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控压钻井技术是当前油气钻井工程领域的前沿技术之一。钻井各个工况的井底压力须保持恒定,才能确保窄密度窗口复杂地层井段的安全、顺利钻进。为此,通过分析前人对各个工况井底压力计算的研究成果,提出了精细控压钻井井底压力计算模型,该模型的环空循环压耗计算包含了多相流动的重力压降、摩阻压降和加速度压降梯度。在塔里木盆地实施了1口井的精细控压钻井作业,用停泵工况由地面回压泵施加的回压值与计算值比较,最大误差为0.30MPa,能满足工程实际需要,为今后精细控压钻井井底压力精确计算与控制提供了理论支撑。
Managed pressure drilling technology is currently one of the leading technologies in the field of oil and gas drilling engineering. Bottomhole pressure in each working condition of drilling must be kept constant, so as to ensure the safety and smooth drilling of the complicated strata in the narrow density window. Therefore, by analyzing the previous research results of bottomhole pressure calculation for each working condition, a bottom hole pressure calculation model for fine controlled drilling is proposed. The calculation of annulus circulating pressure loss includes the gravity pressure drop of multiphase flow, Frictional pressure drop and acceleration pressure drop gradient. In the Tarim Basin, a controlled well drilling operation was carried out. Compared with the calculated value, the maximum back pressure applied by the surface pump in the stopping pump condition was 0.30MPa, which can meet the practical needs of the project. It provides theoretical support for accurate calculation and control of bottom hole pressure in pressure-controlled drilling.