004/10/20 |
Noriyuki Tokuda, Shunya Takahashi(Japan Oil, Gas and
Metals National Corporation), Makoto Watanabe(Japan Oil
Development), Takeshi Kurose(CRC Solutions) |
Research Project Team on Carbonate Reservoir |
| [Abstract] Recently it has become a common practice to construct
3D coreflooding simulation model to interpret water displacement
experiments conducted under X-ray CT scanning. The unknown
grid block parameters i.e. kro/krw and Pc curves are required
to be optimized to get reasonable matching with experimental
data such as changes of grid block water saturation. In
order to evaluate the matching process efficiently a new
automated history-matching program has been developed.
This program applies Genetic Algorithm to optimize several
coefficients for normalized kro/krw and Pc curves for
each litho-facies. Several blind tests were carried out
on hypothetical coreflooding models by changing the conditions
of velocity and wettability to investigate the degree
of accuracy and limitation of the program. The result
of the reproducibility of the relative permeabilities
was excellent for both water-wet and oil-wet cases regardless
the velocity of coreflooding. On the other hand, the degree
of reproducibility was not necessarily satisfactory for
capillary pressure curves especially in high velocity
case. Sensitivity of the controlling parameter in Genetic
Algorithm such as crossover rate and mutation ratio was
also investigated. The suitable values are estimated,
though no simple trend was found. The program was finally
applied to the interpretation of actual water displacement
tests on oil-wet carbonate cores. The program successfully
gave a reasonable set of kro/krw and Pc curves for each
litho-facies and demonstrated its capability of grid block
parameter optimization. |
|
|
| 10937 |
New GTL Process -Best Candidate for Reduction of CO2
in Natural Gas Utilization-(SPE 88628) |
2004 SPE Asia Pacific Oil & Gas Conference and Exhibition
(APOGCE)
2004/10/20 |
Yoshifumi Suehiro, Masaru Ihara, Kazuhito Katakura(Japan
Oil, Gas and Metals National Corporation), Arata Nakamura,
Atsushi Sakamoto(INPEX Corporation), Kenichi Kawazuishi,
Ryuichiro Kajiyama(CHIYODA Corporation), Kenichiro Fujimoto,
Yasuhiro Ohnishi(Nippon Steel Corporation), Hideo Okado(Japan
Petroleum Exploration Corporation, Ltd.), Toshio Shimizu(COSMO
Oil Corporation, Ltd.) |
Research Project Team on Emerging Gas Technologies |
| [Abstract] Japan Oil, Gas and Metals National Corporation (JOGMEC),
which is a former Japan National Oil Corporation (JNOC),
has been developing natural gas to liquids (GTL) conversion
technology since the year of 1998 in collaboration with
five private Japanese companies, namely; JAPEX Co. Ltd.,
Chiyoda Corp., COSMO Oil Co. Ltd., Nippon Steel Corp.,
and INPEX Corp. Our new GTL process is particularly effective
when it is applied to natural gas feed stock containing
20-40mol% of CO2. It does not require the three expensive
items; (1) an oxygen supply plant, (2) a unit for CO2
separation from natural gas, and (3) a H2 separation unit
to optimize gas composition. The reduction of these facilities,
which are indispensable to the conventional GTL process,
would results in less CAPEX and OPEX. For our new GTL
process, the most preferable CO2 content in feed natural
gas is around 30mol%. Therefore, in case that the CO2
content is less than 30mol%, some amount of CO2 can be
supplied from other CO2 sources, such as flare gas, associated
gas, remaining CO2 of EOR and exhausted gas from oil refinery
and LNG plant. This paper aims to present applications
of our new GTL process to enable an economic exploitation
of gas reserves in South East Asia and Australia, by taking
into account the operation results of the Yufutsu GTL
pilot plant of 7BPSD located at Tomakomai city in Hokkaido
of Japan, and the study results of process simulation
and the economics. We present an attractive combination
scheme for our new GTL process with LNG plant by utilizing
CO2 exhausted from LNG plant. It reduces initial projectfs
investment compared with a stand-alone GTL plant located
in South East Asia and Australia, where infrastructure
of an LNG plant can be for common use with our GTL plant. |
|
|
| 10935 |
A Turbine Flow Meter for Multiphase Flow(SPE 88741) |
The 11th Abu Dhabi international Petroleum Exhibition
and Conference
2004/10/13 |
Zhenyan Li, Hirokazu Kitami, Hiraku Kawaoto(Oval Corporation),
Tomoko Watanabe(Japan Oil, Gas and Metals National Corporation) |
Research Project Team on Carbonate Reservoir |
| [Abstract] This paper introduces a new concept and the test result
of a multiphase flow meter (MPFM), which JOGMEC (Old JNOC)
and OVAL Corporation have developed based on a turbine
type flow meter to measure the multiphase flow rate of
individual phases in oil, water and gas production lines
without the need for separation or complex sensor technologies
(1)(2). It is expected that the MPFM should bring a significant
cost-down and improved operability and maintainability,
compared with commercially available a multiphase flow
meter in terms of nuclear-absorption type density measuring.
