US2275416A - Bellows type slugging foot valve for wells - Google Patents

Description

March 10, 1942. A. BOYNTON 2,275,416

BELLOWS TYPE SLUGGING FOOT VALVE FOR WELLS Filed Nov. 28, 1958 3 Sheets-Shet l ALEXANDER BOYN TON, IN VENT 0R 0 g 2 243! ATTORNEYS.

b M14 BY MM March 10, 1942. A Y N 2,275,416

BELLOWS TYPE SLUGGING FOC JT VALVE FOR WELLS Filed Nov. 28, 1938 5 Sheets-Sheet 2 ALEXANDER BOYNTZHV, INVENTOR,

2 m; Kim

Fig 5 ATIURNEYS.

March 10, 1942. A BOYNTON 2,275,416

BELLOWS TYPE SLUGGING FOOT VALVE FOR WELLS Filed Nov. 28, 1958 3 Sheets-Sheet 3 l A A "IIIIIIIIIIIIA/ ATTORNEYS.

Patented Mar. 10, 1942 UNITED STATES PATENT OFFICE BELLOWS TYPE SLUGGING roo'r VALVE FOR WELLS Alexander Boynton, San Antonio, Tex.

Application November 28,1938, Serial No. 242,771

7 Claims.

My invention relates to a means for expelling liquids from wells by the force of compressed air or gas acting under a slug of liquid.

One of the objects is to provide a slugging foot valve for well tubing whereby slugs of well liquid of difierent lengths or weights can be automatically expelled by simply varying the air or gas pressure within the well casing exterior of the eduction or flow tubing. By increasing the air or gas pressure the length of the slug is increased, and vice versa.

Unlike the other inventions disclosed in my patents numbered 2,042,583, 2,010,135, 2,006,909, and 1,968,633, this invention allows the air or gas pressure used to operate the device to contact the producing formations of the well. The ultimate recovery from almost any oil well would be increased by holding a certain pressure upon the producing formation. This device may be adjusted to hold any desired pressure within a well.

The use of clock timing devices to operate the machinery to flow the accumulated liquid from a well at predetermined intervals is avoided by this device which uses the weight of the accumulated well liquid to open the foot valve and cause the well to flow. In adjusting the flowing interval to the production by weighing the liquid as it comes into the well I accomplish directly and positively the purpose that all other timing devices arrive at by indirect and often inaccurate information.' This statement is made clear by assuming that a given well should be flowed as often as it will produce onebarrel of oil which is estimated to accumulate in the well each two hours.

If a timing device (of which there are many) be then installed to fiow the well every two hours and the production of two. hours should be in fact only one-half barrel, the improper flowing interval will continue until the error is discovered and the. timing device reset to the proper interval; whereas with this invention the device waits for the barrel of oil to enter the well whether the time interval be ten minutes or ten hours, whereupon the contents of the well will be discharged. Furthermore, the mechanical setting or adjustment of the ordinary timing device may be wholly avoided, for in this invention the time interval between slugs expelled from the well may be changed by merely changing the air or gas pressure, as stated, used to expel the slugs.

A pressure responsive element employing a metallic bellows, hermetically sealed at both ends,

is anchored at one end with the other end free. 7 Upon the free end a valve is mounted. This valve normally engages a seat against which it is urged by the expansive force of the bellows. The expansive force of the bellows is, in turn, governed by the expansive force of a coiled spring. The bellowsis mounted Within the lower end of an eduction tube, commonly called the flow tubing, which extends into the well liquid. While the valve is closed no Well liquid can enter the flow tubing, but when the weight or pressure of the well liquid reaches a predetermined value, this Weight or pressure causes the bellows to contract and open the valve, whereupon the air or gas pressure in the well external of the flow tubing and above the accumulated well liquid, forces the well liquid out of the well through the flow tubing. When the slug of well liquid has been so expelled the pressureupon the bellows decreases and causes the bellows to elongate, thereby again closing the valve and completing the operating cycle. A lubricated latch, housed within the bellows assembly, is employed to make the valve action snappy in both directions.

The foregoing and other advantages will more clearly appear from the following specification and drawings in which:

Fig. 1 is a vertical section of a well equipped with this device.

