页岩气水平井固井技术难点与对策浅析

钟文力，洪少青，吕聪，张大翔，尹玺

(中国石化西南石油工程有限公司固井分公司，四川德阳 618000)

摘要：有效封固页岩产层，避免气体窜漏和稳定气井产量，是页岩气水平井固井的难题。在分析总结页岩地层特征、钻井施工条件及后期完井工艺特点的基础上，指出页岩气水平井固井技术难点主要集中在井壁的稳定性较差、套管安全下入难度大、套管居中度不高、油基钻井液驱替及界面清洗困难、顶替效率不高、后期大型压裂对水泥石性能要求高等方面。针对这些难点，从有效通井、扶正器合理安放保证套管居中、高效前置液技术、采用塑性水泥浆体系等几个方面提出了提高页岩气水平井固井质量的技术对策，为今后页岩气水平井固井提供借鉴。现场应用表明，该配套技术提高了水泥环的封固质量。

关键词：油基钻井液；页岩气；固井；塑性水泥浆

中图分类号:TE256

作者简介：第一钟文力(1987年生)，男，硕士研究生，助理工程师，2012年毕业于中国地质大学(武汉)，从事固井技术研究工作。邮箱：290941494@qq.com。

Difficulties and Countermeasures for Shale Gas Horizontal Well Cementing

Zhong Wenli, Hong Shaoqing, Lv Cong, Zhang Daxiang, Yin Xi

(CementingCompanyofSinopecSouthwestOilfieldServiceCorporation,Deyang,Sichuan618000,China)

Abstract：Effective sealing of shale gas layer to avoid gas leakage and stabilized gas production is difficult for shale gas horizontal well cementing. Based on analyzing and summarizing shale formation features, drilling conditions and characteristics of well completion technology at late stage, it was point out that difficulties in shale gas horizontal well cementing concentrated in poor sidewall stability, great difficulty in safe casing running, lower centering degree of casing, difficult displacement of oil-based drilling fluid and hard boundary washing, lower replacing efficiency, and high requirement of large-scale fracturing on cement paste performance, etc. Technical solutions for enhancing shale gas horizontal well cementing quality were proposed in terms of effective drifting, rational placement of stabilizer to guarantee casing centralizing, efficient preflush technique, and use of plastic cement slurry. All these could be reference to shale gas horizontal well cementing in future. Field application showed that the new technology could enhance cementing quality of cement ring.

Key words: oil-based drilling fluid; shale gas; cementing; plastic cement slurry

页岩气是一种重要的非常规天然气，在我国储量和产能潜力巨大[1，2]。由于页岩含泥质较多，具有易膨胀、易破碎，且储层孔隙度和渗透率低的特点，其完井方式通常是套管固井后射孔完井，采用多级分段压裂增产技术来提高页岩气气井产量，因此对固井技术要求很高[3-9]。

与常规固井相比，页岩气井固井除水泥浆性能要求高外，还需要安全下入长水平段套管和提高套管居中度，采用有效手段驱替油基钻井液及满足后期压裂要求。……