Optimization of Stimulation Treatments for Improved Oil Recovery in Complex Lithological Reservoirs

Abstract Well stimulation normally consists of matrix acidizing, acid fracturing and proppant fracturing. The optimum stimulation treatment depends on both reservoir characteristics and the formation damage mechanism. The oil recovery can be improved with successful stimulation treatments. This paper presents a case study of a pilot stimulation project in the Onbysk oil field in Tatarstan, Russia. The objective of this project was to optimize stimulation treatments in geologically complex reservoirs for the improved oil recovery. The Onbysk field consists of seven stacked reservoirs with a complex lithology of shaly sandstone and limestone with microfractures. Different stimulation techniques have selective applications to different reservoirs for improved oil recovery. The improved oil recovery has been evaluated using production history data and decline technique.