Fig. 2 is a vertical section of the preferred form of this invention.

Fig. 3 is a horizontal section on the line 33, Fig. 2.

Fig. 4 is a horizontal Fig. 2.

Fig. 5 is a horizontal section on the lines 5-5, Figs. 2, '7, 8, 13.

Fig. 6 is a horizontal section on the lines 15-45, Figs. 2, '7, 8.

Fig. '7 is a vertical section of a modified form of the invention shown in Fig. 2.

Fig. 8 is a vertical section of a further modified form of the invention shown in Fig. 2.

Fig. 9 is a horizontal section on the line 99, Fig. '7.

Fig. 10 is a horizontal section on the lines 10-40, Figs. 2, 7, 8.

Fig. 11 is a horizontal section on the line section on the line 4-4,

Hll, Fig. 8.

Fig. 12 is a horizontal section on the line 12-12, Fig. 8.

vertical section of the line I4I4, Fig. 15, of the bellows bottom connection.

Fig. is a bottom end view of the part shown in Fig. 14.

Fig. 16 is a vertical section of the arc ring member on the line I6--I6, Fig. 17.

Fig. 17 is a bottom end view of the part shown in Fig. 16.

Fig. 18 is a view partly in elevation and partly in vertical section of the lower end of the bellows spring guide pipe shown in Fig. 7.

Fig. 19 is a vertical section of the bellows spring guide pipe shoe shown in Fig. 7.

Fig. 20 is a top end view of the part shown in Fig. 19.

Fig. 21 is a vertical section of the upper portion of the spacer nipple shown in Fig. '7.

Fig. 22 is a view partly in elevation and partly in vertical section on the line 22-22, Fig. 23, of the latch shaft carrier shown in Fig. 8.

Fig. 23 is a bottom end view of the part shown in Fig. 22.

Fig. 24 is a broken elevation illustrating the upper portion of the bellows spring guide pipe shown in Fig. 8.

Corresponding characters are employed throughout the drawings to indicate and refer to corresponding parts.

Similar but somewhat different parts in figures illustrating modifications of the invention are designated by adding capital A to the first modification, capital B to the second modification, and capital C to the third modification, and so on, to the number used to designate the similar part in the preferred form. Different portions of the same part are referred to by adding a, b, c, and so on (small letters) to the number employed to designate the part as a whole.

Fig. 1 shows a well equipped with this device in which the outer casing 46 is sealed above the ground surface G by a casing head 41 having two openings one of which is closed by a bull plug 48, the other being connected with a pipe line 49 for the purpose of conveying compressed air or gas to the well. The eduction tube is suspended centrally within the casing 46 and proximate its upper end rests upon a, plate 36 to which it may be welded as shown at 4011. of coupling 40 or otherwise joined in leak proof contact therewith.

Cap 31 is then screwed down upon lead ring 36, L

at the same time compressing lead ring 39, to form a seal against the escape of formation gas from the well. Any other casing head arrangement that will aiford a seal between the well casing and the flow tubing may be used; many such casing heads being well known to the art.

The device shown in Fig. 2 or either of the modifications shown in Figs. '7, 8, and 13, may be installed within the bracketed space A, Fig. 1.

The device may be allowed to hang from the casf ing head, coupling M and all lower parts being omitted, or tubing 42 joined to the device by coupling 4i may extend to cap 44 supporting all or part of the weight of the tubing on bottom of the well B, nipple 43 having perforations 43a being provided to allow ingress of well liquid to the device. Stage lifts 45, preferably of the type shown in my Patent No. 1,952,581, may be installed at intervals in the eduction tube 35, as shown.

With particular reference to the device shown in Fig. 2, the upper end of case reduced 25 is threadedly joined to flow tubing 35, as appears in Fig. 1. The lower end of this reducer is threadedly joined to the upper section of case 29 which, for manufacturing convenience to avoid long counterboring operation in upper section of 29, is joined to the lower section 29c by weld 29b. The external threads of the lower part 290 provide means for attaching a tubing extension 42 by means of a coupling M, and the internal threads engage lock ring 30 to hold the fins 28b of the bellows bottom connection 28 engaged upon the circular shoulder interior of part 290 as appears in Figs. 2, 7, 8, and 13.

