Nuclear Magnetic-Seepage Joint Measurement Experimental Technology and Field Application of Shale Oil Reservoir

Shale oil reservoirs in Daanzhai section of central Sichuan are mainly developed in Daer sub-section, with rich resource base and great exploration and development potential. A series of reservoir engineering geological characteristics experiments have been carried out in order to form reservoir reconstruction countermeasures and technology suitable for Daanzhai shale oil. The results show that the average porosity of Daanzhai shale oil reservoir in central Sichuan is 5.9%, with pores mainly concentrated in the range of 1-100 nm, and slightly larger pores mainly concentrated in the range of 250-1000 nm, with micro-scale pores developed; The reservoir is mainly composed of shale and limestone interbedding. The fracture pressure of limestone is 9-10 MPa higher than that of adjacent depth shale, which is not conducive to the longitudinal expansion of the fracture. The test of temporary plugging and diversion fracturing technology has significantly increased the complexity of the fracture; Shale crude oil has the characteristics of high viscosity, low wax content and low gum content. It has good fluidity in shale supporting fractures, natural fractures and dislocation fractures, and hardly flows in the matrix, and is mainly used for oil displacement by osmosis; The innovatively established nuclear magnetic resonance (NMR) – permeability test technology can quantitatively characterize the flow ability of shale oil in porous media and the permeability and oil displacement ability. In the Daanzhai shale oil reservoir, the optimized soak time is not less than 6 days, and the pressure control and fluid drainage has achieved a more stable stage of fluid discharge. The test oil production has increased from “oil flower” to nearly 2 tons/day, making a major breakthrough in “oil production”.