四川盆地长宁地区页岩气水平井组“拉链式”压裂实践

Application of zipper fracturing of horizontal cluster wells in the Changning shale gas pilot zone,Sichuan Basin

经过几年的探索和实践,在四川长宁—威远国家级页岩气示范区内相继完成一批直井和水平井体积压裂改造并获得工业产能,初步形成了自主页岩气储层改造技术,下一步需要探索解决的就是如何通过"工厂化"模式来提高压裂作业效率的问题。为此,介绍了我国第一个页岩气丛式水平井井组长宁A平台的部署情况,针对该平台压裂改造工艺要求和四川盆地山地地形特点,对该平台"工厂化"作业模式进行了优化设计,在国内首次采用"拉链式"压裂作业模式对该平台开展了"工厂化"压裂。通过地面标准化流程、拉链式施工、流水线作业和井下交错布缝、微地震实时监测,实现了每天平均压裂3.16段,最大限度增加储层改造体积,充分体现了"工厂化"压裂对页岩气丛式水平井平台大规模体积压裂改造的提速、提效作用。同时还针对该井组"拉链式"压裂的施工工艺、作业模式、地面配套以及压后初步评价进行了综合研究分析,"拉链式"压裂实践表明:2口井的"拉链式"压裂相对于该地区前期水平井单井压裂作业而言,效率提高78%、增产改造体积增加了50%。

After several years of exploration practices in the Changning-Weiyuan national-level shale gas pilot zone, industrial production has been achieved in a number of vertical and horizontal wells completed by SRV fracturing and stimulation, and a series of independent shale gas reservoir stimulation technologies were initially developed. The next step is to continue to explore a factory-like model to improve the efficiency of fracturing operation. Therefore, this paper introduced the deployment of Changning Platform A, the first cluster horizontal shale gas well group, and the design optimization conducted for the factory-like operation model of this platform according to the requirements for platform fracturing stimulation technologies and the landform characteristics of Sichuan mountainous areas. On this basis, a zipper fracturing model was first proposed for factory-like fracturing of the platform. In combination with standard field facilities, zipper fracturing, assembly line work, downhole fracture staggered arrangement, and microseismic monitoring in real time, 3.16-section fracturing was averagely completed every day, maximizing the stimulated reservoir volume and fully reflecting the performance of factory-like fracturing in improving the speed and efficiency of the large-scale SRV fracturing of shale gas cluster-well platform. Moreover, we systematically researched and analyzed the construction process, operation model, ancillary ground facilities and post-fracturing initial evaluation of the zipper fracturing in the well cluster. Finally it was concluded that the zipper fracturing in the two wells increases the efficiency by 78 % and stimulated reservoir volume by 50 % compared with the single-well fracturing at the preliminary stage in this area.