滇东地区页岩气调查云宣地1井钻探施工难点及对策

Drilling difficulties and solutions for Well Yunxuandi-1 for shale gas survey in eastern Yunnan

摘要:

云宣地1井是滇东地区一口小口径页岩气调查井，该井主要钻遇了寒武系、泥盆系、石炭系及二叠系地层。钻探施工过程中遇到了恶性漏失、裂缝性漏失、岩石挤压破碎及井内掉块等井下复杂情况。通过钻头优选、钻井液优化、多种堵漏措施相结合、顶漏钻进及侧钻施工技术等针对性措施，解决了大套灰岩地层因大型溶洞或纵向裂隙发育而引起的恶性漏失、井内掉块等问题，避免了钻井液密度过大而导致井壁失稳的井下复杂情况的发生，提高了机械钻速，保证该井顺利完钻。该钻探施工经验可为后期滇东地区复杂灰岩地层钻探施工提供借鉴。

Abstract:

Well Yunxuandi-1， a small-diameter shale gas survey well in eastern Yunnan， was drilled through mainly Cambrian， Devonian， Carboniferous and Permian strata. In the process of drilling， a lot of complex downhole situations were encountered such as severe leakage， fracture leakage， rock breaking and stone falling. To this end， multiple relevant measures， such as drill bit and drilling fluid optimization， combination of various plugging measures， blind drilling， sidetracking， were adopted to solve the problems of severe leakage and block falling caused by large karst caves and longitudinal fractures in massive limestone formation， which avoided wellbore failure caused by excessive drilling fluid density， and improved mechanical efficiency. The drilling experience can provide reference for future drilling of complex limestone strata in eastern Yunnan.