We had adopted integral calculus method and established
a mathematics model. In addition, we have examined the
characteristics of the MPFM using a number of liquids
with different viscosities (1-20mPas). The test result
shows that the volumetric flow rate of each phase are
possibly measured with an uncertainty within }10% of full
scale while the water cut varies from 0% to 100%, and
the gas void fraction varies from 30 to 90%. To confirm
the MPFM reliability, MPFM monitoring was done for one
year in an oil reservoir with water flooding in the wellhead
platforms (WHPTs) in the Middle East. The MPFM measurement
system can obtain enough accuracy to measure flow rates
in each phase. |
|
|
| 10934 |
Reservoir Characterization Study of the Cuitlahuac Gas
Field in the Burgos Basin, Northern Mexico |
SEG 2004 International Exposition & 74th Annual Meeting
2004/10/12 |
Shinichi Matsuzawa, Yusaku Konishi(Japan Oil, Gas and
Metals National Corporation), Tomohisa Nishizuka(Idemitsu
Petroleum Norge A.S.), Arturo Perez Aldana, Efrain Mendez
Hernandez, Jose Alberto Santana Fernandez(PEMEX Exploration
and Production) |
Overseas Survey Team |
| [Abstract] A recent trend in reservoir studies is the integration
of petrophysical, geological and geophysical information
in high-resolution reservoir models. Success in integrated
reservoir characterization depends on identifying seismic
and petrophysical attributes that are well correlated
to the properties being modeled e.g., lithofacies, porosity
and fluid type. This study employed integrated petrophysical
analysis, well-based rock property study, acoustic and
elastic inversions, AVO modeling and attribute generation
to characterize Oligocene gas reservoirs in the Cuitlahuac
Gas Field in the Burgos Basin of northern Mexico. Cuitlahuac
Gas Field has produced over 320 Bcf since its discovery
in 1972. Current daily production is 28 MMcfd. Production
is from thin-bedded Tertiary fluvio-deltaic clastics with
complex reservoir geometry. Of nine well-based seismic
attributes generated from petrophysical logs (Poisson's
Ratio, Acoustic Impedance, Shear Impedance, Lambda, Mu,
Bulk Modulus, Lambda-Rho, Mu-Rho and Vp/Vs), acoustic
impedance (AI) most effectively discriminates sandstone
from shale - but only in the shallower section. Amplitude
versus offset (AVO) analysis shows Class I response in
the shallower section and Class II response in the deeper
section. On the other hand, fluid substitution shows that
Mu-Rho and Lambda-Rho are good discriminators for both
lithology and fluid type. To capture detail in the thin
gas reservoirs, high-resolution stochastic inversion was
performed on the 3D seismic volume. The resulting acoustic
and shear impedance volumes show good correlation with
well log data. The attributes Lambda-Rho and Mu-Rho were
calculated from the acoustic impedance (Ip) and shear
impedance (Is) volumes. The seismic-derived Lambda-Rho
and fluid type at each well were integrated using sequential
indicator simulation with collocated cokriging to obtain
a reservoir model. |
|
|
| 10933 |
Attenuation measurements from sonic full waveform logs
in gas hydrate bearing sediments |
SEG 2004 International Exposition & 74th Annual Meeting
2004/10/10-15 |
Jun Matsushima(Japan Oil, Gas and Metals National Corporation) |
Methane Hydrate Research Project Team |
| [Abstract] Full waveform logs from the Nankai Trough off central
Japan are used to estimate both compressional and shear
attenuation in gas hydrate bearing sediments. The high
attenuation of the compressional waveforms and high attenuation
of the shear waveforms correlate well with the presence
of gas hydrate inferred from the resistivity log. On the
other hand, we observed the high attenuation of the compressional
waveforms and low attenuation of the shear waveforms below
the gas hydrate stability zone. This can be explained
by the presence of partially gas-saturated sediments.
