AAPG Bulletin, V. 83 (October 1999), No. 10, P. 1624-1641.
 

Reservoir and Production Analysis of the K40 Sand, South Timbalier 295, Offshore Louisiana, with Comparison to Time-Lapse (4-D) Seismic Results¹

Andrew R. Hoover,² Tucker Burkhart,³ and Peter B. Flemings⁴

©Copyright 1999.  The American Association of Petroleum Geologists.  All Rights Reserved

¹Manuscript received December 21, 1997; revised manuscript received March 4, 1999; final acceptance April 1, 1999.
²Texas Gulf Coast Resources, Shell Continental Companies, Houston, Texas 77079; e-mail: [email protected]
³Shell Offshore, Inc., New Orleans, Louisiana 70161; e-mail: burkhart@ shellus.com
⁴Pennsylvania State University, Department of Geosciences, University Park, Pennsylvania 16802; e-mail: [email protected]
 

This project was supported by the Columbia University/Pennsylvania State University 4-D seismic consortium, whose sponsors are Amoco, Chevron, Exxon, Norsk-Hydro, Pennzoil, Shell, Statoil, Texaco, and UNOCAL. Shell Offshore, Inc. provided data and allowed publication of results. Shell employees J. Beer, T. Stellman, M. Kohli, G. Purdy, A. Berni, and C. Jones provided valuable assistance and suggestions. Landmark Graphics Corporation, Mincom, Lamont 4-D, and AVS provided software support. S. Nelson, P. Walsh, and H. Johnson assisted with manuscript preparation. 

ABSTRACT

Reservoir and production characteristics of the K40 sand (South Timbalier Block 295, offshore Louisiana) are used to track the oil-water contact as it moved vertically 80 m between 1988 and 1994. This zone of water sweep is associated with a strong decrease in seismic amplitudes observed from comparison of 3-D (three-dimensional) seismic curves acquired before hydrocarbon production (1988) and during production (1994). The Pliocene K40 sand is an overpressured (0.80 psi/ft) turbidite reservoir deposited in a slope minibasin. Wireline and seismic data are used to develop a geologic model for this reservoir. This analysis, combined with production history and log data, indicates that relatively uniform water sweep was effectively imaged by time-lapse (4-D) seismic over most of the reservoir. The lack of seismic dimming in some parts of the reservoir is attributed to poor drainage of low-permeability lithofacies. In addition, it may not be possible to image drainage of reservoir zones with less than 10 m of original net pay with these data. These results illustrate the potential of time-lapse seismic analysis for illuminating the dynamic behavior of producing reservoirs and indicate that preproduction seismic surveys, not originally intended for use in time-lapse (4-D) seismic analysis, have value as baselines for seismic monitoring studies.