煤级梯度是预测深部储层煤化作用程度的基础。基于实测的85组镜质体最大反射率、不同煤层气区块煤炭/煤层气地质勘探报告中2 213组镜质体最大反射率/干燥无灰基挥发分产率与煤层埋深数据和242组岩浆侵入煤层后镜质体最大反射率与煤层距侵入体距离数据，分析了不同煤层气区块中不同变质作用类型下煤级分布及煤级梯度特征，对比了深成变质作用、区域岩浆热变质作用及接触变质作用下煤级梯度的差异性。研究结果表明：我国不同煤层气区块中深成变质作用下煤级梯度（R_{o, max}/100 m）介于0.013% ～0.068%，均值为0.032%，煤级梯度与镜质体最大反射率均值呈正相关关系；区域岩浆热变质作用下煤级梯度介于0.09% ～0.45%，均值为0.18%；接触变质作用下煤级梯度介于20% ～454%，均值为106%，煤级梯度与煤层距侵入体距离的关系呈多段式变化，煤层距离侵入体越近，煤级梯度越大。不同变质作用类型下煤级梯度差异显著，主要由热源特征决定，煤化作用时间、岩层热导率、最大埋深对煤级梯度也有重要影响。我国煤化作用复杂，对不同煤层气区块中不同变质作用类型下煤级梯度的研究对深部储层煤级预测及煤炭/煤层气资源勘探开发均具有一定的指导意义。

Coal rank gradient is fundamental for predicting the degree of coalification in deep reservoirs. This study, based on the measured maximum reflectance of vitrinite of 85 sets, the maximum reflectance of vitrinite /dry ash-free basis volatile yield of 2 213 sets from different coalbed methane blocks' geological exploration reports, and 242 sets of maximum reflectance of vitrinite post-magma intrusion in relation to the coal seam distance from the intrusion, analyzed the coal rank distribution and gradient characteristics under different types of metamorphism. The differences of gradients between deep metamorphism, regional magmatic thermal metamorphism, and contact metamorphism were compared. The results show that the coal rank gradient (R_{o, max}/100 m) under deep metamorphismin in different coalbed methane blocks in China ranges from 0.013% to 0.068%, with an average of 0.032%, and shows a positive correlation with the average maximum reflectance of vitrinite. Under regional magmatic thermal metamorphism, it ranges from 0.09% to 0.45%, with an average of 0.18%. Under contact metamorphism, it ranges from 20% to 454%, with an average of 106%. In the contact metamorphism induced by magmatic intrusions, the coal rank gradient exhibits a multi-stage variation. The closer the coal seam is to the intrusion, the greater the coal rank gradient. The differences in coal rank gradient under different types of metamorphism are significant, mainly determined by heat source characteristics, with coalification duration, thermal conductivity of rock layers, and maximum burial depth also playing crucial roles. China's coalification process is complex, making the study of coal grade gradient under different types of metamorphism and in different coalbed methane blocks has guiding significance for predicting coal rank of deep reservoir and for the exploration and development of coal/coalbed methane resources.