A Review of Gas Injection Projects in California

Abstract

Summary This paper summarizes reservoir and recovery data for 12 of the more important gas injection pressure maintenance projects in California. These projects were initiated during the period from 1940 to 1960 and the reservoirs are now approaching depletion. A brief description of each project is included. Introduction In the period between 1940 and 1960 a number of gas injection projects were initiated in California oil pools for the purpose-of maintaining reservoir pressure. Since most of these reservoirs are nearing the end of their productive life under the current methods of operations, it seems an appropriate time to review the performance of these projects. The remaining producible oil reserves are so small relative to past production that substantial uncertainties production that substantial uncertainties in estimates of future production will have little effect on the estimated ultimate recovery. The study has been confined to immiscible gas displacement projects. There have been a few attempted miscible gas displacement and gas cap cycling projects, but there have not been enough to furnish a body of credible comparative data. The criteria which have been considered in selecting the projects to be reviewed can be summarized as follows:The entire reservoir was either unitized or under the control of a single company so that an adequate reservoir management program could be carried out without the interference of competitive operations.The total volume of gas injected was considered to be sufficient relative to reservoir size to have a substantial effect on performance. Data considered to be adequate for the purpose of this study were obtained on 12 projects which are listed in the attached Table 1. The data were obtained from the operators of the projects, published technical papers, projects, published technical papers, unpublished engineering reports in our files, and statistics compiled by the Conservation Committee of California Oil Producers. In only two cases were the published data adequate for the purposes of this study, so a representative review would have been impossible without the cooperation of the companies operating the other projects. I would like to express my appreciation for the data and assistance given me by the following companies: ARCO Oil and Gas Co. Chevron USA Inc. Sun Exploration and Production Co. Texaco USA Inc. Unocal Corp. I would also like to acknowledge the assistance of Adell Gibson, without whom this project would never have been completed. P. 213