Control factors of high and stable production of Jurassic Da'anzhai Member tight oil in central Sichuan Basin, SW China

Abstract

Abstract: By systematically analyzing the basic geological characteristics of tight oil in Jurassic Da'anzhai Member in the middle of Sichuan Basin (Central Sichuan area) and combining with a large number of exploration and development data, we examine the main controlling factors and exploration direction for high and stable production of tight oil. Tight oil in the Da'anzhai Member has the following characteristics: large and low abundance resources; generally tight, relatively high quality reservoirs; adjacent source rocks and reservoirs, favorable migration and accumulation of oil; extensive oil-bearing pores. Development practice reveals that the high and stable production oil wells for tight oil are mainly distributed in fractured vuggy reservoirs in the shore-lacustrine sedimentary subfacies, and fractures are very important in affecting the high and stable production of tight oil in the Da'anzhai Member. Natural gas plays an important role (gas drive) in petroleum migration and accumulation and high production of oil wells. Combined with the characteristics of high and stable production, exploration and development results, drilling cost and other factors, it is considered that the Da'anzhai Member located in the middle and south part of Sichuan Basin is a promising field for exploration and development of tight oil in the Jurassic of the Sichuan Basin. Key words: Sichuan Basin, Jurassic system, Da'anzhai Member, tight oil, shell limestone, high and stable production, controlling factors