压井动态过程的理论分析及模拟计算

THEORETICAL ANALYSIS AND SIMULATED CALCULATION OF DYNAMIC WELL CONTROL

文中的动态井控理论模型是以气体溢流进入井内同泥浆形成两相混合物并存于环空中为基础，考虑了气液两相流动不同流型下的气体滑脱速度以及气液两相流动摩阻的影响，用有限差分方法建立了求解动态井控理论模型的差分方程组，给出了求解的具体算法。通过模拟计算研究了地层压力、溢流时间、压井排量及环空尺寸等对压井操作及压井最大套压等的影响。经过与压井实际数据的对比表明动态井控理论的计算结果比纯气栓泵送模型更符合并控实际。

A tbeoretical mddel of dynamic well control estabished in this paper is based on the as-sumption that a gas-mud two phase mixture is formed when gas flows into the well at kicking. The effects of gas slip velocity and frictional pressure drop in every flow pattern of two phase flow are taken into account.The finite difference method is used in solving mathematical equations and the algorithm of solving this numerical model is given. Two grid systems are built to overcome the difficulties in well control simulation. The effects of formation pressure, kick volume,size of annulus and pump flow rate on killing operation and on the maximum casing pressure are studied by computer simulation. Compared with experimental kill data,this model yields a closer result to actual case than that of a pump-out model.