US 3484141 A
Description (OCR text may contain errors)
Dec. 36, 1969 c. H.coL1 ETT 3,484,141
OIL WELL PROTECTOR C/AELESLL 60u. 7
Dew m i969 c. H. COLLETT BWMM OIL WELL PROTECTOR Filed June 19, 1967 3 Sheets-Sheet 2 5 INVENTQR Z7 BY Dec. m, 1969 C, Q ;CQLLETT 3,484,141
@1L WELL PROTECTORv Filed June 19, 1967 3 Sheets-Sheet 5 fw@ i I NVE NTOR.
Wada* Mw, im
United States Patent O US. Cl. 398-4 13 Claims ABSTRACIF F DSCLUSURE A protector or guide for pump rods or drill pipe which consists of longitudinally slotted sections applicable transversely to the rods or pipe and interconnected at their adjacent ends in axially spaced relation.
This application is a continuation-in-part of my application Ser. No. 410,845, tiled Oct. 30, 1960, which is a continuation-in-part of my application entitled Oil Well Protector tiled Aug. 17, 1964, with Ser. No. 389,956, both of which are now abandoned.
This invention relates to improvements in protectors adaptable for use in guiding or centering well pump rods,
and adaptable for mounting on drill pipe to protect the surrounding casing. As an example, the invention will be described with particular reference to protectors for use during well drilling, in respect of certain embodiments and with reference to a well pump rod in respect of another embodiment.
A common practice has been to prevent excessive wear by various protective devices. During drilling, the casing and drill pipe Wear as a result of the pipe movements against the casing. Excessive amounts of this wear have been prevented by applying to the drill pipe so-called protectors. A typical protector is a cylindrical, sleeve-like wear resistant elastomeric body extending entirely around the rod or pipe. lIn the usual case, several protectors surround the pipe at different intervals along its length and space the pipe from the casing. During drilling, fluid circulation is maintained down through the drill pipe and the return flow occurs in the space and passage between the drill pipe and the casing. For reasons well known, it is desirable that the return flow be as unrestricted as possible within the limitations of the pipe and casing diameters, but the casing protectors nearly ll the passage between the pipe and casing and necessarily impose restrictions to return uid iiow.
rl`he usual practices have been to employ protectors, whether of the so-called slip-on or split sleeve types, that are essentially continuously circular bodies in order to give full circular casing protection even though the circular continuity involves ow restrictions which are undesirable but have had to be accepted.
In accordance with the present invention, I am able to achieve both adequate casing protection and much less ow restriction than is imposed by conventional protectors. Generally considered, the invention contemplates a protector so formed that at all transverse locations it allows an eective flow passage. The casing-engaging surfaces are so distributed longitudinally of the pipe as to afford, in effect, the practical equivalent of full circular protection.
More particularly, the invention provides an improved protector generally characterized as comprising a sleeve section applicable to the drill pipe in a gripping engagement therewith. While one sleeve section can be used, it is preferred to use a pair of like sleeve sections disposed in axially offset relation at opposite sides of the pipe, the sleeve sections of a pair being interrelated against rota- ICC tion relative to each other around the pipe axis and against axial movement relative to each other. By axially staggering the sleeve sections of a pair, each individual sleeve section obstructs the flow passage only to a degree that may be roughly half the restriction imposed by the usual protector.
The invention has among its specic objects to form a protector of a pair of curved wear-receiving bodies of suitable elastomeric or plastic material, to the insides of which are secured arcuate metallic sleeve sections adapted to be transversely or laterally sprung onto the pipe in sustained gripping engagement therewith. Provision is made for interconnecting the sleeve sections of a pair in axially oifset or staggered relation and most desirably an axial distance apart so that the elastomeric bodies are not immediately opposite each other or do not occupy the same level. In applied condition, the protective bodies may be disposed at opposite sides of the drill pipe when seen in plan, but they are axially spaced apart when seen in elevation. This relationship may be referred to as axially oifset or as staggered Preferably the sleeve sections are interconnected by the interengagement of projecting parts of the metallic sleeve sections in a manner locking the lsleeve Sections against both rotation and axial movement relative to each other around and along the pipe axis.
It will be understood that the foregoing references to drill pipe and casing protection are merely illustrative and that similar problems obtain in the pumping of wells with the usual sucker rod pump and string of sucker rods. As in the case of drill pipe protectors, sucker rod protectors, generally referred to as guides are mounted at axially spaced locations along the string of rods and serve to prevent frictional engagement of the production tubing or casing or pipe by the rods so as to prevent excessive rod or pipe wear and so as to reduce frictional drag. Such rod guides desirably should not impede the flow of fluid in the annular space between the rods and the pipe, but yet full circle bearing engagement with the pipe is substantially essential.
