超低渗透油藏分层注水数值模拟研究及应用

Numerical simulation of separated layer water injection for ultra- low permeable reservoirs

超低渗透油藏非均质性强,层间吸水能力差异大,注入水在油层平面和剖面上分布不均匀,分层注水时各层位配注水量标准不明确,部分井分层注水后对应油井不见效。为此,从油藏工程的角度出发,在两层不同渗透率级差砂体条件下,利用数值模拟方法,确定了超低渗透油藏开发初期注水方式选择标准,绘制了不同渗透率级差储集层合理的分层配水图版。不同渗透率级差储集层存在最佳配注比,渗透率级差越大,低渗透层需要分配的注水量越大,两层之间的最佳配注比与渗透率级差成对数关系。

There are strong heterogeneity, large difference in interlayer water adsorption ability, non uniform distribution of injected water in the plane and vertical direction ,unclear standards of water allocation of each layer at separated layer water injection, and no effective response of corresponding wells after the separated lay water flooding of some wells in ultra - low permeability reservoirs. From the viewpoint of reservoir engineering, under the condition of two - layer sandbodies with various permeability ratios, the selection criteria of water injection mode was determined at initial stage of develop- ment, and the charts of reasonable water allocation for reservoirs with various permeability ratios were plotted by adopting numerical simulation. The simulation results showed that there is an optimal ratio of water allocation for reservoirs with vari- ous permeability ratios;the larger the permeability ratio is, the bigger the water injection volume of low permeability layer is;the optimal ratio of water allocation of two layers changes in logarithm relation with permeability ratio.