Research on Optimal Design of Screen Out Fracturing in Unconsolidated Sandstone Reservoir Based on Fluid Solid Coupling Theory

Loose sandstone reservoirs account for a large proportion of oil and gas resources in the world, but due to weak cementation and serious sand production problems, oil well production is seriously affected. Screen out fracturing can not only effectively control sand production, but also improve reservoir production. It is an efficient development mode for loose sandstone reservoirs, but its internal mechanism needs further study. Therefore, the interaction of reservoir stress and fluid seepage in the development of unconsolidated sandstone is fully considered, the fluid solid coupling deformation field equation and seepage field equation of unconsolidated sandstone are derived, and the fluid solid coupling mathematical model of unconsolidated sandstone reservoir is established. The COMSOL software is used to conduct numerical simulation of horizontal well staged screen out fracturing in Gudao Oilfield, verify the rationality of the model, and analyze the impact of fluid solid coupling on the productivity of unconsolidated sandstone reservoir, The screen out fracturing parameters of unconsolidated sandstone reservoir are further optimized. The research shows that the simulation results of the established numerical model agree well with the actual production data, and the average error is controlled within 5%; Fluid solid coupling has a great impact on the initial productivity of unconsolidated sandstone reservoirs, but the impact can be ignored when the production days exceed 350 days; Taking productivity as the optimization objective, the number of fractures, fracture length and fracture conductivity of staged screen out fracturing for horizontal wells are optimized.