考虑水平井筒压力损失的数值模拟方法

水平井在油气田开发中的应用越来越广泛,但现有的水平井数值模拟方法存在以下问题:对水平井的处理较为简单,多没有考虑流体在水平井筒内的压力损失,由此所得的模拟计算结果与实际水平井结果存在着较大的差距.本文针对这一问题,在直井黑油模型的基础上建立了考虑水平井井筒压力损失的数值模拟模型,编制了水平井数值模拟软件;模型中考虑了流体在水平井筒内流动时四种压力损失(包括摩擦损失、加速损失、混合损失和重力损失)的影响,软件还可模拟计算地层的各向异性;考虑水平井筒压力损失后所求解的为“加边七对角稀疏矩阵”,本文还寻求了一种新的解法——分块矩阵乘法结合预处理共扼梯度法,试算表明该方法具有较快的收敛速度.最后应用所研制软件,对影响水平井产能、井筒压力损失、井底流压的参数进行了对比计算和分析,其结果对实际水平井优化设计具有一定的指导意义.

THE METHOD OF RESERVOIR NUMERICAL SIMULATION WHEN CONSIDERING THE PRESSUREDROP ALONE THE HORIZONTAL WELL-BORE

The application of horizontal well technology has become wider in the developing of oil field.However there is a problem in the current methods of horizontal well numerical simulation:most of them do not consider the fluid pressure drop alone the horizontal well bore.So,it makes a relatively great deviation between the actual result of developing process and the result of numerical simulation.To solve this problem,we set up a new kind of horizontal well numerical simulation model in this paper,which based on the vertical well black oil simulation model.It considers the influences of 4 kinds of pressure losses when the fluid flows in the horizontal well bore (including well friction loss,acceleration pressure loss,mixture pressure loss and weight loss).The numerical simulation program based on the model can also deal with the anisotropic formation.Because the relevant matrix is a "seven diagonal sparse matrix with an attached column" when we consider the pressure drop alone the horizontal well bore,we develop a new mathematical method,which is called "partitioned matrix multiplication combined with preliminary treatment of conjugate gradient".The trial solution of this method has indicated a faster convergence rate.By the numerical simulation program,we correlate,compute and analyze the factors that influence the horizontal well production,pressure loss alone the well bore and flowing bottomhleo pressure.According to the results,we can give suggestions to the optimum design of the horizontal well.