中石油非常规储层水平井压裂技术进展

中国石油天然气集团公司(以下简称中石油)从2006年启动水平井改造专项攻关以来,水平井压裂技术实现了从无到有再到无限级段分段的跨越,2015年实现了最高分段数26段。10年间,中石油在非常规储层水平井压裂改造技术领域取得了突出进展:(1)自主研发了水平井双封单卡、封隔器滑套、水力喷砂和裸眼封隔器4套水平井压裂主体工艺技术;(2)自主研发了复合桥塞、套管固井滑套2项水平井大排量体积改造主体工艺技术,配套体积改造优化设计理论、压裂液体系、裂缝监测等技术,初步形成体积改造技术体系和水平井工厂化作业模式;(3)自主研发的压裂工具、液体体系等关键技术,不动管柱多级滑套水力喷砂分段压裂技术、液体胶塞分段技术等,达到了国际先进水平或同期国际领先水平。据统计,2014年中石油水平井分别占油井和气井总数的3.2%和13.1%,其对油田和气田产量的贡献率分别达到9.9%和39.7%。最后,指出了新区高密度完井压裂工程试验、老区老井体积重复压裂试验等中石油新一轮水平井改造技术的攻关重点方向。

CNPC's progress in horizontal well fracturing technologies for unconventional reservoirs

Horizontal well fracturing technology has been developed greatly from scratch to multi-stage fracturing since China National Petroleum Corporation (CNPC for short) initiated the research on horizontal well stimulation in 2006 with 26 stages achieved in 2015. Over the past decade, CNPC has made remarkable progress in horizontal well fracturing technologies for unconventional reservoirs. First, four sets of principal processes for horizontal well fracturing are developed independently, including double-packer and single-slip, packer sliding sleeve, hydraulic jet and open hole packer. Second, two principal processes for high-rate volumetric stimulation of horizontal well are independently developed, i.e., composite bridge plugging and cementing sliding sleeve, and the support optimal design theory of volumetric stimulation, fracturing fluid system and fracture monitoring technology are also established. And thus, the volumetric stimulation technology system and the factory-like horizontal well operation mode are preliminarily formed. Third, the independently developed key technologies of fracturing tools and liquid systems reach the advanced international level or the leading international level of the same year, such as the hydraulic-jet staged fracturing technology with multi-stage sliding sleeve in fixed string and the gel plug segmentation technology. Based on the statistics, horizontal wells account for 3.2% of oil wells and 13.1% of gas wells, and their contribution ratios to oil field and gas field output are 9.9% and 39.7%, respectively. Finally, it is pointed out that CNPC should take the fracturing engineering tests of high density completion and the volumetric refracturing tests in mature fields and old wells as the new research objects of horizontal-well stimulation technologies.