Comparative analysis for the impact of different natural fracture surface characteristics on CBM fracturing

In order to accurately analyze the impact of natural fracture surface characteristics on the effect of hydraulic fracturing in coal reservoir,based on the observations of eight coalbed methane wells and the natural fracture surface characteristics in southern Qinshui Basin,the authors observed and contrasted the natural fracture surface features from two coalbed methane wells(F1and F2). The natural fracture surface features of F1 shows a tortuous and rough feature and with many secondary cracks,while F2 demostrates the opposite feature. The authors found that the coal reservoir fracturing fracture morphology are more short and wide than the surface monitoring value and the theoretical model projections;the natural fracture surface is straight,smooth and the surface does not develop secondary cracks obtained more long and narrow fracture. The results show that the unique natural fracture surface characteristic of coal reservoir is one of the main factors that cause the actual fracture more short and wide. The different natural fracture surface characteristics influence the fracturing process by affecting the fluid pressure gradient that in turn affects the final fracturing result.