Metallic bellows I8 is soldered or welded to its bottom connection 28 at 280, the upper end of the bellows being soldered or welded to the top end connection I! at IIa. Said end connection I! is threadedly connected to the valve I6 the shoulders of these members being recessed and soldered or welded as shown at IBd. Above the body of the valve I6 is a seat member 2'! threaded within the case reducer 25. Said seat member has an axial opening to receive an extension I upon the valve. In the closed position of the valve IE it engages seat 21a of said valve seat member 21 which is secured in place by a packing ring 26 screwed down on packing 5|. A bellows spring guide pipe I2, preferably polished inside and outside, may be pressed over the lower circular extension of a latch shaft carrier II upon which it may be crimped as shown or otherwise fastened thereto. This guide pipe has an easy sliding fit between the interior of the bellows and the exterior of spring I4.

At the lower end the guide pipe has an easy working fit over a bottom spring shoe I5 positioned within the bottom guide 5 which lands at its lower end upon a circular shoulder 28d in the bellows bottom connection 28. Upon its upper end the guide pipe supports the spring shoe I3. The spring l4 bears under some compression against upper shoe I3, which in turn contacts the annular lower extension of the shaft carrier II. Axially of the guide pipe is a latch shaft 3. The upper portion of latch shaft 3 is connected to latch shaft sub I, threadedly engaged with the internal threads of latch shaft carrier II and is secured in position by lock nut 2. It will be noted that the threaded upper portion of the shaft sub is relatively long so that the shaft may be thereby raised upward in chamber I Go or lowered therein in order to place latch balls 4 toward the lower end of the shaft in proper position to engage upon the upper and lower arcs I91) and I (Fig. 16) or upon either arc as may be desired, of an arc ring I9 which has a snug fit within the lower central opening in member 28. Said arc ring is held against shoulder 282 by nipple 20 which is urged against the lower end of arc ring member I9 by lock ring 2|. Said lock ring engages upon the internal threads in the lower end of the bellows bottom connecting member 28.

Latch shaft 3 which is threadedly engaged with the sub I, has a shoulder 31 against which the ball roof 6 is urged by the force of an adjusting spring 8. Said spring acts to impinge the latch balls 4 between a ball roof 6 and a ball floor I. The ball roof and floor are beveled to slope outwardly on their adjacent ends so as to urge the latch balls outwardly against the inner surface of the arc ring I9 and over or partly over either or both ends I91) and I90 of the arc ring seen in Fig. 16. The horizontal travel of the balls is governed and limited by the valve travel and by the vertical position of the latch shaft 3, as is apparent and as is fully set out in my aforementioned patents numbered 2,042,583, 2,010,135, 2,006,909, and 1,968,633.

Mounted on the latch shaft 3 below the latch balls is a spring 8. The spring adjusting nut 9 on the lower end of the latch shaft is for the purpose of adjusting the compression of spring 8 in its office of regulating the force transmitted to the latch balls. The proper position of nut 9 is secured by lock nut Ill.

The purpose of the bellows l8, and. spring l4,

is to provide a pressure responsive element. The

bellows assembly being anchored atits lower end, all movement of the bellows is transmitted to valve l6. It is important that the chamber within the bellows be hermetically sealed against the entrance of pressure fluid from without in order to keep the bellows pressure responsive. In producing this seal, base plate 22 contacts a rubber washer 22a urged upwardly by chamber plug 23 the lower end of which is soldered or welded to the bottom end of connection 28 as shown at 23a. Seal plug 24 has a central extension of reduced diameter to prevent lock ring 24a. from bein forced into the central vertical passage through plug 23 and is screwed in upon lock ring 24a and soldered or welded at 24b to complete the hermetical seal of the lower end of the bellows assembly. In order to adjust the position of the latch shaft sub I, valve l6 must be removed and while these adjustments are being tested the hermetical seal of the upper end is produced by packing I66, this seal being reinforced by weld Hid after the proper shop test has been obtained. The bellows chamber should be partially filled with a lubricant. Care must be taken to leave enough air space or partial vacuum above the lubricant to allow the bellows to compress far enough to open valve ports lfib by allowing these ports to take position somewhat below seat 21a on the down stroke. This air pocket or vacuum above the lubricant within the latch housing not only provides for proper length 'of valve stroke but causes the pressure inside and outside the bellows to remain equal, less the expansive force of spring [4, it being assumed that the force of the bellows which is either somewhat compressed or elongated will be negligible. Horizontal passages la, a, vertical passage lb, and slots 3d provide for the free circulation of the latch lubricant as the bellows alternately contracts and expands in operation as will be later explained.

