低渗透油层中单相液体渗流特征的实验研究

单相液体的渗流特征是油气渗流研究的基础问题,低渗油层中的渗流特征迄今研究尚少,这方面的研究对于低渗透油气田的开发具有理论及实际意义。本文总结了低渗透油层中单相液体渗流特征的实验研究结果,分别研究了蒸镏水、低浓度盐水和模拟原油通过天然岩心和人连岩心流动的渗流曲线特征,实验结果显示单相液体在低渗透岩心中渗流的特殊规律。在低渗流速度下流动为非线性,在较高渗流速度下为具有初始压力梯度的拟线性流动,在渗流速度由低到高的变化过程中,流动呈现非达西型的渗流特征,这种渗流曲线特征和岩心渗透率直接有关,当渗透率增大时(实验岩心渗透率为183.6×10~(-3)μm~2)出现达西流动情况。实验表明,这种非线性——线性非迭西型流动可能是低渗透油层中流体渗沆的基本特征。

A Laboratory Study on Percolation characteristics of Single Phase Flow in Low-Permeability Reserviors

Single phase flow characteristics are a basic problem in studying oil and gas flow in reservoirs. Few researches have ever been made on the characteristics of oil and gas flow in low-permeability reservoirs. Such research is very important in theory and practice for developing low-permeability reservoirs. This paper sums up the laboratory research results of single phase flow characteristics in low-permeability reservoirs and flow curves' characteristics of distilled water, low saline water and simulated crude oil which were made to flow through artificial and natural cores. The experiment results show a special law of single phase flow through low-permeabity cores. The single phase flow through low-permeability cores is non-linear one at lower percolation velocity, but it is a simulated linear flow with starting pressure being gradient at higher percolation velocity. When percolation velocity changes from low to high, the single phase flow shows non-Darcy's flow characteristics. This kind of the flow curves' characteristics is directly related to the core's permeability. As the permeability increases, the core permeablity in experperiments is 183.6×10~(-3)μm~2, the single phase flow changes into Darcy's flow. The experiments show that this kind of non-linear, linear and non-Darcy's flow may possess basic flow characteristics in low-permeability reservoirs.