US2154768A - Means for flowing wells - Google Patents

Description

April 18, 1939. H. c. oTls 2,154,768

MEANS FOR FLOW ING WELLS Filed Feb. 14, 1935 2 Sheets-Sheet l Patented Apr. 18, 1939 UNITED STATES PATENT OFFICE 12 Claims.

This invention relates to new and useful improvements in means and methods of flowing wells.

One object of the invention is to provide an improved method and means for flowing oil wells,

wherein a pressure fluid, such as gas, is employed in a new and novel manner.

A particular object of the invention is to provide a method and means for carrying out the same, wherein both the flow of the influent oil and the infiuent gas are so controlled, as to be admitted alternately, thus producing in the flowing column alternate slugs or stages of oil and gas, rather than an intimate mixture of the same.

A further object of the invention is to provide means whereby a more eificient use of the lifting fluid or gas is accomplished, and also whereby the gas energy is conserved and less waste occurs.

An important object of the invention is to provide a method and means whereby the flowing pressure of the column of oil being elevated, cannot become equal, by an ample differential, to the pressure of the lifting fluid, thus preventing the building up of a back pressure suflicient to de- 25 feat efiicient flowing under varying conditions.

A further object of the invention is to provide means for controlling the admission of lifting gas to the flowing column, and assuring suflicient velocity to prevent said gas seeping or bubbling up through the oil, and thus obviating slippage.

A construction designed to carry out the invention will be hereinafter described, together with other features of the invention.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings, in which an example of the invention is shown, and wherein:

Fig. l is a View partly in elevation and partly in section showing the flowing apparatus mounted in a well casing,

Figure 2 is an enlarged vertical, sectional view of the valve. arrangement showing the gas valve in an open position and the oil valve closed,

Figure 3 is a view similar to Figure 2 showing the gas valve in its closed position and the oil valve opened,

Figure 4 is a horizontal cross-sectional view taken on the line 4-4 of Figure 2,

Figure 5 is a horizontal cross-sectional view taken on the line 5-5 of Figure 2,

Figure 6 is a horizontal cross-sectional view taken on the line 66 of Figure 2,

Figure 7 is a vertical sectional view showing a slightly modified form of the valve head, and

Figure 8 is a view partly in elevation and partly in section showing another form of the invention mounted within the well casing.

In the drawings, the numeral l0 designates a valve housing, which is in the form of a sleeve or coupling having internal screw-threads II at its upper end and internal screw-threads 12 at its lower end. The upper end of the housing is adapted to receive the lower end of a string of tubing l3; while a nipple I4 is screwed into the threads l2 at the bottom of the housing. The nipple is screwed into a coupling 15, which in turn, is screwed on to the upper end of a lower string of tubing l5. By this arrangement, the housing I0 may be placed at the proper elevation in the casing Hi.

The upper end of the casing is closed by an ordinary casing head IT. A tubing head I8 is carried by the casing head so that the upper end of the casing is completely packed off. By observing Figure 1, it will be seen that a fluid pressure storage chamber is formed in the upper portion of the casing above the liquid level A.

A cylindrical valve head I9 is externally screwthreaded at 20 and the upper end of the nipple I4 is internally screw-threaded at 2| to receive the threads 20, whereby said head may be screwed down into said nipple at the lower portion of the housing ID. The head is surmounted by a cylindrical cage 2|, having its upper end open and provided with a ground seat 22. This seat receives the ground face 23 of an annular shoe 24 having substantially the same external diameter as the cage 2|. Both, the cage and the shoe, are considerably smaller than the internal diameter of the housing l0 so as to provide an ample space therebetween.

A small string of tubing 25 extends axially above the shoe 24 in the tubing I 3. This string of tubing 25 is considerably smaller than the internal diameter of the tubing l3, so as to provide ample flow space for the fluid passing up the tubing l3. The lower end of the string 25 screws into the upper end of the case 26 of a check valve. The case 26 contains a ball valve 21 which is adapted to close upwardly against a seat 28, as is shown in Figure 3. This check valve acts to pre.. vent a back flow up the string of tubing 25, but

to open and permit a free flow down through said head 24, may be lowered into the string I3 until the face 23 engages the seat 22. Owing to the curvature of the seat, it is obvious that the head will center itself on the cage and form a fluidtight seal therewith.

