冲洗液安全密度窗口的实验模拟及有限元分析

Experimental Simulation and Finite Element Analysis on Safe Density Window of Flushing Fluid

摘要:

在钻探工程中，冲洗液的密度选择至关重要。密度过大有助于护壁和悬渣，但会增大钻进阻力；密度过小，则会降低其悬渣能力，并影响钻孔稳定性。在孔壁稳定性力学分析的基础上，自行建立试验模拟装置进行井壁稳定性模拟。与此同时，采用有限元方法来模拟钻孔稳定问题，得出合理的冲洗液安全密度窗口。对比结果表明，利用ANSYS有限元分析软件模拟来确定冲洗液安全密度窗口具有一定的可行性。利用有限元模拟分析既可以缩减前期冲洗液的试验费用，又能给钻探提供合理的冲洗液安全密度窗口，对优化冲洗液的密度具有现实的参考价值。

Abstract:

Flushing fluid’s density is very important in the drilling project. Large density is helpful for wall protection and dreg suspension but will increase drilling resistance at the same time; while too small density will reduce the capability of dreg suspension and influence the stability of wellbore. Based on the mechanical analysis on the borehole stability, simulation device was established to simulate the stability of borehole wall. Meanwhile, the stability of wellbore was also simulated by finite element method to obtain the reasonable safe density window of flushing fluid. Comparison results show certain feasibility of simulation using ANSYS finite element analysis software to determine the safe flushing fluid density window. Using finite element simulation analysis not only can reduce the cost of flushing fluid test in earlier stage, but also can provide the safe density window of flushing fluid, which has practical reference value to optimize the density of flushing fluid.