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Bottom-like flowing pressure (BHFP) prediction for multi-stage fractured horizontal shale gas with constant rate production is a key problem of stable production period estimation. Based on the transient linear flow theory of multi-stage fractured horizontal shale gas, the rate-time superposition function (Qg・t0.5)sup is proposed, a type curve identification charts of pseudopressure difference [m(pi)-m(pwf)]-rate-time superposition function (Qg・t0.5)sup is established, a parameter group of m which could reflect reservoir properties and fractured effect is determined, an BHFP prediction analytical solution function for constant rate production shale gas well is constructed. This method is applied in constant rate production and variable rate production shale gas wells, the results show that there is an excellent coincidence rate between predicted BHFP and monitored BHFP, which is above 95%, and the forecasting precision of stable production period is above 90%. This BHFP prediction method has an important guiding significance for stable production period prediction, rational proration of multi-stage fractured horizontal shale gas well with constant rate production. [ABSTRACT FROM AUTHOR]

Since the successful development of the shale gas test well group in Fuling shale gas field in 2013，the cumulative yearly shale gas production capacity of 10.0 billion cubic meters has been built by the end of 2017.Due to the impact of geologic conditions and technical measures on shale gas wells，the production performance of shale gas wells is significantly different from that of the conventional gas wells.The rapid decrease in initial production and long-time linear flow result in great difficulties in accurate calculation of gas production per unit pressure decrease and well-controlled dynamic reserves，and thus in proper design of gas field development scenarios.Therefore，based on the accurate grasp of the production characteristics of shale gas，the prediction method of gas production per unit pressure decrease and well-controlled reserves were set up in terms of the production data of some typical producing wells in the block，and could be used for effective prediction of the changes in gas production per unit pressure decrease and well-controlled reserves with production time.The study showed that the angle between the extension direction of horizontal section and the maximum principal stress should be as less than 40° as possible，the well spacing should be within 400-600m，and wells should be deployed as cluster cross wells in the pattern of “six wells per pad”，so as to make full use of existing platforms and available resources，to provide guidance for the construction scale of gasfield，to realize the effective large-scale development of shale gas，and to serve as a reference for the economical and effective development of southern marine shale gasfields and other gas fields of the same type at home and abroad. [ABSTRACT FROM AUTHOR]