Research on the construction of running casing in U well in soft outburst-prone coal seam

China is rich in coalbed methane resources, has the total proven reserves of about 30×10¹²m³~35×10¹²m³, thus accelerating the development of coalbed methane can not only alleviate the contradiction of energy source shortage, but also ensure the safety of coal mine. The current development of coalbed methane is performed by ground extraction method, U well as a kind of horizontal well, can maximize the exposed area of reservoir, and increase the gas production. In the case of the project of test research on the ground coal seam gas horizontal well in Xishan Dongyu coal mine, it will introduce some key construction technology about drilling horizontal well in soft outburst-prone coal seam, like structure design of the well, drilling parameters, hole trajectory control, drilling fluid, machining and running the coal seam production casing and so on.