丁山区块常压页岩气压裂认识及实践  

Understanding and practice of fracturing in normal-pressure shale gas,Dingshan block,Sichuan Basin

作　　者：林孝礼 周向东[1] 支林 邓翔元 LIN Xiaoli;ZHOU Xiangdong;ZHI Lin;DENG Xiangyuan(Petroleum Engineering Supervision Center,Sinopec Southwest Oil&Gas Company,Deyang,Sichuan 618000,China)

机构地区：[1]中国石化西南油气分公司石油工程监督中心,四川德阳618000

出　　处：《天然气技术与经济》2024年第6期7-14,共8页Natural Gas Technology and Economy

摘　　要：针对四川盆地盆缘丁山常压气藏压裂裂缝复杂度低且缝控储量不足、压后排液难产能释放慢、可采储量低效益开发难三项技术挑战,以改造区储量充分控制、减轻排液负担及降低改造成本为目标,研究形成了以极限限流射孔促均衡技术、压-排一体化综合降负技术为主的技术措施和“减阻剂+助排剂”简易配方为降本措施的丁山盆缘常压页岩气高效低成本改造工艺。研究结果表明:①采用“极限限流射孔”保证多簇均匀起裂,单段覆盖率由75%提高至90%,改造体积较前期提高15%;②通过“压-排一体化综合降负技术”降排液负担,优化用液强度15~20m^(3)/m,加砂强度1.5~2.0m^(3)/m,配套压后不闷井快速开井排液、初期即下油管、气举助排等手段能够保障改造体积同时实现储层产能释放;③采用“低伤害低成本压裂液体系”,能够在储层改造需要的前提下有效控制成本。实践证明,2022-2023年新一代常压气藏低成本高效压裂技术已推广实施6井次,较前期实施井改造效果提高60.2%,压裂成本降低15.3%,为后续低品位常压储层规模效益开发提供了经验。Normal-pressure gas reservoirs in Dingshan block along the margin of Sichuan Basin are confronted with technical challenges,i.e.,low fracture-induced complexity giving rise to shortage of fracture-conditioned reserves,inconvenient post-fracturing drainage creating slow productivity release,and small recoverable reserves and difficult benefit development.With three objectives of addressing these challenges,such as the adequate reserve control in stimulation areas,and the reduction of both drainage load and stimulation cost,an efficient stimulation process with low cost,which the extreme limited-entry perforation to promote equilibrium and the integrated fracturing and drainage for composite load reduction are conducted as the dominant measures,and the simple formula of"drag reducer+cleanup additive"is used for cost reduction,has been developed for the normal-pressure shale gas in this block.Results show that(i)the extreme perforation can ensure the uniform initiation of fracture clusters,enhance the coverage rate from 75% to 90% in single-stage fracturing,and make the stimulated reservoir volume(SRV)by 15% higher than before;(ii)the drainage load is released through the composite load reduction,and the intensity of both fracturing fluid and proppant is optimized to be 15-20 m^(3)/m and 1.5-2.0 m^(3)/m,respectively.The rapid startup and drainage after fracturing without shut-in,running tubing during the initial fracturing,and gas lift cleanup can release the productivity while SRV assurance;and(iii)the fracturing-fluid system with low damage and cost can cut down the cost under such stimulation.Practice has proven that,after the application of this new low-cost fracturing technology to normal-pressure gas reservoirs by 6 well times from 2022 to 2023,the stimulation effect is improved by 60.2% and the fracturing cost reduced by 15.3%,respectively,which may provide successful experience for the subsequent large-scale benefit development in the low-grade reservoirs with normal pressure.

关 键 词：四川盆地盆缘 丁山常压页岩气藏 下志留统龙马溪组 低成本高效压裂 限流射孔 压排一体 降本 

分 类 号：TE377[石油与天然气工程—油气田开发工程]