US3045751A - Flow control method for wells and apparatus therefor - Google Patents

Description

July 24, 1962 E. A; RODGERS FLOW CONTROL METHOD FOR WELLS AND APPARATUS THEREFOR Filed July 21, 1958 2 SheetsSheet 1 INVENTOR.

5 T .Eler-f a Rodgers I "1% Hrs HGE'NT .v;khhfi &fl .llllltll |!I||Il.lH vllllllllll llllllllllllllllll .illllllllllllll July 24, 19 62 E. A. RODGERS FLOW CONTROL METHOD FOR WELLS AND APPARATUS THEREFOR Filed July 21, 1958 2 Sheets-Sheet 2 IN V EN TOR.

Mummnmw United States Patent O 3,945,751 FLQW CONTROL METHOD FOR WELLS AND APPARATUS THEREFOR Y Elbert A. Rodgers, 4520 Spencer Drive, Wichita Falls, Tex. Filed July 21, 1958, Ser. No. 749,862

3 Claims. (Cl. 166-54) This invention relates to flow control devices for oil and gas wells, and more particularly to a device for controlling the flow of gas and water from the producing stratum through the bore hole of a well and to tanks or other place of storage.

Various flow control devices have been proposed heretofore; however, these for the most part, had to be specifically designed for a given operating pressure and for a given differential of pressure between the pressure of the producing stratum and the back pressure on the production line leading to the separator, tank, or the like.

The present device is of a character which may be placed either in the bore hole of a well, at a point within the production string of pipe or tubing in the lower portion of the well, or at any point along the length thereof, or, it may be placed exteriorly of the well head, to perform the desired function of permitting a maximum amount of'oil to be produced with a minimum loss of gas.

The manner of installation of each device rests with the individual operator, who is guidedby the particular conditions and needs of the well being produced. Should the well have certain characteristics, which might require the removal of the flow control device, and if the well has suflicient volume of gas and oil, an installation externally of the casing head might be most favorable. However, under other conditions, an installation within the string of producing pipe or tubing might be most favorable.

The present device is an improvement over my well flow control devices as disclosed in my prior, co-pending applications, Ser. No. 457,714, Oil and Gas Flow Control Device, filed September 22, 1954, now Patent No. 2,844,- 206-, and Ser. No. 605,006, now Patent No. 2,905,246, Liquid Level and Pressure Control Valve for Oil Wells,

filed August 20, 1956. While the above mentioned devices each have an individual field in which they are most proficient, the present device is adaptable to a wider range of conditions of producing oil.

An object of this invention is to provide a flow control device for oil wells and the like, wherein the maximum of oil is permitted to flow from the well, with a minimum loss of volume of gas.

Another object of the invention is to provide a flow control device for oil Wells wherein the device will retain the greater portion of the gas within the producing stratum.

A still further object of the invention is to provide a liquid level control for a producing well, wherein the flow of the well may be regulated in accordance with the production.

Still another object of the invention is to provide a flow control device which is simple in construction, positive in operation, easy to install and to remove, and which requires no regulation or operation attention.

With these objects in mind and others which will become manifest as the description proceeds, reference is to be had to the accompanying drawings, in which like reference characters designate like parts in the several views thereof, in which:

FIG. 1 is a vertical sectional view through an oil well, with portions broken away, shortened, and with portions shown in elevation to bring out the details of construction;

FIG. 2 is an enlarged longitudinal, sectional view taken through the flow control device, with parts broken away ice and shortened, and showing the flow control device in one position;

FIG. 3 is a sectional view taken on the line 33 of FIG. 2, looking in the direction indicated by the arrows, and on a slightly larger scale;

FIG. 4 is a view similar to FIG. 3, taken on the line 44 of FIG. 2, looking in the direction indicated by the arrows;

FIG. 5 is a sectional view taken on the line 5-5 of FIG. 2, looking in the direction indicated by the arrows;

FIG. 6 is an elevational view of an installation of a modified form of the flow control device above the ground, and showing the casing head and piping arrangement used for such installation;

FIG. 7 is a longitudinal, sectional view with parts broken away and shortened to show the details of con struction of the form of device as used in the piping arrangement shown in FIG. 6;

:FIG. 8 is a sectional view taken on the line 88 of FIG. 7, looking in the direction indicated by the arrows; and

FIG. 9 is a sectional view taken on the line Q9 of FIG. 7, looking in the direction indicated by the arrows.

