Abstract: In view of the lack of specific method of activating natural fractures in the ultra-deep fractured clastic reservoir in Cretaceous Bashijiqike Formation in Tarim Oilfield, the natural fractures of the reservoir in the study area was analyzed for conditions of realizing shear-based activation and tension-based activation according to the Moore-Coulomb failure criterion, and the fracture conductivity in hydraulic fracturing and acid fracturing was simulated and tested. The results of the study show that the conductivity of fractures with mutual dislocation in hydraulic fracturing was 100 to 1 000 times that of fractures without mutual dislocation, the conductivity of fractures without mutual dislocation was increased by more than 1 000 times after sand addition and the shear slip of natural fractures in fracture network fracturing could also achieve stimulation effects, so sand addition had an important influence on the stimulation effect of fractures without mutual dislocation; moreover,if sand was added, whether fracture with mutual dislocation had no essential effect on the conductivity. In fracture network acid fracturing, the filled natural fractures were under a lower closure stress (less than 20 MPa), the acid-rock reaction time had little effect on the conductivity; under higher closure stress, the longer the acid-rock reaction time, the greater the dissolution degree of fillings and the higher the retention degree of conductivity. Effective conductivity could be obtained by filled natural fractures through acid erosion, but did not obtained by non-filled natural fractures through acid erosion. The study results provide technical support for the stimulation of fracture networks in the ultra-deep reservoir in the Kuqa Piedmont.

Key words: fractured clastic reservoir, natural fracture, hydraulic fracturing, acid fracturing, conductivity, Tarim Oilfield