基于应力敏感常数的致密砂岩储层应力敏感性评价研究

Research on Stress Sensitivity Evaluation Experiments of Tight Sandstone Reservoir Based on Stress Sensitivity Constant

利用渗流应力耦合拟三轴实验系统,针对华北、青海等区块共34块天然砂岩岩心展开应力敏感性测试实验。基于应力敏感常数对实验结果进行拟合,获得砂岩储层岩心应力敏感常数与渗透率的变化关系。结果显示,岩心应力敏感常数能够表征砂岩储层岩心渗透率的应力敏感特性,应力敏感常数越大,砂岩渗透率应力敏感性越强,且砂岩应力敏感常数随岩心渗透率的增大而减小。

The sensitivity test experiment of 34 natural sandstone samples from north china, Qinghai and other oil fields are carried out with the seepage flow stress coupling simulation triaxial experiment system. Based on the stress sensitivity constant evaluation method, the fitting curve between stress sensitivity constant and rock permeability could be achieved. The results have shown that stress sensitivity constant could represent the characterization of stress sensitivity of sandstone permeability. The higher stress sensitivity constant is, the stronger the stress sensitivi- ty of sandstone permeability is. Moreover, stress sensitivity constant of sandstone decreases with the increase of the sample＇s permeability.