平行水平井网水驱剩余油分布规律实验研究

海洋油田狭窄的开发环境与高开发成本，促进了水平井开发方式在海上油田注水开发中广泛应用。针对中国海上油田储层多为三角洲碎屑岩沉积，储层非均质性强，目前采用平行水平井网注水开发效果欠佳，大量剩余油存在的实际情况，采用水驱油物理模拟实验方法，研究了驱替速度和储层非均质性对平行水平井网水驱剩余油分布规律的影响。实验结果表明，均质储层中的采出程度较非均质储层高，剩余油分布于采油井趾部附近; 驱替速度的变化不会影响均质储层剩余油分布位置; 在渗透率级差不同的平面非均质储层中，级差大、储层高渗透带的渗透率较小的非均质储层见水晚，最终采出程度和平均驱油效率略高于级差小、渗透率较高的储层，剩余油均主要位于中、低渗透区采油井跟部—中部附近区域; 级差小，渗透率高的储层中剩余油分布于低渗透区采油井跟部附近区域。平行井网更适合在较低的驱替速度; 平行水平井网更适合于级差较大、储层渗透率最大值较小的非均质储层，该研究为油田水平井井网设计方案提供了理论和技术支持。

An Experimental Study on the Distribution of Residual Oil by Water Flooding in Parallel Horizontal Well Pattern

The narrow development environment and high development cost of offshore oil fields have promoted the wide application of horizontal well development methods in water injection development in offshore oil fields. In view of the fact that most of the reservoirs in China's offshore oilfields are delta clastic deposits with strong reservoir heterogeneity, the current parallel horizontal well pattern water injection development is not good in effectiveness, and a large amount of remaining oil remains underground. The effects of displacement velocity and reservoir heterogeneity on the distribution of remaining oil from water flooding in parallel horizontal well pattern are studied by means of water flooding physical simulation experiment. The experimental results show that the degree of recovery in homogeneous reservoirs is higher than that in heterogeneous reservoirs, and the remaining oil is distributed near the toe of the production well. The change of displacement velocity will not affect the distribution of remaining oil in homogeneous reservoir. In the plane heterogeneous reservoirs with different permeability contrast, the higher the stage difference is, the later the water breakthrough occurs in the heterogeneous reservoir with lower permeability in the high permeability zone, and the ultimate recovery degree and average oil displacement efficiency are slightly higher than those with small permeability contrast and high permeability zone. The remaining oil is mainly located in the area near the heel-central part of the production well in the middle and low permeability zones. The remaining oil in the reservoirs with small grade difference and high permeability value in the high permeability zone is distributed in the area near the heel of the production well in the low permeability zone. The experimental study has concluded that parallel well pattern conditions are more suitable for lower displacement speeds and parallel horizontal well patterns are more suitable for heterogeneous reservoirs with larger grade differences and smaller maximum reservoir permeability, which provides theoretical and technical support for the design of horizontal well pattern in oilfield.