Continuous Sand Fracturing Technology with Slick Water for Continental Shale Oil in the Dagang Oilfield

Horizontal shale oil wells have the problems of high fluid volume and a low sand ratio during conventional slick water fracturing, which lead to poor stimulation effect. For this reason, a slick water system was developed with variable viscosity by selecting a polymer-based friction reducers and optimizing the dosage of clay stabilizers, demulsifying cleanup additives, and persulfate gel breakers. With the system, it was possible to adjust the viscosity of slick water by changing the dosage of polymer-based friction reducers. Then, the proppants composed of 70/140 mesh quartz sand and 40/70 mesh ceramsite were selected after a conductivity simulation. Finally, after pilot tests, a slick water technology for continuous sand fracturing suitable for the continental shale oil reservoirs in the Dagang Oilfield was proposed, which was tested in Well GY2H. As a result, the technology increased the construction efficiency and silt carrying capacity of the unit liquid, reduced the consumption of the fracturing fluid, and formed an effective fracture-network system, achieving excellent reservoir reformation and fracturing stimulation. The field tests proved that this technology could accommodate continuous sand fracturing with slick water in horizontal shale oil wells, providing a technical support for the efficient development of shale oil.