We concluded that sonic attenuation from both monopole
and dipole waveforms should give new insight to characterize
gas hydrate bearing sediments and gassaturated sediments. |
|
|
| 10932 |
Predicting Permeability through 3D Pore-Space Images
Reconstructed Using Multiple-Point Statistics |
SCA 2004 International Symposium
2004/10/9 |
Hiroshi Okabe(Japan Oil, Gas and Metals National CorporationI,
imperial College London), Martin J. Blunt (Imperial College
London) |
Petroleum Engineering Research Team |
| [Abstract] Pore-scale network modeling can predict multiphase flow
properties with arbitrary wetting conditions if the network
represents the geology of the sample accurately. Such
pore-scale modeling uses topologically disordered networks
that realistically represent the pore structure. To generate
the network it is first necessary to have a three-dimensional
voxel-based pore-space representation that is constructed
by either a direct imaging technique such as micro-CT
scanning, stochastic methods, or object-based approaches.
Micro-CT scanning is the most promising among these three
approaches since it is the most direct. However, its resolution
- a few microns - means that for many rocks, particularly
carbonates, significant porosity cannot be imaged. Furthermore,
alternative approaches, such as reconstruction through
simulating the geological processes by which the rock
was formed, such as sedimentation and diagenesis, may
be problematic for many materials whose depositional and
diagenetic history is uncertain or complex. Statistical
reconstruction is more general and is not limited by the
pore size. Statistics of the pore space are obtained from
readily available experimental data such as thin-section
images. Using only single and two-point statistics in
the reconstruction often underestimates the pore connectivity,
especially for low porosity materials. We use multiple-point
statistics for pore space reconstruction that preserves
higher-order information, describing the statistical relation
between multiple spatial locations. This is a general
method that gives images that preserve typical patterns
of the void space seen in thin sections. The method is
tested on a carbonate sample from the Middle East. Permeability
is predicted directly on the 3D images using the lattice
Boltzmann method. The numerically estimated results are
in good agreement with experimentally measured permeability.
Furthermore, this method provides an important input for
the creation of geologically realistic networks for pore-scale
modeling to predict multiphase flow properties. |
|
|
| 10931 |
Development of automated history-matching program based
on Genetic Algorithm for X-ray CT core flooding experiment |
SCA 2004 International Symposium
2004/10/7 |
Noriyuki Tokuda, Shunya Takahashi(Japan Oil, Gas and
Metals National Corporation), Makoto Watanabe(Japan Oil
Development), Takeshi Kurose(CRC Solutions) |
Research Project Team on Carbonate Reservoir |
| [Abstract] Recently it has become a common practice to construct
3D coreflooding simulation model to interpret water displacement
experiments conducted under X-ray CT scanning. The unknown
grid block parameters i.e. kro/krw and Pc curves are required
to be optimized to get reasonable matching with experimental
data such as changes of grid block water saturation. In
order to evaluate the matching process efficiently a new
automated history-matching program has been developed.
This program applies Genetic Algorithm to optimize several
coefficients for normalized kro/krw and Pc curves for
each litho-facies. Several blind tests were carried out
on hypothetical coreflooding models by changing the conditions
of velocity and wettability to investigate the degree
of accuracy and limitation of the program. The result
of the reproducibility of the relative permeabilities
was excellent for both water-wet and oil-wet cases regardless
the velocity of coreflooding. On the other hand, the degree
of reproducibility was not necessarily satisfactory for
capillary pressure curves especially in high velocity
case. Sensitivity of the controlling parameter in Genetic
Algorithm such as crossover rate and mutation ratio was
also investigated. The suitable values are estimated,
though no simple trend was found. The program was finally
applied to the interpretation of actual water displacement
tests on oil-wet carbonate cores. The program successfully
gave a reasonable set of kro/krw and Pc curves for each
litho-facies and demonstrated its capability of grid block
parameter optimization. |
|
|
| 10930 |
Upscaling Method of Relative Permeability from Plug
Core to Whole Core |
SCA 2004 International Symposium
2004/10/7 |
Shunya Takahashi, Noriyuki Tokuda, Toshiyuki Nakashima(Japan
Oil, Gas and Metals National Corporation) |
Research Project Team on Carbonate Reservoir |
| [Abstract] This paper presents the results of the interpretation
of several unsteady-state coreflood experiments and discusses
a method to estimate the relative permeability of the
whole core using the data of the smaller scale cores and
their characteristics. A water displacement test was conducted
on a heterogeneous carbonate whole core (target core),
then a series of the same test followed on the several
plug cores that were extracted from the target core. Each
test on the plug cores was interpreted by 3D coreflood
simulation model that was constructed based on the detailed
core characterization data. A newly developed simulation
matching program called GEMAP *(1) that adopted genetic
algorithm was employed to derive a set of normalized kro/krw
and Pc curves representing each pore-type as grid data.
