Stratigraphic Architecture and Sandstone Reservoir Quality in
Deep-Shelf Gas Plays of Texas State Waters

Robert G. Loucks and Shirley P. Dutton, co-principal investigators

The deep-shelf gas play in the Gulf of Mexico (GOM) is focusing exploration attention below 15,000 ft in the shallow waters of offshore Texas State leases. Ultradeep wells targeting large structures below the present-day Texas shelf are planned to be drilled to depths from 20,000 ft to as much as 30,000 ft for sandstones deposited in deep-water depositional settings. At these depths the greatest unknown and most critical risk factor is reservoir quality. The ability to predict reservoir quality (porosity and permeability) and physical characteristics of ultradeep reservoir rocks has lagged behind our understanding of other parts of the petroleum system, such as depositional facies, traps, and petroleum migration.

The unknowns that remain about reservoir quality in these ultradeep drilling targets make this a critical area for further research. To address these risks, BEG formed a consortium of companies to focus on the stratigraphic architecture and distribution of primary depocenters and the understanding of diagenesis and reservoir quality of deep Gulf Coast sandstones below 15,000 ft. Our major research goal is to decrease the exploration risk of sandstone distribution and reservoir-quality prediction by (1) mapping from seismic data general stratigraphic architecture and areas of deep to ultradeep primary depocenters and (2) understanding the uncertainty involved in preservation or enhancement of porosity and permeability at depth. Our project should encourage drilling activity by focusing exploration on lower risk areas and preventing drilling below reservoir basement. Our work can (1) focus deep exploration on areas of thicker lowstand systems tracts, (2) provide methods for forecasting reservoir quality in deep to ultradeep sandstones, and (3) form the basis of later site-specific diagenetic modeling studies where numerical models can be applied.


For more information, please contact:

Bob Loucks, co-principal investigator.
Telephone (512) 471-0366;

Shirley P. Dutton, co-principal investigator.
Telephone (512) 471-0329;

July 2005