The string 25 extends upward in the string I3 to a point well above the liquid level A. An elbow 3|], forming part of an inlet head, is fastened on the upper end of the string 25 and projects through the tubing I3, as is shown in Figure 1. The elbow has a reduced port 3| communicating with the storage chamber of the casing so as to admit the pressure fluid, such as gas, into the elbow and then to the string 25. For the sake of clarity, the string of tubing I3 may be referred to as the flow string, while the string 25 may be referred to as the lifting fluid string.

The valve cage 2| is formed with an annular beveled seat'32. Below this seat and immediately above the head I9, the cage is formed with ports 33 communicating with the housing II]. A valve disk 34 is mounted in the cage above the seat 32 and is beveled on its under side so as to engage said seat and form a fluid-tight joint therewith.

It will be observed that the valve 34 is of less diameter than the internal diameter of the cage, so as to provide a passage between the valve and the cage. By this construction, the lifting fluid, which flows down the lifting fluid string, will be permitted to by-pass the valve, whenever the same is opened, to the ports 33 into the housing ID. The area of the clearance between the valve 34 and the cage will determine the rate of flow of the lifting fluid, past the valve and into the housing. This area must be such as to provide a flow of gas of suflicient velocity to assure lifting of the slug or stage of oil above the slug of gas, thereby preventing the gas seeping through the oil and causing slippage.

The valve is provided with a depending stem 35, which extends axially through a passage 36, in the top of the head I9, and thence through a chamber 31, below said passage. The lower end of the head I9 is counter-bored to receive an ordinary valve seat ring 38, which is provided with the usual valve seat 39 for receiving a ball valve 40. The stem is long enough to engage the valve 40 and displace it downwardly as is shown in Figure 3, and so hold it when the disk 34 engages its seat 32. It is noted that if desired, the lower end of the stem may be fastened to the ball so that said ball and the disk move as a unit.

The ring 38 telescopes the upper end of an elongated cylindrical valve cage 4|, which has its upper end screwed into the lower end of the head I9. This cage contains a coiled spring 42 which supports the valve 40. When the valve 34 is forced downwardly to open the valve 40, the spring 42 will be compressed so as to raise the ball 4|! and thus close the valve, when the pressure on the disk 34 permits. Upwardly inclined ducts 43 extend from the chamber 31 to the interior of the housing I0. These ducts permit the liquid, which passes the valve 40, to flow into the housing and since said ducts are of relatively small cross-sectional area as compared to the crosssectional area of the chamber, it will be manifest that they provide a restriction of the flow from cross-sectional area of the chamber 31 whereby said ports do not restrict the flow of liquid into the chamber when the valve is unseated; also said ports are located so that the ball 40 moves below the same out of alinement therewith when it is in its completely open position. These ports act to strain the oil, or other liquids, which enter the cage.

It is pointed out that the valve disk 34 controls the passage of the lifting fluid, such as gas. When this valve is closed against its seat 32 no gas is admitted to the housing II] for elevating the liquid in the string I3. The valve ball 40 is normally closed and controls the passage of liquid, such as oil, through the ring 38 to the housing I 0.

In Figure 1, the valve housing H3 is shown as located a substantial distance below the oil level A, while the inlet port 3| is located a substantial distance above said oil level. This arrangement permits the lifting fluid, such as gas under pressure, to enter the member 30 from the storage chamber, formed in the casing I3, and pass down the lifting fluid string 25. Oil will flow up the string of tubing I5 and fill the nipple I4. Oil will also enter the cage 4| through the ports 44.

