页岩气井排水采气工艺综合优选方法

目前排水采气工艺的选择采用现场经验法和宏观控制图版法，考虑因素欠缺，工艺实施效果较差，文章根据压力供给与临界携液原则，结合经济效益分析，开展了页岩气井排水采气工艺综合优选。根据误差分析优选Mukherjee-Brill两相流模型用于计算页岩气井筒压力分布，确定排水采气工艺的压力适用界限；考虑产液量、液滴变形和造斜率变化引起的液滴碰撞，建立页岩气井全井筒临界携液流量模型，确定排水采气工艺的携液适用界限，最终建立页岩气井排水采气工艺综合优选方法。实例分析表明，页岩气井临界携液流量模型的预测精度达94.1%，页岩气井排水采气工艺综合优选方法能够实现“一井一策”的排水采气工艺定量优选，优选后的排水采气工艺具有良好的排液增产效果与经济效益。

ComprehensiveOptimalSelectionMethodof Drainage Gas Recovery Technology for Shale Gas Horizontal Wells

Current methods of selecting drainage gas recovery technology depend on experience and macroscopic control chart, which fail to consider influence factors comprehensively and lead to poor drainage effect. Therefore, a comprehensive optimal selection method of drainage gas recovery technology in shale gas horizontal wells is developed according to the pressure supply principle, the critical flow rate principle and the economic benefit analysis. The pressure application boundary of drainage gas recovery technology is determined, and Mukherjee-Brill’s model is selected to calculate the wellbore pressure profiles in shale gas horizontal wells based on error analysis. The liquid carrying application boundary of drainage gas recovery technology is determined, and a new critical flow rate model for the whole wellbore of shale gas horizontal wells is established, which takes into account the liquid flow rate, the liquid-droplet deformation and the liquid-droplet energy loss caused by the change of buildup rate. Then, the comprehensive optimal selection method of drainage gas recovery technology in shale gas horizontal wells is established. Field case analysis shows that the precision of liquid loading prediction of the new critical flow rate model is 94.1%. The “One Strategy for One Well” comprehensive optimal selection method of drainage gas recovery technology could optimize drainage gas recovery technology quantitatively. The optimal drainage gas recovery technology has good drainage effect and economic benefit.