中东低渗透碳酸盐岩油藏多层水驱物理模拟

Physical simulation for multi-layer water flooding of low permeability carbonate reservoir in the Middle East

为研究中东某低渗透碳酸盐岩油藏在不同驱替方式时的渗流机理,提高各类油层的动用程度,开展了3种不同驱替方式的水驱油物理模拟实验。选取2组不同渗透率级别的岩样,针对1-1号和2-1号岩样进行2层合注分采实验,1-2号和2-2号岩样进行分注合采实验,1-3号和2-3号岩样进行常规单层注采实验,并结合低磁场核磁共振技术,分析了不同注采模式时微观孔隙结构的开发效果。实验结果表明,同一注采方式时,不同岩样的含水率和最终采收率差距很大,低渗透层采取合注分采时的采出程度高于单层注采,高渗透层采取单层注采时的采出程度高于合注分采,分注合采时的采出程度相差不大。核磁共振数据还表明,原油主要分布在大孔喉半径范围内,经过水驱之后,动用的主要是大孔喉范围内的原油,小孔喉半径部分内的原油主要是通过渗吸作用得到动用。

To study the percolation mechanism of different low permeability carbonate reservoirs in the Middle East under various injection-production patterns, and increase the production degree of all types of oil layers, three different injection-production pat- terns of water flooding physical simulation experiments were carried out. Two groups of rock samples with different permeability grade were selected. For 1 1 and 2-1 rock samples, two layer injection production experiments were carried out. Rock samples No. 1-2 and No. 2-2 were used to separate injection and production. Rock samples No. 1-3 and No. 2-3 were injected into the conventional single layer injection production test. In addition, combining with nuclear magnetic resonance （NMR） technology, the production effectiveness of microscopic structure in different injection production modes was analyzed. The results show that for the same injection-production pattern, the moisture content and ultimate recovery degree of different permeability samples are very different. Low permeability rock hashigher recovery degree while launching co injection and separate production patterns than single layer injection and production, nevertheless high permeability rock hashigher recovery degree while launching single layer injection and production patterns. NMR results indicate that most oil distributes in large pores, and the driven oil also distributes in large pores, the oil in small pores is employed by imbibition.