断层对煤层瓦斯具有封闭和通道的双重作用，这主要取决于断层的封闭能力。针对断层对瓦斯封闭能力定量化表征方法，结合断裂带结构发育多元学说，分析了断裂带结构参数（两盘煤层对接系数、泥质含量、紧闭系数等）对断层封闭性的影响规律；考虑了诱导裂隙带宽度与渗透率的相关性，提出了一个断裂带泥岩等效厚度的计算公式和一种渗透率补偿算法，以此为基础，依据低速渗流理论，实现了断层极限封闭压力计算，继而对断层封闭性进行量化表征。研究结果表明：①断层封闭性主要受控于断裂带内部结构与断层端面受力状态，考虑顶底板围岩封闭能力和煤储层压力，利用断裂带结构参数和断层封闭压力可对断层封闭性进行综合定量表征；②诱导裂隙带煤层渗透率与距端面距离负相关，离端面越远，综合渗透率越低，最后趋近于原始煤层渗透率；③等效泥岩厚度越大，断层极限封闭压力越高，断层封闭性越好；④沁水盆地郑庄−樊庄区块的寺头断层封闭性计算结果显示，该断层封闭压力高于4.67 MPa，大于储层压力3.83 MPa。然而，该断层走向上的封闭能力存在差异，北东向断层端面封闭性好，西南向断层端面封闭能力则相对较差。研究成果对于科学判识断层的瓦斯封闭能力，指导井下煤与瓦斯突出预测及地面煤层气高效开发具有重要技术支撑作用。

Fault has the dual function of sealing and channel to coal seam gas, which mainly depends on the sealing ability of the fault. Aiming at the quantitative characterization method of fault sealing ability to gas, combined with the multi-element theory of fault zone structure development, the influence of fault zone structure parameters ( two-wall coal seam docking coefficient, the shale content, the tightness coefficient, etc. ) on fault sealing are analyzed. Considering the correlation between the width of the induced fracture zone and the permeability, a formula for calculating the equivalent thickness of the mudstone in the fault zone and a permeability compensation algorithm is proposed. According to the low-velocity seepage theory, the calculation of the limit sealing pressure of the fault is realized, and then the fault sealing is quantitatively characterized. The results show that:①The fault sealing is mainly controlled by the internal structure of the fracture zone and the stress state of the fault plane, considering the sealing capacity of the roof, the floor and the coal reservoir pressure, the fault sealing ability would be quantitatively evaluated by using the structural parameters of the fault zone and the fault sealing pressure; ②The permeability of the coal seam in the induced fracture zone is negatively correlated with the distance from the fault plane, the farther away from the fault plane, the lower the permeability, and approaches the permeability of the original coal seam finally; ③ The greater the equivalent mudstone thickness, the higher the ultimate sealing pressure of the fault, and the better the sealing ability of the fault; ④The calculation results of Sitou fault sealing in Zhengzhuang-Fanzhuang Block of Qinshui Basin show that, the fault sealing pressure is higher than 4.67 MPa, which is greater than the reservoir pressure of 3.83 MPa. However, there are differences in the sealing ability on the fault strike, with good sealing ability on the northeast fault plane and relatively poor sealing ability on the southwest fault end. The research results have important technical support for scientifically judging the gas sealing ability of the fault plane, guiding the prediction of coal and gas outbursts, and serving the development of coalbed methane.