The relative permeability curves of the plug cores were
computed by the two-phase upscaling in-house program called
CAVLUP *(2) that was initially developed for reservoir-scale
upscaling problem. Both capillary-limit and viscous-limit
upscaled kro/krw curves were computed by the program.
The kro/krw curves were also determined by different method
i.e. steady-state coreflood simulation and compared with
the upscaled curves. The result showed that the capillary-limit
upscaling method could reasonably reproduce the kro/krw
curve generated by steady-state coreflood simulation of
the same displacement velocity to that of the actual experiment.
Based on the statistical data of porosity, permeability
and pore-type, 3D stochastic models were constructed for
the target core. A total of 100 kro/krw curves were computed
using CAVLUP. On the other hand, 3D deterministic model
was constructed to re-optimize the kro/krw and Pc curves
of each pore-type and compute kro/krw curve by simulation
matching. The result showed that the average upscaled
curve of the stochastic models was close to that of the
optimized model. It was concluded that the kro/krw curve
of the target core could be reasonably estimated from
plug-core-scale data by the same upscaling method as applied
to reservoir scale problem. |
|
|
| 10929 |
Multiple-Point Statistics to Generate Pore Space Images |
Geostats 2004
2004/9/27-28 |
Hiroshi Okabe(Japan Oil, Gas and Metals National Corporation, Imperial
College London), Martin J. Blunt (Imperial College London) |
Petroleum Engineering Research Team |
| [Abstract] Multiple-point statistics (MPS) on a two-dimensional
(2D) thin section image is used to generate a three-dimensional
(3D) pore space image with an assumption of isotropy for
orthogonal planes. The method gives images that preserve
typical patterns of the void space seen in thin section.
Using only single and two-point statistics in the reconstruction
often underestimates the void connectivity, especially
for low porosity materials; however, multiple-point statistics
method significantly improves the void connectivity. The
method is tested on sandstone and carbonate samples. Permeability
is predicted directly on the 3D images using the lattice
Boltzmann method (LBM). The numerically estimated results
are in good agreement with experimentally measured permeability.
Furthermore, the method provides an important input for
the creation of geologically realistic networks for pore-scale
modeling to predict multiphase flow properties. |
|
|
| 10924 |
Analysis of Oil-Water Flow Tests in Horizontal, Hilly-Terrain,
and Vertical Pipes(SPE90096) |
The SPE Annual Technical Conference and Exhibition
2004/9/26-29 |
Plat Abduvayt(Waseda University), Ryo Manabe(Inpex Co.,
Ltd.), Tomoko Watanabe(Japan Oil, Gas and Metals National
Corporation), Norio Arihara(Waseda University) |
Petroleum Engineering Research Team |
| [Abstract] The flow pattern, pressure drop and water holdup were
measured for oil-water flow in horizontal, hilly-terrain
(}0.5and }3) and vertical pipelines at a temperature
of about 35} 5 C and a pressure of about 245 kPa using
the large-scale multiphase flow-test facility of Japan
Oil, Gas and Metals National Corporation (JOGMEC). Test
lines of 4.19 inch (106.4 mm) ID and 120 m total length
were utilized which included a 40 m horizontal or hilly-terrain
and a 10 m vertical test sections sequentially connected.
The flow pattern was determined by visual observation
with video recordings, and a flow pattern map was made
for each condition. New flow patterns were identified
for horizontal and hillyterrain flow, such as oil flow
in a snake-like shape at top of pipe at high rate of water
flow, and water flow at bottom of pipe at high rate of
oil flow. New holdup and pressure drop data are presented
for each flow condition. The flow rate and inclination
angle influences holdup and pressure drop behaviors. In
vertical flow, when the oil superficial velocity exceeds
a certain value, the pressure drop decreases exponentially
as the superficial oil velocity increases. Slippage between
the phases was analyzed using the measured water holdup
plotted against the input water cut with inlet oil flow
rate as parameters. It was found that the slippage changed
significant with slightly changes in inclination angle.
