Gas lift negative pressure pump

Abstract

The invention relates to the technical field of downhole tools for gas-lift wells of oil and gas wells and particularly relates to a gas lift negative pressure pump. The gas lift negative pressure pump comprises a pump body composed of an inner working barrel and an outer working barrel, wherein two ends of the pump body are respectively an upper connector and a lower connector; the pump body is provided with an air inlet, and a nozzle is installed in the pump body; a diffusion tube, a throat pipe, a nozzle sleeve and a cross-shaped assembly are successively installed on the same axis in the inner working barrel along the direction from the upper connector to the lower connector; the aperture of the diffusion tube is from the largest to the smallest in the direction from the upper connector to the lower connector; and a cavity is formed between the throat pipe and the nozzle sleeve. The pump can solve the problem that deep wells with lower pressure cannot amplify the producing pressure difference because gas injection pressure acts on the oil layer, and can also solve the problem that high-yield wells with higher pressure and capacity cannot further amplify the producing pressure difference because the gas injection pressure and the liquid column pressure below a working valve enable an oil layer produces excessive return pressure, thus greatly increasing the yield of the gas-lift wells in the case that gas injection pressure, gas injection volume and costs are unchanged.

Description

Technical field: [0001] The invention relates to the technical field of downhole tools for gas lift wells of petroleum and natural gas wells, in particular to a gas lift negative pressure pump. Background technique: [0002] Compared with other mechanical recovery methods, gas lift production has many advantages, such as strong adaptability, that is, it can be applied to deep wells, shallow wells, high oil-gas ratio wells, high sand content wells, deviated wells, and horizontal wells. It is easy to manage and relatively low in cost. Low. However, since the flow pressure of the oil layer in the continuous gas lift well is equal to the gas injection pressure in the annular space plus the pressure generated by the dynamic liquid surface at the working valve, the pressure in the tubing is equal to the pressure generated by the liquid column below the working valve plus the mixed gas column above the working valve. The combination of pressure and back pressure leads to the disad...

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Problems solved by technology

[0003] For deep wells with low pressure, sometimes the gas injection pressure is almost equal to the flow pressure, so because the gas injection pressure acts on the oil layer, the production pressure difference cannot be enlarged, which not only affects the production of the oil well, but also has a high gas injection ratio, seriously affecting The lifting efficiency is reduced; shallow wells with lower pressure cannot produce normally at all

[0004] For high-production wells with high pressure and production capacity, since the gas injection pressure and the liquid column pressure below the working valve directly act on the oil layer, excessive back pressure will be generated on the oil layer, so that the production pressure difference cannot be further enlarged. Seriously affect the production and lift efficiency of gas lift wells

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