四川盆地页岩气水平井B环空带压原因分析与对策  

Causal analysis and countermeasures on B sustained casing pressure of shale-gas horizontal wells in the Sichuan Basin

作　　者：陶谦 陈星星[3] TAO Qian;CHEN Xingxing(State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development, Beijing 100101, China;SINOPEC Research Institute of Petroleum Engineering, Beijing 100101, China;SINOPEC Chongqing Fuling Shale Gas Exploration and Development Co., Ltd., Fuling 400020, Sichuan, China)

机构地区：[1]页岩油气富集机理与有效开发国家重点试验室 [2]中国石油化工股份有限公司石油工程技术研究院 [3]中石化重庆涪陵页岩气勘探开发有限公司

出　　处：《石油钻采工艺》2017年第5期588-593,共6页Oil Drilling & Production Technology

基　　金：国家重大专项示范工程"彭水地区常压钻井及高效压裂工程工艺优化技术"(编号:2015ZX05069-002);中石化科技攻关项目"改善天然气井水泥环长期密封性技术研究"(编号:P14112)

摘　　要：四川盆地页岩气井环空带压井比例较高,对气藏高效开发和气井井筒完整性带来了挑战。通过对国内页岩气开发区块环空带压实际情况的具体分析,运用同位分析方法确定气体来源,采用物理模拟试验方法开展页岩气井环空带压机理研究,明确了不同水泥浆体系下压裂过程中水泥环密封失效规律,形成了改善水泥环密封性能、缓解分段压裂井环空带压现象的关键技术:在浆柱结构完全满足密封要求的基础上,利用相间填充技术和降低水泥石孔隙度方法,开发出低孔隙度低弹性模量水泥浆体系,弹性模量低至4.2 GPa,相比常规水泥石35%的孔隙度,孔隙度降低27.1%,水泥石弹性变形能力大幅提升。现场5口井的应用实践证明,固井质量优质率达到100%,且未发生环空带压现象,对环空带压的控制具有良好的借鉴作用。In the Sichuan Basin,the percentage of shale gas wells with sustained casing pressure(SCP)is higher,bringing about the challenges to the efficient development of gas reservoirs and the wellbore integrity of gas wells.In this paper,the actual SCP situations in domestic shale gas development blocks were analyzed specifically.The gas source was determined by using the isotope analysis method,and SCP mechanisms of shale gas wells were studied by means of physical simulation experiment.Accordingly,the failure laws of cement sheath in different cement slurry systems in the process fracturing were figured out,and the key technologies to improve the sealing capacity of cement sheath and relieve the SCP phenomenon in staged fracturing wells were developed.When the cement slurry column can structurally satisfy the sealing requirement completely,a cement slurry system of low porosity and Young’s modulus was developed by means of the interphase filling technique and the set cement porosity decreasing method.Its Young’s modulus is only4.2GPa,and its porosity is27.1%(the porosity of conventional cement set35%).And the elastic deformation capacity of cement set is enhanced dramatically.The new cement slurry system has been practically applied in5wells.And its high-quality cementing rate is100%with no SCP.This research provides the good reference for SCP control.

关 键 词：环空带压 页岩气井 固井 水泥浆 分段压裂 

分 类 号：TE256[石油与天然气工程—油气井工程]