A study on the evaluation of geological sweet spots in the super deep strike slip fault controlled reservoir

Abstract

There are complex strike-slip fault systems in the Ordovician carbonate strata in the T-sh area of Tarim Basin. They are the primary storage space and flow channel of hydrocarbon resources. Scientific evaluation of internal space and conductivity of different parts along the main faults is the decisive factor for efficient development of the T-sh reservoir. Based on the 3-D seismic and the coherent body data, the fault structure models in the reservoir of the S1 and S5M fault zones are established. The original regional geomechanical parameters are determined according to the core testing results and logging data. The local stress field near the fault is studied based on the numerical simulation method. The sliding trend coefficient, expansion coefficient, and comprehensive conductivity coefficient of faults in the reservoir of S1 and S5M fault zones are quantitatively evaluated. The results show that the Ordovician strata in S1 and S5 fault zones are in a strike-slip faulting stress regime. The vertical stress (SV) gradient is 0.0243 MPa/m, the maximum horizontal stress (SH) gradient is 0.0246 MPa/m, the minimum horizontal stress (Sh) gradient is 0.0177 MPa/m, and the orientation of Sh is 166.27 °–197.25°. Based on the simulation results, it is found that there is an apparent correlation between the sliding trend coefficient of the faults and mud loss. The expansion coefficient is positively correlated with venting and production. The research results have practical significance for geological sweet spots prediction and drilling construction in the T-sh oilfield.