US 3148004 A
Description (OCR text may contain errors)
Sept. 8, 1964 E. D. HALL ETAL.
DRILL PIPE PROTECTOR Filed Aug. 1, 1962 dan@ E. Ha, dr. INVENTORJ H M f e M Mmm@ United States Patent O 3,148,004 DRILL PEE PRDTEC'I'OR Elmer D. Hall, Weatherford, and Jesse E. Hall, Jr., Houston, Tex., assignors to Weatherford Oil Tool Company, Inc., Houston, Tex., a corporation of Texas Filed Aug. 1, 1%2, Ser. No. 214,030 3 Claims. (Cl. 308-4) This invention relates to protector devices of the type applied to drill pipes in rotary drilling to protect the casing from abrasion by the tool joints and also for application to a drill collar in stabilizing and guiding the same in the hole.
Heretofore, drill pipe or casing protectors of the above type have consisted mainly of hollow cylindrical bodies of rubber or rubber-like material which engage both the drill pipe upon which the body is mounted and the surrounding casing or other wall. The body or collar may be formed of one piece, in which case it must be severely stretched in being applied to the drill pipe. Alternately, the body may be longitudinally split and then, after being applied laterally to the pipe, contracted circumferentially, as by wedging pins, cams, or a suitable stretching tool so as to firmly grip the pipe.
However, all such devices heretofore used have had serious disadvantages. One such disadvantage is that the shear forces which the rubber will resist are limited by the tendency of the rubber to ow or break down. Such forces may be due either to fluid pressure within the well or to the striking of obstacles on the well wall. Consequently it has been customary to embed reinforcing metal plates in the rubber, while retaining the rubber-tometal contact between the protector and drill pipe thought to be necessary to frictionally hold the protector in position. Another disadvantage is that in stretching the protector body in applying it to the drill pipe, pores may be formed in the rubber. If these pores are iilled with iiuid at the high pressures which exist deeply within a Well, such trapped iiuids may expand or implode when subjected to lower pressure upon being withdrawn from the well, thus damaging or even destroying the protector. At the same time, the wings or other radial projections may be caused to swell radially and fold so as to materially affect the guiding action. Still another disadvantage of current types of protectors, which rely upon rubber-to-metal contact for firm attachment to the drill pipe, is that the rubber tends to soften at the high temperaure sometimes encountered within a well, thus weakening the attachment of the protector to the drill pipe.
Finally, conventional types of drill pipe protectors have not been usable as drill collar stabilizers both because of the very heavy longitudinal and circumferential stresses to which these members are subjected and also because of the rapid wear on the bore wall engaging wings or other projection.
Accordingly, an object of the present invention is to provide novel means for attaching a protector device to a drill pipe or collar.
Another object is to provide a drill pipe or collar protector having a body mainly of rubber or like elastic material, but in which such material is not relied upon for frictionally gripping the drill pipe or collar.
Another object is to provide a protector for drill pipes or collars in which the elastic material of the body need not be excessively stretched during application to the pipe or collar.
Another object is to provide a protector for a drill pipe or collar in which substantially the entire circumferential stress tending to lodge the protector on the pipe or collar is borne by longitudinally resilient metal bands.
Another object is to provide a protector for a drill pipe or collar in which the holding means encompassed in the protector device involves substantially the contact of metal parts, rather than the resilient frictional action of rubber-to-metal contact heretofore utilized in anchoring such devices to the pipe or collar.
Still another object is to provide a drill pipe protector device which can be utilized as a drill collar stabilizer.
The protector according to the present invention consists mainly of a hollow, generally cylindrical body of rubber or rubber-like material having radial wings for engaging the surrounding casing or well wall. In one form of the invention, wear resistant inserts are provided in the wings. The cylindrical body is split longitudinally to form semi-cylindrical halves and extending around the inner face of each half are a plurality of relatively narrow-metal bands, the inner faces of which are flush with the inner face of the semi-cylindrical body, although a thin coating of body material may be provided on the bands, incident to the molding operation. Loops are provided at the ends of the bands, which, when the body parts are assembled about a drill pipe or collar, are secured together by wedging pins so that the collar halves are drawn tightly about the pipe. The longitudinal resilience of the bands is relied upon for secure clamping of the body to the pipe. Thus, only slight stretching of the rubber body material occurs.
In the accompanying drawings which illustrate the invention,
FIG. l is a perspective view showing the protector mounted upon a drill pipe within a well casing;
FIG. 2 is an enlarged perspective view showing part of a disassembled half of the protector device;
FIG. 3 is a horizontal section through the protector assembled about a pipe;
FIG. 4 is a partial longitudinal section taken on line 4-4 of FIG. 3; and
FIG. 5 is a detail perspective view showing a modification.
FIG. 1 illustrates at 8 a portion of a drill pipe inserted in a casing 9 set during the rotary drilling of a Well. Received about pipe 8 is the novel protector, including a hollow generally cylindrical body defined by identical semi-cylindrical parts A and B having Wings 10 for engaging the casing wall to prevent the pipe or a tool joint thereon from rubbing against the casing. As shown in FIG. 2, protector half A consists of a generally semicylindrical body part 11 of rubber or similar elastomeric material from which projects the radial ribs 10. The opposite body part B is identical, but reversed, so that only one part will be explained in detail.
