Print this pageAbstract: "The Big Banana," Geologic Mapping and Thermal Recovery in a Vertical Reservoir, North Midway Field, California
PONEK, MICHAEL F., Texaco E & P, Bakersfield, CA;A. G. MATTHEWS, PE, Texaco E & P Technology Department, Houston, TX
Thermal recovery at the North Midway Field has been historically an economic success. However, our oil production performance could not be predicted. The forecasted performance was based on a highly faulted geologic model of the Potter Sand in the Monterey Formation. In general, the produced oil volume and production rate has not matched the geologic model.
In 1990, a reevaluation of the existing log data led to a new structural interpretation and field development strategy for the North Midway Field. Reprocessed dipmeter data was compared to the log signature of several wells drilled into the Potter Sands. Vertical to slightly overturned beds were resolved with only minimal faulting. Recent drilling and surface mapping confirmed the overturned structure. The oil sands outcrop directly over the productive interval and are sealed at the surface by a tar mat. Additional reservoir details such as desaturated zones, variable oil/water contacts, and reservoir rock characteristics were identified, allowing detailed mapping and accurate volumetric oil calculations of the Potter Oil Sands.
Based on the revised geologic model and reservoir simulation, an improved
steamflood design involves drilling both highly deviated production wells
and vertical injectors on tight 1-1/2 acre spacing. At present, the wells
are being monitored to determine heat migration characteristics and effectiveness
of the new steam flood design.
AAPG Search and Discovery Article #90935©1998 AAPG Pacific Section Meeting, Ventura, California