四川盆地什邡气田浅层砂岩储层改造的难点及对策  

Difficulties and countermeasures in shallow sandstone reservoir reconstruction in the Shifang Gas Field,Sichuan Basin

作　　者：刁素[1] 栗铁峰[1] 勾宗武[1] 朱礼平[1] 

机构地区：[1]中国石化西南油气分公司工程技术研究院

出　　处：《天然气工业》2013年第2期52-55,共4页Natural Gas Industry

基　　金：国家科技重大攻关专项"四川盆地低渗气藏储层改造工艺技术研究"(编号:2011ZX05002-004-003)

摘　　要：四川盆地什邡气田浅层砂岩储层加砂压裂施工压力异常、压后增产效果较差,剖析其原因主要是:水锁伤害严重,多裂缝等近井效应明显,主缝延伸困难,压裂液效率低,有效缝长较短。针对上述问题,提出以下对策:优化压裂液配方,提高润湿接触角,降低毛细管力,同时采取针对性的工艺措施:小排量起裂,较早的支撑剂段塞技术,中—低排量控制缝高延伸,配合纤维网络携砂改善支撑剂沉降剖面和液氮助排等高效返排工艺。试验井的应用结果表明:前置液阶段初期支撑剂段塞入地后监测压力变得平稳,15h返排率64.4%,最终返排率72.5%,压后井口油套压6.7MPa下测试产气量为8.4×104 m3/d,增产效果显著。该技术措施在多口井推广应用,增产效果较工艺改进前有较大幅度的提高,可为类似气藏的开发提供技术支持。This paper aims to offer solutions to the problems of abnormal pressure in the sand fracturing operation and poor yield increasing result achieved by fracturing treatment in the shallow sandstone reservoirs of the Shifang Gas Field, Sichuan Basin. Such main reasons are first summarized through a thorough analysis as severe water lock damage, obvious well proximity effect （e. g. multiple fractures）, difficulty in main fracture extension, low efficiency of fracturing fluids, and short length of effective fractures. Ac cordingly, the fracturing fluid formula is optimized, the wet contact angle is enlarged, and capillary force is decreased. Meanwhile, some specific technical measures are taken, namely, high-efficiency flowback technologies, including fracture initiation at a small discharge capacity, adoption of earlier slug by proppant, controlling fracture height extension with a medium- and low-discharge capacity, improving proppant settling section with coordination of a sand-carrying fiber net, and liquid nitrogen cleanup. According to the application results of pilot test wells, the monitoring pressure became stable after the proppant slug was set at the earlier preflush stage. The fracturing liquid flowback rate was 64.4~ in 15 h and the final flowback rate 72.5~. As a result, the yield in the post frac production test of a well was 8.4 × 10^4 m3/d under the wellhead oil casing pressure of 6.7 MPa. After the above technical meas- ures were widely used in many wells, their yield has been significantly increased. In conclusion, this study provides a technical sup- port for similar gas reservoir exploration and development.

关 键 词：四川盆地 什邡气田 致密储集层 压裂(岩石) 水锁 多裂缝 纤维 液氮 现场应用 

分 类 号：P618.13[天文地球—矿床学]