US2201451A - Well swab - Google Patents

Description

May 21, 1940- B. E. Fmr-misml 2,201,451

4 Sheets-Sheet 2 B. E. 4FARP-@ISH WELL SWAB Filed Feb. 27, 1957 May 2l, 1940.

May 2l, 1940. B. E. PARRISH WELL swAB Filed Feb. 27, 1957 I 4 Sheets-Sheet 3 B. E. PARRlsH WELL SWAB May 21, 1940.

Filed Feb. 2'7, 1957 4 Sheets-Sheet 4 Y nur 0km ii.

Patented May 2l, 1940 UNITED STATES PATENT OFFICE WELL swan Benjamin E, ran-a1., n.11, rex. .Application February 21, 1237, semi No. 128,047 y 21 Claims.

This invention relates to new and useful improvements in well swabs.

'I'his application is illed as an improvement on the well swab disclosed in my co-pending application, filed July 22, 1935, Serial Number 32,561.

Qne object of the invention is to provide an improved swab having all of the advantages of the swab' disclosed in my co-pending application and which is particularly adapted for use in oil wells, being constructed so as to descend rapidly in the well uid, whereby the swab may-be run in a minimum amount of time.`

An important object of the invention is to provide an improved swab wherein the packing element is constructed in sections arranged to be displaced out of horizontal alinement with each other so that the iiuid may by-pass said element, the displacement being automatic on the downstroke; said sections being mounted on a supporting mandrel, whereby said mandrel not only serves as a support for the packing element but also acts as a guideduring the displacement of the sections, thereby eliminating an auxiliary -guide means and making for a more simple and an improved well swab having a split elastic packing element with one half of said element arranged to undergo vertical movement with relation to the other half, and improved means for limiting the distortion of the packing whereby distortion of the packing element beyond its elastic limits is prevented.

Still another object of the invention is to provide an improved swab wherein the packing element is constructed in units, the parts of the various units being interchangeable with each other, whereby manufacturing costs are minimized and assembly of the device greatly simplified.

A still further object of the invention is to provide an improved swab wherein all valves, balls, seats, etc., are eliminated and wherein the size of the iiuid by-pass may be readily adjusted to control the speed at which the swab descends through iiuid in the well casing or tubing; the assembly being simple in. manufacture and air--v ranged to be attached to any suitable lowering rod, cable or device.

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 jto the accompanying drawings, in which an example of the invention is shown, and wherein: y

Figure 1 is an elevation of a swabconstructed in accordance with the invention, and showing the packing element in its packing position,

Figure 2 is a view similar to Figure 1 and showing the sections ofthe packing element if placed vertically `from each other,

at right angle Figure 3 is an elevation taken to Figure 1,

Figure 4 is an elevation taken at right angle 20 to Figure 2,

Figure 5 is a transverse, vertical sectional view of the swab, taken on the line 5-5 of Figure 3 and showing the mandrel in elevation,

Figure 6 is a view similar to Figure 5 taken on the line 6-6 of Figure 4,

Figure 7 is an isometric view ofthe supporting mandrel,

Figure 8 is a perspective view showing the elements of each section. 0r unit of the packing member separated from each other,

Figure 9 is a horizontal, cross-sectional view, taken on the line 9 9 of Figure l,

Figure 10 is a horizontal, cross-sectional view, taken on the line ID-II) of Figure 1, and

Figure l1 is a horizontal, cross-sectional view, vtaken on the line II-II of Figure 2.

In the drawings, the numeral I0 designates a mandrel which is preferably made of a solid piece of metal, or other suitable material. The mandrel is substantially cylindrical in cross-sections and has its upper end provided with screw threads II, whereby a box I2 may be screwed thereon. The box is provided with an upwardly extending integral nipple I3, which is of s'uch size as to receive the standard threaded box (not shown) at the lower end of the usual sucker rod, whereby the mandrel may be readily connected to said rod and lowered into the well casing A. It is pointed out that the box I2 may be readily removed and a similar box having a nipple of a diil'erent diameter may be substituted therefor, whereby the mandrel could be lowered by means of a pipe or cable instead of a sucker rod. With such arrangement specially designed couplings are unnecessary and the mandrel may be connected with any of the usual lowering devices.

The lower end of the mandrel Il) is provided with screw thread i4, whereby a plug i5 may be attached to the lower end of the mandrel. The plug preferably has its lower end rounded so that as the mandrel is lowered into the iluid, such lowering is facilitated by this rounded portion.