Therefore, a further object is to provide a protector or guide which comprises body sections applicable transversely to the pump rod through longitudinal slot in the body and interiittingly interengageable at the adjacent body ends with adjacent bodies disposed on opposite sides of the rod, and wherein the protector or guide bodies are composed of a molded plastic material having the properties of being wear resistant and self lubricating or low friction, nylon being an example of such material. I The invention has various additional features and objects, all of which will be understood from the following detailed description of the illustrative embodiments shown by the accompanying drawings, in which:
FIGURE 1 shows in elevation a protector applied to a drill pipe;
FIGURE 2 is a fragmentary enlarge-ment of the protector and drill pipe showing of FIGURE 1, in which portions of the elastomer bodies of the protector are removed to expose the metallic clamping sleeve sections;
FIGURE 3 is a cross-section taken on line 3-3 of FIGURE 2;
FIGURE 4 is an enlarged fragmentary section on line 4 4 of FIGURE 2;
FIGURE 5 is a View illustrative of the use of a tool for removingia protector from the pipe;
FIGURE 6 is a section taken on line `6 6 of FIG- URE 5;
FIGURE 7 is a section taken on line 7-7 of FIG- URE 5;
FIGURE 8 is a showing in perspective of one of the gripping sleeve sections;
FIGURE 9 is a fragmentary showing of a variational sleeve section interconnection;
FIGURE 10 shows in elevation a protector or guide applied to a pump sucker rod;
FIGURE ll is an enlarged fragmentary view in longitudinal section, as taken on the line 11-11 of FIG- URE 10; and
FIGURE 12 is an enlarged view in transverse section, as taken on the line 12-12 of FIGURE 10.
Referring iirst to FIGURE 1, a protector generally indicated at 1t) is mounted on a drill pipe 11 within a well casing 12 at any location along the drill pipe proximate to or removed from the pipe couplings or tool joints, not shown. The protector 10 may be characterized as comprising one, or a pair, or more, of arcuate bodies la and 10b located on opposite sides of the pipe 11 when seen in plan and arranged at entirely diierent levels or otfset longitudinally of the pipe 11 when seen in elevation. Considered in plan, a pair of bodies provide for at least 360, and preferably in excess of 360, protective bearing surface, but since each body is only about 180 in extent and the bodies 10a and 10b are axially staggered or axially spaced apart when seen in elevation, there is left unrestricted a substantial ow passage 13 between the drill pipe and casing and between the bodies 10a and 10b. Thus, in contrast with the conventional full circular body protector, the protector 10 permits adequate practical flow through the passage 13 and considerable openness between the bodies 10a and 10b. This is partly because of the non-restrictive nature of an interconnection 1-4 between the pair of bodies and also because of the spacing given by the frustoconical end surfaces of the staggered pair of bodies.
Each of the bodies 10a and 10b includes a tubular spring steel clip-like sleeve section 1S curved in transverse cross-section for a little more than a half circle or 180 in arcuate extent. The springiness and contour of a sleeve section are such that when snapped around the pipe by a motion having a transverse component, the sleeve section has adequate gripping capacity in relation to the pipe 11. Merely as illustrative, in its initial formation a sleeve section may be stamped and pierced yfrom at sheet stock to provide circumferentially extending and' apertured rib configurations to enhance the resistance of the sleeve section to circular spreading. Then the sheet stock may be rolled to the partially circular or partially tubular form illustrated. After this, the sleeve section may be heat-treated to impart to the metal the qualities of spring steel strongly resilient when radially expanded and capable of strongly gripping the drill pipe and lying closely against the drill pipe surface. Typically, the metal thickness of a sleeve section may be in the order of about 1/16 to /gg of an inch.
