Recently Added in Bulletin
This study demonstrates a method for generating fault envelope grids on full-field reservoir models where fault cores are modeled. Volumetrically expressed fault cores substantially influence forecasts of field behavior and should be considered during production planning.
Desktop /Portals/0/images/_site/AAPG-newlogo-vertical-morepadding.jpg?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true 28973
Organic-rich shale and siliceous shale that was deposited from suspension near upwelling zones are key exploration targets for shale oil and gas in the southeastern Sichuan Basin, China. Seven lithofacies have been identified, and turbidity current mudstones are the principal exploration targets for tight oil.
Desktop /Portals/0/images/_site/AAPG-newlogo-vertical-morepadding.jpg?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true 28970
Four seals and five pressure systems are recognized in the Sichuan Basin, southwest China; Based on mechanisms analysis and hydrocarbon generation history, a pressure evolution model has been constructed which includes a normal pressure stage, an overpressuring stage, and an overpressure releasing stage.
Desktop /Portals/0/images/_site/AAPG-newlogo-vertical-morepadding.jpg?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true 28982
This sequence stratigraphic study in the Neuquén Basin, Argentina, contributes to the understanding of the relationship between organic matter, clay minerals, facies, stacking patterns, and relative sea-level changes in this exceptional shale-oil and shale-gas unconventional reservoir.
Desktop /Portals/0/images/_site/AAPG-newlogo-vertical-morepadding.jpg?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true 28969
Thermochemical sulfate reduction (TSR) is complex and cannot be simply represented. The application of three-dimensional reactive transport modeling presented in this paper is a good example of how such an approach to investigate TSR can be used prior to drilling.
Desktop /Portals/0/images/_site/AAPG-newlogo-vertical-morepadding.jpg?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true 28979
A modelling approach is presented in which surfaces are used to represent geologic heterogeneities that control the spatial distribution of reservoir rock properties. This method offers improved results in mm to cm scale intercalations of mudstone and sandstone.
Desktop /Portals/0/images/_site/AAPG-newlogo-vertical-morepadding.jpg?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true 28965
This paper presents new data for the Rub' Al-Khali Basin, Saudi Arabia, constraining the age, depositional environment, petrography, regional correlation, and fluid system of these Middle Jurassic silicic sands. This play is independent of underlying and overlying systems.
Desktop /Portals/0/images/_site/AAPG-newlogo-vertical-morepadding.jpg?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true 28976
A suite of surface-based models of heterolithic, cross-bedded tidal sandstones has been investigated via flow simulation in order to calculate effective permeability. Effective permeability is highly anisotropic and decreases as the mudstone fraction increases.
Desktop /Portals/0/images/_site/AAPG-newlogo-vertical-morepadding.jpg?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true 28967
Fluid migration along deep fault zones affected porosity in the Lower Saxony Basin.   Hydrothermal origin of ascending fluids rich in iron and CO2 increased porosity along fractures. Carbonate dissolution in the calcitic host rock increased porosity and permeability near the fracture walls.
Desktop /Portals/0/images/_site/AAPG-newlogo-vertical-morepadding.jpg?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true 28492
Analysis of the burial and thermal history of an Ordovician field in the Illizi Basin, Algeria, using thermal maturity, apatite fission-track, fluid inclusion microthermometry, sonic velocity, and biostratigraphic data provides independent, and consistent constraints on the evolution of the structure.
Desktop /Portals/0/images/_site/AAPG-newlogo-vertical-morepadding.jpg?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true 28493
Recently Added in Interpretation
Please check back for more information.
Recently Added in Environmental Geosciences
We herein document temporal changes in dissolved and gaseous methane concentrations in 12 domestic water wells completed in Late Devonian clastic aquifers in northeastern Pennsylvania over time periods from 0.2 to 2 yr. Wells with initial methane concentrations regarded as low (<5 mg/L), moderate (5–15 mg/L), and high (>15 mg/L) were all used in our study for comparative purposes.
Desktop /Portals/0/images/_meta/meta_DEG_200x200.png?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true&format=jpg 28328
We report the results of analysis and interpretation of 19,278 predrilling groundwater samples from water wells in the Appalachian Basin for dissolved methane collected from 2009 to 2012 (11,309 samples from northeastern Pennsylvania and 7969 samples from a western area that included north–central West Virginia, eastern Ohio, and southwestern Pennsylvania).
Desktop /Portals/0/images/_meta/meta_DEG_200x200.png?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true&format=jpg 28327

Net fluid production and pressure data were gathered to estimate the amount of CO2 storage space available and the potential for additional oil recovery using CO2-enhanced oil recovery (EOR) in the Phacoides sandstone, McKittrick oilfield, San Joaquin Valley, California. 

Desktop /Portals/0/images/_meta/meta_DEG_200x200.png?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true&format=jpg 22319

One of the challenges confronting carbon dioxide capture and sequestration (CCS) in geologic media over extended periods of time is determining the caprock sealing capacity. If the pressure of supercritical carbon dioxide (scCO2) injected in the repository overcomes the caprock sealing capacity, leaking of scCO2 may enter other porous formations, compromising the storage formation, or even may go back to the atmosphere, and thus the process of sequestration becomes futile.

Desktop /Portals/0/images/_meta/meta_DEG_200x200.png?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true&format=jpg 22320

Examination of historical water-quality data (major cations and anions and total dissolved solids [TDS]) for Rock Creek, located in eastern Nebraska’s saline wetlands north of the Platte River, revealed that concentrations of sodium (Na), chloride (Cl), and TDS increased significantly in the downstream reach below the town of Ceresco, exceeding the U.S. Environmental Protection Agency (USEPA) secondary drinking water standards of 250 mg/L for Cl and 500 mg/L for TDS.

