Fracturing Fluid Flow And Proppant Distribution Laws In CBM Well

CBM fracturing technology as the main field of coalbed methane production stimulation measures developed by wide attention of scholars at home and abroad and got rapid progress, But there is no software specifically for CBM fracturing. Compared with conventional fracturing, coalbed methane fracturing has its own specialty:First, from the geological attributes of coal seams, the seams are micro-fractures and cleat development, coal permeability and porosity and other physical parameters are extremely sensitive to stress, when the pressure injected into coal seams split, the seam will re-open natural fractures, leading to coal fracturing fluid loss fracturing fluid than conventional formation fracturing serious; second is from the fracturing process, the general use of low viscosity fracturing coal seams, high displacement pumping methods, pumping sand concentration is relatively low, and because a wide seam cracks, This leads to particularly serious proppant settlement in the cracks.In this paper the authors conducted coal rock stress sensitivity experiments, measured under different confining pressures of changes of coal seam permeability is deduced, according to the experimental data, drived the calculation formula of the dynamic permeability of coal reservoir that changed with the formation of effective stress.and on this basis, the calculation of the stress sensitivity of the consideration of fracturing fluid filtration coefficient. The results of the study show that,Coal reservoir permeability decreases with formation of effective stress reduction is orders of magnitude growth, considering the growth of comprehensive stress sensitivity of fracturing fluid filtration coefficient far outweigh does not consider the stress sensitivity cases comprehensive fracturing fluid filtration coefficient.Based on these studies, the preparation of the coalbed methane fracturing proppant distributed computing software, the software can simulate the temperature distribution, proppant concentration, etc.,in the process of coalbed methane fracturing.it has a very important guiding significance on the CBM fracturing design and site construction.