Exploration and practice of coalbed methane resources effective development technology in deep, high stress and low permeability conditions

In order to achieve the high efficient development of the coalbed methane in deep, high stress and low permeability conditions, this paper took the deep coalbed methane reservoir of Zhengzhuang-Libi development block as research object where lies in the Qinshui basin, and analyzed the development effects and adaptability of different well types including vertical well, multi branch horizontal well and L-type CBM horizontal well, and determined the L-type CBM horizontal well with continuous tubing drag fracturing as the development technology, and investigated and evaluated the development effect.The results show that the capacity of vertical well and multi branch horizontal well was limited due to high crustal stress and stress anisotropy; the L-type CBM horizontal well with continuous tubing drag fracturing realized the stress reconstruction and strengthened the effective connectivity between horizontal wellbore and fracture network, which obtained the good development results at depths greater than about 700 m.The highest gas production reached 25 000 m³/d, which hit record levels in deep, high stress and low permeability conditions.