双6储气库大尺寸注采井钻井技术

Drilling technique for large-diameter injection-production wells of the Shuang-6 Underground Gas Storage

为解决现有双6储气库注采井网无法满足高月调峰需求的问题,优化部署首批3口大尺寸注采井。针对大尺寸井高强度注采交变载荷影响、大井眼钻井液携岩屑能力弱、固井顶替效率低等技术难题,优化设计盖层井身结构,技术套管封隔盖层顶部,生产套管封隔盖层中部,Ø177.8 mm油层尾管半程固井封固盖层底部,提高了井筒完整性;采用连续岩屑称重技术实时监测岩屑返出量,降低井下事故风险;优选固井工具和施工参数,同时改善套管居中度提高固井质量,取得了良好的实践效果。超声波成像测井结果显示,已完钻的双6-H431井Ø339.7 mm技术套管的固井质量合格率为93.1%;Ø244.5 mm生产套管的固井质量合格率达到99.9%,盖层连续优质井段长达221 m,远高于储气库钻井行业标准。研究成果可为辽河储气库及国内其他储气库后续的大尺寸井钻井工程提供实践经验。

To deal with the incompetence of the current injection-production well pattern of the Shuang 6 Underground Gas Storage(UGS),the first three large-diameter injection-production wells were deployed.Given the intensive alternating load during injection and production,insufficient cutting-carrying of drilling fluids and low cement slurry displacement efficiency in large wells,optimize the design of the wellbore structure of the cover layer,seal the top of the cover layer with technical casing,seal the middle of the cover layer with production casing,and seal the bottom of the cover layer with a half way cementing of theØ177.8 mm oil layer tail pipe,improving wellbore integrity;the continuous cutting weighting was performed to monitor cutting return in real time and reduce risks of downhole accidents;the cementing tools and parameters were optimized and the casing centering was enhanced for better cementing quality.These efforts resulted in excellent effects in practice.The cement bond logging showed the cementing qualification rates of theØ339.7 mm intermediate casing andØ244.5 mm production casing of the drilled well Shuang 6-H431 reach 93.1%and 99.9%,respectively,and the high-quality cemented section along the caprock is 221 m long.These indicators are far higher than those specified in the industrial standard of underground gas storage.This research provides practical experience for drilling engineering of large-diameter wells in the Liaohe UGS as well as other UGS in China.