Liquid Gas Separator

Abstract

A float operated separator valve attached at the bottom of an oil-gas well including a delivery pipe with ports therein, a valve sleeve slidable on the pipe with openings therethrough which when the valve is open align with the ports in the pipe, the sleeve being positioned inside and connected to a cylindrical float with its top open for receipt of fluid. The ports and openings being in alignment to provide a passage up the delivery pipe when the float is full of fluid, but as the fluid in the float drains the float lifts due to buoyancy, thereby closing off the passage.

Description

BACKGROUND OF THE INVENTION

The usage of bottom hole separators has been instrumental in increasing the production of some types of wells for several years. While they primarily have been used in oil producing wells to conserve the reservoir gas energy (U.S. Pat. No. 2,905,246), they are also used in gas wells. Even in a gas well fluids will seep into the bottom of the bore hole, building up a static head. If the liquid is permitted to accumulate to too great a depth, it can seal off the gas flow from the producing formation and stop any production in the well. These and similar problems can be solved by the use of a device which separates the gas from the liquid at the bottom of the well and assists in removing the liquid from the well by a conventional rod pump or gas lift.

SUMMARY OF THE INVENTION

The separator of the present invention is connected to the end of a section of delivery pipe, which is held in the tubing string by a conventional pack-off. Liquid collecting in the separator flows up the delivery pipe through the pack-off and from there is raised to the surface by conventional means.

The separator includes a section of pipe having a closed end with entry ports approximate its closed end. The sliding portion of the separator comprises a hollow cylindrical float having an open top with a closed bottom. Attached to the closed bottom of the float is a valve sleeve having circumferentially spaced openings therein. Slidably received in the valve sleeve is the previously mentioned section of pipe with the ports therein. When the float is empty of fluid, the buoyancy of the outside fluid causes it to raise so that the ports in the delivery pipe are blocked by the valve sleeve. When sufficient fluid spills over the top and fills the float member, it will sink to a position aligning the openings in the valve sleeve with the ports in the delivery pipe, thereby allowing the fluid within the float to flow up the delivery tube due to the pressure differential. When the level of fluid in the float drops sufficiently low, the float will be buoyed upwards, shutting off the flow.

It is therefore the principal object of the present invention to provide a separating device which may be introduced, located, and retrieved, from the well using standard wire line equipment.

It is a further object of the present invention to provide a liquid gas separator which may be raised or lowered independently of the other equipment positioned in the well bore.

Another object of the present invention is to provide a liquid gas separator which is of maximum simplicity and minimum size.

Further objects of the invention will be in part apparent and in part pointed out specifically hereinafter in connection with the description of the drawing which follows and in which:

FIG. 1 is a partial longitudinal section of a conventional well utilizing the present invention with portions of the well broken away to conserve space;

FIG. 2 is a longitudinal section of the separator to an enlarged scale with portions of its length broken away to conserve space; and

FIG. 3 is a partial section taken along lines 3 -- 3 of FIG. 2.

Referring to the drawings and more specifically to FIGS. 1 and 2, the liquid gas separator of the present invention is generally identified by reference numeral 10. A conventional well casing 12 is shown extending down to a producing formation 14. Located inside the casing 12 is a string of tubing 16 with a conventional pack-off 18 (symbolically shown) placed therein. Connected to the pack-off 18 and extending therethrough is a section of delivery pipe 20 which supports the separator tool 10. While not shown in the drawings, some conventional well known form of fluid pump means such as a rod pump or gas lift is placed in the tubing 16 immediately above the pack-off 18.

The liquid gas separator 10, as seen in FIG. 2, comprises a cylindrical float 21 with a top opening 22 and an enclosed bottom 23. Concentrically located within the float 21 and attached to the bottom 23 is a sleeve member 24 which functions as the moving member of the valve. Threadably attached to delivery pipe 20 is a short section of delivery pipe 25 with a conical guide shoe 26 located at the bottom end thereof and a collar portion 27 located at the upper end thereof. The last mentioned collar 27 and guide shoe 26 function as stop limit means for the slidable sleeve member 24. Located in the delivery pipe 25 are four ports 30 circumferentially located around the tube. These ports can best be seen in FIG. 3. Located in the sleeve member 24 are eight openings 32 all of which are joined by a circumferential groove 34 located on the inside of sleeve 24. When sleeve 24 is in its lower most position, as viewed in FIG. 2, the openings 32 are in alignment with the ports 30, opening a passage into the center of delivery pipe 25. The purpose for groove 34 is to provide an open passage between ports 30 and openings 32, regardless of their relative angular positions. Located in the tubing string 16 just below the pack-off 18 is a vent 19 which allows the fluid to enter the bottom of the tubing 16.

