摘要
控压钻井技术能够控制地层流体侵入井眼,有效解决窄密度窗口等钻井工程问题。通过建立一维非定常流动模型,并利用有限差分法求解,发现控压钻井中不宜将气侵速率控制过高,否则不利于岩屑携带;井口回压对接近井口位置的气体膨胀影响较大,所施加井口回压值应考虑井筒含气率变化引起的钻井液柱压力变化;施加的井口回压能够有效控制井底压力,从而控制井底气侵速率。结合现场资料进行模拟计算,与现场实测结果进行对比分析,验证了模型的适用性。
Managed Pressure Drilling（MPD） technology can prevent formation fluid invading wellbore, and it can solve drill- ing problems such as narrow density window effectively. By the establishment of one-dimensional unsteady flow model, a fi- nite difference method was used. The result showed that it was unfavorable to limit high speed of gas invasion, otherwise it would be disadvantageous to carry cuttings. Wellhead back pressure had a great impact on the gas expansion of well head, and the imposing wellhead back pressure value should consider the changes of drilling fluid column pressure caused by the changes of wellbore gas rate. Wellhead back pressure could effectively control the bottom hole pressure, so gs to control the gas cut speed. Combined with field data, the simulation was calculated. And compared the measured results with the analysis, the applicability of the model was verified.
基金
国家自然科学基金(51274168)
国家重点基础研究发展计划(973项目)(2013CB228003)资助
关键词
控压钻井
井口压力
多相流动
压力控制
Managed Pressure Drilling
wellhead pressure
multiphase flow
pressure control
