Multi-zone limited-entry injection through casing can have a serious problem – the inability to achieve efficient recovery due to lack of steam conformance. Poor sweep effiency results in steam migration into unwanted sands, cold temperatures in areas needing a steamchest, and an overall lack of oil recovery.
The failure of limited-entry injection through casing was noticed after a portion of Texaco's Kern River lease failed to achieve steam breakthrough. In July, 1996, this portion of the field had undergone a recompletion, in two distinct sands, utilizing casing limited-entry technology. After several years of injection, one sand had achieved a 0% increased recovery and the other sand had only achieved a 57% sweep efficiency. Because the cost of steam is one of Texaco's main expenses, it is important to use this resource effectively and economically. Limited-entry injection through tubing has proven to be a more efficient method for multi-zone flooding and is widely used throughout Texaco's Kern River operation.
The summer project, as a chemical engineering intern in the productions department, was to prepare and implement programs to reconfigure the field from limited-entry-casing injection to limited-entry-tubing injection in an economical and environmentally safe manner.
Multi-zone limited-entry injection through tubing is the most effective, economical, and environmentally safe answer. During August, 2000, the 20 injector wells in the project area underwent this reconfiguration process, the results of which are being awaited. This paper will document the process utilized to complete the project during the internship and the environmental, health and safety processes that were implemented.