Assuming that the valve 40 is closed and the valve 34 is open, as is shown in Figure 2, the lifting fluid will pass downwardly and outwardly through the ports 33 into the housing ID. If no oil was standing in the housing, the gas would merely flow up the string 3, but if oil was standing the gas would elevate such oil. Under this condition, there will be a pressure exerted downwardly against the ball 40 by reason of the pressure exerted by the lifting fluid on top of the disk 34. The pressure acting downwardly against the valve 40 is under these conditions the same as that acting upwardly against the entire under area of the valve 34: When this pressure on the lower area of valve 34 is low enough with respect to the downwardly acting fluid pressure on top of the disk 34, there will be suflicient differential pressure across the disk 34 to start the valve 40 to move downwardly from its seat 39, against the action of the submergence pressure acting upon it. As the valve 40 leaves its seat, the oil or influent is admitted through the ring 38 into the chamber 31, more rapidly than it can pass out or escape through the ports 43, thus the pressure within said chamber is built up more rapidly than the flowing pressure which acts against the under side of the valve 34. This rapidly increasing pressure in the chamber 31 acts downwardly against the ball 40.

The increase in the pressure acting downwardly against the valve 40 in addition to the gas pressure acting downwardly on the disk and through the stem causes said valve to move downwardly against the tension of the spring 42, to a fully open position thus permitting a free entry of the oil into the chamber 31 and outwardly and upwardly through the ducts 43 into the housing I0. Of course, as the ball moves to wide open position, the disk is seated to out 01f the admission of gas. When the valve 40 isfully opened, the influent or oil will have a free entrance through the ports 44 into the chamber 31, from which it will flow through the ducts 43.

When the valve 40 is thus moved downward to its limit, the pressures across it are equalized and consequently a change in the area under submergence pressures takes place. When the valve 40 was closed, or when it was partially opened, whereby there was a'restriction of the influent entry at the valve seat 39, the area of the valve contact with said seat was under the higher submergence pressure. It is pointed out that when the valve 40 is wide open with theisubmergence pressure, that is the pressure of the influent, equalized across it, only the smaller area of the valve stem 35 is under the higher submergence pressure.

From the foregoing, it will be seen that the flowing pressure acting upwardly against the under surface of the valve 34 must increase before this energy, together with the submergence pressure acting against the area of the lower end of the stem 35, will overcome the action of the lifting fluid pressure which is holding the valve 34 on its seat 32. Until this takes place the point of restriction of the influent is the combined areas of the duct 43. When the flowing pressure of the oil, in the housing l0, and the back pressure created thereby acting against the underside of the valve 34, rises high enough, such increase coacting with the tendency of the spring 42 to expand, will cause said valve 34 to move upwardly and again admit the lifting fluid below said valve.

As the valve 40 nears its seat the point of influent restriction is again between this valve and its seat, thus an excess of energy is made available, whereby the valve 40 is snapped against its seat, which cuts off the influent entry and opens the valve 34, as before described. It becomes apparent that when once the valve 43 is opened to admit oil, the flowing pressure of the fluid in the housing ID must rise or increase before the influent will be cut on. This pressure Will always be reached before the flowing pressure becomes equal to the lifting fluid pressure.

The operation of the valve 40 and disk 34 is one of alternate admission of oil and lifting gas. With the parts in the position shown in Figure 2, the gas is entering the tubing and the submergence pressure is acting against the ball 4!] and through the stem 35 to aid in holding the disk 34 unseated. Of course, the flowing pressure in the tubing is also acting against the underside of the disk to hold the same raised. As the load in the tubing lightens, the flowing pressure beneath the disk decreases to a predetermined proportion of the gas pressure, whereupon the pressure above said disk starts the disk downwardly. Downward movement of the valve moves the ball 45! oh its seat to permit the liquid to enter the chamber 3! to build up a pressure therein as has been explained. This pressure in the chamber aids the gas pressure above the disk to open the ball 40 to its wide open position, permitting seating of the disk-whereby the parts are immediately and quickly moved to the position shown in Figure 3. In this position, there is no pressure differential across the ball 40, since the ball is subjected to the submergence pressure on all sides. As the oil or other liquid enters the housing it, it will be manifest that the underside of the disk 34 is acted upon by the flowing pressure and the submergence pressure through the stem 35 and when these pressures reach a predetermined point sumcient to overcome the gas pressure above the disk, said disk begins to move upwardly. As soon as movement of the disk begins, the valve 40, of course, moves upwardly and as it approaches its seat, the flow of oil into the chamber 3'! is pinched, whereby the pressure in said chamber above the valve 40 is decreased. This causes a pressure differential to be again set up across the valve 40,

