有效驱替理论在低渗透油藏中的应用分析

在低渗透油藏，注水井附近地层具有较高的注水压差，因而也具有较高的视渗透率。在生产井附近地层同样也具有较高的生产压差，和较高的视渗透率，可称为易流动半径。但是在低渗透储层中，易流动半径很小。而注采井问有很长的压力平缓段，压力梯度低，视渗透率也低，渗流能力很低，称为不易流动带，是影响低渗透油藏有效开发的主要因素。减小注采井距，在相同的压差下压力平缓段减小，压力梯度增大，视渗透率也有较大提高。在较高的压力梯度和较高视渗透率的双重作用下，渗流量会有较大的提高，水驱效果得到改善。为此，对低渗透油田适当减小注采井距，可以建立较大的驱替压力梯度和有效的驱油效果，能改善注水状况和采油状况，提高采油速度和最终采收率。

Application Analysis of Effective Displacement Theory in the Low Permeability Reservoir

In low permeability reservoirs, the strata near injection wells has high injection pressure,thus has high apparent permeability. Formation near the well in production also has high production pressure and high apparent permeability, can be called easily flow radius. However, in low permeability reservoirs, easy flow radius is very small. The injection wells and oil wells have a long fiat section of the pressure, the pressure gradient is low, as the penetration rate is also low, very low flow capability, known as the difficult flow zone, affecting the effective development of low permeability reservoirs. To reduce the spacing can decrease gentle pressure in the same section of the pressure difference, and increase the pressure gradient, the penetration rate can been improved greatly. In the high pressure gradient and the higher the dual role as the penetration, the seepage will be greatly improved, water flooding effect will also be improved. Therefore, to decrease injector spacing in the low permeability reservoirs can create a larger displacement pressure gradient and improve oil displacement effect, can also improve water injection status and production status to enhance oil recovery rate and ultimate recovery.