Attempt Of Activated Carbon Radon Measurement Method Used To Monitor The Fracture Of Hydraulic Fracturing

In the process of developing CBM,fracturing technique is an important measure to rise the production of coalbed methane to the low permeability coal seam,and the form and scale of the fractures are important reference for the arrangement of the well pattern.Therefore,it useful to study the length,width,heigth,azimuth angle and fracturing scale deeply.At present,the numerical simulation method is often used to simulate the shape of fractures,and the fracturing monitoring technology is more mature than the microseismic method,but this method should have high quality observation wells.Therefore,it is worthwhile to study on activated carbon radon measurement method for on need of observation wells.In this paper,based on the collection of a large number of literatures,the research status of radon technology for activated carbon is reviewed,the influence of rock fracturing on the radon precipitation is analyzed,and the reasons of being radon anomaly after fracturing the underground coal(rock)was discussed.And the reasons why activated carbon measurement method is fitful to monitoring was discussed,it is feasible to to monitor the fracturing and cracking of coal(rock)seam on the ground by using activated radon measurement method.The field test of activated carbon messurement monitoring is carried out in combination with the actual situation of fracturing of some coalbed methane wells in the block of northern Shizhuang.In this paper,the lithology of the stratum,the distribution of coal seam,the mechanical properties of coal,the geostress and the distribution of coalbed methane are explained.The the activated carbon measurement method monitoring of in the whole test area was carried out before the fracturing construction of the CBM wells.The distribution of the radon background values in the test area was given and the monitoring was carried out three times after the fracturing construction,and the radon was changed The distribution of the plane.By analyzing and comparing the radon anomaly range obtained by the four monitoring work and the semi-long simulation of fracturing fractures obtained by numerical simulation,the effect of the radon method on the monitoring of fracturing fractures was evaluated.The existing results only show that the activated carbon measurement method can respond to radon anomaly caused by fractured coal seams and can not prove that the method can monitor the length and azimuth of fracturing fracture.