US 4,393,928 AGranted

Apparatus for use in rejuvenating oil wells

OwnerCharles E. Warnock, Sr.inventor

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Abstract

A sub incorporating a check valve is connected into the lower end of a well pipestring. This valve will pass hot steam injected down the pipestring to the formations to loosen up the thick crude oil. The check valve prevents back flow and thus will hold the high pressure steam. To resume production, the production pump can then be lowered through the pipestring. The pump itself is provided with an extended probe member which will unseat the check valve when the pump is in proper position so that production pumping can resume.

Claims2

Dependent claims

An apparatus for use in rejuvenating oil wells wherein such rejuvenation involves injecting steam through a pipestring and holding the steam under pressure in the well for a period of time before a production pump is lowered into the pipestring to resume production pumping operations, including, in combination:

(a) a sub incorporating a check valve comprising a valve seat, ball and spring biasing the ball against the seat, said sub having exterior upper and lower threads for insertion into the pipestring so that steam can pass down through the pipestring and through the check valve to the surrounding formations, the check valve blocking back flow of steam into the pipestring, said sub having internal threads at its upper and lower ends, and a reduced diameter central opening defining an annular shoulder facing said upper end, said seat being receivable in said upper end for seating on said annular shoulder;
a threaded collar received in said upper internal threads to hold said seat against said annular shoulder;
and a spring cage threadedly received in said lower internal threads of said sub for holding said spring for said check valve in a manner to urge said ball upwardly through the reduced diameter central opening against said valve seat, whereby said check valve can be easily disassembled for maintenance purposes;
and
(b) a hollow probe member having a lower narrow nose portion with a plurality of openings in its lateral wall, the diameter of said nose portion being less than the diameter of the seat for said check valve, the upper end of said probe member having threads for threaded engagement with the lower end of said production pump such that the probe member can be substituted for the normal pump screen threadedly held therein, whereby after steam has been injected into the well, the check valve will hold the pressure and block back flow so that said production pump can immediately be lowered while said well is cooling and the pressure is dropping, said probe member serving to enter said valve seat and unseat said ball to thereby open said check valve and permit production pumping of the well to resume.

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Dependencies are inferred from the claim text.

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Abstract

(a) a sub incorporating a check valve comprising a valve seat, ball and spring biasing the ball against the seat, said sub having exterior upper and lower threads for insertion into the pipestring so that steam can pass down through the pipestring and through the check valve to the surrounding formations, the check valve blocking back flow of steam into the pipestring, said sub having internal threads at its upper and lower ends, and a reduced diameter central opening defining an annular shoulder facing said upper end, said seat being receivable in said upper end for seating on said annular shoulder;
a threaded collar received in said upper internal threads to hold said seat against said annular shoulder;
and a spring cage threadedly received in said lower internal threads of said sub for holding said spring for said check valve in a manner to urge said ball upwardly through the reduced diameter central opening against said valve seat, whereby said check valve can be easily disassembled for maintenance purposes;
and
(b) a hollow probe member having a lower narrow nose portion with a plurality of openings in its lateral wall, the diameter of said nose portion being less than the diameter of the seat for said check valve, the upper end of said probe member having threads for threaded engagement with the lower end of said production pump such that the probe member can be substituted for the normal pump screen threadedly held therein, whereby after steam has been injected into the well, the check valve will hold the pressure and block back flow so that said production pump can immediately be lowered while said well is cooling and the pressure is dropping, said probe member serving to enter said valve seat and unseat said ball to thereby open said check valve and permit production pumping of the well to resume.

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