Researchon Application Of Staged Fracturing Technique Of Shale Gas Horizontal Wells In XX Block

XX is located in southeast Sichuan basin in China, which has deep burial depth, high fracture pressure and high temperature. Therefore, the pressure is too high and proppant injection is too difficult during hydraulic fracturing operation. The horizontal well staged fracturing technique for such shale reservoir is not mature and lack of experience so far, so this research is carried out to provide a support for efficient development of shale gas in this block.Firstly, based on geological characteristics of XX Block, fracability evaluation of shale reservoir was made, and the fracability of this reservoir was estimated by analogy method in this study. And distance between clusters was optimized by the maximum induced stress difference model of hydraulic fractures. Then adesign of horizontal well staged fracturing of S2 was optimized in this block. In this part, the optimal cumulative gas production after fracturing was regarded as the objective function to build an optimal model of fracturing parameters of staged fractured horizontal well. The results of fracture length, conductivity and amount of fractures were optimized to determine reasonable fracturing operation parameters, and anoverall optimal design of fracturing was formed. Then fracturing materials were optimized by geological characteristics of shale reservoir in this block. Finally, suitable staged fracturing process and tools of this block were optimized by being compared with different operation displacement of horizontal well staged fracturing process.High friction reduction and low damage hybrid fluid of slick water and low surfactant tension gel was used as fracturing fluid, together with low-density and high-strength ceramic proppant to the target well. The operation process of experiment well was a 12-stage fracturing, with a cumulative fracturing fluid volume of 2.95×104m3, maximum displacement of 13.6m3/min. Complex networks were formed in reservoir near this well and high industrial gas production of 10.5×104m3/d was reached after the reservoir be fractured.