Lessons Learned from the Hydraulic Fracturing Test Site in Xinjiang Conglomerate Reservoirs

Objectives/Scope: In order to more intuitively determine the horizontal and vertical distribution and fractures in the MaHu demonstration area, coring wells were used to determine the occurrence of hydraulic fractures in horizontal wells. At the same time, the results are jointly verified with microseismic monitoring results and tracer testing results, providing a basis for well spacing optimization, fracture spacing optimization, and reservoir numerical simulation. Methods, Procedures, Process: In order to observe the longitudinal fracture extension height and proppant placement height, the coring well branch crosses the hydraulic fracture extension area. The design direction of the branch is perpendicular to the maximum horizontal principal stress direction of the demonstration area, parallel to the horizontal well direction of the demonstration area, and the coring length is 323 m. The coring well trajectory is designed to collect cores with well spacing of 200 m and 100 m, and fracture spacing of 10 m and 20 m. Results, Observations, Conclusions: Based on the analysis of the obtained coring results with a total length of 323 m, the geometry and complexity of the fractures formed are closely related to the reservoir lithology. The CT scan results of collected core samples show that the fracture spacing is 0.2 to 1 per meter, and the fracture spacing is smaller than the fracture cluster spacing, indicating that complex fracture networks can be formed in conglomerate reservoirs with a large stress difference of 15 MPa. The types of fractures obtained are diverse, with the exception of tensile fractures around the gravel, shear fractures recorded in the sandstone section, and fracture zones with concentrated development of fractures recorded in the near wellbore section, enriching the formation mechanism of conglomerate fracture networks. Novel/Additive Information: The whole well coring of horizontal wells collects important visual data for fracturing and completion of horizontal wells, which can improve the stimulation process of horizontal well reconstruction.