Development Characteristics of Silurian Strike-Slip Faults and Fractures and Their Effects on Drilling Leakage in Shunbei Area of Tarim Basin

In recent years, the Ordovician fault-controlled fracture-cavity reservoirs developed in basement strike-slip fault zone Shunbei area of Tarim Basin has achieved major breakthroughs. However, during drilling process area, problem mud leakage frequently interbedded Silurian sandstone and mudstone strata overlying target layer is very significant, it seriously affected normal wellbore stability. this study, taking No. A Strike-slip Fault Zone as an example, development characteristics faults fractures, strength in-situ stress field, influence these factors on were systematically studied using 3D seismic, logging, drilling, well log, engineering construction data. The results show that S 1t significantly larger than 1k , amount sandy largest; strong extension negative flower-shaped right-order swan-type caused serious stratigraphic fragmentation. increases with increase distance. Moreover, closer to fault, higher frequency leakage. When distance between exceeds 300 m, possibility decreases significantly. dominated by high-angle vertical tension-shear fractures good opening; while low-angle structural horizontal bedding fractures. differences fracture type cause be . addition, intervals identified R/S-FD method are agreement intervals, which further indicates degree key factor leading study also found difference principal stresses dominant high