Microdamage and Adaptability Evaluation of Slickwater Used in Gulong Shale Oil Reservoir

Gulong shale oil reservoir is rich in resources, high in clay minerals, and densely developed bedding fractures. Generally, reverse composite volume fracturing technology is used to establish oil and gas flowing channel, in which slickwater is beneficial to opening bedding fractures and improving the complexity of artificial fractures. The microscopic damage and adaptability research of slickwater on reservoir are of great significance for improving fracturing effect. This paper take the microscopic damage and adaptability of slickwater to Gulong shale reservoir as research object. Micro damage experiments of five kinds of slickwater were conducted to research the micro damage and adaptability of slickwater to Gulong shale reservoir. The results of nuclear magnetic resonance and CT analysis show that the binding degree of type B, C, and E slickwater is small, the pore damage is small, the total porosity increases greatly, and the number of fractures increases, which is conducive to the fracturing fluid backflow. The scanning electron microscope analysis results show that the chemical element adsorption of type B and E slickwater is relatively light, pore filling is not serious, element migration is prominent, and intergranular pores increase. Comprehensive analysis shows that type B and E slickwater have good adaptability to Gulong shale oil reservoir. The research results are of great significance to the optimization of hydraulic fracturing fluids for the Gulong shale, the identification of the characteristics of pore throat damage caused by fracturing fluids, and the adaptability of fracturing fluid to reservoirs, which are conducive to improving the effectiveness of reservoir stimulation.