延拓法在油气相平衡计算中的应用

THE APPLICATION OF CONTINUATION ALGORITHM TO CALCULATION OF PHASE EQUILIBRIUM OF RESERVOIR FLUIDS

用延拓法、经典的Newton算法和Broyden算法分别计算了四个实际油气体系的露点 (用PR方程 ) ,对同一体系的重馏分使用同样的临界参数 ,对比不同压力初值下这三种方法的迭代收敛情况。对同一体系同样的压力初值对比了改变重馏分的临界参数拟合实验露点时这三种算法的适应性。结果表明延拓法对初值要求低 。

Continuation ( or Homotopy) method was applied to calculate the dew-point pressures of four gas condensate systems under reservoir temperatures in comparing with Newton iterative method and Broyden method. The effects of initial iteration pressures on the convergence of dew-point pressures were studied based on the results from the three different methods. The Peng and Robinson equation of state was used for all calculations. The results showed that continuation method is an efficient algorithm for the phase equilibrium calculations of reservoir fluids.