川西非常规气藏压裂改造工艺初探

Study on fracturing technology for unconventional gas reservoirs in western Sichuan

新场地区须家河组五段地层为砂泥岩互层的非常规储层,储层厚度平均500 m左右,脆性矿物含量约60%且天然裂缝发育,通过体积压裂改造具备形成大型缝网的条件。针对该类储层的地质特征,在引进国外页岩气压裂工艺的基础上,研制形成的降阻水体系降阻率达到80%、探索形成的分层压裂工艺及体积压裂的规模、排量、停泵次数等施工参数,通过现场实施得到验证,压后平均产量为3.5×104m3/d,取得较好改造效果。

The fifth member formation of Xujiahe Formation in Xinchang area is an unconventional reservoir with inter- layered sandstone and mudstone. The average thickness of the reservoir is about 500 m,with about 60% content of brittle mineral and developed natural fractures, and has conditions of forming large fracture networks through volume fracturing stimulation. Aiming at the geological characteristics of the reservoir, based on the introduced foreign shale -gas fracturing process, the reducing water blockage system was developed, with the resistance reduction rate of 80%. The separate layer fracturing technology and construction parameters such as the scale and displacement of volume fracturing, the pump stop frequency, etc. , have been verified by the field implementation. The average gas production after fracturing was 3.5 × 104 m3/d,obtaining good stimulation results.