In describing the operation it will be assumed that the device shown in Fig. 2 is installed within the bracketed space A, Fig. 1. Air or gas under a certain pressure is then turned into the annular space between the well casing 45 and the fiow tubing 35 via the pipe line 49 unless the Well produces enough gas to operate the device. In that event the casing head opening connected to the pipeline 49 may be closed by a plug.

For illustration it will be assumed that the latch and bellows assembly is adjusted to open ports it?) by causing them to quickly take position somewhat below seat 21a at 125 lbs. pressure upon the bellows, and to close these ports by again assuming the position shown in Fig. 2 when the pressureupon the bellows declines to 95 lbs. Air or gas pressure is now built up to 100 lbs. per sq. in. within the casing exterior of the tubing. Well liquid is rising above the level of the device. When the weight of the well liquid reaches the value of 25 lbs. per sq. in. upon the bellows (making a total of 125 lbs.) the latch will release and the latch balls will roll with a snap action from the position shown in Fig. 2, and engage upon the lower end of the arc ring liquid will now be forced by the 100 lbs. of air or gas pressure above it into the fiow tubing 35 via the openings between fins 28b, through ports I61), and opening IBc. When all of the accumulated oil or other well liquid has been forced into the flow tubing it will manifestly be followed by the air or gas and be expelled from the well thereby. The latch and bellows assembly being adjusted, as stated, to expand and close at lbs. pressure, valve I61 will again close by assuming the position shown in Fig. 2 when the slug has been expelled and the pressure within the well reduced to 95 lbs. The input of compressed air or gas through pipe line 49 should be restricted by a valve or otherwise so that the pressure within the well will quickly drop 5 lbs. below the assumed lbs. when the slug is expelled. The cycle just described automatically repeats under operating conditions.

It is apparent that the efficiency with which the device operates will largely depend upon the volumetric ratio between the interior of the flow tubing and the annular space between the flow tubing and well casing which contains the-slug at the time when the valve opens. If the cubical contents of the annular space containing the slug when the valve opens equals twice the cubical contents of an equal length of flow tubing the slug will weigh 50 lbs. per sq. in. in the flow tubing and will be expelled by the 100 lbs. of air or gas. If the contents of the annular space be three times that of an equal length of the flow tubing the slug will weigh '75 lbs. per sq. in. in the flow tubing and will be duly expelled by the 100 lbs. air or gas pressure.

It is also apparent that if the contents of the annular space is too great as compared with the contents of an equal length of the flow tub.- ing the slug will offer too much resistance per sq. in. and stall the lifting force. To avoid this condition use larger flow tubing or set the latch to close the valve at less difference between the opening and closing forces,

It will thus be seen that slugs of large diameter in the well and which offer little resistance to the flow of liquid into the well can be changed in form to longer and heavier per sq. in. slugs in the flow tubing, thereby accomplishing the double purpose of placing comparatively slight back pressure upon the producing formation by admitting a large short slug exterior of the flow tubing and of reforming this slug in the flow tubing to more nearly balance the pressure used to expel it, it being apparent that the more nearly the load balances the power the greater will be the operating efficiency.

It will be noted that the latch travel provides that the valve ports Nib are so far below seat 2111 that this seat will not be damaged by abrasive substances in the well liquid.

The slugging foot valve shown in Figs. 7, 8, and 13 operate in exactly the same manner as the device shown in Fig. 2 except that the means for adjusting the latch is different in each of these figures.

