AAPG Bulletin, V. 83
(October 1999), No. 10,
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: [email protected] 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.
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.