摘要
××井桥塞座封于井浅处,下桥塞前下层测试时井口最高关井压力达到46.8MPa,桥塞下部气体的上顶力达85.4t。由于钻具重量远远低于下部气体产生的上顶力,靠泥浆液柱压力来平衡该力不可行,在钻桥塞与下部井筒连通瞬间,下部压缩高压气体瞬间释放将会出现一个极大的上顶力推动井内钻具急速上行,给地面井控工作带来极大的困难和风险。同时受井控要求限制,钻扫参数选择余地小,钻扫时加钻压困难,钻扫桥塞时间长;且套管磨损加剧,影响正常井控。通过对井口装置及施工工具的优化选择,确定了一套合理的施工工艺方案,确保了此次欠平衡钻磨桥塞成功完成,为以后类似井况的施工积累了宝贵经验。
Bridge plug of one well is set at shallow position. The maximum shut-in pressure at wellhead reaches 46.8MPa before setting the plug. And gas uplifting force under bridge plug is 85.4t. Because the weight of drilling tool is much lower than the uplifting force, it's impossible to balance the force by mud column pressure. While instantly connecting with wellbore by drilling through bridge plug, the released compressed high-pressure gas will cause a strong force to push drilling tool up with a great speed. That brings big problem and risk to ground well control. Moreover, due to the restriction of well-control requirement, there are fewer choices for drilling sweeping parameters and increasing drilling pressure. Also, there exists long sweeping time and severe casing wear-out. Through optimizing wellhead equipments, a feasible plan has been established to ensure the success of unbalanced drilling bridge plug and then offer an experience for similar cases.
出处
《天然气勘探与开发》
2010年第1期76-79,共4页
Natural Gas Exploration and Development
关键词
欠平衡
钻磨桥塞
井控
防喷器
underbalanced, drilling bridge plug, well control, blowout preventer