When viewed in plan, approximately as shown in crosssection in FIGURE 3, the sleeve section 15 has a normal (unstressed or off the pipe) diameter in the order of about %2 to 1A; of an inch smaller than the outside diameter of the drill pipe. For application to drill pipe having an outside diameter of 31/2 inches, the normal or unsprung internal diameter of the sleeve section may be about 3% inches. The sleeve section when unstressed has an arcuate extent in excess of 180, the amount of excess being compatible with the ability of the sleeve section to be sprung apart at its open side to be moved with a transverse component onto the drill pipe and thereafter to spring or snap into iirm concentric engagement therewith. Generally it will be preferred to give the sleeve section an arcuate extent in the range of about 190 to 195, although FIGURE 3 shows an arcuate extent of about 240. Accordingly, when sprung onto the pipe, the sleeve section will maintain a strong grip resisting displacement along and rotationally about the pipe axis. The grip is made more secure by providing the sleeve section with inside irregularities that tend locally to grip and slightly penetrate the pipe surface.
.4 As illustrative of such irregularity formation, the sleeve section metal may be struck inwardly at 16 to provide sharp edge tongues 17, see FIGURE 4, which under the strongly constrictive force of the sleeve section tend to bite to the pipe surface. As will be noted, one set of the tongues 16a may be struck angularly and inwardly of the sleeve section and in one direction toward its longitudinal center, to resist both rotational and axial displacement of the sleeve section relative to the pipe, and a second set 16b of the tongues may be similarly angularly oriented but pointed in the opposite direction.
Each protector body 10a and 10b also includes a wear pad 18 of any suitable non-metallic material capable of being secured, preferably by bonding, to the sleeve section 15 and of extended serviceability in frictional engagement with the casing 12. Generally it is preferred to mold the wear pads 18 of an elastomer such as natural or synthetic rubber, although less yielding materials such as the tougher plastics, typically nylon, may be used. Assuming rubber composition, the wear pad 18 is molded on and bonded directly to the sleeve section surface, the strength of the interconnection being enhanced by the rib openings 20 through which the rubber interlocks. By reference to FIGURE 3, it will be noted that the Wear pad 18 has an inner periphery of about the same arcuate extent as the sleeve section 15.
Means are provided for interconnecting the bodies 10a and 10b by an interconnection 14 in a manner preventing rotation about the pipe axis relative to each other and preventing axial movement relative to each other. As a convenient form of interconnection, permitting individual application of the sleeve sections to the pipe in the FIG- URE l pair relation, or a greater number of sleeve sections in series, each sleeve section 15 on opposite edges and at opposite ends has terminals 15a of identical form extending beyond and not covered by the wear pads 18. The terminals in plan are arcuately shaped in accordance with the curvature of the intermediate portion of the sleeve section. Tongues 22 stop short of the vertical edges of the sleeve section. Each of the terminals 15a at both side edges and at both ends is formed with a recess 23 partly deine'd by a shoulder 24 at the inside of an inclined edge 25. Each of the tongues 22 has bevelled edges 26 and hook shoulders 27. All of the terminals of each sleeve section are preferably so formed in order to permit interconnection of any number of the sleeve sections.
One of the bodies, say 10a, may be secured in place on the' drill pipe by placing the open side of the sleeve section against the pipe and hammering or otherwise driving the sleeve section fully onto the pipe. The companion body 10b then is axially displaced and reversely positioned and is driven onto the pipe in a similar way with tongues 22 brought into general alignment with the recesses 23 so that the tongues enter the re'cesses and approximately occupy the FIGURE l relation. Interengagement of the shoulders 24 and 27 prevents sleeve sections rotating relative to each other about the pipe axis. Any tendency of the sleeve sections to move apart axially during service is arrested by abutment of the sides of the tongues with the slot or recess edges.
The relative proportions of the tongues and the slots or recesses can be varied. If very easy interengagement is desired, the axial dimension across the tongue 22 can be made slightly less than the corresponding dimension across the recess mouth between the shoulders 24 and 27. There' is then no resistance to interpositioning of the parts. If a rmer interengagement is desired, the axial dimension across the tongue is made somewhat greater than the distance across the recess mouth. Then when the parts are assembled, the bevelled edges 26 of the tongues cam on the' inclined edges 25 and on the similar edges of the adjacent tongues to distort the spring material axially until the tongues lie within the rece'sses and the shoulders 24 and 27 snap behind each other, relieving the metal stress. Depending also upon the proportions of the parts, some of the tongues can cam over the others of the tongues by movement in a radial direction until the parts snap into snug Occupancy of the recesses by the enlarged tongues. Bevelling of the metal edges may assist the latter snap action. While more force is necessary to apply the sleeve sections when the tongues are enlarged, the interconnection is more secure since something more than mere separation is necessary to disconnect the sleeve sections.