Mounted on the mandrel I0 is a flexible or elastic packing element it. The packing element is constructed of two halves or units B and C which are semi-circular in cross-section and are arranged to fit around the mandrel as clearly shown in Figure 9. Both units of the packing element are exactly alike so that when they are positioned in horizontal alinement with each other they form an annular packing element. The unit B is slideable vertically throughout the length of the mandrel. Ill, while the unit C is mounted in a ilxed position at the lower end of said mandrel as will be explained. With this arrangement the unit B may be displaced vertically out oi hori- 'zontal alinement with the other unit C.

Since each unit is exactly like the other, a description of one will sufiice. Each unit includes an elastic or resilient packing member I1 which is substantially semi-circular in cross-section and which has its outer surface tapered inwardly at its upper and lower ends, as is clearly shown in Figure 8. The upper end of the packing member is adapted to fit within the recess i8 of a thimble i9. 'I'he thimble is substantially semi-circular in cross-section and is arranged to snugly fit the outer surface of the cylindrical mandrel I0. The inner wall of the thimble i9 is extendeddownwardly to form a projecting skirt 2li which extends contiguous to the inner wall of the packing member when said member is in position within the thimble. For fastening the upper end of the packing member within the recess I8 of said thimble, the packing element is formed with a radial opening which is in alinement with an opening 2| which is formed in the inner wall of the thimble (Figure 5). The outer wall of the thimble is formed with a reduced opening 22, the inner end ofwhich is enlarged to the diameter of the openings and 2|, whereby an internal annular shoulder 23 is formed in the outer wall of said thimble. It is noted that the openings 2|, I1 and 22 are in alinement with each other. After the upper end of the packing member l1 has been inserted into recess I8 of the thimble I9 and before the unit is placed around the mandrel, as will be explained, a pin 24 is inserted into the opening from the inside of the thimble. This pin has a diameter of such size as to snugly ilt in the openings 2| and I1' and into the enlarged portion of the opening 22. The extreme outer end of the pin is reduced as shown at 24' so as to tlt within the reduced opening 22 in the outer wall of the thimble. The off-set or shoulder formed on the pin 24 abuts the internal annular shoulder 23 in the outer wall of the skirt, whereby outward movement of the pin is prevented. Whenthe unit is mounted on the mandrel I0, the inner end of the pin engages the outer surface of said mandrel, whereby inward displacement of the pin is prevented. When it is desired to remove the pin, it is merely necessary to remove the unit from the mandrel and push the pin inwardly out of the opening. With such arrangement a most simple and effective retaining means is provided for holding the packing member in place within the thimble i9.

The lower end ot the packing member i1 is inserted within the recess 25 of a thimble 2i, which is similar in construction to the upper thimble I9. The lower end of the packing member is retained within the lower thimble by a pin 21, similar to the pin 24. It is noted that when the packing member is secured between the thimbles il and 26, the inner. end of the skirt 2li of the upper thimble and the inner end of the lower skirt 2l of the thimble 26 are spaced from each other. This position is clearly shown in Figure 5, and occurs when the packing member l1 is in its normal or undistorted position.

For slideably mounting the unit B on the mandrel I0 said mandrel is provided with a pair of diametrically opposite grooves or keyways 28 which extend vertically throughout the length of the mandrel. Each thimble I9 and 26 is provided with inwardly projecting ribs or keys Il which are located at the inner surface thereof. The ribs or keys are adapted to slide within the grooves or recesses 29 in the mandrel and obviously, prevent displacement of the unit from said mandrel. In mounting the unit on said mandrel it is only necessary to remove the plug i5 at the lower end thereof, and to slide the unit upwardly on the mandrel, whereby the keys 30 engage the groove. The plug is then returned to the lower end of the mandrel and it will be seen that the unit B is confined to a vertical movement between said plug and the socket I2 at the upper end of the mandrel.

