Volume fracturing for horizontal wells in Yongchuan deep shale gas reservoirs

When a horizontal well is fracked in a deep shale gas reservoir, the injection pressure is high, proppants are hard to be pumped down, and stable production does not sustain. To address these issues, geological characteristics of the Yongchuan Longmaxi reservoir were analyzed. With the goal of creating fracture networks through multistage volume fracturing, the following combinations were used: optimized high-viscosity and low-viscosity fluids, 70/140 + 40/70 + 30/50 mesh proppants and large-bore bridge plugs that are soluble or do not need to be drilled out. A geophysical technology for predicting geological and engineering sweet spots was used to determine the interval of each stage and cluster. Propped fracturing was ensured using a special mixing technique in six-stage mixed injection mode. In addition, fracture complexity was strengthened by perforation optimization, temporary plugging of fracturing mouths, and post-treatment shut-in. Good stimulation performance is obtained in implementation wells and the volume stimulation objectives are obtained.