Research On Prediction Technology Of Coal Fracture Crack Height

Hydraulic fracturing is the preferred way and main measures of coalbed methane yield. coalbed methane wells must pass through fracturing to form the industrial air flow, but to realize the high efficient production faces many difficulties, such as coal seam fracturing fracture height of accurate prediction is one of the key technology problem needed to be solved, and also that is a big difficult and common problem the abroad faced. Accurately determine the coal seam fracture height, select a reasonable construction parameters for improving the coal seam success rate and post fracturing production has a very important significance.For the technology of coal seam fracturing highly predictive, through research work during the Masters, the paper made the following findings:(1) Using the log interpretation crustal stress techniques and fracturing stress analysis techniques were coal seam fracture morphology discrimination, used in Erdos east gas Hancheng block 138 wells, mastered the coal seam fracture morphology rules and laid the coal seam fracturing simulation basis(2) Using fracture simulation software were applied for 73 wells(the case is determined vertical seam), combined with well temperature testing fracture height, using multiple linear regression method to be checked for fractures in the simulation results and presented simple and feasible formula.(3) Using conventional logging data and fracturing information, application of gray correlation analysis, preferably out of the main parameters that affect fracture height (depth, coal seam thickness, density, acoustic time, fracturing displacement, the total amount of sand, pre-liquid percentages, construction total liquid volume), on this basis, constructed to predict the coal seam fracturing height of the double hidden layer neural network model, and the formation of fracture height of the neural network forecasting techniques.(4) Based on the above two technologies, developed the coal seam fracturing height prediction software, application software for the calculation of fracture height three wells, compared with the calculation results and well temperature tests fracture height, show that: using neural network computing fracture height accuracy rate was 86.4%, and using simulated checking calculated fracture height accuracy was 87.2%. Description using coal seam fracturing highly predictive technology developed software are reasonable, in the early fracturing of CBM wells can be used to calculate the height of the construction fracturing wells, for judging whether fracturing pumping program to provide a reasonable basis, optimization of coal seam fracturing system laid the foundation for the future.