With more detailed reference to the drawing, the numeral 1 designates generally, the bore hole of a well in which a casing 2 is installed, which casing is of the general character 'which forms a wall substantially throughout the depth of the well, and which usually has a perforate portion on the lower end thereof, the per forations 3 thereof admit fluid thereinto, such as oil and gas, from the producing formation, which is designated by the numeral 4. A tubing or production string of pipe 6 is lowered within casing 2 and is usually suspended within casing head 8 by a collar 10. The lower end of the production string has a seating collar 12 therein, in which a tapered or cupped sealing element 14 is fitted, which forms a fluid tight joint within the length of tubing 6. A further tubing 6a extends downward from seating collar 12 to a point near the bottom of the well and has perforations 16 therein to permit the passage of fluid thereinto. The cupped element 14 has an axial opening therethrough, the ends of which element 14 are preferably threaded. The lower end of the cupped-element 14 has an eduction tube 18 screw threaded thereinto and which tube extends downward into tubing 6a. A shell as surrounds the eduction tube 18 and has the lower end thereof closed by a plug 22, as will best be seen in FIG. 2.

The upper end of the shell 20 has an apertured closure 24 screw threaded thereinto, so that the closure 24 surrounds the eduction tube 18. The eduction tube 18 has a set collar 26 secured thereto by means of set screws 28 so as to limit the downward movement of shell 20 with respect to eduction tube 18. The lower end of the tube 18 has a tubular guide 30 sleeved thereon, which guide is fitted axially within shell 20 and is screwthreaded into the upper end of plug 22. A transverse opening 32 passes through the tubular guide 30 so as to permit equalization of pressure between the interior and exterior of tubular guide 30, upon relative movement of shell 20 with respect to eduction tube 18. A fitting 34 is screw threaded into the lower end of eduction tube 18, which fitting has transverse holes 36 formed therethrough, which holes are of gauged size and pass therethrough immediately above the upper end of guide 30. The fitting 34 has an out-turned flange 38 thereon, which is adapted to seat on the upper face of guide 30 to form a substantially fluid tight seal therewith. The outside diameter of fitting is of a size to fit loosely and s1idably within the inside diameter of tubular guide 30.

As oil is produced from the well, it will flow into the tubing 6a through the perforations 16 therein, and as the liquid rises upward in tubing 6a, the shell 20, the lower end of which is closed, will be buoyed up until the upper face of the tubular guide 30 seats on the lower face of out-turned flange 38, which faces form a fluid tight seal therebetween. The upper end of the shell has circumferentially spaced holes 40 formed therein, as will best be seen in FIGS. 2 and 3. The holes 40 admit fluid from the exterior of the shell 20 to the interior thereof. When the liquid level rises within the tubing 6a until the level thereof reaches the holes 40, and since the shell 20 has suflicient buoyancy to be buoyed upward within the liquid in tubing 6a, the upper end of the tubular guide 30 will be in abutting relation with the lower face of out-turned flange 38, and with the shell 20 in this position, the tubular guide 30 and the fitting 34 will form a valve to close the openings 36 in the eduction tube 18. With the open ings 36 closed, the shell will continue to fill with liquid until the weight of the shell combined with the weight of the liquid therein exceeds the buoyancy thereof, whereupon, the shell will move downward to partially or entirely uncover one or both of the holes 36, in a graduated amount, to enable the pressure being exerted thereon by the pressure in the formation to cause the oil to move upward under the hydrostatic and/or gas pressure within the eduction tube 18, thence out through axial opening within the cupped element 14, upward into production pipe or tubing 6 to the top of the well.

FIG. 1 shows the manner of placing the flow control device in a well, with the gas, oil and water strata being indicated with the arrows and indicating the pressure of the gas upon the upper surface of the oil and the hydrostatic pressure of the water indicating the upward pressure on the interface between the oil and water.

