孔隙压力作用下岩石力学及声发射特性试验研究  

Experimental Study on Rock Mechanics and Acoustic EmissionCharacteristics under Pore Pressure

作　　者：陈明 曾纪文 贺浩 Chen Ming;Zeng Jiwen;He Hao(Wuhan Geological Survey Foundation Engineering Co.,Ltd,Wuhan,Hubei 430070;Geotechnical Engineering Technology Research Center of Hubei Geological Bureau,Wuhan,Hubei 430070)

机构地区：[1]武汉地质勘察基础工程有限公司,湖北武汉430070 [2]湖北省地质局岩土工程技术研究中心,湖北武汉430070

出　　处：《资源环境与工程》2023年第6期784-791,共8页Resources Environment & Engineering

摘　　要：为模拟衰竭式开采对储层岩石力学特性的影响,采用MTS岩石力学试验系统和声发射测试系统,对储层岩石进行不同孔隙压力作用下的三轴压缩声发射试验,分析孔隙压力减小对岩石强度、变形、渗透率及声发射特征参数的影响。结果表明,孔隙压力的变化对峰值应力的影响最大,其次是轴向应变、泊松比和径向应变,对弹性模量的影响最小;随着孔隙压力的减小,弹性模量、峰值应力、轴向应变和径向应变呈线性增大,而泊松比和渗透率分别呈线性和指数减小;破坏模式均以剪切破坏为主,主破裂面倾角在60°~80°范围内且随孔隙压力减小而减小;整个加载过程中声发射事件均大致经历了初始沉寂期(Ⅰ)、随机分布期(Ⅱ)、聚集爆发期(Ⅲ)3个阶段;起裂应力、损伤应力同峰值应力随孔隙压力减小呈线性增大,会导致水力压裂过程中需要的破裂压力比较大。研究成果可揭示衰竭式开采对储层岩石力学特征的影响规律,为油气田开发动态分析提供一定的借鉴作用。In order to simulate the influence of depletion mining on the rock mechanical properties of reservoir rock,the MTS rock mechanics test system and the acoustic emission test system are used to conduct triaxial compression acoustic emission tests under different pore pressures on a reservoir rock.The influence of pore pressure reduction on the strength,deformation,permeability and acoustic emission characteristic parameters of the rock is analyzed.The results show that the change of pore pressure has the greatest influence on the peak stress,followed by axial strain,Poisson s ratio and radial strain,which has the least influence on the elastic modulus.With the decrease of pore pressure,the elastic modulus,peak stress,axial strain and radial strain increase linearly,while Poisson s ratio and permeability decrease linearly and exponentially,respectively.The inclination angle of the main fracture surface ranges from 60°to 80°and decreases with the decrease of pore pressure.Acoustic emission during the entire loading process can be divided into three stages:I initial silent period,II random distribution period and III aggregate burst period.The crack initiation stress,damage stress and peak stress increase linearly with the decrease of pore pressure,which will lead to a relatively large fracture pressure during hydraulic fracking.The research results reveal the influence law of depletion mining on the rock mechanics characteristics of the reservoir,which provides a certain reference for the dynamic analysis of oil and gas field development.

关 键 词：孔隙压力 力学特性 声发射特征 衰竭式开采 

分 类 号：P642.3[天文地球—工程地质学]