Study On The Shale Utilization Law Of Hydraulic Fracturing In Changning-Weiyuan Block

The effective development of shale gas has played an important role in the world’s energy structure.China is rich in shale gas reserves,and the shale in the Changning-Weiyuan block has good potential for development.For different reservoir conditions,the laws of shale pneumatic application are different.At present,there are few studies on the hydraulic fracturing kinetics of shale reservoirs,and corresponding studies are urgently needed.Taking the Longmaxi Formation shale in the Changning-Weiyuan block as an example,basic mechanical properties of shale,pore structure and pore size distribution determination of basic mechanical tests were carried out.Based on the determination of shale physical parameters,indoor triaxial hydraulic fracturing experiments,CT scanning experiments and PFC discrete element numerical simulation methods were used to study the hydraulic fracturing extension mechanism and influencing factors.The study shows that: the shale hydraulic fracture has the characteristics of high-speed expansion,and the generated fractures are tension fractures;the value of hydraulic fracture penetration pressure increases with the increase of the surrounding pressure;the fracture extension length and the number of bond breakage are positively correlated with the water injection pressure;the higher the water injection pressure,the more it has an enhanced effect on the fracture extension along the fluid injection direction,increasing the transformation volume,increasing the complexity of fracture grid formation and achieving good fracturing effect.Based on the IMEX calculation module of CMG software,a shale gas development model is established to analyze the influence of engineering parameters and reservoir properties on the shale gas flow law,and the factor analysis method of SPSS is applied to determine the main influencing factors.By analyzing the results of shale gas production and reformed volume,the following conclusions are obtained: among the fracturing parameters,an increase in the number of fracturing segments and an appropriate increase in fracture length,height and segment spacing can Among the fracturing parameters,increasing the number of fracture segments,fracture length,height and segment spacing can change the flow conductivity of shale reservoirs,increase the fracture reformation volume,increase the effective utilization of shale gas and increase the gas production;among the reservoir properties,porosity has less influence on shale gas production,but permeability is closely related to shale gas transportation;Statistical Analysis of the fracture volume,hydraulic fracture cluster number,fracture length,fracture height,fracture segment number,cluster spacing of six factors are the main factors affecting the effective utilization of shale gas.Based on the study of the fracture expansion mechanism of hydraulic fracturing in shale reservoirs in the Changning-Weiyuan block and the utilization law of shale gas,we provide ideas and means to optimize the fracture parameters of hydraulic fracture fracture network and provide technical support for the effective development of shale gas reservoirs in the Changning-Weiyuan block.The paper has 72 figures,15 tables and 100 references.