METHOD FOR DEVELOPMENT OF MULTI-HOLE COAL-METHANE WELL Russian patent published in 2024 - IPC E21B43/16 

FIELD: well drilling.

SUBSTANCE: invention relates to production of methane from coal beds, namely to the final stage of construction of wells for extraction of methane from coal beds. Disclosed is a method of developing a coal-methane multi-hole system of wells consisting of a vertical well and a well with a horizontal end, which includes intensification and performance of works associated with installation of surface and downhole pumping equipment, connection of installation with inert gas to annular space of vertical well, performing pressure testing of the assembled line for the maximum pressure expected at the wellhead, starting the pump in the vertical well at rated capacity, after which inert gas is pumped in portions, preventing the bottomhole pressure growth of more than 0.5 atm/day. At that, formation fluid level is reduced in vertical well by replacement of pumped fluid with inert gas, with creation of minimum depression on developed reservoir. When the liquid level reaches about 10–15 m below the milling interval of the production string, gas injection is stopped. After that, the installation with inert gas is connected to the annular space of the well with a horizontal end, the assembled line is pressurized and the inert gas is injected, controlling portions of gas injection and capacity of the pump unit, thereby reducing the level of formation fluid in the system of wells below the milling interval. Further, gas injection is stopped, pressure in the line is released and the line is disassembled. Pump unit remains in operation to maintain the achieved value of the formation fluid level. Then, while maintaining the required level in the system of wells, the annular pressure is reduced to the target parameters through the ball valve of the vertical well.

EFFECT: improving development efficiency of the system of wells by performing smooth development of depression funnel, providing additional intensification and cleaning of natural fracturing due to alternating action from excess gas pressure in the well to the planned value.

1 cl, 2 dwg