In Fig. '7, a modification of the device shown in Fig. 2, guide pipe IZA has two slots l2a in its lower end asappears in Fig. 18. These slots fit over and engage upon shoulders 32a of guide pipe shoe 32, clearly shown in Figs. 19 and 20, this shoe being welded at 32?) to spacer nipple 3! having shoulder 3Ia engaging upon shoe 32. This nipple positions the ball roof 5A. The two opposite arms of shoe 32 have a sliding fit withat I90 Fig. 16. The 25 lbs. per sq. in. of well 7 in slots 5b of bottom guide 5A.

This construction provides that as latch'adjusting sub I is raised or lowered to position the ball roof by means of its threaded connection with member II the compression of spring I4 is not altered thereby. The proper position of latch shaft carrier H is secured by externally threaded ring 59 and the proper position of the latch ball roof which determines the working relation of all other parts of the latch is secured by nut 2. Ring HJA out in two vertically is fitted into a reduced diameter of shaft 3A and held in place by spring base 9A as shown.

It is apparent that bellows top connection i'EA, chamber plug 23A, case reducer 25A, and case 29A correspond in purpose to the very similar parts bearing the same numerals without the subscripts in Fig. 2.

The device shown in Fig. 8 carries its latch assembly upon a shaft 313 which shaft is adjusted up or down by means of threads upon its upper end engaging with threads in the central opening in member 16A. Grooves 3e longitudinally of the shaft, 3B, provide that the opening I61 above shaft 313 may have free communication with the opening above the lubricant within the latch chamber, and slots la, Figs. 22 and 23, slots I21), Fig. 24, together with ports 5a and slots Ida provide for circulation of the latch lubricant. Lock nuts 2A and 34 secure the latch and latch spring adjustment. Screwing 33 upward raises the latch balls and lessens the compression of spring l4, and vice versa. screwing down latch shaft carrier nut l IA lowers the latch balls and increases the compression on spring M, and vice versa. It will be observed that fingers [2c of guide pipe I2B are soldered or welded upon carrier nut l IA as shown at I lb, these parts being detailed in Figs. 22, 23, and 24. It is furthermore apparent that spacer nipple MA corresponds in purpose to nipple Si in Fig. '7, both nipples serving to position ball roof 6A, thereby controlling the latch adjustment.

Fig. 13 employs a spacer nipple E3 contacting upper spring shoe |3A to hold spring M in proper compression while spacer collar MB is screwed up or down upon the intermediate threaded portion of shaft SC to contact and position ball roof 63. It will be noted that in this construction guide pipe I20 is stationary and at its upper end is held within the central bore through bellows top connection i'lB, whereas in Figs. 2, 7, and 8 this member travels and works over a guide at its lower end. Member 513 in Fig. 13 being pressed in, welded, or otherwise secured within the lower end of guide pipe IZC, rests on the shoulder 23d of bellows bottom connection 28A, (Figs. 2, '7, 8, and 13) and in turn supports bottom spring shoe I5A. Valve 15B corresponds in purpose to valves l8v and 5A shown in the preceding forms as is apparent.

In this construction the spring compression and the ball roof are adjusted by independent parts, whereas in Fig. 8 both means of adjustment may be employed to accomplish either of these purposes.

In deep wells it will be found that some form of stage lift, preferably, of the type disclosed in my Patent No. 1,952,581, should be installed at intervals of 200 to 300 feet in the flow tubing as shown at 45 in Fig. l to reduce the starting pressure. This is especially true if the well is flowed at intervals as most oil wells, particularly small ones, should be operated. If stage lifts are in stalled at intervals, as stated, they should be adjusted to open responsive to a pressure within the flow tubing somewhat more per sq. in. than the weight of the slugs to be expelled by the foot valve after the surplus liquid has been expelled from above the level at which the foot valve operates. Such adjustment of the stage lifts prevent them from being opened by the slugs that pass them after the foot valve begins to operate. These auxiliary lifts, therefore, remain inactive except at such times as they are needed to lower an accumulated head of well liquid at low operating pressure.

A colloidal substance may be inserted into the annular space within the well casing exterior of the flow tubing through either of the two openings on the side of the casing head at proper intervals to gravitate downward and settle upon the top of each slug as the same accumulates in the well casing, and to form the base of each slug as it is forced into the flow tubing; thus to provide for a minimum of slippage and intermingling of the air or gas and well liquid as the slugs are expelled.

