BEEUNAS, MARK A., THOMAS A. HUDSON, JOSANN A. VALLEY and WESLEY Y. CLARK, Chevron Production Co., New Orleans, LA; and DAVID K. BASKIN, Chevron Research Technology Co., La Habra, CA

Abstract: Reservoir Continuity and Architecture of the Genesis Field, Gulf of Mexico (Green Canyon 205): An Integration of Fluid Geochemistry within the Geologic and Engineering Framework

Due to the high cost of developing deepwater reserves, it is imperative that all pertinent data be collected, analyzed and integrated into the reservoir model to insure the greatest possible accuracy. An area often overlooked is the compositional analyses of reservoir fluids collected from producing wells, DSTs, MDTs and core extracts. Detailed chromatographic analysis of the oils also provides information about the connectivity of the oil column vertically within a well and laterally between wells.

Oil compositions are based on gas chromatogram fingerprints and compared using software that rapidly scans the chromatograms and identifies peak ratios useful for comparing the oil samples. The application of hydrocarbon compositional analysis for continuity evaluation is based on the premise that oil samples from a single hydrocarbon accumulation (continuous reservoir) will have similar compositions, whereas production from separate hydrocarbon columns (different sand/fault block) will usually have discernibly different compositions.

Hydrocarbon compositional results from Genesis reservoirs have provided additional validation of suspected discontinuities within the major reservoir sands (N1, N2 and N3L). Of particular importance are suspected transmissibility restriction interpreted in the N1 and N3L sands, based on pressure transient data and a corresponding area of lower seismic amplitude and minor vertical offset. Significant compositional differences of the hydrocarbons across these restrictions support their existence and suggest potential barriers to production.

AAPG Search and Discovery Article #90924©1999 GCAGS Annual Meeting Lafayette, Louisiana