Geological and engineering factors of high water production in coalbed methane wells and water control measures

In order to solve the problem that it is difficult to effectively reduce reservoir pressure in high-water-producing CBM wells, it is necessary to take targeted measures to control coal seam water according to the reasons for the high-water production of coal beds. Through geological and engineering research on high-yield water CBM wells in the Gude well area of Liupanshui coal field from seven aspects in⁃ cluding coal contents, porosity, water content, structure, drilling, fracturingand drainage, etc., to find out the specific reasons for the high-yield water production of CBM wells, and to take effective water control measures to achieve the purpose of depressurization desorp⁃ tion and gas production of coalbed methane wells. The research shows that there are many coal seams in the Gude well area, and the meth⁃ ods of multi-coal seam group fracturing and combined seam drainage and production canimprove the development efficiency of coalbed methane resource;the water content of the formation in the Gude well area is weak, and the coal seam has poor porosity and permeability. The formation water production is weak, but the fault structure is relatively developed, which increases the risk of water content and water production in the fault fracture zone; the probability of the CBM well directly drilling into the fault is small, but the radius of influence of the fracturing construction is generally more than 100 m, which is easy to communicate with the nearby wellbore. The fault fracture zone increases the risk of high water production in coalbed methane wells;the fracturing construction of CBM wells in the Gude well area com⁃ municates with the fractured zone in the upper fracturing section, resulting in high water production. Cement injection and plugging meas⁃ ures can be taken to control water and the coal seam after the water control operation. The water production of gas wells has dropped signif⁃ icantly, and the water production has dropped by more than 80%, and the pressure of the reservoir has been effectively reduced. The re⁃ search and engineering application provide technical guidance for water control, production and efficiency enhancement forhigh-yield CBM wells in fault-fractured zones. © 2022 China Coal Society. All rights reserved.