This paper provides new experimental data of flow pattern,
water holdup and pressure drop measured particularly at
horizontal, hilly-terrain and vertical conditions with
largediameter pipes. These are the indispensable information
of developing reliable prediction models for oil-water
two-phase and gas-oil-water three-phase flow in pipelines. |
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| 10917 |
Report for International Gas Union on Methane Hydrate |
International Gas Union
Working Committee 1
2004/9/15-17 |
Yoshihiro Tsuji(Japan Oil, Gas and Metals National Corporation) |
Methane Hydrate Research Project Team |
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| 10916 |
The challenge of JOGMEC to develop the new GTL process
utilizing CO2 contained in natural gas |
SPE-ATW "High CO2 Gas Field Development and Production"
2004/9/8 |
Masaru Ihara(Japan Oil, Gas and Metals National Corporation) |
Research Project Team on Emerging Gas Technologies |
[Abstract] Natural gas with clean characteristics in combustion
is expected to be the alternative energy resources to
oils in the near future, but the natural gas resources
more than 5Tcf, which is only around 2% of the discovered
natural gas fields, are mainly developed for LNG market,
nevertheless further promotion of its utilization will
also be beneficial to environmental preservation. The
balance around 98% of the natural gas fields are left
undeveloped due to almost stranded natural gas reserves,
which is generally small or medium range of natural gas
fields inappropriate to LNG supply. JOGMEC has been tackling
the research and development of the natural gas conversion
technology from the year of 1998 till 2004 in collaboration
with five Japanese private companies for JAPEX, CHIYODA,
COSMO OIL, NIPPON STEEL and INPEX, in order to aim at
establishing the option technology to explore stranded
gas reserves.
The JOGMEC-GTL process differs from other conventional
GTL processes in two main sections:
1) The synthetic gas (“Syngas”) production applies the
steam (H2O)/CO2 reforming rather than Auto-thermal Reforming
(“ATR”) or Non-catalytic Partial Oxidation (“POX”) used
in other processes (“conventional GTL processes”), and
2) The Fischer-Tropsche (“FT”) synthesis employs the slurry
reactor with noble metal or non-noble metal catalysts,
as compared to the Co or Fe based catalysts used in the
conventional GTL processes.
Thus, JOGMEC -GTL process is expected to prominently get
effective in energy efficiency as applied against the
natural gas reserves containing relatively high CO2. JOGMEC-GTL
process is capable to utilize CO2 contained in the natural
gas and does not require any O2 supply. Namely, the characteristics
of the process in contrast to those of the existing ones
using ATR or POX are (1) no use of the O2 generator, (2)
no use of the CO2 removal unit, and (3) no use of the
H2 conditioning unit for Syngas. Such facility savings
will bring about the remarkable reduction of the plant
cost for its election and operation. The suitable conditions
for the JOGMEC-GTL process will meet with the plant scale
of 5,000 to 15,000 BPSD and the case of CO2 contents being
20 to 40mol% in the natural gas. The economic evaluation
does indicate that the JOGMEC-GTL process is more economical
than the conventional ones when applied under those conditions.
Our challenges conducted until the end of 2003 have delivered
the outcomes (1) recorded around 5,000 operation hours
by the identical catalyst of Syngas production and (2)
produced GTL products at continuous daily rate 7.3BPSD
exceeding the design capacity of 7BPSD at the Yufutsu
GTL pilot plant in September 2003, supported by the promising
catalysts of syngas production and FT synthesis and the
attained efficient total process. Our new challenges also
have been commenced focusing on (1) the enhancement of
the promising catalysts of Syngas production and FT synthesis
through the evaluation of the long run reliability and
(2) the development of scale-up methods for the total
process.
This presentation introduces the outline and the characteristics
of JOGMEC-GTL process, characteristics of GTL products,
the catalysts performance of syngas production and FT
synthesis viewing the current test results derived from
the Yufutsu GTL pilot plant, and the project roadmap viewing
the economic evaluation in the feasibility study between
JOGMEC and Pertamina. |
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| 10915 |
Interfacial Tension Measurement between Oil and Gas
Phase under High Temperature and High Pressure Condition :
Effect of Pressure on Interfacial Tension and Comparison
of Minimum Miscible Pressure by Vanishing Interfacial
Tension Technique and Slim Tube Test Method |
25th Annual Workshop & Symposium, Collaborative Project
on Enhanced Oil Recovery, IEA
2004/9/6 |
Komei Okatsu(Japan Oil, Gas and Metals National Corporation) |
Petroleum Engineering Research Team |
| [Abstract] One of the most important factors that affect oil displacement
efficiency on gas flooding is interfacial tension between
oil and injected gas. But the behavior of interfacial
tension under high temperature and high pressure has not
investigated so much. For the investigation of gas flooding,
an interfacial tension measurement apparatus based on
pendant drop method, using a high temperature and pressure
visual cell and PVT apparatus have been developed. Combining
the visual cell for the measurement and PVT apparatus,
Interfacial tension can be measured under complete equilibrium
condition and density of liquid phase can be measured
by the density meter. This paper presents the outline
of the apparatus and the results of the interfacial tension
measurement between 3 crude (recombined) oil and CO2 systems
In each case, the pressure effect on interfacial tensions
were investigated and Minimum Miscibility Pressure (MMP)
by Vanishing interfacial tension (VIT) technique and Slim
Tube Test method were compared with. |
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| 10914 |
Observation of Natural Gas Hydrate Dissociation in Natural
Sediments with X-ray CT Scanner |
32nd International Geological Congress, in Firenze
2004/8/28 |
Toshiharu Okui(Japan Oil, Gas and Metals National Corporation),
Takashi Uchida(Japan Petroleum Exploration), Yoshihiro
Matsuda(Tokyo Univ.) |
Methane Hydrate Research Project Team |
| [Abstract] Dissociation of gas hydrate in natural core samples
was visualized with an X-ray CT scanner. The natural core
samples were obtained at the JAPEX/JNOC/GSC et al. Mallik
5L-38 Production Well in Canada. During the measurement
confining and pore pressure were independently controlled
and temperature of the sample was carefully maintained.
