应力对泥页岩储层脆性影响的试验分析及应用

发布时间：2018-05-07 09:01

本文选题：地层应力 + 埋深　；参考：《石油钻探技术》2017年03期

【摘要】：随着地层埋深增加,岩石脆性降低,逐渐由硬脆性转变为韧性,而常规矿物组分法评价泥页岩脆性时没有考虑地层应力(埋深)的影响,因此评价结果存在一定误差。为此,从岩石脆性的最初定义出发,在不同围压条件下对陆相泥页岩岩样进行了力学测试,并利用应变法分析了泥页岩的脆性特征。结果表明:随着围压升高,泥页岩的弹性应变与塑性应变均增大,而脆性指数降低;泥页岩的弹性应变与塑性应变具有非常好的正相关性。对于文中所研究区块,埋深1 250.00,2 500.00和3 500.00 m处及埋深3 500.00~5 000.00 m和5 000.00~6 000.00m范围内的泥页岩脆性指数分别约降低5.97%,8.55%,10.74%,14.00%和18.00%;当泥页岩储层中脆性矿物含量分别大于65%,60%,55%和小于50%时,其开发埋深下限分别为6 000.00,5 000.00和3 000.00m以及基本不具备商业开发价值。研究结果表明,将应力(埋深)对泥页岩脆性的影响定量化,可以对采用矿物组分法计算的泥页岩脆性指数进行校正,为优选可压裂层段提供依据。
[Abstract]:With the increase of formation depth, the rock brittleness decreases, and gradually changes from hard brittleness to toughness. However, the influence of formation stress (buried depth) is not taken into account in the conventional mineral component method, so there is a certain error in the evaluation results. Therefore, starting from the original definition of rock brittleness, the mechanical tests of continental shale samples were carried out under different confining pressures, and the brittleness characteristics of shale were analyzed by strain method. The results show that with the increase of confining pressure, the elastic strain and plastic strain of shale increase, while the brittle index decreases, and the elastic strain and plastic strain of shale have a good positive correlation. For the blocks studied in this paper, the brittleness index of shale in the depth of 1 250.002 500.00 and 3 500.00 m and in the range of 3 500.000.005 000.00 m and 6 000.000 00m is about 5.977.8.550.74 14.00% and 18.00% respectively, and when the content of brittle minerals in shale reservoir is more than 650.60,5555% and less than 50,0000m, the brittleness index of shale is decreased by 5.978.550.74 14.00% and 18.00m, respectively. The lower limit of development depth is 6 000. 000. 000. 000.00 m and 3 000. 00m respectively. It has no commercial development value. The results show that quantifying the effect of stress (buried depth) on shale brittleness can correct the shale brittleness index calculated by mineral component method and provide the basis for selecting fracturing zone.
【作者单位】：贵州煤矿地质工程咨询与地质环境监测中心;贵州省煤层气页岩气工程技术研究中心;西安石油大学地球科学与工程学院;
【基金】：国家科技重大专项“盘县-金沙地区海陆交互相页岩气勘查评价应用试验”(编号:2016ZX05034004-007)部分研究内容
【分类号】：P618.13;TE311

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