More Effective
Use of Outcrops in Deep-water Studies
Nilsen, Tor H.1, Roger D. Shew2,
Gary S. Steffens3, Joseph R.J. Studlick4 (1) Deceased,
N/A, CA (2) University of North Carolina at Wilmington/Consulting Geologist,
Wilmington, NC (3) Shell International E & P Inc, Houston, TX (4) Maersk
Oil America Inc, Houston, TX
Whether a geoscientist is focused on the
basin, region, play, prospect, field, or reservoir scale in working with
deep-water deposits, selection of key analog data is critical. Outcrop data can
greatly assist in the construction of conceptual models using qualitative data
and in reservoir performance predictions using quantitative statistics. Outcrop
data provide the physical link between well-based data and seismic data.
However, as there are thousands of
published papers on the hundreds of deep-water outcrops, selecting the one(s)
applicable to your needs and extracting he right data can be problematic. From
a recent compilation of > 100 deepwater outcrops, AAPG's Atlas of Deep-water
Outcrops, we have summarized the data and developed a simplified workflow to
assist the worker in identifying the “best” outcrop(s). We eliminated those
outcrops that are inaccessible, difficult to travel to, little studied, poorly
exposed, and/or lacking a large 2-D or some 3-D perspective.
We characterized 75 outcrops by basin
setting, age, and depositional setting as key selection parameters. Additional
data available for each outcrop are stacking patterns, net:gross, grain size,
and references; most outcrops have detailed architectural element data as
channel dimensions, bed lengths, bed thicknesses, and textures of reservoir and
non-reservoir rocks. Using such criteria, one can quickly identify the best
outcrops to use. These data can then be used to establish ranges and better
estimates of sand thicknesses, connectivities, stacking patterns, and recovery
efficiencies. Use of photos from such outcrops and preferably a visit to the
outcrop by the work team can greatly assist the understanding of and create a
better “picture” of the deep-water deposits being studied.
AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California