Extending circumferentially around the inner face 12 of the body part are a plurality of relatively narrow metal bands 13, each having somewhat elongated loops or eyes 14 and 15 at its extremities. These bands are spaced apart slightly more than .the width of a band so that the band end loops of the complementary reversed part may lit therebetween in the assembly.
As shown in FIG. 3, loops 14 and 15 are formed by end portions 16 and 17 of the bands which are bent back upon themselves and then secured, as by spot welding, to the overlapped band parts. The rubber-like body material is formed by a molding process and the bands are seated in the mold in such a way that they will be firmly secured to the inner face of the molded part with substantially the entire inner faces of the bands and body part flush and with the loop end portions 14 and 15 being exposed. A thin coating of the elastic body material may be forced over the inner surfaces of the bands during the molding operation. However, experience has shown that this thin coating does not have the weaknesses of rubberto-metal attachments of previous devices wherein the inner portions of the rubber body, relied upon to frictionally grip the drill pipe and subjected to heavy distorting forces Patented Sept. 8, 1964` materially limit the longitudinal and iiuid forces which these prior devices will withstand. Also, during the molding process, a portion of the rubber material is forced, as at 18, into the inner extremity of each loop 14 and 15 so as to form a resilient body tending to resist lateral contraction of the loop and, thereby, contributing to the longitudinal resiliency of the metal band.
In assembling the protector with a drill pipe, the protector halves are simply applied laterally in complementary relationship upon the drill pipe. Thereafter, a pair of drift or Wedging pins 20 are inserted oppositely into the registering staggered loop eyes and driven home. This, in turn, slightly stretches bands 13, but well within their elastic limit, so that their resilience is maintained and the device thereby strongly secured to the pipe. Only slight stretching of the rubber occurs during such clamping action and ultimately the end faces 20, 21 and 22 of the rubber body material are drawn together.
Accordingly, in operation, the longitudinally resilient metal bands themselves, possibly thinly coated with rubber, as explained above, directly engage the drill pipe so that there is no substantial or destructive deformation of the rubber body material even in resisting much greater longitudinal and Iiuid forces than previous devices are able to withstand. In the appended claims, reference to the inner faces of the band and body as being flush or substantially hush comprehends the possibility that a thin film of rubber or other body material may cover the inner faces of the bands, such lm having no material adverse effect upon the tight frictional gripping of the pipe by the bands or upon the overall resilience or flexibility of the device. The terms resilient and elasticf as used herein, refer to the relative ability of a body to resume or return to the original shape after straining. To insure this relationship, each pair of metal bands 13 completely surrounding the drill pipe preferably will be in inner circumference slightly less than the outer circumference of the pipe for which the protector is intended. This, necessarily, will result in stretching of the metal bands during application. The Width, thickness, and material of the bands, accordingly, will be such as to provide sufficient resilience to withstand the forces to which the protector is subjected in use, to insure an elastic limit well beyond the longitudinal stretch of the bands contemplated in assembly, and to prevent breakage or excessive distortion in the wedge pin eyes.
FIG. shows a radial wing part 10a of a protector device, constructed as explained above. However, the outer surfaces of the wings a are provided with multiple discrete hardened inserts, 23, for resisting wear in engaging the bore wall, as in the case of a drill collar stabilizer. This type of device will be mounted upon the drill collar customarily provided at the bottom of the drill string and adjacent the bit.
The configuration of the protector body may be otherwise designed so as to provide the necessary circumferential voids and projections permitting well fluids to pass the device, while retaining the guiding and protection function. Also, the number of bands, and their sizes and materials may be adjusted in accordance with the requirements of the particular protector body. The invention may be modiiied in these and other respects as will occur to those skilled in the art, and the exclusive use of all modifications as come within the scope of the appended claims as contemplated.
l. A protector for a drill pipe or collar comprising a hollow, generally cylindrical, longitudinally split body of elastomeric material and a plurality of individual metal bands disposed in the inner surface of said body, said bands extending circumferentially1 around said inner surface and being of slightly less length than the periphery of the pipe or collar for which said protector is intended and having securing elements on the end portions thereof for clamping said bands and said body tightly upon a pipe or collar, substantially the entire inner surfaces of said bands being flush with said body inner surface for f rictionally gripping the pipe or collar.
2. A protector as described in claim l in which said securing elements comprise loops on the ends of said bands and wedge pin means inserted in said loops for drawing said bands and said body tightly about a pipe or collar.
3. A protector for a drill pipe or collar comprising a hollow generally cylindrical body of molded elastic material,
a plurality of metal bands,
each of said bands being embedded in and extending partially around the inner face of the body and terminating in exposed end portions, and
securing means at the adjacent end portions of the bands,
substantially the entire inner surface of said bands being hush with the surface of said body and said bands when unstressed being of slightly lessvlength than the peripheral dimension of the pipe or collar for which it is intended,
whereby the inner surface of said bands will frictionally grip the pipe or collar to maintain said protector in position.
References Cited in the le of this patent UNITED STATES PATENTS