Bulletin Article

7969
 

Diagenesis significantly impacts mudstone lithofacies. Processes operating to control diagenetic pathways in mudstones are poorly known compared to analogous processes occurring in other sedimentary rocks. Selected organic-carbon-rich mudstones, from the Kimmeridge Clay and Monterey Formations, have been investigated to determine how varying starting compositions influence diagenesis.

7968
 

Umiat field in northern Alaska is a shallow, light-oil accumulation with an estimated original oil in place of more than 1.5 billion bbl and 99 bcf associated gas. The field, discovered in 1946, was never considered viable because it is shallow, in permafrost, and far from any infrastructure. Modern drilling and production techniques now make Umiat a more attractive target if the behavior of a rock, ice, and light oil system at low pressure can be understood and simulated.

The Umiat reservoir consists of shoreface and deltaic sandstones of the Cretaceous Nanushuk Formation deformed by a thrust-related anticline. Depositional environment imparts a strong vertical and horizontal permeability anisotropy to the reservoir that may be further complicated by diagenesis and open natural fractures.

Experimental and theoretical studies indicate that there is a significant reduction in the relative permeability of oil in the presence of ice, with a maximum reduction when connate water is fresh and less reduction when water is saline. A representative Umiat oil sample was reconstituted by comparing the composition of a severely weathered Umiat fluid to a theoretical Umiat fluid composition derived using the Pedersen method. This sample was then used to determine fluid properties at reservoir conditions such as bubble point pressure, viscosity, and density.

These geologic and engineering data were integrated into a simulation model that indicate recoveries of 12%–15% can be achieved over a 50-yr production period using cold gas injection from five well pads with a wagon-wheel configuration of multilateral wells.

Environmental Geosciences Article

5779
 

 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.

Explorer Article

9502
 
Explorer Article

Mystery of the deep: No one knows for sure what quantity of gas hydrates awaits discovery deep in the earth, but projections are auspicious.

8583
 
Explorer Article

On March 27, 1964, Mike Mitchell and others were in the field working on a research project with professor Ruth Schmidt from the geology department at ACC when they experienced the Great Alaskan Earthquake, the most powerful earthquake in recorded U.S. history.

8580
 
Explorer Article

Ruth Schmidt, one of the first 100 women members of AAPG, is celebrated for her brilliant and adventurous career geologic career.

8049
 

Online registration is open for this year’s AAPG Annual Convention and Exhibition, which will be held April 6-9 at the George R. Brown Convention Center in Houston – and reduced registration fees are still available for those who act fast.

Explorer Emphasis

8053
 
Explorer Emphasis Article

A multi-client seismic database maps prospects and pitfalls in the largely uncharted Arctic North Slope.

8050
 

Seismic Outlook: After several years of plenty, 2014 is expected to be a comparatively lean year for the seismic industry, a few localized hot-spots around the world notwithstanding.

Explorer Historical Highlight

10218
 

The history of oil development in Alaska is often presented as a heroic tale, but long before the 1968 discovery of the Prudhoe Bay field (16 billion barrels and counting), the industry experience was marked by a great deal of frustration and failure.

Coming Soon

Check back often. "Find an Expert" feature is coming online soon!

Jon R. Schwalbach Jon R. Schwalbach Advisory Counselor (2012-2015) Aera Energy LLC (805) 648-8518
John Thomas Williams John Thomas Williams President (2014-2015) Petrolog Inc (805) 231-3793
Kurt Edward Neher Kurt Edward Neher President Elect (2014-2015) Occidental Oil & Gas Corp. (661) 412-5203
Jonathan Patrick Allen Jonathan Patrick Allen Vice President (2014-2015) Chevron (661) 654-7516
Vaughn Grant Thompson Vaughn Grant Thompson Editor (2014-2016) Occidental Oil and Gas
Daniel Evan Schwartz Daniel Evan Schwartz Past President (2014-2015) Aera Energy LLC +1.661.665.5832
Malcolm Edward Allan Malcolm Edward Allan Secretary (2014-2015) Geological Consultant (661) 665-8558
Cameron Denney Campbell Cameron Denney Campbell Treasurer (2014-2015) Chevron (713) 304-5787
Rebecca Michelle Greenberg Rebecca Michelle Greenberg Treasurer Elect (2014-2015) Occidental Oil & Gas Corp. 562-624-3327

The House of Delegates of the AAPG is made up of delegates from affiliated societies and international regions throughout the world. They are selected by popular vote from within their respective areas and serve a three year term.

Who Is My Delegate?