关键词: 低渗透油藏, 启动压力梯度, 两相流, 增维精细积分法, 状态方程

Abstract:

The simulating analysis of two-phase oil-water flows in a low permeability reservoir was carried out by an increment-dimensional precise integration method. First of all, the state equation denoted with the pore fluid pressures at mesh nodes were established based on finite difference principle. Secondly, the recurrence formulae of pore fluid pressures and moisture saturations at mesh nodes were built up according to the increment-dimensional precise integration method . Finally, the simulation of two-phase oil-water coupled flows for a typical five point area water injection as an example was carried out by means of the increment-dimensional precise integration method and IMPES, respectively. Results show that the data required by the increment-dimensional precise integration method are in good accordance with those by IMPES, and the increment-dimensional precise integration method is reliable. At the same time, the effective law of startup pressure gradients on  water cut and oil production has been investigated. Results show that the startup pressure gradients have an outstanding effect on water cut and oil production, and the existence of the startup pressure gradients will enhance the difficulty of oil development.

Key words: low permeability reservoir, startup pressure gradient, two-phase flow, increment-dimensional precise integration method, state equation