William A. Miller¹, David M. Wheeler², Travis C. Wilson³

(1) Miller Consulting Services, Littleton, CO
(2) Ensign Oil & Gas, Inc, Denver, CO
(3) Colorado School of Mines, Golden, CO

ABSTRACT: 3C-3D Seismic Characterization of the Eva South Morrow Sand Unit, Texas County, Oklahoma

A 3-component, 3-dimensional (3C-3D) high-resolution seismic survey was acquired over the Eva South Morrow Unit in T3N-R11ECM of Texas County, Oklahoma to characterize the producing Upper Morrow sandstone reservoir which is currently under secondary recovery by waterflood. The ultimate goal of this characterization was to identify reservoir extents and possible compartmentalization in order to plan additional drilling to increase the ultimate secondary recovery of the field and prevent premature abandonment. This project was funded in part by a grant from the Department of Energy through the Reservoir Class Field Demonstration Program-Class Revisit.

Three component recording was utilized with a standard, vertical component, vibroseis source to capture both compressional wave (P) and converted mode shear wave (P-SV) information. Using P-SV waves to obtain shear wave seismic information was advantageous in that it did not require the significant added expense of mobilizing a shear wave source in addition to the compressional source. Excellent structural definition of the bounding fault system to the field was achieved which illustrated its complex nature. The overall valley system geometry and gross reservoir sandstone distribution were imaged with both the P and P-SV seismic data, and further analyses and processing of the data are being done to further enhance the reservoir interpretation.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado