Optimization of multi-cluster fracturing in deep reservoirs based on stress field reconstruction effect

Since rock plasticity under in-situ conditions poses challenges during fracturing stimulation, extensive research is necessary on deep gas and oil reserves, which will be the primary area of future development. This paper created a competitive, multi-cluster fracture propagation model that considered elastoplastic rock deformation and nonlinear fracture characteristics in deep reservoirs. It also proposed an optimal fracture design of “dense fracture distribution, non-uniform perforation and alternating staged fracturing” based on stress field reconstruction. The findings indicated that suitably reducing the spacing between clusters and increasing the number of perforated clusters minimized local in-situ stress variations through stress interference among fractures. This mitigated the limiting effect of plastic deformation on the propagation of hydraulic fractures, demonstrating a viable approach for enhancing the expansion of fractures in deep reservoirs. The elastoplastic fracture propagation mechanism was examined to elucidate the advantages of close-cutting fracturing technology. The impact of various fracture techniques was analyzed using stress field reconstruction. Alternate fracturing displayed a high degree of stress reconstruction with an extensive propagation range, which facilitated the propagation of multiple fracture clusters in the subsequent fracturing section. The findings offer a theoretical basis for fracture design of deep reservoirs.