The coal measure shale strata (CMSS) is rich in coalbed methane and shale gas. However, different thicknesses and high heterogeneity between the coal and shale typically result in difficultly predicting hydraulic fracture height growth. The feasibility of multi-gas production and the optimal layer for fracturing in CMSS requires a better understanding of fracture vertical propagation mechanism. In this paper, a three-dimensional model of a hydraulic fracture crossing CMSS layer was built according to geological characteristics, based on the rock seepage-stress-damaged coupled finite element method. The influence of geological factors and construction factors on the hydraulic fracture expansion was investigated. The results showed that (1) The physical property and geological conditions presented a huge difference between different lithological rock with various depth; (2) The increase of displacement and fracturing fluid viscosity, the inhibition effect on vertical fracture extension became weak. The augment of displacement was more helpful to the vertical propagation of fracture; (3) Under low permeability difference and small horizontal minimal principal stress difference, fracture length propagated enough distance and fracture height extension gap connected more the production layer. Therefore, the favorable conditions for forming balanced fracture geometry were as follows: permeability difference from 0–3 and stress difference from 1–2 MPa. (4) The 11th layer was chosen as the best fracturing layer in Shanxi Formation. The fracture height was about 26.13 m and the thickness of pay layers accounted for 42.32% of the height. The research results provide theoretical guidance for the optimal fracturing layer and fracturing construction parameters in CMSS.

煤系页岩地层（CMSS）富含煤层气和页岩气。然而，煤和页岩之间的不同厚度和高非均质性通常导致难以预测水力裂缝高度的增长。多气生产的可行性和 CMSS 压裂的最佳层级需要更好地了解裂缝垂直扩展机制。本文根据地质特征，基于岩石渗流-应力-损伤耦合有限元法，建立了穿越CMSS层的水力裂缝三维模型。研究了地质因素和施工因素对水力裂缝扩展的影响。结果表明：（1）不同深度的不同岩性岩石的物性和地质条件存在巨大差异；(2) 排量和压裂液粘度增加，对裂缝垂向延伸的抑制作用减弱。位移的增加更有利于裂缝的垂直扩展；(3)在低渗透率差和小水平最小主应力差下，裂缝长度延伸足够远，裂缝高度延伸间隙与生产层的连接更紧密。因此，形成平衡裂缝几何形状的有利条件为渗透率差 0～3 和应力差 1～2 MPa。(4) 11层被选为山西组最佳压裂层。裂缝高度约为 26.13 m，产层厚度占高度的 42.32%。研究成果为CMSS优化压裂层数和压裂施工参数提供了理论指导。