Well backwashing valve and oil extraction tube column

Abstract

The invention provides a well backwashing valve and an oil extraction tube column. A floater is arranged in a floater containing cavity in a shell, the density of the floater is smaller than the density of flushing fluid and is larger than the density of formation liquid, in the oil extraction stage, the formation liquid flows out of an upper connector from a lower connector through a first channel, the floater containing cavity and a second channel in sequence, in the well backwashing stage, well washing liquid injected from an oil sleeve annulus enters the floater containing cavity from theupper connector through a second channel, the floater floats to form blocking with a valve seat, the well flushing fluid cannot enter the first channel, therefore normal well washing circulation is established, the problem that well washing liquid cannot scour the interior of an oil well pump due to the fact that the well washing liquid leaks into the stratum and cannot reversely flow out of a wellhead is avoided, monitoring of the annulus liquid level of a rod-pumped well cannot be affected, and important data are provided for production of the pumping well; moreover, the oil extraction process and the well backwashing process can be quickly switched, the oil extraction efficiency is improved, and in addition, water injection can be realized.

Description

technical field [0001] The invention relates to the technical field of oil and gas exploitation and well flushing, in particular to a backflushing well valve and an oil production string. Background technique [0002] Carbonate reservoirs have the characteristics of large reservoir leakage, and the bottom hole pressure is generally much lower than the hydrostatic column pressure at the depth of the well after the oil well is transferred to the pumping unit for production. The pumping string often has wax deposits, dead oil, suspended sand and other things that affect normal oil production. Regularly performing reverse circulation well cleaning on the pumping well can effectively reduce the number of pump inspections and increase oil production. [0003] However, the normal well flushing cycle cannot be established in carbonate reservoirs dominated by cavernous reservoirs. The flushing fluid injected back into the well usually leaks into the formation and cannot be returned ...

AI Technical Summary

Problems solved by technology

[0004] The invention provides a backwash well valve and an oil production string to establish a normal well wash cycle and avoid the problem that the well wash fluid cannot be flushed out of the wellhead due to the leakage of the well wash fluid into the stratum and the inside of the oil well pump.

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