The present device is so constructed that it can be used in the bore hole of an oil well to enable the formation to release the oil therefrom in such manner that the oil will be produced by the pressure of the gas being exerted on the upper face of the oil in the reservoir and by the water pressure being exerted on the lower interface between the oil and water in the reservoir. By producing the oil only, and placing the present device at such level as to withdraw the oil from between the gas and Water in the formation, the gas and water will come closer together to enable the maximum recovery of oil with a minimum loss of free gas. Such restraints as allow only a gauged amount of fluid to pass into the bore hole may be made by chokes or the like, however, it is preferable to have the openings in the present device larger than any bottom hole chokes so that the holes in the device will not restrict or restrain the maximum flow of oil from the formation.

Operation of First Installation As the oil and gas moves through the perforations 3 of casing 2, and through perforation 16 of tubing 6a into the bore hole 1 under the normal gas pressure within the producing formation 4, the liquid level will rise in tubing 6a until the shell 20, the lower end of which is closed, floats upward, as the apertured closure 24 is in sliding relation with eduction tube 18, whereupon the upper face of tubular guide 30 will seat against the lower face of out-turned flange 38, which will prevent the escape of gas through holes 36 in fitting 34.

The shell 20 may be of such length as to cause the liquid level in the tubing 6a to rise to the desired height. The tubing 6a fills until the liquid overflows through circumferentially spaced holes 40 into shell 20 until the shell 20 receives sufficient liquid therein, such as oil or oil and water, to cause the shell to move downward to partially or completely open one or more of the holes 36, as the tubular guide 30 moves downward. However, the shell 20 is limited in its downward movement by set collar 26 secured to the eduction tube 18, and will engage the lower face of apertured closure 24. With the shell 20' moved downward until one or both the openings 36 are open, or at least partially open, the pressure from the 4 formation will be exerted on the face of the liquid within the tubular shell 20, which will cause the liquid level within the tubular shell 20 to be lowered, thereby driving the liquid into the eduction tube 18 and thence upward through axial opening in cupped element 14 into the tubing 6 to the surface of the ground.

As the liquid level is lowered in shell 20, the shell becomes more buoyant, and when the buoyancy approaches equilibrium, the out flow of liquid into the eduction tube 13 will be substantially balanced with the liquid coming into shell 20 through the openings 40. Since the holes 36 are below the surface of the oil, once the tubing 6a is filled with liquid to its operating level, the free gas is stopped from flowing out through holes 36. However, in the production of oil, a certain amount of gas is in solution in or entrained within the oil, and under high pressure, the bubbles of gas are minute, however, as the gas passes upward through eduction tube 18 into tubing 6, the pressure is lowered and these bubbles expand, thereby aiding in the flowing of oil from the well. However, the free gas within the formation is restrained therein, which gas exerts a differential of pressure between the formation and the inside of the tubing 6, so as to constantly maintain a gauged flow of liquid upward through tubing 6. However, if at any time, production of oil from the formation should decrease, the tubular shell 20 will correspondingly adjust the tubular guide 30 with respect to the holes 36, thereby reducing the output of oil without allowing the gas to escape from the formation.

In this manner the oil-gas ratio of the production is much lower than it would be if the method of using free flowing gas to flow the oil to the top of the well was employed.

Modified Form of Invention A modified form of installation of the device is shown in FIGS. 6 to 9, inclusive, which installation is made above ground, and in a manner which will enable the ready removal of the device for inspection and service, or replacement, as desired.

