Research and Application of Backflow Law of Longdong Tight Shale Oil Proppant

Hydraulic fracturing is an effective method for the development of tight shale oil reservoirs, which can improve the production and recovery efficiency of shale oil wells. The backflow of proppant after fracturing seriously affects the efficiency of fracturing construction and oil well production capacity, and sand flushing after fracturing also increases construction costs. Controlling blowout is the main way to prevent proppant backflow in shale oil horizontal wells, but many wells still have a large amount of proppant backflow into the wellbore during the initial stage of blowout. By establishing a visualization experimental evaluation method for proppant backflow, the critical velocity of proppant backflow and the influence of different confining pressure conditions on the critical velocity were obtained under conditions such as no proppant backflow and fiber anti proppant backflow. The backflow law of proppant at different stages was analyzed. The visualization experiment directly observed that the main sand produced in the early stage of proppant was collapsed sand, and even at very low flow rates, proppant still flowed back into the wellbore, The fiber anti proppant backflow technology can effectively improve the critical speed of proppant backflow and reduce the degree of sand production in the early stage. And one well test was conducted on Longdong shale oil field, and the effect of preventing proppant backflow was significant. This provides new ideas and theoretical basis for the evaluation and research of proppant reflux.