which pressure differential aids in quicklyand immediately moving the ball to its seated position and the disk 34 to its unseated position. Therefore, a snap action is imparted to the valve and disk as they move from one position to another and manifestly, a column of oil and a column of gas are alternately introduced into the tubing.

It is pointed out that except momentarily the valve and disk are not open at the same time and therefore, a column of oil is admitted, after which a slug of gas is admitted, the latter bodily lifting the oil to the surface.

By varying the tension of the spring 42 on the areas of the valve, disk and stem 35, the closing of the valve 34 may be varied with respect to differential pressures. By this step the flowing pressure is prevented from too closely approaching the lifting gas pressure before operating the valves.

In Figure '7 I have shown another form, wherein the inclined ducts 43 in the head [9 are eliminated. The axial passage 36, through which the stem 35 of the valve 34 extends, is enlarged so that the said stem has a loose fit within the passage. This forms an axial space 36 around said stem and liquid which passes the valve 40 may flow upwardly through this space and escape into the housing through the ports 33.

In Figure 8 I have shown a view in which a casing packer 50 is set in the casing around the tubing section [5 just below the coupling Hi. When this is done the oil level in the casing is, of course, below said packer; therefore the lifting fluid string 25 may be eliminated. The elbow 30 may be screwed onto the upper end of a nipple 5| and this coupled to the reduced upper end of the cage 2!.

What I claim and desire to secure by Letters Patent is:

1. A well flowing apparatus comprising, a flow tubing having an oil inlet and a lifting gas inlet,

a valve for controlling the oil inlet, a valve for controlling the gas inlet, said valves free from positive connection with each other and being independently movable and operable by pressure differentials, and means above the oil admitting Valve and free from connection with the gas inlet valve for restricting the flow of oil past the oil inlet valve to reduce pressure differentials across said valve whereby it may be quickly opened.

2. A valve assembly comprising, a housing, a head having a valve seat and communicating above its seat with the housing, a single unbalanced oil valve closing upwardly against the seat of the head, a cage having a valve seat and communicating with the housing below its seat, and a single unbalanced gas valve closing downwardly against the seat of the case, a connection between the valves, the gas valve being closed by a gas pressure acting downwardly thereon, whereby the oil valve is dislodged from its seat.

3. A well flowing apparatus, including, a flow tubing having an oil inlet and a lifting gas inlet, a gas valve for admitting lifting gas to the flow tubing, an oil valve unconnected with the gas valve for admitting oil to the flow tubing, said valves being independently operable, an extension attached to one of the valves for engaging and operating the other valve, and means co-acting with the oil admitting valve for restricting the flow of oil upon the initial opening of said valve, whereby the pressure diiferential across saidvalve is sufficiently reduced to permit the valve to quickly move to a full open position.

4. A well flowing apparatus including, a flow tubing, a single unbalanced valve for admitting lifting gas to the flow tubing, a single unbalanced valve for admitting oil to the flow tubing, means adjacent the oil admitting valve for restricting the rate of flow of admitted oil to create a back pressure above the valve when the same is opened, whereby the differential pressure across the valve is reduced and an element between the valves whereby one is closed as the other is opened.

5. A well flowing apparatus including, a flow tubing having an oil inlet and a lifting gas inlet, a gas valve for admitting lifting gas to the flow tubing, a ball valve for admitting oil to the flow tubing and being free from connection with the gas valve, and an extension attached to the gas valve for engaging and operating the ball valve.

