高压气藏不动管柱分层压裂工艺研究与应用

Study and application of technologies for separate layer fracturing without pulling string in high pressure gas reservoir

川西低渗高压气藏具有多层系的特点,层间距离一般在十至百米左右。为了提高气井产量与开采经济效益,鉴于气井加砂压裂后压井会严重伤害储层,影响压裂效果,采用压裂管柱直接作为生产管柱,研究形成了以FCY211及Y241封隔器不同组合的两层不动管柱分层压裂工艺。同时,在成熟的两层分压工艺基础上,结合投球选压工艺,研究形成了以"工具分层+投球选压"不动管柱三层分层的压裂工艺。现场应用实践表明,分层压裂极大地增加了单井的产能,取得了明显经济效益,对类似气藏的多层压裂与开采提供了有益参考。

Western Sichuan gas reservoirs are characterized by low permeability and high pressure with multilayers ranging from 10m to 100m between each layer. In order to improve the productivity of the gas producers and achieve good economic efficiency, fracturing strings are used directly as the string of production due to the fact that serious reservoir damage might occur and the postfracture response might be affected when killing well after sand fracturing. Therefore, separate fracturing technology was used with two layers separated by FCY211 or Y241 packers. Meanwhile, on the basis of the results of using the technology of two-layer separate fracturing, three-layer separate layer fracturing was developed with ＂packer and ball off ＂ fracture technology. Field application results indicated that the separate layer fracturing can increase the gas productivity of individual well greatly and achieve obvious economic benefits, which provided a good example for separate layer fracturing and the gas production in similar multilayer gas reservoirs.