基于FLAC的疏松砂岩井眼安全钻井周期研究

Research on Safety Drilling Cycle in Unconsolidated Sandstone Reservoir Based on Fast Lagrangian Element Method

快速拉格朗日元法(FLAC)可以更好计算材料大变形、非线性、物理不稳定性等问题,能在疏松砂岩钻井过程中准确确定安全钻井周期,避免出现缩径、卡钻等事故。结合锦州20-2N油田岩心的实验数据,应用FLAC3D软件,最终得出如下结论:该油田井眼附近体积切应变速率的最大值在最大应力区产生,而体积切应变速率的最小值在与最大应力区成50°处产生;该区块安全钻井周期为30d,可以不考虑蠕变引起的钻井安全周期问题。

Fast Lagrangian Element Method(FLAC) can be better for solving nonlinear problems,large material deformation problems,physical instability problems and so on,it can be used to accurately determine the safety drilling cycle in unconsolidated sandstone reservoirs,to avoid shrinkage,sticking and other accidents.By using the data of core testing in Jinzhou 20-2N Oilfield and application of software FLAC3D,it is finally got that the maximum volume shear rate emerges in the maximum stress area as well as the minimum volume shear rate emerges at a 50-degree angle to the maximum stress area.The ultimate conclusion indicates that the safety drilling period in this block is 30 days,and the safety problem induced by screep is not to be considered.