To assist in removal of a body from the pipe, the sleeve section may be formed with an outward boss 28 having a key slot 29 to receive an appropriate tool 3U. The tool 3G comprises a cylinder 31, see FIGURE 6, containing a plunger pin 32 beyond a compressed air inlet 33. The cylinder has a cross key which may be thrust through the slot 29 and then turned 90 as shown in FIGURE 7 so that the cross key engages the inside surface of the boss 28. Compresse'd air delivered to the cylinder thrusts the pin 32 against the pipe surface and the reactive pressure of the cross key outwardly against the boss 28 rocks one end of the sleeve section off of the pipe as illustrated in FIGURE 5. The sleeve section can then iinally be re moved by hand. No more than the foregoing is necessary if the tongues 22 are relatively free lits in the recesses, but if the tongues are large enough to require springing of the metal to snap into place, then it is likely that a prying tool will also have to be used to assist in springing the tongue metal so that the tongues can be snapped out of the recesses.
FIGURE 9 illustnates a variational form of interconnection between the sleeve sections. Adjacent Sleeve section terminals 36 and 37 are interengaged by the reception of arcuate tongues 38 on one of the terminals within arcuate recesses 39 in the other terminal. The interengagement is accomplished by rotating one of the sleeve sections relative to the other one about a 'horizontal or transverse axis. The amount of such rotation required is more than can be accomplished within the well casing 12, so that once interengaged, the rotated parts cannot reversely rotate yand become disengaged within the well casing. Transverse or radial separation is then impossible except outside the casing 13. The tongues 38 have axially extending end projections 40 received within the correspondingly shaped recess extensions 41. Entry of the semidovetail projections 40 into their respective extensions is accomplished by rocking the terminal 37 in the direction of the arrow within the recess 39, bringing the associated parts into interrelated positions.
The projections 40 can be easy lits in the recess extensions 41 since the parts are interlocked (while within the casing 12) against both relative axial and rotary displacement. But, as before, the projections 40 can have a width slightly greater than the mouth of the extensions 41 so that the projections 4d not only snap over the diameter of the drill pipe, but also snap into the recess extensions 41.
A series of more than two bodies can be interrelated as shown in FIGURE 9 by appropriate end formations of the various bodies and in a long series of bodies both the interconnections of FIGURE 2 and those of FIGURE 9 can be used.
In all cases, whether one or more of the protectors are used, the return path for the drilling uid or liquid, alr though sinuous because of the staggered positioning of the various bodies, is much greater than previously available with circular protectors and is comparable in cross sectional area with the supply path for the drilling liquid through the drill pipe. Despite the axial spacing of successive bodies or protectors, the protectors are close enough together on the drill pipe so that complete circumferential protection is given to the casing, any practical deviation of the easing being much greater than a reasonable axial spacing of the protectors on the drill pipe.
Referring now to FIGURES 10-12, there is shown an embodiment lof the invention which is best suited to use as a sucker rod guide to centralize the sucker rod in the Well production pipe which may be tubing or casing in the case of tubingless completion of the well.
As in the previously described embodiments the guide comprises a pair of similar sleeve sections a and -110b interfittingly interengaged at their adjacent ends and disposed on opposite longitudinal sides of a sucker rod 111 which is adapted to be reciprocated in a pipe or casing 112 so as to effect operation of the usual sucker rod pump (not shown) disposed in the oil reservoir.
Likewise, as in the case of the previously described embodiments each sleeve section extends about the rod 111 an extent slightly in excess of 180 so that when thus mounted on the rod 111, full circle bearing contact with the wall of pipe 112 is afforded, but Iadequate practical flow passage 113 is provided at the sides of the rod member 111 opposite the respective sleeve sections. In order to assure adequate ow passage at the region of the intertitting interengagement of the sleeve sections, each of them has its end formed as a segment of a fustrum of a long cone which diverges from the connecting end of the respective sleeve towards its mgidsection.
More specifically the small ends of the frusto-conical segments provide terminals 11511 including tongues or fingers 122 which extend arcuately for intertitting inten engagement in slots or recesses 123 also provided in each terminal inwardly of the fingers l122. It will be understood that if desired the fingers and slots may be provided with axially extended interengageable walls as in the case of the previously described embodiments. However, such retention of the sleeve sections l10n and 110b against transverse separation is not essential to practical operability of the present guide.
