页岩气藏压裂水平井Blasingame产量递减分析方法建立与应用

根据常规油气藏压裂直井Blasingame产量递减样板曲线建立方法,使用渐近法建立了拟稳态流动阶段无因次压力与无因次时间的线性关系获取方法,重新定义无因次参数,形成了考虑气体吸附和溶解的页岩气藏压裂水平井Blasingame典型样板曲线。结合页岩气藏物质平衡理论,将实例数据与样板曲线进行拟合,验证了Blasingame产量递减分析方法在页岩气藏压裂水平井生产数据解释中的有效性。研究结果表明：①基于新无因次变量,吸附、溶解影响下页岩气藏压裂水平井Blasingame样板曲线边界控制流阶段再次归结为一条斜率为-1的直线,结合吸附等实验数据,可有效降低拟稳态阶段的多解性;②页岩气藏压裂水平井Blasingame样板曲线受储量相关参数和裂缝参数的双重影响,储量相关参数越大,样板曲线位置越低,裂缝参数越大,样板曲线位置越高。③长期动态资料分析可有效获取储层物性参数、改造情况以及单井控制动态储量参数,基于拟合结果,为未来生产动态预测奠定了基础。

Establishment and application of Blasingame production decline analysis method for fractured horizontal well in shale gas reservoirs

According to the method of establishing the type curve of Blasingame production decline for fractured vertical well in conventional oil and gas reservoirs, and using the asymptotic method, this study sets up the simple method of acquiring the linear relationship between dimensionless pressure and dimensionless time in the quasi-stable state flow phase. Meanwhile, dimensionless parameters are redefined, and a typical Blasingame type curve of the shale gas reservoir fractured horizontal well considering gas adsorption and dissolution is formed. Based on the material balance theory of shale gas reservoir, the example data is fitted to the type curve to verify the validity of Blasingame production decline analysis method for interpreting the production data of fractured horizontal wells in shale gas reservoirs. Research results suggest that:(1)based on the new dimensionless variables, the boundary control flow phase of the Blasingame type curve of fractured horizontal well in shale gas reservoir under the influence of adsorption and dissolution is again reduced to a straight line with the slope of -1. Combined with the experimental data about adsorption, the multiple solutions of the quasi-steady state can be effectively reduced; (2)Blasingame type curve of the fractured horizontal well in shale gas reservoir is dually influenced by reserve-related parameters and fracture-related parameters. The larger the reserve-related parameters are, the lower the position of type curve is; the larger the fracture-related parameters are, the higher the position of type curve is. (3)Long-term dynamic data analysis can help effectively obtain the physical parameters and transformation conditions of reservoir and achieve the single-well control of dynamic reserve parameters. Based on the fitted results, it lays the foundation for future production dynamics prediction.