Classification of residual oil reserves and methods of its recovery

Abstract

Many oil and gas fields are currently at a late stage of development, while most of them are being developed using flooding. These fields are characterized by the decreasing oil and liquid flow rates and accelerating water-cut. During the development process, the majority of oil reserves are extracted not using methods of production enhancement. Though, oil reserves within undeveloped areas are a valuable source for recovery. To involve residual reserves in active development, it is necessary to make a reasonable justification and a choice of the most effective geological and technical measures that take into account various geological field and well reservoir characteristics. Residual oil reserves at the late stage of development are classified as hard-to-recover and are mainly concentrated in areas not covered by flooding laterally and vertically. They belong to various categories that differ in the geological and technological characteristics. In this regard, it is necessary to plan various geological and technical measures taking into account the structure of residual reserves and patterns of their distribution. Studies of complex oil and gas fields were performed and a detailed analysis of the geological and physical characteristics, parameters of reservoir heterogeneity along with operational, geological and commercial assessment of reserves development were conducted.