元坝气田HF-1陆相深层页岩气井分段压裂技术及效果

陆相深层页岩储层的改造难度比普通浅层页岩储层更大,其主要的改造措施是以水平井加上大型分段压裂为主。元页HF-1井便是四川盆地元坝气田的1口陆相超深页岩气水平探井,完钻斜深4 982m,垂深3 661.80m。为此,在分析陆相超深页岩储层改造技术难点和试验研究的基础上,优选出一套适用于本井储层改造的技术方案:采用自主研发的复合压裂液和压裂工艺技术,进行大排量、高砂比、大砂量、多级可钻式桥塞封隔分段压裂改造。除第一段采用连续油管射孔、光套管压裂外,后续各段均采用地面泵送"电缆+射孔枪+可钻桥塞"工具串,入井至预定位置,电缆点火座封、桥塞丢手后上提射孔枪至射孔位置进行射孔,随后进行分段压裂,施工结束后快速钻掉桥塞进行测试。现场实践结果表明:超深页岩气储层压裂达到了"一天两段压裂"的目的,刷新了施工排量最大、单段加砂量最大、平均砂比最高、钻塞时间最短等17项国内页岩油气井压裂作业施工技术指标。该井的储层改造成功为以后国内深层页岩气水平井实施大型分段压裂改造积累了技术及现场施工经验。

Staged fracturing technologies for continental ultra-deep shale gas wells and their effects:A case study of Well HF-1 in the Yuanba Gas Field,Sichuan Basin

Compared with common shallow shale gas reservoirs, the simulation technologies for continental ultra-deep shale gas reservoir are much more complex, and one of the main stimulation measures is horizontal well drilling plus large-scale staged fracturing. Well HF-1 is a continental ultra-deep horizontal prospecting well in the Yuanba Gas Field, Sichuan Basin, and its drilled oblique depth is 4 982 m and vertical depth is 3 661.8 m. For this reason, based on an analysis on technical difficulties in continental ultra-deep shale reservoir simulation and experimental studies, an optimal technical proposal was made suitable for shale reservoir simulation, and the self-developed composite fracturing fluid and fracturing technologies were taken to conduct staged fracturing simulation with large displacement, high sand ratio, large sand amount, and multi-stage drillable bridge plug packers. The fracturing at the first stage was conducted with coiled tubing perforation and light drive pipe. In the follow-up stages, the "cable+perforating gun+drillable bridge plug" tool string was first pumped from the ground to the predetermined position in the well; secondly, cables were used for ignition, a packer was set down and sealed, a bridge plug was released, and a perforating gun was lifted up to the position for perforation; thirdly, staged fracturing was conducted and a test was made after a rapid drilling-off of the bridge plug upon the completion of project. Field practices show that the fracturing of ultra-deep shale gas reservoirs realized the purpose of the "two-stage fracturing per day" and renewed 17 technical indicators of domestic shale oil and gas well fracturing operation, including the largest displacement, the maximum single-section sand amount, the highest average sand ratio, and the shortest drill-out time. The success of Well HF-1 has provided technical and field construction experience for the large-scale staged fracturing of horizontal wells in domestic ultra-deep shale reservoirs.