裂缝性低渗储层应力敏感性的尺度模型

Scale Model of Stress Sensitivity for Low Permeability Fractured Reservoirs

摘要: 裂缝性致密储层存在非均质性、应力敏感性及各向异性，而应力敏感性评价实验的岩心尺寸(通常为25 mm)受取心条件及实验条件限制，不可能无限放大，因此实验测试的流动尺度远远小于井下实际流动尺度，导致实验数据不能直接描述实际储层流动规律。该项目计划采用岩石力学分析方法及介质串并联模型，研究得到裂缝性致密储层应力敏感性的尺度模型。尺度模型中考虑岩心尺寸、井下流动尺寸、裂缝密度、裂缝产状、地应力等因素。对孔隙型岩心和裂缝性岩心分别进行应力敏感实验，尺度模型给出由小尺寸孔隙型岩心和裂缝性岩心的应力敏感实验规律推导实际储层大范围流动规律的方法。项目将把应力敏感尺度模型应用于产能预测，研究裂缝性致密储层水平井、多分支水平井及分段压裂水平井产能计算的新方法。

Abstract: There are heterogeneity, stress sensitivity and anisotropy in the fractured reservoir with low permeability while the sizes of the cores (the diameter is usually 25mm) in the experiment about the stress sensitivity are limited by the coring and experimental conditions and are not likely to be magnified indefinitely, so the flow scale in the experiment test is far less than the actual under- ground flow scale, which results in that the flow law of the real reservoir cannot be directly de- scribed by the experimental data. The scale model of stress sensitivity for fractured reservoir with low permeability is established by the analysis method in rock mechanics and the series-parallel model of the medium. The size of the cores, the size of the undergroud flow, fracture density, crack occurrence, in-site stress and so on are considered in the scale model. Stress sensitivity experi- ment of porous cores and fractured cores should be respectively performed and the scale model provides the method of deducing large range of flow law in real reservoir according to the law of stress sensitivity experiment about the small size of porous cores and fractured cores. The scale model will be used to predict the productivity and to study new methods of the productivity cal-culation in horizontal well, multi-branch horizontal well and staged fracturing horizontal well with low permeability fractured reservoir.