The Research Of Development Effects And Fine Potential Tapping About The Sa Ⅱ Group Oil Layer In The Taibei Development Block

A sedimentary feature of a delta outer-front facies and prodelta with a main lake wave transformationly affected was argued through a detailed geologic study for the oil layers in the Sa Ⅱ Group reservoir of the Taibei Development Block. The characteristics of the sand body distribution was mainly divided into four types of a wide area distribution, local closely grouped, scattered distribution and large pinch-out area distribution. The reservoirs gradually became much worse from the north side to the south side, and occurred a pinch-out area in the southern Tai 14 row. The outside delimited reservoirs were mainly developed with the average perforated sandstone thickness of a single well of 9.9 meters, a small development thickness and poor continuity, belonging to a low permeability and low porosity reservoir. At the same time, through the analyses of the status of oil wells or injection wells, the high injection pressure and the poor water absorption in the injection wells and the low reservoir pressure, the poor liquid producing capacity, and the non-effective water injection in the oil wells were addressed. At present due to a relatively worse development effect, thus the fine development countermeasures are proposed in time to improve the development effect. Through the meticulous study of the problems existing in the development, four measures such as perforation adding, fine dominating fracture of single sand body, surfactant injection and water injection by increasing pressure were made, and the feasibility was carried out and the on-site tests were implemented. The effective communication between the oil wells and injection wells was established and the effect of injection can be seen earlier after water injection The well spacing was shortened and the injection-production relationship was improved at the same time by perforation adding by the study of the establishment of the effective communication between the outside delimited reservoirs by the fine control fracturing and the fracturing of the oil and water wells designed personalized. Therefore, the effective employ of the thin and poor reservoirs was achieved, and the interaction force between oil and water was decreased, making the injection pressure dropped and the water-flood injection rate increased through the surfactant injection which can change the wettability on the surface of the rock. The Darcy velocity of the water injection and the number of the flow voids were increased by an increasing pressure, and the injection capacity of the injection wells and water absorption ability of the reservoirs were improved. By means of the evaluation of four methods of the field effects, a better effect in the primary stage was thought and the development effect of the Sa Ⅱ group reservoir in the Taibei Development Block was improved. This is not only playing a guiding role for the development of ultra-low permeability oil layer, but also supplying the guarantee for the stable production of a crude oil.