The unit C is constructed exactly as is the unit B and is mounted on the mandrel il in a similar manner. However, the inwardly projecting ribs or keys 30 of the thimbles of the unit C engage in diametrically opposite slots or keyways 3|. The length of the keyways 3| is less than the length of the lzeyways 28, being substantially the vertical length of the unit C. Thus the grooves or keyways 3| extend from the lower end of the mandrel In to a ,point opposite the upper end of the unit C. It is noted that the keyways 3l extend contiguous to the keyways V29 and therefore the lower end of the latter are combined with the former to form a comparatively wide groove at the lower end of the mandrel. Since the keyways or grooves 3| terminate at the upper end of the unit C it will be seen that when said unit is mounted on the mandrel, the uppermost thimble i9 of the unit will abut the end of the groove 3|. It will be held in this position by the engagement of the plug i5 with its lower end, whereby the unit C is mounted in a fixed position incapable of movement with relation to the mandrel, on said mandrel. Since the grooves 29 within ,which the unit B is slideable extend throughout the length of the mandrel and it will be evident that this unit may slide vertically with relation to the unit C which is attached in a fixed position on said mandrel.

In operation, the assembly is secured to a single pipe, sucker rod or other lowering device and lowered into the well casing A with the parts in the position shown in Figures 1, 3 and 5. As soon as the assembly strikes the fluid within the well casing, the fluid pressure will immediately raise the unit B of the packing element on the mandrel i0, the vertical keys 30 on the thimbles of said unit sliding upwardly in the diametrically opposite grooves or keyways 29. The mandrel is of sufficient length so as to permit the unit B to move upwardly to the position shown in Figures 2, 4 and 6, with the lower end of the unit B opposite the upper end ofthe unit C.

'I'he thimbles I9 and 26 oi.' both units B and C are inclined inwardly toward their outer end and due to this inclination, it will be seen that an enlarged space D, as indicated in Figure 4, is provided between the units B and C when the former is in its raised position. This space permits the fluid to flow from beneath the assembly upwardly thereby and is substantially equal to the crosssectional area oi.' the casing A, whereby there isv prac'tically no resistance to the downward passage of the assembly in the well casing. The enlarged by-pass permits the assembly to be lowered rapidly and each rim may be madein a minimum length oi time. It is obvious that the displacement of the units of the packing assembly out of horizontal alinement with each other acts as a valve to permit by-passlng of the fluid on the downstroke of the device.

When the assembly has reached its lowermost position and the raising operation has begun, the uid pressure above the assembly will immediately act upon the raised unit B ioA lower the same. This unit will of course, immediately move downwardly on the mandrel until the lower end of its thimble 2l rests upon the plug I5 screwed on to the lower end of said mandrel. In this position, the unit B is opposite the stationary or fixed unit C and the fluid will then act upon both umts to force the thimbles I9 thereof downwardly toward the lower thimble 26, whereby the resilient or elastic packing members I'I which are confined between said thimbles, are expanded into engagement with the inner wall of the well casing A. The upper thimble I9 will move downwardly until the inner edge of the skirts which project downwardly therefrom, strike the inner edge of the upwardly projecting skirts 28 on the lower thimble 26. When this occurs. further distortion of the packing member II is prevented. Therefore, it will be seen that the extended skirts provided on the thimbles provide a positive means for preventing a distortion of the packing member I'I beyond the elastic limits of said members. The inner faces of the thimbles I9 and 26 of both units are machined so that when the two units are in horizontal alinement, a ground joint which prevents leakage is formed. Continued upward movement of the assembly after the packing members l1 have moved into engagement with the well casing A, will lift the iiuid above the packing element and at the same time the well of the casing will be swabbed.

It is pointed out that when the swab is being lowered in the `well casing and the unit B is in its raised position (Figure 4), there is a possibility that a stone, rock or other extraneous matter may become lodged in the space D between the lower thimble 26 of the unit B and the upper thimble I9 of the unit C. Due to the inclination of the outer wall of the thimble, it will be seen that should this occur, a downward movement of the upper unit C will provide a shearing or cutting action as the lower thimble of the unit C slides downwardly with relation to the upper thimble 26 and the unit C. This shearing action would remove any extraneous matter which might become lodged between the units' and therefore any danger of such extraneous matter preventing the units from moving back into horizontal alinement upon the beginning of the upstroke is eliminated.

From the above, it will be seen that a swab wherein the packing element is utilized as a valve is provided. 'Ihe structure is such that the entire assembly is made of a minimum number of parts and may be quickly and easily attached to or detached from the mandrel. The removal of the plug I5 from the lower end 'of said mandrel will permit both the units B and C to be slid from the lower end of said mandrel. After the units are removed, it is only necessary to knock out the pins 24 and 21 to entirely disassemble each unit. This makes for easy replacement of the packing member I'I.

