数字岩心技术在页岩弹性模量计算中的应用

Application of Digital Core Technology in Elastic Modulus Calculation for Shale

弹性模量是页岩气勘探开发寻找甜点的一项重要参数,也是直接决定水力压裂效果的重要指标。由于页岩通常具有极高的脆性,很难通过传统岩石力学实验方法来测定其弹性力学特征。为进行弹性模量预测,采用最新的数字岩石物理手段,结合扫描电子显微镜成像、页岩矿物质组分定量确定和有限元数值模拟等方法,通过模拟页岩数字岩心在线弹性范围内的应力应变的响应过程,计算出页岩数字岩心的有效弹性参数,并通过对不同尺寸计算区域的模拟计算结果进行比较,验证了此方法的取样代表性。模拟计算结果与实际测井数据比对也证实了此方法的有效性。

Elastic modulus is an important parameter for sweet-spot discovery in shale gas exploration and development, and also an signif-icant index to determine hydraulic fracturing effect. It is very difficult for conventional experiment method of rock mechanics to measureelasticity features of shale due to its extremely high brittleness. To predict elastic modulus, up-to-date digital petrophysical method com-bined with scanning electron microscope imaging, quantitative mineral component determination of shale and finite element numerical sim-ulation is used. Based on modeling the stress-strain response process of digital shale cores in the range of linear elasticity, effective elasticparameters of the digital cores can be calculated. Through comparison of the modeling calculation results of the calculated areas with differ-ent sizes, the sampling by this method is verified to be representative. The comparison of modeling calculation results and the actual log-ging data can also prove the effectiveness of the method.