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An Integrated Approach to Characterization and Modeling of Deep-water Reservoirs, Diana Field, Western Gulf of Mexico*

By

Morgan D. Sullivan,¹ J. Lincoln Foreman,² David C. Jennette,³ David Stern,² Gerrick N. Jensen,⁴ and Frank J. Goulding⁴

Search and Discovery Article #40153 (2005)

Posted May 9, 2005

*Online version of article with same title by same authors in AAPG Memoir 80, 2004, Integration of Outcrop and Modern Analogs in Reservoir Modeling--editors: G.M. Grammer, P.M. "Mitch" Harris, and G.P. Eberli; available for sale at http://bookstore.aapg.org.

¹ExxonMobil Upstream Research Company, Houston, Texas, U.S.A.; Current affiliation: Department of Geosciences, California State University, Chico, California U.S.A. (mdsullivan@csuchico.edu)

²ExxonMobil Upstream Research Company, Houston, Texas, U.S.A.

³ExxonMobil Upstream Research Company, Houston, Texas, U.S.A.; Current affiliation: Bureau of Economic Geology, The University of Texas, Austin, Texas, U.S.A. (david.jennette@beg.utexas.edu)

⁴ExxonMobil Exploration Company, Houston, Texas, U.S.A.

Abstract

The situation presented at the Diana field in the western Gulf of Mexico is a common one in exploration and early development: a hydrocarbon reservoir expressed by a single-cycle seismic event and limited appraisal wells spaced thousands of feet apart. There is excellent core coverage that enables close calibration of seismic and well data. Integration and analysis of the data suggest a relatively channelized reservoir in an updip position, becoming more sheetlike and layered downdip. This subsurface data, however, does not have the resolution to provide the dimensional and architectural information required to populate an object-based three-dimensional geologic model for more accurate flow simulation and well-performance prediction. To solve these uncertainties, deep-water outcrop analog data from the Lower Permian Skoorsteenberg Formation in the Tanqua Karoo Basin, South Africa, and the Upper Carboniferous Ross Formation in the Clare Basin, western Ireland, were integrated with the seismic and well data from the Diana field. Bed-scale reservoir architectures were quantified with photomosaics and by correlation of closely spaced measured sections. Bed continuity and connectivity data, along with vertical and lateral facies variability information, also were collected, as these factors ultimately control the reservoir behavior. From these measurements, a spectrum of channel dimensions and shapes were compiled to condition the modeled objects. These dimensions were compared to Diana specific seismic and well data and adjusted accordingly. The advantage of the resulting Diana geologic model is that it incorporates geologic interpretation, honors all available information, and models the reservoir as discrete objects with specific dimensions, facies juxtaposition, and connectivity. This study provides the framework for optimal placement of wells to maximize the architectural and facies controls on reservoir performance.