稠油油藏边水推进规律物理模拟实验

Physical experiment on edge water drive law of offshore heavy oil reservoir

在边水活跃的稠油油藏开发过程中,因边水侵入而导致油井含水率上升快、采收率低,开发效果较差。为认清稠油油藏边水推进规律,在明确其地质及开发特征的基础上,建立储层均质及非均质二维可视化物理模型,对单直井、双直井和单水平井3种不同井型开采条件下边水推进规律及其对剩余油分布的影响进行实验研究。结果表明:不同井型开采条件下,均质油藏边水均沿压力梯度最大处向油井推进,非均质油藏边水主要沿压力梯度最大处和高渗透区推进;相同井型开采条件下,均质油藏边水推进前缘较为明显,采出程度高于非均质油藏。双直井开采条件下,储层采出程度远高于单直井,即增加油井数有利于采出程度的提高;对比单直井和单水平井条件下储层采出程度,水平井具有更好的开采效果。

During the development process of heavy oil reservoir with active edge water, edge water invasion will cause the water cut of production well to rise rapidly and the consequent low oil recovery efficiency. In order to better understandings of edge water drive law of offshore heavy oil reservoir and its effects on remaining oil distribution, 2D visible physical models with different well-type have been built, which are based on geological characteristics and development features of offshore heavy oil reservoir. The experimental results are shown as follows. First, edge water primarily encroaches through the areas of maximum pressure gradient in homogeneous res-ervoir. However, for heterogeneous reservoir, edge water mainly encroaches through high permeability part and the areas with maximum pressure gradient. Meanwhile, in comparison with heterogeneous reservoir, a more distinct water/oil front and higher reserve recovery degree will be obtained in homogeneous reservoir under the same conditions. Second, there is a higher reserve recovery degree obtained by double vertical wells compared with single vertical well. Thus, increasing the number of production well is beneficial to the improvement of reserve recovery degree. Third, horizontal well has a better effect on reservoir development than vertical well.