不同脆性岩石的声发射特征

发布时间：2018-10-04 19:36

【摘要】：目前针对岩石声发射的试验主要集中在研究岩石的力学特性方面,关于岩石脆性的声发射试验相对较少。为了研究岩石脆性的声发射特征,对4种不同脆性的岩石试样进行了单轴压缩和声发射检测试验,所用试样为含砂比不同的自制水泥砂石,试验得到了试样的应力-应变曲线和声发射计数曲线。结果表明:试样中的含砂比与岩石脆性正相关;脆性越强,应力-应变曲线的弹性变形段斜率越大,峰后应力跌落越快,形变量越大,出现明显声发射信号的时间越早,声发射计数的最大值越大;峰前声发射计数曲线显示,随着岩石脆性的增加,试样破裂方式由渐进式破裂向突发式破裂过渡,裂缝形态由张性裂缝向剪性裂缝及混合裂缝转变。整体而言,岩石脆性不同,声发射特征也不同,根据声发射特征可以判断岩石脆性的强弱。该试验结果对于评价岩石脆性及水力压裂选层方案设计等具有理论参考价值和现实意义。
[Abstract]:At present, the acoustic emission test of rock is mainly focused on the study of rock mechanical properties, and the acoustic emission test on rock brittleness is relatively few. In order to study the acoustic emission characteristics of rock brittleness, uniaxial compression and acoustic emission testing tests were carried out on four different brittle rock samples. The stress-strain curves and acoustic emission counting curves were obtained. The results show that the sand content ratio in the specimen is positively correlated with the rock brittleness, the stronger the brittleness, the larger the slope of the elastic deformation section of the stress-strain curve, the faster the post-peak stress falls, the larger the deformation, and the earlier the apparent acoustic emission signal appears. The larger the maximum value of acoustic emission count, the more the peak acoustic emission counting curve shows that with the increase of rock brittleness, the fracture mode of the specimen changes from progressive fracture to sudden fracture, and the fracture morphology changes from tensile fracture to shear fracture and mixed fracture. As a whole, the rock brittleness is different and the acoustic emission characteristics are different. The rock brittleness can be judged according to the acoustic emission characteristics. The experimental results are of theoretical reference value and practical significance for evaluating rock brittleness and hydraulic fracturing plan design.
【作者单位】：东北石油大学石油工程学院;东北石油大学电气信息工程学院;渤海钻探工程有限公司工程技术处;
【基金】：国家自然科学基金项目“页岩气藏压裂岩体突变特征及多重分形缝网逾渗演化研究”(编号:51404073);国家自然科学基金项目“页岩局部脆性表征与压裂裂缝交互耦合演化机制研究”(编号:51574088) 中国博士后科学基金项目“页岩气藏压裂介观逾渗系统演化与气体流动机理研究”(编号:2014M550180);中国博士后科学基金特别资助项目“页岩压裂岩体局部脆性破裂与缝网演化多重分形特征研究”(编号:2016T90268) 黑龙江省博士后青年英才计划特别资助项目“煤岩脆塑性表征与岩体压裂突变破裂演化机理研究”(编号:LBH-TZ-0503)联合资助
【分类号】：TE311

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