元坝124井超深井钻井关键技术

Key Drilling Technique Used in Yuanba-124 Ultra-deep Wells

元坝地区地质因素复杂,存在陆相地层厚度大、砂泥岩互层频繁、可钻性差以及自流井组-须家河组地层超高压、压力窗口窄等特点,所钻井普遍存在溢流、井漏、垮塌等复杂和事故,机械钻速低,施工周期长。元坝124井是元坝地区的一口重点预探井,钻井过程中先后实践应用了气体钻井、控压钻井等多项新技术,创造了元坝区块钻井周期最短、机械钻速最高等多项记录。除了我国超深井自身气体钻井、控压钻井技术水平较以前有了大幅度提升外,下部陆相地层引进了Smith公司"孕镶金刚石钻头+涡轮钻具"技术、海相地层应用了"国民油井抗高温螺杆+贝克休斯高效PDC钻头"复合钻井,显著提高了机械钻速,有效缩短了该井钻井周期。该井平均机械钻速2.8m/h,钻井周期253.84d,是目前元坝地区钻井周期最短的一口。

Geological conditions in Yuanba Area were complicated,such as thick terrestrial formation,frequent glutenite interbedds,poor drill-ability,overpressure and narrow pressure window in Ziliujing-Xijiahe Formation.Complex cases and accidents like overflow,lost circulation and well collapse were often induced during drilling.Well Yuanba-124 was an exploratory well in the area.Gas drilling,pressure-controlled drilling,etc.were used during the drilling of Well Yuanba-124.New records were set up for shortest drilling cycle,the highest ROP,et al.The key point is that compound drilling with impregnated diamond bit plus turbodrill of Smith Company is introduced by using the lower terrestrial formation and compound drilling with Anti-high Temperature Screw of National Oil Wells plus HCD506ZX PDC bit of Baker Hughes was used in marine reservoirs.ROP was improved and tripping times were shortened,so drilling cycle was shortened greatly.The average ROP is 2.8m/h,and the drilling cycle is 253.84d,it is the well with the shortest drilling time in Yuanba Area.