川西深层须家河组气藏压裂改造难点和工艺技术对策

川西地区须家河组砂岩气藏埋藏深,温度高,异常高压,岩性致密,作为勘探开发核心技术的压裂改造技术能否获得突破,将直接制约深层气藏的勘探开发进程。通过工程地质特征分析,指出压裂改造的主要难点是破裂压力超高、闭合压力超高、施工压力超高、压裂液综合性能要求高和排量提升困难。详细分析了川合148井测试压裂和主压裂的成功作业过程和川合139井不成功的压裂作业。通过这2口井现场试验的对比分析,认为深层须家河组气藏的加砂压裂改造是可行的,但由于异常复杂的地质特征,压裂改造的难度仍然很大。为了有效解决这些技术难题,提出了一系列有针对性的工艺技术对策,以期能为深层气藏下一步压裂改造技术攻关提供有益的参考。

Difficulty of Gas Reservoir Fracturing and Its Technology Countermeasures in Xujiahe Formation in Western Sichuan

The sand gas reservoir of Xujiahe Formation,in west Sichuan Basin,has characters of deep burial,high temperature,unconventional high pressure, and quite compact,thus,as the key technology of exploration and development,whether the hydraulic fracturing technology have been made a breakthrough can directly limit the process of gas reservoir's exploration and development.In this paper,through analysing the geologic characters,it points out the main difficulties of hydraulic fracturing,which includes super-high breakdown pressure,super-high closure pressure,ultra-high pumping pressure,high comprehensive performance of fracturing fluid,and difficult increasing of slurry flow rate.It describes in detail the successful operations on minifracturing and main fracturing in Well CH148,and simply introduces the unsuccessful fracturing on Well CH139.Compared with the 2 wells' field experiments,the hydraulic fracturing on deep gas reservoir of Xujiahe Formation is feasible,but for the complicate geologic feature,it is quite difficult on the reservoir's hydraulic fracturing.In order to resolve the problems,it puts forward a series of corresponding countermeasures,which can provides good references for the reservoir's further hydraulic fracturing research.