The well casing 2 has a casing head 8 thereon, in which a tubing 6 is positioned so as to be within the bore hole of the well substantially as shown in FIG. 1. A coupling 10 is screw threaded onto the upper end of the tubing 6, which fits on the casing head 8 to support the tubing within the well, but the tubing does not have a flow control device within the length thereof, as shown in FIG. 1. The tubing 6 extends upward and is preferably reduced in size, and has a valve 51 therein. A pipe 52 extends upward from valve 51, which pipe has a T member 54 thereon, a pipe 56 extends upward from one branch of the T member 54, which pipe 56 preferably has a pressure gauge 58 therein to enable the proper determination of the working pressure on the tubing 6. A valve 60 is within pipe 56 intermediate T member 54 and a T member 62 in the pipe 56, so as to enable the closing off of pressure, when desired, or by opening the valve, the fluid will by-pass the flow control device, which is designated generally by numeral 64. A pipe 66, of smaller diameter, extends outward from the other branch of T member 54, which pipe has a valve 68 therein, which valve is in close proximity to the T member 54 to enable closing the valve for servicing the flow control device 64. Unions 61 and 70 are provided in pipes 56 and 66, and a union connection is provided within a pipe 74, which pipe 74 leads from the flow control device 64, near the top thereof. The pipe 66 connects with the lower end of a shell 76 by an L 78. A valve 80 is positioned intermediate the upper end of flow control device 64 and T 62, with an interconnecting nipple therebetween. A valve 73 is positioned within pipe 74, which pipe interconnects with a branch of T 75 in pipe 56, which T 75 is positioned at a point intermediate a valve 84 and the discharge end of pipe 56 which leads to the tank, separator, or the like. A union 72 is in pipe 74.

Within the flow control device 64 is an eduction tube as well as proper installtaion and maintenance.

, 18 which is similar to that shown in FIG. 2, and which eduction tube has an apertured closure 24 fitted thereon for sliding relation therewith, and which closure is screw threaded into the upper end of a shell 20. The lower end of shell 20 is closed by means of a plug 22 which is screw threaded thereinto. The plug 22 has a central tubular guide member 30 upstanding therefrom, which guide member is screw threaded into the upper side of plug 22. The tubular guide 30 has a transverse hole 32 formed therethrough, to allow the pressure therein to equalize with the pressure exterior thereof. The eduction tube 18 has a fitting 34 screw threaded into the lower end thereof, which screw threaded portion thereof has a transverse opening 36a therethrough, as will best be seen in FIGS. 7 and 8.

The fitting 34 has an out-turned flange 38 thereon, which is adapted to complementarily seat on the upper face of tubular guide member 30-, when the shell 20 is in the uppermost position. The tubular guide forms a sliding fit with fitting 34 so as to open or close transverse opening 36a, upon downward or upward movement, respectively, of the shell 20, as will be more fully brought out hereinafter.

The shell 20 has circumferentially spaced holes 48 around the upper end thereof, to admit liquid thereinto from the annular space between casing 76 and shell 20, as the liquid level therein rises. The eduction tube 18 is screw threaded into the lower end of pipe fitting 86, which fitting has an axial opening 88 therethrough. The fitting 86 has a valve 80 on the upper end thereof so as to control the flow of liquid upward therethrough. A nipple 82 connects with the upper end of the valve 80 and to one branch of the T within pipe 56.

A screw threaded opening 98 is formed in a side of casing 76, near the upper end thereof, and into which opening 90 the pipe 74 is screwed. A valve 73 is provided between the casing 76 and the pipe 56, to enable the closing of the pipe 74, for reasons to be brought out hereinafter.

A set collar 26 is secured to eduction tube 18 by means of screws 28, so as to limit the downward movement of shell 20 with respect to eduction tube 18. It is preferable to have the pipe arrangement substantially as shown in FIG. 6, which will enable proper setting of the device,

Furthermore, this installation enables the ready removal of the flow control device 64, without the necessity of shutting down the well, as the production therefrom may be bypassed through pipe 56, by opening valves 51, 6t) and 84, and by closing valves 68, 73, and 80.

In instances where a well has unusually high gas pressure, and the form of the device, as shown in FIGS. 7 and 8, is used, slots 82 may be formed in the upper face of tubular guide member 30 which will prevent out-turned flange 38 from forming a positive seal therewith, when in seated position. And since there is clearance between the inner diameter of tubular guide 30 and the outer diameter of fitting 34, fluid will be permitted to leak thereby and through transverse openings 36a. This arrangement is necessary only on wells which have very high gas pressure, wherein gas pockets form in the upper end of casing 76 and prevent entrance of oil thereinto. These slotted openings will permit a small amount of gas to escape, when necessary, to permit oil to flow into casing 76.

The pipe 66 is preferably of considerably reduced size with respect to pipe 52, so as to give the proper differential of pressure between the incoming oil and the oil passing out through pipe 82, which pipe 82 is substantially larger than pipe 66.