Both depressurizing and heating processes, which are considered
as typical potential gas production processes from hydrates,
were simulated in laboratory scale for the field gas production
tests. As a result, dissociation was clearly observed
as difference of CT values. Obtained three-dimensional
CT data in the cores were processed to image dissociation
behavior. It was indicated that dissociation behavior
was strongly influenced by quality of samples, especially
saturation and distribution of hydrates in sediments.
Natural core samples, transported from Canada to Japan,
were set in a core holder especially designed for this
experiment. Conditions were carefully changed into hydrate
dissociation zone. Difference of dissociating behavior
in depressurizing and heating processes was observed respectively
with X-ray CT scanning. Dissociation was clearly distinguished
as CT value change that was mainly caused by gas phase
formation. Dissociation behavior depended upon occurrence
of gas hydrate. Commonly gas hydrate in all samples immediately
began to dissociate when they were exposed to theoretical
dissociation conditions of pure methane hydrate both in
depressurizing and heating processes. However, highly
saturated sample dissociated very slow. Additionally after
the pressure was sufficiently released the gas expanded
through pore space. It was suggested that the gas could
not move in pore space so smoothly after dissociation. |
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| 10911 |
Hydrogen isotope fractionation by microbial methanogenesis
in culture experiments |
32nd International Geological Congress, in Firenze
2004/8/27 |
Hideyoshi Yoshioka, Susumu Sakata, Yoichi Kamagata(National
Institute of Advanced Industrial Science and Technology,
AIST ) |
Methane Hydrate Research Project Team |
| [Abstract] Occurrence of microbial methane has been reported in
anoxic sediments of a wide variety of environments, including
freshwater, marine environments, and deep biosphere. The
methane has variations in stable carbon and hydrogen isotopic
compositions. It has been proposed that two primary pathways
of methanogenesis, CO2 reduction and acetate fermentation,
can be distinguished by comparing the carbon and hydrogen
isotopic compositions of the methane with those of the
coexisting carbon dioxide and formation water. In this
study, we present hydrogen and carbon isotopic compositions
of methane produced by a thermophilic hydrogen-utilizing
methanogen, Methanobacterium thermoautotrophicus. Cultures
were grown at 55 and 65 degrees under an atmosphere initially
pressurized at 2 atm with H2 and CO2 in proportion 80:
20. For isotope analyses of methane at different stages
of growth, the cultures in three serum bottles were grown
at each temperature for 24, 47, and 72 hours, respectively,
followed by the collection of gases from the headspace.
We found that hydrogen isotope fractionation factor ranged
from 0.69 to 0.72, showing a decreasing trend with the
progress of the growth phase. These values are similar
to that calculated from data reported for culture experiments
of Methanobacterium formicium and that reported from incubation
experiments of a paddy soil . However, in the cross-plot
of hydrogen isotope ratios of methane and ambient water,
our data points were plotted far from the regression lines
for isotope data of marine sediments and natural gas deposits.
We consider that the inconsistency between our culture
experiments and field measurements would be caused by
some culture conditions which rarely occur in natural
environments. The high concentration of hydrogen gas and
the high temperature of growth are among the candidates. |
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| 10910 |
Population Analysis of Methanogenic Archaea in Subterranean
Gas Fields |
10th International Society for Microbial Ecology
2004/8/22-27 |
Toshihiro Hoaki(Taisei Corporation) |
Methane Hydrate Research Project Team |
| [Abstract] Natural gas deposit of dissolved in water type is distributed
into not only onshore site but also offshore site. Some
fields are thought to be formed by microbial effect, however
the origin of gas and its formation mechanism is not well
known. Anaerobic microbial consortia including methanogenic
archaea produce CH4 from organic matter and the CH4 producing
process is observed in various places. In this study,
we focused on onshore subterranean gas fields at Mobara
and Niigata, which are thought to be microbial origin.
