白云岩油藏低渗透条带对剩余油分布的影响

YM白云岩油藏已进入高含水开采期，如何寻找剩余油并进行挖潜是目前面临的重要问题。该类型储层中普遍存在低渗透条带，建立机理模型，通过对低渗透条带的渗透率、厚度、产状及与储层渗透率的组合关系进行敏感性分析，研究结果表明，渗流阻挡作用的强弱主要与其渗透率大小有关，当渗透率小于0.01 mD时，能够起到较好的渗流阻挡作用；同等条件下，厚度越大，渗流阻挡作用越强；根据分布形态与样式不同，对剩余油的控制程度I类> Ⅱ类> Ⅲ类> IV类；若有两条交错的低渗透条带，则对剩余油的控制程度V类> VI类。低渗透条带在一定生产时间内可以形成渗流屏障，成为控制剩余油分布的重要因素。

Influence of Low-permeability Layers on Remaining Oil Distribution in Dolomite Reservoir

The high water-production stage has started in the YM dolomite reservoir; however, the important issue is how to locate and potentially tap the remaining oil. Low-permeability layers are ubiquitous in this type of reservoir. A mechanism model was built for sensitivity analysis of permeability, thickness, attitude of the low-permeability layers, and reservoir permeability. The results show that the effect of a flow barrier depends mainly on the permeability of the layers. When permeability is lower than 0.01 mD, the flow barrier functions well. It was found that, all conditions being equal, the thicker the low-permeability layers the stronger would be the flow barrier function. According to the distribution form and style, the controlling degrees of the remaining oil are types I > II > III > IV. If two interlaced low-permeability layers were present, the controlling degrees would be types V > VI. The low-permeability layers are able to form fluid barriers over a short production time, which become the main controlling factors on the distribution of the remaining oil.