In the latter connection, the sleeve sections 110e and 110b are molded of a single body of plastic material having an internal radius slightly less than the radius of the rod 111 so that the sleeve segments `are adapted to transversely snap onto the rod 111, the sleeve sections thereby being retained against transverse displacement and against axial m'ovement with respect to the rod 11 by the inherent resilience of the material under stress. The sleeve sections 110:1 and 110b are preferably molded of a material having the quality of wear resistance and low friction such as nylon, for example, and in order to facilitate their application to the rod, the sleeve sections may be preheated to soften the same, as by emersion in hot water for a period of time.
While in the previously described embodiments, a wear pad is joined with a supporting sleeve section, the embodiment now being described is unitary in the sense that the one piece plastic body is thickened at 118 so as to provide the desired lateral extension and wear pad region on body portion.
Also, it is now notable, that when the sleeve sections 110a and 1-10b are on the rod 111 and confined within the pipe 112, the plastic bodies will engage the pipe 112 to prevent suicient transverse movement of the sections as to break the interfitting coengagement of fingers 122 in grooves 123. Thus when the guide is in use it is impossible for it to come off of the rod.
Among other advantages of the two bodies, one is particularly evident when the environment causes substantial wear on one side and not on the other. lWith the present arrangement, `only one body, the worn one, need be removed for repair or replacement. In many installations this feature substantially reduces waste and cost.
What is claimed is:
1. A protector for a circular cylindrical member within a substantially concentric circular cylindrical casing spaced therefrom to leave an intervening annular passage; comprising a iirst sleeve section having a body extending part way around said member and abutting one side thereof at a predetermined axial location, a second sleeve section having a body extending part way around said member and abutting the other side thereof at a location spaced axially from said predetermined location, and interfitting means at one end of the body of each of said first and said second sleeve sections for interlocking said sleeve sections and holding said sleeve sections against rotation relative to each other about said member and against sliding movement relative to each other along said member, the bodies of the respective sleeve sections being disposed in axially spaced relation along said meniber and being staggered on opposite sides of the median plane extending axially of said member, and in which said interfitting means engage and disengage upon rotation of one of said sleeve sections relative to thek other of said sleeve sections about a transverse axis coinciding with said plane.
2. A protector as in claim 1 including wear pads on both of said sleeve sections disposed thereon to leave a sinuous unobstructed portion of said passage between and alongside said wear pads.
3. A protector as in claim 1 in which said inter-fitting means engage and disengage upon rotation of one of said sleeve sections relative to the other of said sleeve sections about a transverse axis.
4. A protector as in claim 1 in which said interfitting means engage and disengage upon relative movements of said first sleeve section and said second sleeve section greater in amount than can be accomplished within said annular passage.
5. A protector or guide for an elongated member within a substantially concentric pipe spaced therefrom to leave an intervening annular passage comprising a first sleeve section extending more than 180 around one side of said member and open at the other side of said member, a second sleeve section extending more than 180 around said other side of said member and open at said one side of said member, and intertting means consisting of end portions of the respective sleeve sections interconnecting said sleeve sections together about said member with said sleeve sections in staggered oppositely axially extended relation on said member.
6. A protector or guide as defined in claim 5, wherein said intertting means comprise interengaged fingers and recesses at the end portions of said sleeve sections, said fingers extending circumferentially to enable lateral application of said sleeve sections to said member at the open sides thereof.
7. A protector or guide as defined in claim 5, wherein said sleeve sections have arcuate inside surfaces on a radius slightly less than the radius of the outside of said member, whereby said sleeve sections snap onto said member.
8. A protector or guide as defined in claim 5, wherein said sleeve sections are provided with outwardly enlarged body portions engageable with said pipe.
9. A protector or guide as defined in claim 8, wherein said sleeve sections are composed of metal and said enlarged body portions consist of elastomeric pads bonded with said metal sleeve sections.
10. A protector or guide as defined in claim 3 wherein said sleeve and said enlarged body portions are composed of molded plastic material.
11. A lprotector or guide as defined in claim 8, wherein said sleeve and said enlarged body portions are composed of molded plastic material and the adjacent ends of said body portions are segments of a frustrum of a long cone.
12. A protector or guide as defined in claim 5, wherein said interfitting means comprise interengaged ngers and recesses having opposing walls extended axially of said sleeve sections to prevent transverse separation of said sleeve sections.
13. A protector or guide as defined in claim 12, wherein said fingers and recesses extend arcuately to allow interengagement in response to movement of one of said sections about a transverse axis.
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MARTIN P. SCHVVADRON, Primary Examiner LUCIOUS L. JOHNSON, Assistant Examiner U.S. Cl. X.R.