While I have shown and described the preferred embodiment of my invention and such few modifications thereof as may be set out within the limits of a patent, it will be understood that the same are illustrated examples only, and are not intended to limit minor variations in the construction and apparent uses of the device.

I claim:

1; A device for lifting liquid from wells including a well casing, a tubing therein, means on said casing to seal about the upper end of said tubing, means to conduct pressure fluid to the interior of said casing, a plurality of flowing valves spaced apart along said tubing, a downwardly opening foot valve in and adjacent the lower end of said tubing, means supported in said tubing to hold said valve resiliently closed, bellows means connected therewith below the valve to be subjected to the pressure of well liquid rising within the tubing whereby said bellows means is compressible by fluid pressure of a predetermined amount thereon to open said valve, said bellows being sealed against access of fluid into the same and means on said valve to guide said valve to and from its seat.

2. In a device for lifting fluids from wells the combination comprising, a tubing, a valve seat in the bore of said tubing, 9. downwardly opening valve in said bore adapted to engage said seat, a bellows member having a sealing connection with the lower end of said valve, a support for said member in spaced relation with and below the valve seat in said tubing, means on said support to seal the lower end of said member to maintain a closed chamber in said member, a spring associated with said support to hold said valve seated, means to adjust the tension on said spring, and means to latch said valve resiliently in both opened and closed positions.

3. In a device for lifting liquid from wells, a well casing, a well tub-ing therein, means to seal the upper end of said casing about said tubing, a pressure fluid inlet to said casing, a partition across said tubing spaced from the lower end thereof, there being a central opening in said partition forming a valve seat, a valve normally closing upon said seat, a support below said valve, said support being constructed to freely admit fluids from one side to the other thereof, a bellows member connecting said support and said valve and sealing therewith, a spring in said member, a sleeve between said spring and said member, said member being collapsible by fluid pressure to compress said spring and open said valve.

4. In a device for litfing liquid from wells, a well casing, an eduction tube therein, an upwardly closing valve in said tubing adjacent the lower end thereof to close the axial passage in the tubing, means below said valve holding said valve normally closed, and a compressible bellows shaped element mounted axially of said tube adjacent said holding means, sealed against entrance of fluid thereto, and responsive to a predetermined fluid pressure outside thereof to withdraw said valve from its seat, whereby well liquid and gaseous pressure fluid are conducted into said tube below said element andupwardly past said element to lift the said liquid in said tube.

5. A tubing, a transverse partition therein having a longitudinal passage, a downwardly opening valve in said passage to control the flow of fluid through said tubing, a bellows member having a sealing connection with the lower end of said valve, a support for said member in said tubing, means in said support to seal the lower end of said member, a spring associated with said support to hold said valve seated, means to separate said spring from said bellows member, means to adjust the tension on said spring, said tubing forming an open conduit about said bellows member upwardly to said passage for the flow of fluid through said longitudinal passage into the tubing.

6. In a device for expelling liquid from wells,

a well casing, an eduction tube therein, an ananular space between said casing and tube, a closure means between said casing and tube proximate the upper end thereof, means for admitting pressure fluid into said annular space, a transverse plate in the bore of said tube proximate th lower end'thereof, an opening axially of said tube in said plate, a valve seat surrounding the lower end of said opening, a valve, and a pressure responsive element subjected to the fluid pressure in the eduction tube below said plate and normally holding said valve engaged upon said seat, said element having a lower connection secured within said tube below said plate to cause all movements of said element to be at the upper end thereof to actuate said valve.

7. In a device of the class described, an eduction tube, a transverse plate in the bore of said tube, said plate having a circular vertical opening and a valve seat around the lower extremity of said opening, a valve, a pressure responsive element normally holding said valve upon said seat but responsive to external pressure to unseat the valve, vsaid element being secured within said tube proximate the lower end thereof and below said plate whereby said element is subjected to pressure below the transverse plate, two springs and a latch within said element, one of said springs being adapted to resist compression of said element and the other spring being adapted to control the force of said latch.

ALEXANDER BOYNTON.

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