Response relation between fracturing curve and reservoir pollution degree of coalbed methane wells

In order to study the relationship between response curve and the pollution degree of fractured reservoir, taking Shizhuang block in Qinshui basin as an example, wells with different sensitivity of reservoir in the block were selected, through comparison of the difference of the dropping trace characteristics after the hydraulic curve reaches the fracture pressure in the fracturing curves of fracturing operation in different wells, the response law of hydraulic dropping trace and the reservoir sensitivity was summed up. Then in the same block according to the dropping trace of the hydraulic curves, the sensibility of reservoir was judged in several wells. According to the calculation model of reservoir permeability damage ratio, the permeability damage ratio of several well development sections was calculated. The results found that the wells with strong predicted reservoir sensibility had higher reservoir permeability damage ratio, and reservoir was seriously polluted. Wells with weak reservoir sensibility was slightly polluted. It shows that the dropping trace after the hydraulic curve reaches the fracture pressure can reflect the reservoir pollution degree, and provides the basis for later engineering development.