吉木萨尔页岩油藏人工裂缝渗透率变化规律

为研究吉木萨尔页岩储层人工裂缝渗透率在油藏生产过程中的变化规律,基于新疆吉木萨尔页岩油藏储层条件,开展不同闭合压力、不同岩性、不同铺砂浓度对裂缝渗透率影响实验.结果 表明:随着油藏开发程度不断加深,人工裂缝渗透率逐渐降低,主要分为两个阶段,且不同铺砂浓度存在差异.第一阶段:高铺砂浓度下闭合压力小于20 MPa,低铺砂浓度下闭合压力小于15 MPa,支撑剂嵌入和破碎共同导致渗透率急剧降低,降低幅度分别为60.16％、82.21％.第二阶段:高铺砂浓度下闭合压力20 ～35 MPa,低铺砂浓度下闭合压力15 ～35 MPa,仅发生支撑剂破碎使得渗透率下降相对较慢.同时,由于泥岩强度较粉砂岩强度更大,支撑剂嵌入深度较低,使得在同等条件下,泥岩储层比砂岩储层的人工裂缝渗透率更大.

Study on permeability variation of artificial fracture in Jimusaer shale reservoir

In order to study the variation law of artificial fracture permeability in Jimusar shale reservoir during reservoir production, based on the reservoir conditions of Jimusar shale reservoir in Xinjiang, the effects of different closure pressure, lithology and sand concentration on fracture permeability were carried out. The results show that: with the deepening of reservoir development, the permeability of artificial fracture gradually decreases, which is mainly divided into two stages, and there are differences in different sand concentration. In the first stage, when the closure pressure is less than 20MPa at high sand spreading concentration and less than 15MPa at low sand spreading concentration, the permeability decreases sharply due to proppant embedding and crushing, and the reduction ranges are 60.16% and 82.21% respectively. The second stage: when the closure pressure is 20 ~ 35MPa at high sand concentration and 15 ~ 35MPa at low sand concentration, only proppant breakage occurs and the permeability decreases relatively slowly. At the same time, because the strength of mudstone is greater than that of siltstone, and the depth of proppant is smaller, the permeability of artificial fracture in mudstone reservoir is higher than that in sandstone reservoir under the same conditions.