Manufacturing is simplied and cost greatly reduced by forming diametrically opposite vertical grooves or keyways in the mandrel. These grooves not only serve as a positive guide means for the movement of the unit B but also provide a positive means for holding the unit on the mandrel. By so utilizing the grooves, it is not necessary to employ extraneous guide means for the unit B: The parts of each unit are interchangeable with the parts of all the other units and thus all the thimbles present in both units may be used on either one and either at the upper or lower end of each. 'I'he packing members II are exactly alike and can be mounted in either the unit B or the unit C. The interchangeability oi' the parts makes for easy assembling of the device as well as materially reducing the cost of manufacture. It is again noted that the by-pass D is of such size as to eliminate any great resistance in the downward travel of the assembly which makes for rapid lowering oi' the device in the well uid present in the well casing A. The provision of the box I2 having the nipple I3, an integral part thereof, eliminates the necessity of providing special coupling, whereby the assembly may be lowered by any suitable lowering device now on' the open market.

What I claim and desire to secure Patent is:

1. A well swab including, a mandrel having vertical grooves therein, a packing assembly mounted on the mandrel and including a pair of units which are arranged to be displaced out oi.' horizontal alinement with each other to permit the well fluid to freely by-pass the assembly on the downstroke of the swab, and means on each unit for engaging the grooves of the mandrel for retaining said units on said mandrel.

2. A well swab including, a mandrel, a packing assembly mounted on the mandrel, said assembly including a stationary unit and a movable unit, said movable unit being arranged to be displaced vertically out of Ahorizontal alinement with the stationary unit, and lco-acting grooves and ribs on the mandrel and units for retaining the units in position on said mandrel.

3. A well swab including, a mandrel, a packing assembly mounted on the mandrel, said assembly including a stationary unit and a movable unit, said movable unit being arranged to be displaced vertically out of horizontal alinement with the stationary unit, and co-acting grooves and ribs on the mandrel and units for retaining the units in position on said mandrel, and for guiding the movable unit in its vertical movement.

4. A well swab including, a mandrel, a packing assembly carried by the mandrel and comprising a pair of units, the mandrel and units having coacting grooves and ribs for retaining the units on said mandrel, and an elastic packing element constructed in two sections, one of which is mounted in one of the units which is stationary on the mandrel, the other section being carried by the other unit which is movable vertically on the mandrel, whereby the latter packing section may be displaced vertically with relation by Letters to the other section to provide an enlarged space to permit the well fluid to by-pass the packing element freely on the downstrokeof the swab.

5. A well swab including, a mandrel, a packing assembly mounted on the mandrel, said assembly including a stationary unit and a movable unit, said movable unit being arranged to be displaced vertically out of horizontal alinement with the stationary unit to permit the well iluid to freely by-pass the assembly on the downstroke of the swab, the movable unit being arranged to move back into horizontal alinement with the stationary member and to be distorted into packing position with said stationary member upon the upstroke of the swab, and co-acting grooves and ribs on the mandrel and units for retaining the units in place on said mandreL l 6. A well swab including, a mandrel, a packing assembly mounted on the mandrel, said assembly including a stationary unit and a movable unit, said movable unit being arranged to be displaced vertically out oi.' horizontal alinement with the stationary unit to permit the well fluid to freely by-pass the assembly on the downstroke of the swab, the movable unit being arranged to move back into horizontal alinement with the stationary member and to be distorted into packing position with said stationary member upon the upstroke of the swab, and co-acting grooves and ribs on the mandrel and units for retaining the units in place on said mandrel, and for guiding the movable unit in its movement.

'1. A well swab including, a mandrel having vertical grooves therein, a packing assembly mounted on the mandrel and including a pair of units which are arranged to be displaced out of horizontal alinement with each other to permit the well uid to freely by-pass the assembly on the downstroke of the swab, each unit comprising an elastic packing member substantially semicircular in cross-section so as to t around the mandrel, confining elements at each end of the member for holding said member therebetween, and means on said elements for engaging the grooves of the mandrel for retaining the units on said mandrel.

8. A well swab including, a mandrel having vertical grooves therein, a packing assembly mounted on the mandrel and including a pair of units which are arranged to be displaced out of horizontal alinement with each other to permit the iluid to freely by-pass the assembly on the downstroke of the swab, each unit comprising anA elastic packing member substantially semi-circular in cross-section so as to t around the mandrel, conilning elements at each end of the member for holding said member therebetween, means on said elements for engaging the grooves of the mandrel and for guiding the movable unit in its movement, and means for limiting the distortion of the packing members.

