The researchers studied how coal measure reservoirs in Qinshui Basin, China, change under different pressures. They found that coal has higher initial porosity and permeability than sandstone and mudstone. As pressure increases, the permeability of all three types of rock decreases. Coal is more sensitive to pressure at lower levels, while sandstone and mudstone are more resistant to deformation. A model based on the Langmuir equation accurately analyzed the stress sensitivities of porosity and permeability in the rocks.