Desktop /Portals/0/images/_meta/meta_DEG_200x200.png?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true&format=jpg 22324

This study simulated the injection of supercritical phase CO2 into the South Georgia Rift (SGR) basin to evaluate the feasibility of long-term storage. Because of the lack of basin data, an equilibrium model was used to estimate the initial hydrostatic pressure, temperature, and salinity gradients that represent our study area. 

Desktop /Portals/0/images/_meta/meta_DEG_200x200.png?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true&format=jpg 22322
We use sediment ages and mercury (Hg) concentrations to estimate past and future concentrations in the South River, Virginia, where Hg was released between 1930 and 1950 from a manufacturing process related to nylon production. In a previous study, along a 40 km (25 mi) reach, samples were collected from 26 of 54 fine-grained deposits that formed in the lee of large wood obstructions in the channel and analyzed for grain size, Hg concentration, and organic content. We also obtained radiometric dates from six deposits. To create a history that reflects the full concentration distribution (which contains concentrations as high as 900 mg/kg [900 ppm]), here, we treat the deposits as a single reservoir exchanging contaminated sediments with the overlying water column, and assume that the total sediment mass in storage and the distribution of sediment ages are time invariant. We use reservoir theory to reconstruct the annual history of Hg concentration on suspended sediment using data from our previous study and new results presented here. Many different reconstructed histories fit our data. To constrain results, we use information from a well-preserved core (and our estimate of the total mass of Hg stored in 2007) to specify the years associated with the peak concentration of 900 mg/kg. Our results indicate that around 850 kg (1874 lb) of Hg was stored in the deposits between 1955 and 1961, compared to only 80 kg (176 lb) today. Simulations of future Hg remediation suggest that 100-yr timescales will be needed for the South River to remove Hg-contaminated sediments from the channel perimeter through natural processes.
Desktop /Portals/0/PackFlashItemImages/WebReady/hero-EG-Journal-21-1-2014.jpg?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true 5780

 SONAR, historical and aerial photographs, and vibracoring were used to assess the type and thickness distribution of sediments impounded by Gold Ray Dam on the Rogue River in southern Oregon. From these data, a volume of about 400,000 cubic yards (

Equation EG13006eq1

) of sediment was determined for the inundated area of the reservoir.

Overall, sediment volumes in the impounded part of the reservoir were less than expected. There are three possibilities that may explain the perceived absence of sediment: (1) the gradient of the Rogue River in this stretch is less, and therefore sediment yields are less; (2) the extraction of gravels and/or other impediments upstream decreased the availability of sediments delivered into the reservoir; and/or (3) sediment was deposited by a prograding delta that filled in the inundated area of the floodplain upstream from Gold Ray Dam. The amount of sediment deposited on this inundated floodplain may have been as much as 1,800,000 cubic yards (Equation EG13006eq2), bringing the total amount of sediment impounded by Gold Ray Dam to Equation EG13006eq3 yards (Equation EG13006eq4).

Applied sedimentology is not only vital to developing a depositional model for the filling of a reservoir, but also providing insights into depositional and erosional changes that will occur upon the removal of a dam. In particular, the processes of delta formation, reoccupation of abandoned channels, and avulsion are paramount in determining sediment accumulation and distribution in reservoirs.

Desktop /Portals/0/PackFlashItemImages/WebReady/hero-EG-Journal-21-1-2014.jpg?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true 5779
Shales are becoming the most important source of natural gas in North America, and replacement of coal by natural gas is reducing CO2 emissions and improving air quality. Nevertheless, shale gas is facing strong opposition from environmental nongovernmental organizations. Although these organizations have greatly exaggerated the potential negative environmental impacts of shale gas and shale oil, methane leakage and contamination of groundwater and surface water by flowback and produced waters are serious concerns. These contamination pathways are not unique to shale gas and shale oil, and they are manageable.
Desktop /Portals/0/PackFlashItemImages/WebReady/shale-gas-opportunites.jpg?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true 3421
The West Virginia Division of Energy is currently evaluating several deep saline formations in the Appalachian Basin of West Virginia that may be potential carbon dioxide (CO2) sequestration targets. The Silurian Newburg Sandstone play, developed in the 1960s and 1970s, primarily involved natural-gas production from reservoir rock with well-developed porosity and permeability. High initial pres-sures encountered in early wells in the Newburg indicated that the overlying Silurian Salina Formation provides a competent seal. Be-cause of the large number of CO2 point sources in the region and the favorable reservoir properties of the formation (including an esti-mated 300 bcf of natural-gas production), the Newburg Sandstone was evaluated for the potential geologic storage of CO2. Within the Newburg play, there are several primary fields separated geographi-cally and geologically by saltwater contacts and dry holes. Previous studies have determined the storage potential within these individual fields. This study shows that the Newburg is more suitable for small-scale injection tests instead of large-scale regional storage operations.
Desktop /Portals/0/PackFlashItemImages/WebReady/evaluation-of-the-Newberg-Sandstone.jpg?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true 3416


06 May

2016 AAPG Student Chapter YouTube Video Contest Expires today!

07 May

Sequence Stratigraphic Facies Architecture & Reservoir Characterization Of Fluvial, Deltaic And Strand-Plain Deposits - Regular Fee Expires in 1 day

09 May

Eastern Section Pass the Baton: Mentoring, Networking and your Career Expires in 3 days

United States - Eastern Section
09 May

Basic Petroleum Geology for the Non-Geologist Early Tuition - May 5, 2016 Expires in 3 days

United States - Gulf Coast Section - Texas