武隆浅层页岩气大位移水平井钻井关键技术

Key drilling technologies for large-displacement horizontal wells in shallow shale gas reservoirs of Wulong

摘要:

武隆浅层页岩气资源禀赋差，效益开发难，增加水平段长度或实施大位移水平井是提高单井产量的重要手段。针对浅层页岩气大位移水平井面临的井身结构优化难、钻具安全风险大、钻井液性能要求高、套管下入困难、完井漏失风险大等技术难题，开展了基于四压力剖面精准预测的井身结构优化、钻具安全延伸能力分析、适应浅层页岩的水基钻井液体系优选、套管下入方式优选及完井水泥浆柱结构优化研究，形成了浅层页岩气大位移水平井钻井关键技术。研究成果在PY1平台6口井进行了现场应用，平均井深3188 m，垂深1000~1200 m，水平段长1532~2250 m，水垂比1.59~2.64，平均机械钻速17.82 m/h，实现了优快钻井与安全成井，为武隆浅层页岩气区块效益开发提供了技术支撑。

Abstract:

Shallow shale gas resources in Wulong are poorly endowed and difficult to develop efficiently. Increasing the length of the horizontal section and drilling large-displacement horizontal wells are important means to increase the production of single well. In view of the technical difficulties faced by shallow shale gas large-displacement horizontal wells， such as difficulty in optimizing the casing program， high safety risk of drilling tools， high requirements for drilling fluid performance， difficulty in lowering casing， and high risk of well completion loss， we have carried out wellbore structure optimization based on accurate prediction of four pressure profiles， analysis of drilling tool safety extension capacity， optimization of water-based drilling fluid system suitable for shallow shale， optimization of casing lowering methods， and optimization of completion cement slurry column structure， forming key technologies for drilling large-displacement horizontal wells for shallow shale gas. The research results were applied on site in 6 wells of the PY1 platform， with an average well depth of 3188m， a vertical depth of 1000~1200m， a horizontal section length of 1532~2250m， a horizontal-to-vertical ratio of 1.59~2.64， and an average mechanical drilling speed of 17.82m/h. This achieved fast drilling and safe well completion， and provided technical support for the efficient development of the Wulong shallow shale gas block.