OPERATION

The gas and oil flowing out of a producing formation 14 will flow up the well casing 12 caused by the reservoir pressure. The gas flows between the casing 12 and the tubing 16, as indicated by arrows 40, while the fluids generally pass up the tubing, indicated by arrows 42. The separator 10 is placed in the tubing 16 at such a point to maintain the fluid level A at a point where best production is possible from the well. The separator 10 is placed in the well by positioning the pack-off 18 with standard wire line equipment. In the case where a rod pump will be utilized to raise the fluid once separated to the surface, the separator 10 and its pack-off 18 may be attached directly to the bottom of the rod pump (not shown in the drawing).

In viewing FIG. 1, the liquid level A has built up to a sufficient height around float 21 to raise the float to its closed position, blocking flow into delivery pipe 20. When the level of liquid A reaches a sufficient height to spill over the top of the float 21, as seen in FIG. 2, the float will fill up with fluid. When a sufficient amount of fluid has entered the float so as to overcome its buoyancy, the float will sink to its FIG. 2 position, opening the ports 30 in the pipe 25 through the openings 32 in the sleeve 24. Since the interior of delivery pipe 25 is connected to the top side of pack-off 18 which is at zero pressure, the liquid will flow through the openings and ports up the delivery pipe 25 and 20 to a point above pack-off 18 where it is lifted to the surface by any sort of conventional rod pumping or gas lift valve. When a sufficient quantity of liquid has been drained from the float, the buoyancy of the float will again lift the openings 32 out of alignment with ports 30, thus prohibiting the flow of any gas into the tubing. When a sufficient quantity of liquid has again accumulated in the well bore, spilling over the top of float 21, the separator will again open the passage in the interior of the float and allow the process to be repeated. While the fluid entering the bottom of casing 12 is mixed with a large amount of free gas surging up the casing, the fluid which overflows the float is allowed to settle in the bottom of the float where the gas is separated therefrom.

In any particular well the liquid may be oil or brine, or a combination of both at varying temperatures and pressures. Almost always the liquid, whatever its nature, will contain a certain amount of solids. While a relatively large particle may be carried upward in the casing to the top of the float, due to the agitation and surging caused by the gas, when that particle enters the relative stable condition within the float, it will settle out at the bottom of the float without obstructing the openings 32. Due to the existence of connecting groove 34 on the inside of sleeve 24, the sleeve or float 21 can rotate on tube 25 without blocking the passage between ports 30 and openings 32.

The chemical nature of both the gas liquid will vary widely with the different locations, but it is to be expected that some degree of corrosion potential will be present in every location. It is impossible therefore, to specify any particular alloy as optimum for all locations. For many wells, stainless steel will be adequate, but for other wells more exotic alloys such as "Monel K" will be required. The number and size of the ports 30 and openings 32, of course, can be varied in number and size for various types of wells without departing from the scope of the invention.

Claims

Having described the invention with sufficient clarity to enable those familiar with the art to construct and use it, I claim:

1. A device for separating oil and gas accumulated in a producing well attached to the bottom of a pack-off placed in the tubing, the separator comprises:

a delivery pipe with a closed lower end extending down through the pack-off, the lower portion of the delivery pipe having ports therein;

a slidable valve sleeve member surrounding the delivery tube and its ports, the sleeve having a plurality of openings therein, all of which are joined by a circumferential groove on the inside of the sleeve;

stop means limiting the downward movement of the sleeve at a point where the ports and openings are in alignment providing an open passage into the delivery tube; and

float means having an open top surrounding the sleeve and attached thereto, whereby as sufficient fluid overflows the open top, the float means sinks, aligning the ports and openings allowing the fluid in the float to pass up through the delivery pipe until sufficient fluid is removed to raise the float.

2. A device for separating oil and gas as set forth in claim 1, wherein the ports in the delivery tube are circumferentially spaced so as to be in communication with the circumferential groove when the sleeve is in its downward position.

3. A device for separating oil and gas as set forth in claim 1, wherein the sleeve member is attached to the bottom of the float means with the openings being spaced upward therefrom whereby fluid carried sediment entering the float means will settle to the bottom of the float rather than flow through the openings.

4. A device for separating oil and gas as set forth in claim 1, wherein the float means defines a fluid chamber with the sleeve member contained therein.

5. A device for separating oil and gas as set forth in claim 1, wherein the ports in the delivery tube are circumferentially and quandrantally spaced so as to be in communication with the circumferential groove when the sleeve is in its downward position, and float means surrounding the sleeve and attached thereto with an open top, whereby as fluid overflows the top, the float means sinks to the downward position, aligning the ports and openings, allowing the fluid in the float to pass up through the delivery tube.

6. A device for separating oil and gas as set forth in claim 1, wherein the stop means is a conical guide shoe closing the lower end of the delivery tube.

7. A device for separating oil and gas as set forth in claim 1, wherein the float means is a cylindrical chamber with its bottom connected concentrically with the bottom of the sleeve member.

8. A device for separating oil and gas as set forth in claim 1, wherein the stop means also limits the upward movement of the sleeve member in a position blocking the ports in the delivery tube.