关键词: 非达西渗流, 压力分布, 导压阻滞系数, 启动压力梯度, 低渗透储层

Abstract:

There exist differences in the pressure propagation law of the low-velocity non-Darcy flow and Darcy flow due to the presence of a starting pressure gradient. The present paper established a model of the non-Darcy flow under conditions of both the fixed bottom-hole pressure and the fixed flow capacity by using a method of steady-state successive approach to unsteady-state solution, and examined pressure-propagation characteristics of the low-velocity non-Darcy flow under the above-mentioned conditions. The study defined a pressure-conductivity retardation coefficient, which was used to representing the effect of the starting pressure gradient on the speed of pressure propagation, namely the greater the coefficient, the longer the time required for the pressure propagation within a given distance. The speed of pressure propagation, however, could be accelerated by increasing liquid yield. Different from the Darcy flow, low permeability reservoirs have a limiting radius, to which once the distance of pressure propagation reaches, pressure is no longer propagating.

Key words: non-Darcy flow, pressure distribution, pressure-conductivity retardation coefficient, starting pressure gradient, low permeability reservoir