9. A well swab including, a single longitudinal supporting member, an elongate packing assembly mounted on the member and including a stationary unit and a movable unit, said movable unit being arranged to be displaced longitudinally out of registration with the stationary unit, and longitudinal means on the single member co-acting with the stationary unit to hold said unit on said member, said means also co-acting with the movable unit for retaining said unit on the member and for guiding the same in its longitudinal movement.

1G. As a sub-combination in a well swab, a packing assembly including, a grooved support,

a split sealing element, and split top and bottom caps therefor, said caps having vertical ribs for engaging the grooved support to retain said assembly on said support.

1l. As a sub-combination in a well swab, a packing assembly including, -a grooved support, a split sealing element, and split top and bottom caps therefor, said caps having means for engaging the grooved support to retain said assembly on said support.

l2. As a sub-combination in a well swab, a sealing assembly including, a recessed support, a pair of upper confining members each semicircular in cross-section, a pair of lower confining members of semi-circular cross-section, and a pair of elastic packing elements coniined between the upper and lower members, said packing elements also being semi-circular in cross-section, each confining member having vertical ribs extending substantially throughout its length at its longitudinal extremities and arranged to coact with a recessed support to retain the assembly on said support.

13. As a sub-combination in a well swab, a single supporting mandrel having diametrically opposed grooves extending substantially throughout its length, each groove having one end enlarged in transverse width whereby the enlarged portion is substantially twice the width of the remainder of the groove.

14. A well swab including, a mandrel, a swab element surrounding the mandrel and including a plurality of registering sections having elastic deformable members arranged to be fdeformed by the liquid lifted when in registration with each other, one of said sections being immovable on said mandrel and the other section being slidable longitudinally on said mandrel from the first section to provide a free by-pass for liquid between said sections, whereby the swab may be quickly lowered in a body of liquid in a well, longitudinal guide means formed on the periphery of said mandrel, and means on the movable section of the element co-acting with said guide means to retain said movable section in registering position and for guiding said section into registration with the stationary section.

15. A well swab including, an elongate supporting member having abutments remotely spaced apart, a packing element mounted on the supporting member and including two sections which in one position are in registry and, one of which is stationary on said member and the other of which is slidable longitudinally between the abutments thereof, the stationary section engaging one of the abutments of the member, and the slidable section engaging the other abutment, whereby its displacement from the other section is limited, and interlocking means between the supporting member and the slidable section of the packing element for retaining said section thereon and against rotation.

16. A well swab including, a mandrel, a swab element surrounding the mandrel and having a displaceable section movable longitudinally approximately its entire length on the mandrel, and means formed on the periphery of said mandrel for guiding the section longitudinally thereof.

17. A well swab including, a single longitudinal supporting member, a packing assembly mounted on the member and including a pair of units, one of which is arranged to be displaced out of horizontal alinement with the other, the supporting member having longitudinal guide means of greater length than either of said units formed on the periphery of the member, and means on the movable unit for engaging said guide means, whereby said unit is held in longitudinal alinement when displaced.

18. A well swab including a single supporting mandrel, a packing assembly carried by said mandrel,.and including a pair of units, one of which is slidable longitudinally of the mandrel relative to the other unit of said pair, and means to mount the slidable unit on the mandrel, thereby to derive sole support from the latter, co-mprising guide means formed on the periphery of the mandrel, and complementary guide means on the slidable unit engaging the guide means of said mandrel to hold the slidable unit against rotation.

19. A well'swab in accordance with claim 18, wherein the guide means on the mandrel consists of a. pair of grooves extending longitudinally of the mandrel and located on opposite sides thereof, to form projections, and wherein the complementary guide means have recesses receiving the projections and portions extending into the grooves.

20. A Well swab including a. single supporting rod, a packing assembly carried by said rod and including a pair of units one of which is movable longitudinally away from the other, said rod having an irregular cross-section, which constitutes its periphery, so as to hold said movable unit against rotation while permitting longitudinal movement thereof, and means carried by the movable unit and engaging the periphery of the rod to mount' the movable unit on the rod.

21. A well swab including a single supporting rod, a packing assembly including a pair of units Carried by said rod, one of which is slidable longitudinally of the rod relative to the other unit of said pair of units, and means to mount the slidable unit onthe rod thereby to derive sole support therefrom, comprising complementary interlocking means between the rod and the-

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