Effect of Fluid Volume and Production Rate on Oil Recovery in Oil Field Development by Waterflooding Methods

Abstract

Abstract The five large oil fields found in the Russian Republic of Tatarstan have been producing from the Devonian sandstone reservoirs for more than fifty years. Currently all of them have entered the maturity stage. In all five fields waterflooding methods have been applied since the very start of production. And though the principal development approaches and strategy do not differ, development rate, volumes of fluid produced, actual and design oil recovery factor (ORF) do differ. The largest of the five fields, Romashkinskoye, has been developed in independent areas divided by injection wells’ rows. There are 21 such areas. Comparative analysis of these areas’ performance is of specific interest. To make a generalized estimate of production performance of the five fields, we have ranked them by a number of geologic parameters. The same ranking has been performed for all areas of the Romashkinskoye oilfield. For the purpose of analysis these areas have been further divided into seven groups by a common integral geologic parameter. The investigation method involves a correlation analysis of the fluid production and oil recovery profiles at different stages of development of both fields and areas; as well as evaluation of the present-day status of development, in that number with account for the tendency towards operating assets’ change. It has been demonstrated that the oil recovery factor and its behavior at different development stages depend to a large extent on reservoir geology. Besides, there is a close correlation between fluid and oil production rates. In mature fields very important factors are status of assets and producing wells’ density. Fields and areas have been identified which call for immediate rejuvenation operations.