煤、岩力学性质是影响煤储层压裂改造效果的关键因素。基于煤的原位条件的全应力-应变试验、煤和顶底板围岩的单轴和三轴力学参数统计，结合FracproPT压裂模拟软件，揭示了深部煤储层原位力学性质，查明了研究区煤、岩组合特征及力学性质差异，探讨了煤、岩力学性质对深部煤储层压裂的影响。研究结果表明：随着温度的增加，煤的弹性减弱，塑性增强，力学强度呈减弱趋势。温度对煤力学性质的影响很小，对于煤整体的力学强度而言，这种影响可以忽略不计。应力增强了煤岩弹性性能和力学强度，且影响显著，在不同的应力范围内其影响特征不同。在弹性变形阶段，随着有效围压的增大，煤的弹性模量增大，泊松比减小，但是在不同围压条件下，弹性模量和泊松比随应力的变化显示出不同的特征。当有效围压为20 MPa时，随着轴向应力的增大，煤的弹性模量和泊松比先快速增大后逐渐恒定。当有效围压为10 MPa时，弹性模量和泊松比在轴向应力加载初期也呈快速增大趋势，但泊松比在轴向应力为10 MPa附近经历短暂的稳定后继续增大。当有效围压为30 MPa时，弹性模量和泊松比开始就是一个相对恒定的值，缺少弹性模量和泊松比的上升段。在塑性变形阶段，随着有效围压的增大，塑性变形发生时对应的应力和应变值增大，且屈服点更加显现，表明随着有效围压的增大，煤的塑性变形延迟出现。在残余强度阶段，随着有效围压的增大，煤的残余强度也有所提高。研究区煤层与顶底板存在7种组合类型，以泥岩-煤-泥岩为主，细砂岩-煤-细砂岩次之，力学性能按照煤、炭质泥岩、泥岩、砂质泥岩、粉砂岩、细砂岩、中砂岩的顺序增强。煤岩弹性模量越大，压裂容易形成高、窄、短缝;煤、岩弹性模量差越大，压裂容易形成矮、长、宽缝。

The mechanical properties of coal and surrounding rock are the key factors influencing the effect of coal reservoir fracturing transformation.Based on full stress-strain experiment of coal under in-situ conditions,and uniaxial and triaxial mechanical parameters statistics of coal and surrounding rock on top and bottom of coal seam,combined with FracproPT fracturing simulation software,the in-situ mechanical properties of deep coal reservoir were revealed,the combination characteristics and mechanical properties differences of coal and surrounding rock in the study area were identified,and the influence of mechanical properties of coal and surrounding rock on fracturing of deep coal reservoir was discussed.With the increase of temperature,the elasticity of coal decreases,the plasticity of coal increases and the mechanical strength of coal decreases.The effect of temperature on the mechanical properties of coal is very small,which can be ignored for the whole mechanical strength of coal.The stress enhances the elastic property and mechanical strength of coal,and the influence is significant.The influence characteristics are different in different stress range.In the stage of elastic deformation,with the increase of effective confining pressure,the elastic modulus of coal increases and Poisson’s ratio of coal decreases,but under different confining pressure conditions,the elastic modulus and Poisson’s ratio of coal show different characteristics with the change of stress.When the effective confining pressure is 20 MPa,with the increase of axial stress,the elastic modulus and Poisson’s ratio of coal increase rapidly and then become constant.When the effective confining pressure is 10 MPa,the elastic modulus and Poisson’s ratio of coal also increase rapidly at the initial stage of axial stress loading,but Poisson’s ratio continues to increase after a short period of stability near the axial stress of 10 MPa.When the effective confining pressure is 30 MPa,the elastic modulus and Poisson’s ratio of coal are relatively constant at the beginning,lacking the rising section of elastic modulus and Poisson’s ratio.In the stage of plastic deformation,with the increase of effective confining pressure,the corresponding stress and strain values increase when plastic deformation occurs,and the yield point is more obvious,which shows that with the increase of effective confining pressure,the plastic deformation of coal is delayed.In the stage of residual strength,with the increase of effective confining pressure,the residual strength of coal also increased.There are seven combination types of coal seam and surrounding rock in the study area,mainly mudstone-coal-mudstone,followed by fine sandstone-coal-fine sandstone,and the mechanical properties are enhanced according to the sequence of coal,carbonaceous mudstone,mudstone,sandy mudstone,siltstone,fine sandstone,medium sandstone.The greater the elastic modulus of coal,it is easy to form high,narrow and short fracturing cracks;the greater the difference of elastic modulus of coal and surrounding rock,it is easy to form short,long and wide fracturing cracks.

1 区域地质背景

2 深部煤储层力学性质

   2.1 样品和实验设计

   2.2 实验仪器

   2.3 实验结果及分析

3 煤、岩组合特征及力学性质对比

   3.1 煤、岩组合类型

   3.2 煤、岩力学性质差异

4 煤、岩力学性质对煤储层压裂的影响

   4.1 煤的弹性模量对压裂效果的影响

   4.2 煤、岩弹性模量差异对压裂效果的影响

5 结论