GAS EXTRACTION METHOD Russian patent published in 2009 - IPC E21B43/00 E21B33/03 

FIELD: oil-and-gas production.

SUBSTANCE: invention relates to the mining industry and can be used in exploiting gas fields through remote, automatic and manual control of well shutting-off devices. According to the method, output wells are drilled in a gas field and are equipped with possibility of formation of exploited pads, which are fitted with production casings, and flow columns are built in them, fitted with underground production equipment, including a controlled gas underground safety valve, and wellhead equipment, which includes an X-mas tree with shutting-off devices, including at least a wing valve and a casing valve. A throttle valve which regulates well flow rate is mounted on a flow line. Monitoring and control devices for the safety shut-off system of the well are mounted, which comprise a low- and high-pressure control valve and a fuse link. At least part of the well pad and gas field is connected to a station or unit of a station for controlling shutting-off devices of the X-mas tree and underground safety valve, which contains a pump-accumulator unit with a power hydropneumatic accumulator and at least one control unit serving the well, with power lines for functional control of actuating mechanisms of shutting-off devices. The power lines are connected to a logical control line, which is provided with at least triple backed-up trigger mechanisms, two of them which are operated by a pulse, transmitted for shutting off the well in case of fire or critically low or high pressure in the flow line. A system has been designed for shutting off the well in a fluid cut-off logical sequence: "wing valve - casing valve - underground safety valve", which operates through a system for delaying transmission of the shut-off command. There is a tandem of the control hydropneumatic accumulator and a throttle in the logical control line in sections for interaction with power lines for functional control of actuating mechanisms of the casing valve and the underground safety valve.

EFFECT: more reliable and accident-free operation of a gas field, reduced cost of extracting gas, simplification of processes due to automatic control of well shutting-off devices.

25 cl, 3 dwg