Injection pressurized casing gas recovery device

Abstract

The invention provides an injection pressurized casing gas recovery device, which is used for recovering the casing gas in the wellhead of an oil field. The device includes: ejector, gas-liquid mixed pump, liquid inlet valve, liquid outlet valve, inlet valve, gas storage tank, gas pressure sensor, gas flow meter, electric valve, control unit, etc., and is made into a skid-mounted piece. The liquid inlet of the ejector is connected with the upstream of the oil well oil outlet pipeline, and the liquid outlet is connected with the inlet of the gas-liquid mixed transport pump. When working normally, both the liquid inlet valve and the liquid outlet valve are opened. When the pressure of the casing gas reaches a certain value, the gas pressure sensor sends a signal to the control unit, and the control unit sends an instruction to start the mixed pump and open the electric valve after a delay; The high-speed flowing liquid in the introducer attracts the casing gas, and after mixing, it enters the mixed transport pump for pressurization, and then enters the oil well outlet pipeline to realize the recovery of the casing gas and avoid the damage caused by burning or venting the casing gas. Energy waste and air pollution.

Description

technical field [0001] The invention relates to an injection pressurized casing gas recovery device, which is used for recovering the casing gas produced in the process of oil recovery in an oil field. Background technique [0002] In oilfield crude oil extraction, as the pressure of reservoir fluid decreases, light components in crude oil, such as methane, ethane, propane, etc., will volatilize from the annular space between casing and tubing to form casing gas. A gas column with a certain pressure is formed, which forces the dynamic liquid level of the oil well to drop, so that the effective production pressure drop of the oil well is reduced, and the production capacity is reduced; a part of the gas enters the pump cavity with the liquid flow, occupies a certain space in the pump cavity, and affects the pump efficiency. An "air lock" occurs, making the well pump inoperable. [0003] Due to the low output of oil well casing gas and the unstable pressure, there is no speci...

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Problems solved by technology

[0002] In oilfield crude oil extraction, as the pressure of reservoir fluid decreases, light components in crude oil, such as methane, ethane, propane, etc., will volatilize from the annular space between casing and tubing to form casing gas. A gas column with a certain pressure is formed, which forces the dynamic liquid level of the oil well to drop, so that the effective production pressure drop of the oil well is reduced, and the production capacity is reduced; a part of the gas enters the pump cavity with the liquid flow, occupies a certain space in the pump cavity, and affects the pump efficiency. "Air lock" occurs, making the well pump unable to work

[0003] Due to the low output of oil well casing gas and the unstable pressure, there is no special gas pipeline to transport casing gas, and the casing gas cannot be recovered and utilized effectively. Strip burning or directly exhaust the casing gas

[0004] In order to solve this problem, there are currently three methods for recovering casing gas: one is to use the power of the pumping unit itself to drive the plunger to recover the casing gas, and pressurize it to enter the wellhead pipeline; this device has a complex structure, and Only suitable for pumping unit oil production, not for submersible pump oil production

The other is to use an air compressor device to increase the pressure of the casing gas, separate the gas from the liquid, and treat the harmful gas before entering the gas storage tank; this method has large investment, high maintenance and management costs, and large power consumption, which is economical. The benefit is not obvious, so it has not been promoted and applied

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