Sludge is precipitated within the formation water in production
well. Therefore we collected the sludge from the well.
Salinity of formation water was similar to that of seawater.
Viable cell density of methanogen was estimated to approx.
105 cells/g-sediment, while total cell density was approx.
107 cells/g-sediment in both Mobara and Niigata. 16S rDNA
clone analysis revealed that a variety of methanogen was
detected including the uncultured clone cluster. Therefore
CH4 could be produced in subterranean field even now.
In addition, a similar to Thermoplasma clone and other
unknown archaeal clone was also detected in the sludge
from a deeper field, which is produced from 1,000m depth.
This result indicates that microbial consortia could be
depending on a temperature and thermophilic or hyperthermophilic
methane producing consortia may be existed in more deep
underground. |
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| 10912 |
Wide-angle Seismic Study of Gas Hydrate Accumulations
in the Eastern Nankai Trough, off Tokai, Japan |
32nd International Geological Congress, in Firenze
2004/8/20-28 |
Maarten Vanneste, Stephanie Guidard, Jurgen Mienert(University
of Tromso), Eiichi Asakawa, Peter Ward(JGI, Inc.) |
Methane Hydrate Research Project Team |
| [Abstract] We used wide-angle multi-component ocean bottom seismometer
(OBS) data in combination with conventional multi-channel
and high-resolution 3D seismic data to study the distribution
and characteristics of gas hydrates and free gas accumulations
in the sediments of the eastern Nankai Trough, a prominent
accretionary wedge, off Tokai, Japan. Seismic data reveal
a very complex and dynamic sedimentation history, dominated
by dipping turbidite and contourite deposits, active channels,
folds, high-angle faults, fluid migration, cold seeps
and mass wasting events. Despite this, the bottom-simulating
reflection (BSR), indicative for the presence of gas hydrates
and free gas, is easily recognized as a laterally-variable
amplitude reflection. The BSR runs sub-parallel to the
seafloor morphology, thereby cross-cutting the stratigraphy.
Remarkably, the BSR is followed by a faint, oblique and
irregular reflection, interpreted as the base of the free
gas zone, as evidenced on the 3D data and time slices.
While the complex subsurface geology is challenging for
wide-angle modelling and inversion procedures, the OBS
data allowed us to construct a 9 layer geophysical model
for the uppermost 700 m of sediments in the eastern Nankai
Trough, in water depths of 930 to 1160 m. Travel-time
inversion gives elevated P-wave velocities, reaching values
of up 2100 m/s. Such high P-wave velocities can be explained
by a partial hydrate saturation of pore space of up to
20% within the ~200 m thick hydrate accumulation zone.
The BSR at ~320 mbsf coincides with a significant drop
in P-wave velocity to values between 1580 and 1750 m/s,
suggesting the presence of small pockets of free gas.
This lower-velocity layer is ~80 m thick. The S-wave velocities
were subsequently derived by event correlation, time picking
and forward modelling of the wide-angle data, and are
up to 700-750 m/s in the hydrate zone. In the gassy layer
underneath the BSR, we observe a small decrease of S-wave
velocity. This might indicate a weak hydrate cementation
of the sedimentary matrix. In the deeper section however,
the surprisingly high P- and S-wave velocities point towards
over-consolidated sediments, attributed to the particular
compressional tectonic setting. The velocities show good
correspondence with well-logging data from nearby boreholes.
The geothermal gradient, inferred from the BSR, equals
40C/km. |
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| 10909 |
Methane Hydrate Detection Using Dense Velocity Analysis,
Offshore Tokai 3D, Japan |
2004 Western Pacific Geophysics Meeting
2004/8/17 |
Takashi Hamajima, Masami Hato(JGI, Inc.), Takao Inamori(Japan
Oil, Gas and Metals National Corporation) |
Methane Hydrate Research Project Team |
| [Abstract] In order to detect high velocity anomaly zones suggesting
the existence of methane hydrate, velocity analysis of
reflection seismic data was conducted. For a delineation
of detailed velocity structure, dense velocity analysis
was performed using an automatic velocity picking tool
we have developed. Significant reduction in analysis time
enables the application to large 3D seismic data. Offshore
Tokai 3D seismic data, acquired over the Nankai Trough,
Japan, was analyzed at a 50m interval in both in-line
and cross-line directions. The analysis covered an area
of 400 square kilometers with a total of 159750 CMPs.
