Discrete Meta-analysis on Effect of Shot Hole Spacing-inclination on Hydraulic Fracture Extension in Deep Coal Seams
It is important to study the influencing factors of fracture extension in coal rock reservoirs to improve the recovery rate of coal bed methane.In order to investigate the influence of different shot hole spacing and inclination angle on the fracture extension law of deep-seated coal rock,discrete element analysis method was used to study the influence of shot hole spacing and inclination angle on the fracture network extension pattern and extension range,taking into account of the stress change characteristics of the coal rock around the wells,the maximum circumferential stress criterion,and the original reservoir and other conditions.The simulation results show that:the number of cracks is the highest when the shot hole spacing is 60 mm,and the morphology of the fracture network is the most complex when the shot hole inclination angle is 45°,i.e.,the complexity of the fracture network of hydraulic fracture increases significantly and the extension range of the fracture network is the largest when the shot hole spacing is 60 mm and the shot hole inclina-tion angle is θ=45°.Through the validation of Y-1 well in Shenfu North Mugua Zone,the prediction results are consistent with the measured data,proving the correctness of the constructed numerical model of coal rock.
deep coal rockhole spacing-inclinationdiscrete elementshydraulic crack extensioncoal rock stress
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