Operation 0 Modified Form of Invention With the device installed within a string of production pipe or tubing exterior of the well head 8, substantially as shown in FIG. 6, the oil is allowed to flow from the formation into the bore hole of the well through the usual perforations in the casing and tubing, as shown in FIG. 1, thence up through tubing 6 to the top of the Well, and if desired, the flow may be partially restrained by a valve 51, and with valves 60 and 68 closed, a reading of pressure may be taken by gauge 58, to determine when a liquid column has built up in tubing 6, which liquid column is permitted to build up by by-passing the gas from the upper portion of tubing 6 around flow control 64, by Opening by- pass valves 60 and 84 until sufficient fluid is present in the tubing 6 to flow the well. When this condition has been satisfied, the valve 68 is opened, and the valve 73 closed, oil is then permitted to enter the well flow device through pipe 66.

As the oil or liquid rises upward within casing 76, the shell 20 will be buoyed up until the upper face of tubular guide 30 is in abutting relation with the lower face of outturned flange 38, having closed transverse openings 36a, and with the liquid rising within casing 76, the liquid will rise until the oil being produced attains the height on shell 20 of the holes 40, whereupon, the liquid will pass into the shell 20 through holes 40 and will rise upward therein until the weight of the liquid within the shell overcomes the buoyancy thereof. Whereupon, openings 36a, which have been closed, are opened to such extent that oil will flow outward into eduction tube 18 in a gauged amount, thence upward through fitting 86, valve 80, nipple 82 into T 62, thence outward into pipe 56 through valve 84 and out through pipe 56, which leads to a tank or other place of storage or disposal.

The pipe 74 is provided intermediate casing 76 and T 75 in pipe 56, which will enable the valve 73 to be opened to determine the operation of the device, as by closing the valve 80, it can be determined if the shell 20 is functioning, as the liquid will rise upward in the casing 76 and flow outward through pipe 74.

As pointed out above, by disconnecting unions 70 and 72 the fitting 86 may be readily unscrewed from valve 80, and since the tubular casing is screw threaded into a fitting 86 at the upper end, and into a fitting 87 at the lower end, the device can be readily disassembled, serviced, reassembled and put back into operation in a minimum of time.

Having thus clearly shown and described the invention,

, what is claimed as new and desired to be secured by Letters Patent is:

1. A flow control device for an oil well having a production string of tubing therein; which device comprises an eduction tube connected to said production string of tubing in fluid communication therewith, an enlarged tubular shell having at least one aperture formed therein near the upper end thereof, which enlarged tubular shell surrounds said eduction tube and is in sliding relation thereon, said enlarged tubular shell having the lower end thereof closed, a tubular guide member having an upper face, which tubular guide member is fitted within the lower end of said enlarged tubular shell centrally thereof and in axial alignment with said eduction tube, a fitting on the lower end of said eduction tube which is in sliding relation with said tubular guide member, said fitting having an opening formed therein, which opening is above said tubular guide member when said tubular guide memher is in the lower-most position, said opening in said fitting being closed by said tubular guide member when said tubular guide member is in the upper-most position, an out-turned flange on said fitting intermediate the length thereof, which flange is in complementary seating relation with the upper face of said tubular guide member when said tubular guide member is in the upper-most position, said fitting on said eduction tube having the lower end thereof closed, said tubular guide member having an opening formed thereinto, which opening is in communication with the hollow portion of said shell, and an abutment on said eduction tube to limit the downward movement of said shell.

2. A flow control device as defined in claim 1; wherein said eduction tube is connected to the lower end of said production string of tubing.

3. A flow control device as defined in claim 1, wherein a seating collar is mounted within said production string of tubing, said seating collar having an axial opening formed therethrough, a sealing element fitted on the upper end of said eduction tube, which sealing element has an axial opening therethrough in communication with the passage in said eduction tube for passage of fluid from below said sealing element to a point thereabove.

References Cited in the file of this patent UNITED STATES PATENTS Battelle Mar. 14, 1933 Halliburton July 3, 1934 Halliburton Feb. 26, 1935 Zublin June 25, 1935 Rodgers Aug. 30, 1938 Rodgers Jan. 3, 1939 Zublin Jan. 21, 1941 Zublin July 16, 1946 Rodgers July 22, 1958

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