In this month's AAPG BULLETIN...

January 2008

GEOLOGIC NOTES

Regional overview of deep sedimentary thermal gradient of the geopressured zone of the Texas–Lousiana continental shelf

Seiichi Nagihara and Michael A. Smith

GOM Shelf Geothermal Gradient

A regional map of the northern Gulf of Mexico shelf geothermal gradient down to ~ 6 km below seafloor reveals trends that may be explained by a combination of differential sedimentation rates and upward pore fluid migration perhaps coupled with differential heat release from the deep igneous basement.

Impacts of volumetric strain on CO₂ sequestration in coals and enhanced CH₄ recovery

R. Marc Bustin, Xiaojun Cui, and Laxmi Chikatamarla

Nitrogen Aids Carbon Dioxide Sequestration

While CO₂ sequestration by injection into deep unminable coal seems is attractive, numerical modeling results indicate pure CO₂ injection markedly reduces permeability to the point it becomes no longer feasible. However, a mixture of N₂ and CO₂ greatly improves injection efficiency while only mildly reducing CO₂ sequestration capacity.

GEOHORIZON

A new technology for the characterization of microfractured reservoirs (Test case: Unayzah Reservoir, Wudayhi Field, Saudi Arabia)

Mohammed S. Ameen and Ernest A. Hailwood

Improved Characterization of Microfractured Reservoirs

A new technology for the characterization of microfractured reservoirs, artificially-enhanced magnetic susceptibility anisotropy (EAMS), is tested at the Unayzah Reservoir, Wudayhi Field, Saudi Arabia, and represents a significant enhancement in efficiency over traditional methods.

ARTICLES

Petroleum generation and migration in the Ghadames Basin, North Africa: A two-dimensional basin-modeling study

Ruth Underdown andJonathan Redfern

Unlocking Remaining Potential: Ghadames Basin

The timing and distribution of petroleum generation in the Ghadmes Basin, which contains important gas-producing reservoirs in Algeria, Tunisia, and Libya, is assessed by regional 2D modeling, focusing on the under-explored Libyan portion of the basin.

Coal reservoir saturation: Impact of temperature and pressure

Amanda M. M. Bustin and R. Marc Bustin

Coal Sorption Capacity

New data indicate that, rather than coal sorption capacity increasing during uplift, it generally decreases, suggesting that, during uplift, an initially saturated coal will desorb gas that then becomes available for migration and potential resaturation of under-saturated coal.

Characterizing the shale gas resource potential of Devonian–Mississippian strata in the Western Canadian Sedimentary Basin: application of an integrated formation evaluation

Daniel J. K. Ross and R. Marc Bustin

Western Canada Sedimentary Basin

A multi-disciplinary approach is used to evaluate the shale gas reservoir properties of Devonina-Mississippian strata in the Western Canadian Sedimentary Basin. Total gas capacity estimates range between 60 and 600 bcf/section, with the Horn River, Muskawa, and upper Besa River Fms. comprising the most promising targets.

Discussion and Reply

Leaves in turbidite sands: The main source of oil and gas in the deep-water Kutei Basin, Indonesia

Discussion: G. Shanmugam

Reply: Arthur Saller, John Dunham, and Rui Lin

Lowstand Turbidites: Discussion and Reply

Discussion of Saller, et al., 2006, centers on evidence for lowstand turbidites. Saller et al. maintain that the data presented supports their interpretations and reiterate the purpose of the paper, which was to present strong evidence for terrestrial organic matter in deep-water sandstones.

About the BULLETIN

First published in 1917 as the Bulletin of the Southwestern Association of Petroleum Geologists--AAPG’s predecessor organization--in order to disseminate scientific material from annual meetings of the S.A.P.G., the AAPG Bulletin changed its name one year later when S.A.P.G. became AAPG.

The AAPG Bulletin has been delivering quality research to the scientific world ever since. The first issue contained papers written by the best-known geologists of the day, and included papers on such topics as South America, Europe, and general geologic problems of structure and sedimentation.

While the 21st-century AAPG Bulletin has undergone some changes since 1917, enlarging to 8 ½ x 11” size to incorporate more material and being published digitally as well as in print, it continues to adhere to the primary purpose of the organization, which is to advance the science of geology especially as it relates to petroleum, natural gas, other subsurface fluids, and mineral resources.

Delivered digitally or in print monthly to each AAPG Member as a part of membership dues, the AAPG Bulletin is one of the most respected, peer-reviewed technical journals in existence, with recent issues containing papers focused on such topics as the Middle East, channel detection, China, permeability, subseismic fault prediction, the U.S., and Africa.