6. A well flowing apparatus including, a flow tubing having an oil inlet and a lifting gas inlet, a gas valve for admitting lifting gas to the flow tubing, a ball valve located above the oil inlet when in a closed position and arranged to move below said inlet when in an open position for controlling the admission of oil to the flow tubing, said ball being free from positive connection with the gas valve, and an extension on the gas valve for engaging and operating the ball valve.

'7. A well flowing apparatus including, a flow tubing having an oil inlet and a lifting gas inlet, a gas valve for admitting lifting gas to the flow tubing, a ball valve located above the oil inlet when in a closed position and arranged to move below said inlet when in an open position for controlling the admission of oil to the flow tubing, said ball being free from positive connection with the gas valve, an extension on the gas valve for engaging and operating the ball valve, and means for restricting the flow of oil to the tubing directly above the ball valve, whereby a back pressure is built up to act against the ball to assist the fluid pressure in operating the same.

8. A well flowing apparatus including, a flow tubing, a valve for admitting lifting fluid to said tubing, a valve for admitting liquid to the tubing, means adjacent the liquid admitting valve for varying the pressure differential across said valve as said valve begins to move from open to closed position and also when said valve begins to move from closed to open position, whereby a snap action is imparted to the valve in its movement, and an element between the valves whereby one is closed and the other is opened.

9. A well flowing apparatus including, in combination with a flow tubing, a valve head connected with the tubing having a chamber therein provided with a restricted flow outlet, a valve seat communicating with the chamber of the head below said outlet, a valve controlling the admission of oil to the chamber of the head exposed to the submergence pressure of the oil, means for admitting lifting fluid to the tubing above said outlet, and means for initially opening said valve, said outlet restricting the flow of oil through the chamber, whereby the pressure differential across said valve is sufficiently reduced to permit the valve to quickly move to a full open position.

10. A well flowing apparatus including, a flow tubing, a valve for admitting lifting gas to the flow tubing, a valve for admitting oil to the flow tubing, the valves co-acting with each other so that one moves to its open position as the other moves to its closed position and vice versa, means for subjecting one side of the gas valve to the flowing pressure and the submergence pressure and the opposite side of said valve to the pressure of the lifting gas, whereby the differential pressure across said valve operates the same, means for subjecting one side of the oil valve to the flowing pressure and its opposite side to the submergence pressure when in a closed position, and means for reducing the pressure differential acting upon the oil valve so that the gas and oil valve may co-act to snap said oil valve to its open position.

11. A well flowing apparatus including, a flow tubing, a valve for admitting lifting gas to the flow tubing, a valve for admitting oil to the flow tubing, the valves co-acting with each other so that one moves to its open position as the other moves to its closed position and vice versa, means for subjecting one side of the gas valve to the flowing pressure and the submergence pressure and the opposite side of said valve to the pressure of the lifting gas, whereby the differential pressure across said valve operates the same, means for subjecting one side of the oil valve to the flowing pressure and its opposite side to the submergence pressure when in a closed position, means for reducing the pressure differential acting upon the oil valve so that the gas and oil valve may co-act to snap said oil valve to its open position, means for equalizing the pressure across the oil valve when the latter is in an open position, and means for setting up a pressure differential when the oil valve begins to move to its closed position, whereby such variation imparts a snap action to the closing of said oil valve.

12. A well flowing apparatus including, a flow tubing, a valve for admitting lifting gas to the flow tubing, a valve for admitting oil to the flow tubing, an element between the valves co-acting with them whereby one is closed and the other is opened and vice versa, means for subjecting one side of the gas valve to the flowing pressure and the submergence pressure and the opposite side of said valve to the pressure of the lifting gas, whereby the differential pressure across said valve operates the same, means for subjecting one side of the oil valve to the flowing pressure and its opposite side to the submergence pressure when in a closed position, and means for reducing the pressure differential acting upon the oil valve so that the gas and oil valve may co-act to snap said oil valve to its open position.

HERBERT C. OTIS.

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