济阳坳陷陆相页岩力学特征及压裂重点攻关方向OA

The continental shale in the Jiyang Depression is characterized by strong heterogeneity,with complex geological structure,well-developed fractures,and diverse lithofacies,with high-frequency interbeds.Compared to North American marine shale,the continental shale in the Jiyang Depression exhibits greater heterogeneity and more pronounced anisotropy,making it impossible to directly apply the successful experience of North American shale oil development,and efficient fracturing faces enormous challenges.This study investigated the mechanical deformation characteristics,anisotropic failure modes,and fracture propagation patterns of continental shale in the Jiyang Depression through rock mechanics and laboratory fracturing experiments.It analyzed and summarized the key issues faced in reservoir stimulation and proposed solutions and future research directions.The results indicate that the strength and deformation of the continental shale in the Jiyang Depression exhibit significant anisotropy with varying lamina dip angles.Shales with moderate lamina dip angles(30°-60°)exhibit lower strength and pronounced plastic characteristics,with failure predominantly controlled by weak laminae.In contrast,shales with larger lamina dip angles(>60°)demonstrate higher strength and are primarily subject to brittle failure.As in-situ stress increases,the difficulty of lamina slip activation increases,causing the shale to transition from brittle to plastic behavior.Additionally,inclined laminae are more likely to undergo plastic deformation,reducing the likelihood of brittle macrofractures.Lamina type is a key factor in controlling the complexity of hydraulic fractures,with moderate laminae favorable for generating fracture networks,while excessive density or high strength of laminae inhibits fracture propagation.The fracturing stimulation of shale oil in the Jiyang Depression faces three major challenges:complex fracture propagation mechanisms in highly heterogeneous reservoirs,uneven fracture propagation among multiple stages in a single well,and interference between wells in multi-well cooperative fracturing.To address these issues,further research is needed on heterogeneous fracture propagation and inter-well stress interference mechanisms,along with strengthened geological-engineering integrated differential design.Additionally,research on well pattern-fracture network coupling optimization methods and the improvement of high-precision monitoring and evaluation systems is crucial for supporting complex fracture network regulation and cubic fracturing development.