Study on horizontal well collapse pressure distribution of deep coal bed in Daning-Jixian Block
The aim of the present work is to study the overall collapse pressure distribution of horizontal wells in deep 8#coal bed in Daning-Jixian area and provide suggestions on the drilling direction of horizontal wells.Firstly,numerical programming was used to calculate the sectional collapse pressure of 8#coal bed in horizontal wells JS6-5P03 based on the calculation model of inclined well collapse pressure and actual coal bed parameters.Secondly,the collapse pressure of 8#coal bed under different azimuths of about 60 wells was calculated,respectively,based on which the collapse pressure distribution of the whole block was obtained by using the sequential Gaussian interpolation method.The results show that the collapse pressure equivalent density of No.8 coal bed in well JS6-5P03 should not be less than 1.376 g/cm3 to avoid collapse.When horizontal wells are drilled with different azimuths,the whole 8#coal bed of Daning-Jixian Block can be divided into low risk collapse zone,medium risk collapse zone and high risk col-lapse zone according to the collapse pressure.The suitable drilling direction in the central part of Daning-Jixian Block is about 180°,the upper part and the lower part,and the recommended azimuth is about 160°.
well wall stabilitycollapse pressuredeep coal bedhorizontal well
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