TP2CX超深开窗侧钻中短半径水平井钻井技术

新疆沙雅地区奥陶系中统一间房组油气藏埋深超过6 900 m,未知因素多、钻井难度大、成本高。为此,在TP2井基础上套管开窗侧钻完成了1口评价井——TP2CX中短半径水平井。该井钻进中遇到开窗点超深、地层可钻性差、小井眼泵压高、深井测量信号传输困难、地层温度高、设计油藏埋深累计误差较大等技术难点。为此,对设计的井眼轨道进行了修正,采用卡瓦坐封式斜向器进行开窗作业,选择适合小井眼和耐高温的无线随钻仪器、螺杆钻具,优化了钻井参数,选择了钻头,调整了钻具组合,形成了适用于超深开窗侧钻中短半径水平井的钻井技术。TP2CX井设计井深7 305.33 m,全角变化率78.40°/100m,水平位移465.85 m;轨道修正后全角变化率为66.67°/100m,实际开窗点井深6 789.42 m,完钻井深7 453.00 m,水平位移565.88 m。该井实现了超深开窗一次性成功,有效解决了油藏埋深误差较大的问题,避免了在超深井中无线随钻仪器和螺杆钻具易失效而引起的起下钻作业,比设计钻井周期缩短26 d,提高了钻井时效,大大降低了钻井成本。 

Drilling Technology of Ultra-Deep Sidetracking in Medium/Short Radius Horizontal Well TP2CX

The depth of Ordovician oil and gas reservoir in Xinjiang Shaya region is more than 6 900 meters.There are many uncertain factors at such depth,making drilling difficult and highly costly.So the ultra-deep sidetracking medium/short radius horizontal Well TP2CX was drilled after Well TP2.There are many technical difficulties,such as ultra-deep casing sidetracking,poor drillability,high pump pressure in slim hole,difficult transmission of measured signal in deep hole,high formation temperature and the big error in well depth design.In view of these difficulties,the wellbore trajectory design of Well TP2CX was modified,whipstock was used for the casing sidetrack,special MWD and PDM were chosen to adapt the slim hole and high temperature,drilling parameters were optimized,the bits were chosen and drilling string was adjusted to form the drilling technology which is suitable for ultra-deep sidetracking medium/short radius horizontal well.Well-bore trajectory design of Well TP2CX:total depth 7 305.33 m,BUR:78.40°/100m,horizontal displacement 465.85 m.The modified well-bore trajectory design of Well TP2CX: BUR 66.67°/100m;total depth 7 453.00 m,horizontal displacement 565.88 m.The technology used in Well TP2CX was very successful for ultra-deep casing sidetrack,effectively solved the issue of the reservoir depth error,avoided unnecessary tripping because of MWD and motor failure,shortened drilling cycle by 26 days,improved ROP,and reduced drilling cost.