Coal/Rock Mechanics Features of Qinshui Basin and Fracturing Crack Control

Taking the hydraulic fracturing of the coal bed methane wells in Qinshui Basin as the research object, in combination with the analysis information on the coal sample measurement and test in the lab and the actual fracturing data of the coal bed methane well, the paper in detail analyzed the fracturing effect of the coal be d methane wells and further stated the coal and rock mechanics features in the research zone affected to the fracturing of the coal seam.The results showed that the el astic modulus of coal and rock in the research zone would be distributed ranging from 25 GPa.When the elastic modulus of coal was lower, the crack width fractured wo uld be higher.With the crack width increased, the crack length would be restricted and the length would be distributed at 5070 m.During the seam fracturing process in t he research zone, the cracks fractured in different degree would be expanded into the seam roof and floor, the crack height would be 920 m and the max crack height C ould be 4 times over the thickness of the fractured seam. The pattern features of the cracks fractured in seam would not have a fixed depth limitation.The crack formatio n fractured in seam would not be only affected by the ground stress, but would be controlled by the local structural stress and the previous existed cracks. There would be a relative high phenomenon to have cracks occurred along a certain direction in a probability.