川西低渗致密气藏难动用储量压裂关键技术研究

川西低渗致密砂岩气藏有相当一部分储量储层改造效果差,气井产能和压力递减快,储量难以得到有效动用.通过对难动用储量压裂难点分析,明确了储量难动用的主要原因是严重水锁、高启动压力梯度、强应力敏感性、复杂渗流形态,压裂过程易伤害,提出了相应的压裂对策,并形成了以低伤害为核心,高效返排为手段的大型加砂压裂技术、多层压裂合采技术的川西难动用储量压裂工艺技术,在现场应用中取得了良好效果.

RESEARCH ON FRACTURING TECHNOLOGY FOR DIFFICULT-TO-PRODUCE IN LOW PERMEABILITY AND TIGHT GAS RESERVOIR IN WEST SICHUAN

Partial low-permeability and tight gas reservoir in West Sichuan has many features, such as bad reservoir stimulation effect, quick depletion of productivity and pressure, reserves difficult-to-production. Through analyzing the fracturing difficulties of the difficult-to-produce reserves, the main reasons of reserves difficult-to-production were determined, that is serious water lock,high threshold pressure gradient,strong stress sensitivity,complex percolation form and easy damaged in fracturing process. Aiming at the difficult-to-produce reserves,the corresponding fracturing technology was put forward,big-frac treatment and the multilayer fracturing technology were formed, and acquire favorable effect in field application.