Lost Hills CO2 Pilot--Evaluation, Design, Injectivity Test Results and Implementation

PERRI, PAT, Chevron USA Production Co., Bakersfield, CA

This paper describes the evaluation, design, and implementation of a DOE funded immiscible CO2 pilot project in the Lost Hills Field, Kern County, California.The pilot consists of four inverted (injector-centered) 5-spot patterns covering approximately 10 acres, and is located in a portion of the field, which has been under waterflood since early 1992. The target reservoir for the CO2 pilot is the Belridge Diatomite. The pilot location was selected based on geology, reservoir quality and reservoir performance during the waterflood. A CO2 pilot was chosen, rather than full-field implementation, to investigate uncertainties associated with CO2 utilization rate and premature CO2 breakthrough, and overall uncertainty in the unproven CO2 flood process in the San Joaquin Valley.This paper summarizes the methodology used in the project evaluation and design including construction of the geologic model, reservoir simulation and CO2 flood predictions, facilities design, and well design and completion considerations. An actual CO2 injectivity test was conducted in March 1999. The results of the injectivity test, which helped in the design of the pilot, are presented.The reservoir management plan and future field potential are also discussed. CO2 injection in the pilot is planned to commence in the second quarter of 2000. The methodology and technical analysis used to evaluate and design the Lost Hills CO2 pilot are applicable to other potential San Joaquin Valley CO2 floods.

AAPG Search and Discovery Article #90911©2000 AAPG Pacific Section and Western Region Society of Petroleum Engineers, Long Beach, California