Results of this analysis clearly show high velocity anomaly
above the BSR, and velocity reversal at the BSR. Viewing
the interval velocity volume with the horizon slices parallel
to the sea floor facilitates recognition of the extent
of the velocity anomaly. The difference between estimated
interval velocities and a standard velocity trend such
as the Hamilton's equation provides another viewpoint
to highlight the velocity anomaly zones. Further studies
will include the calibration of velocities with well log
data for a reliable estimation of hydrate bearing zones. |
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| 10908 |
Delineation of gas hydrate-bearing sediments by multi
seismic attributes using three-dimension seismic survey,
offshore Tokai, Japan. |
2004 Western Pacific Geophysics Meeting
2004/8/17 |
Takao Inamori(Japan Oil, Gas and Metals National Corporation), Masami
Hato(JGI, Inc.) |
Methane Hydrate Research Project Team |
| [Abstract] METI, Ministry of Economy, Trade and Industry of JAPAN,
started "Japan's Methane Hydrate Exploitaion Program"
since the fall of 2001. Bottom Simulating Reflectors (BSRs)
were widely found on the marine seismic survey data acquired
offshore Japan, especially in the shelf slope near the
Nankai Trough. METI conducted three-dimension seismic
survey in 2002. BSRs indicate the existence of gas hydrate,
they, however, do not estimate the amount of gas hydrate
as the reservoir parameters. In order to estimate the
amount of gas hydrate accurately, we have to get the more
detailed reservoir parameters such as the gas hydrate
saturation, the porosity or th shickness of the gas hydrate
reservoir layer. We took notice of the relationship between
the gas hydrate and P-wave interval velocity from the
NMO velocity analysis and P-wave impedance, S-wave impedance
or pseudo Poisson's ratio from the multi attibutes analysis
using the three-dimension seismic survey data. We delineated
the gas hydrate-bearing sediments offshore Tokai Japan.
We compared multi attributes data and borehole logging
data. |
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| 10907 |
Velocity structure of the Kumano Basin in the Nankai
Trough |
2004 Western Pacific Geophysics Meeting
2004/8/15-20 |
Tatsuo Saeki, Jun Matsushima(Japan Oil, Gas and Metals
National Corporation), Sumito Morita(National Institute
of Advanced Industrial Science and Technology, AIST),
Masao Hayashi(Japan Oil, Gas and Metals National Corporation)
|
Methane Hydrate Research Project Team |
| [Abstract] Conventionally, BSR (bottom simulating reflector), which
is considered to be a bottom of the methane hydrate bearing
sediment, has been used for delineation of horizontal
distributions of methane hydrate layers and their base
structures. Detailed velocity analysis is also expected
to provide additional knowledge including vertical distributions
or some others attributes, because the P-wave velocity
of methane hydrates is higher than them of surrounding
sediments. The velocity structure of the Kumano basin
in the Nankai trough using 2D seismic data was analyzed
in order to evaluate the methane hydrate potential. Because
of complex geological structure in the survey area and
large feathering angle occurrence in the data acquisition,
velocity scan panels with the conventional stacking method
had a considerable amount of artificial high and low velocity
anomalies. Against the above problem, the pseudo-3D diffraction
stacking method with multi 2D lines data was applied successfully
for the velocity analysis. At the meeting, we will show
details of the velocity analysis process and the obtained
velocity structure. |
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| 10913 |
Organic Geochemistry of Marine and Terrestrial Gas Hydrate
Deposits |
2004 Gordon Research Conference on Organic Geochemistry
2004/8/9-12 |
Amane Waseda, Takashi Uchida(Japan Petroleum Exploration
Co., Ltd.), Masaru Nakamizu(Japan Oil, Gas and Metals
National Corporation) |
Methane Hydrate Research Project Team |
| [Abstract] Gas origin and migration in marine gas hydrate-bearing
sediments in the Nankai Trough, Blake Ridge and Cascadia
margin, and terrestrial gas hydrate-bearing sediments
in the Mackenzie Delta are investigated using gas molecular
and isotopic data. In the Nankai Trough and Blake Ridge,
the carbon and hydrogen isotope compositions of methane
show that the methane in gas hydrates is generated by
microbial reduction of CO2. In the Cascadia margin, the
origin of methane is interpreted to be mainly microbial
with a trace of thermogenic methane. In the Mackenzie
Delta, the isotopic data show that the gas in gas hydrate
is generated by thermogenic decomposition of kerogen.
Gas isotope profiles in the Nankai Trough and Blake Ridge
suggest progressive decrease in microbial activity with
depth and upward gas migration through the sediment column.
Based on the geochemical and geological data, gas migration
process is inferred to be slow pervasive flow in the Blake
Ridge, active flow to permeable sand layer in the Nankai
Trough, very active flow to surface through fault in the
Cascadia margin, and long migration through fault in the
Mackenzie Delta. |
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