水力压裂缝导流的页岩气藏水平井稳产能力研究

页岩气储量巨大,开发前景被业内广为看好,但其低孔低渗特性使得开发难度高于常规气藏。国外成熟的页岩气藏主要使用水平井压裂技术进行开采。笔者结合页岩气藏水平井压裂后产生水力压裂缝这一情况,建立水力压裂缝导流的页岩气藏水平井后期稳定开采的渗流模型,通过运用等值渗流阻力法,考虑吸附解吸影响,推导出水力压裂缝导流的页岩气藏水平井稳定渗流产能公式,然后采用拟压力替代的方法将适用于油相的产能公式改进为适用于气相的水平井产能公式。通过算例对压裂效果进行研究,结果表明:水力压裂缝数量越多,裂缝间距越小,水平井稳定产能就越大;水平井长度增加超过某一个由该气藏基本参数控制的长度值后,稳定产能的增加值将减缓。

Steady Productivity of Horizontal Well in Hydraulic Fracture Induced Shale Gas Reservoir

Although the shale gas resource is plentiful and has good production prospect,the development of shale gas reservoir with the low permeability and low porosity is more difficult than that of normal gas reservoir.The development method of shale gas reservoir in oversea is horizontal well and hydrofracture.Based on hydraulic fractures in the horizontal well hydrofracture for shale gas reservoir,we establish the late stable production filtration model of the horizontal well in the hydraulic fracturing induced shale gas reservoir.We use the equivalent filtration resistance to deduce the late stable production equation of the horizontal well after considering adsorption and desorption.Then,we use the pseudopressure method to adjust the equation for oil phase to fit the gaseous phase.The results show that the horizontal well production increases with hydraulic fractures increase and hydraulic fractures space decrease.The increase speed of the horizontal well steady productivity becomes low while the horizontal well length increases over a certain value which is controlled by basic data of shale gas reservoir itself.