Yichang Area is a new area for shale gas exploration outside the Sichuan Basin.Taking the shale reservoir of Shuijingtuo Formation in the area as the object,drilling measurements,core testing a-nalysis and logging interpretation were used to obtain current stress information from multiple well points.The study of in-situ stress characteristics was carried out,and the causes of stress difference dis-tribution were discussed.The results show that the current maximum horizontal principal stress direc-tion of the Shuijingtuo Formation in Yichang Area is generally in the NEE direction,and the areas near the boundary fault in the east and west show multi-direction.The current in-situ stress has strong dis-creteness,showing a main distribution characteristic of high in the middle and low in the east and west in the plane,and increasing with depth in the vertical direction.The burial depth is the main factor lead-ing to differences in the vertical distribution of in-situ stress.The principal stress value increases linearly with burial depth.The principal stress from large to small in the main burial depth area of shale reser-voirs is the maximum horizontal stress,vertical stress and minimum horizontal stress,which belongs to the stress state of strike-slip fault.The horizontal stress value and direction of different lithological lay-ers are change.From limestone,siltstone to shale,the stress value generally shows a decreasing trend.The influence of boundary faults is the main cause of the distribution differences of in-situ stress on the plane.Boundary faults cause a decrease of in-situ stress values and a deflection of maximum horizontal principal stress direction parallel to the fault strike.The decrease in stress values and the amplitude of deflection are mainly controlled by the distance from the fault.The research results can provide a basis for the subsequent exploration deployment and fracturing construction plan design of the Shuijingtuo Formation shale gas reservoir in Yichang Area.
关键词
地应力特征/成因/页岩储层/水井沱组/鄂西宜昌地区
Key words
in-situ stress characteristics/causes/shale reservoir/Shuijingtuo Formation/Yichang Area in Western Hubei Province
维普
万方数据