US2515796A - Well casing protector - Google Patents

Description

July 18, 1950 Filed Aug. 6, 1945 J. T. PHIPPS WELL CASING PROTECTOR 2 Sheets-Sheet 2 65b 67 BY A T TORNE Y Pate'ntecl July 18, 1956 UNITED STATES PATENT OFFICE WELL CASING PROTECTOR John T. Phipps, Huntington Park, Calif., assignor, by mesne assignments, of one-third to William F. Sturdivant, one-third to Carl E. Phipps, and one-third to John T. Phipps Application August 6, 1945, Serial No. 609,206

3 Claims. 1

This invention relates to oil well equipment and particularly pertains to well casing protectors and means for applying the same.

In recent years it has become common practice to mount non-metallic sleeves upon oil well drill strings so that as the drill string rotates while extending through a section of set casing the casing will be protected from any whipping or rubbing action produced by the drill string. The most common type of casing protecting sleeve is a solid rubber sleeve having a wall in excess of an inch in thickness and having a bore through it which is of lesser diameter than the diameter of the drill string upon which it is to be mounted. It is difficult to expand casing protector sleeves in applying them onto drill strings for the reason that at the end of each section of drill pipe there is a tool joint which is of larger diameter than the diameter of the body of the drill string. This makes it necessary to expand the casing protector to a much greater diameter than that of the section of pipe upon which it is to seat. It has been found, therefore, that in many instances the rubber walls of the casing protectors have been stretched to a degree which does not insure that they will contract firmly around the body of the drill string and hold against longitudinal movement along the drill string. In fact, it is often found that when a drill string is withdrawn from a well all of the casing protectors which have been mounted upon a section of drill pipe between the tool joints at the opposite ends thereof will be positioned together at one end of the section of pipe. Under such conditions it is evident that the protectors were not arranged along the section of pipe to provide buffers at intervals and to protect the casing adequately. This is particularly true when the drilling operation produces a crooked hole. Various types of devices have been developed for stretching the rubber casing protector sleeve conveniently for placing it over the enlarged tool joint and in a desired set position upon the body of the section of drill pipe. These devices for the most part have been cumbersome, and in some instances have'utilized spring members which may break and result in injury to the drilling crew. It is the principal object of the present invention, therefore, to provide a casing protector and apparatus for applying the same which will insure that the protecting sleeve may be easily placed on a drill string, preferably by the force exerted by the weight of the drill string alone, and which sleeve may be positioned accurately at a selected point along the length of the drill string and held against longitudinal movement.

The present invention contemplates the provision of a tubular sleeve made of rubber or its equivalent and means whereby said sleeve may be expanded over a tool joint and onto the body of a section of drill string, after which it may be easily and effectively anchored in position upon the drill string.

The invention is illustrated by way of example in the accompanying drawings in which:

Fig. 1 is a view in central vertical section through the device by which a casing protecting sleeve is applied, showing it in the initial stage of operation.

Fig. 2 is a fragmentary view showing the final stage of operation of the applying means.

Fig. 3 is a view in transverse section as seen on the line 33 of Fig. 1 and shows the construction of the removable sleeve seat.

Fig. 4 is a view in elevation showing a form of device by which casing protectors may be placed on a drill string while the drill string is lying horizontal in the rack.

Fig. 5 is a view in central longitudinal section showing a complete casing protector and its clamping means as applied to a fragmentary portion of a drill string.

Fig. 6 is a view in transverse section as seen on the line 6-6 of Fig. 5 and shows the manner in which the clamping element is secured in position.

Referring more particularly to the drawing, I0 indicates a section of drill pipe formed with a conventional box H at its lower end. This box is threaded to receive a pin 12 carried by a lower section of drill pipe is which may be held against longitudinal movement of slips [4 in a rotary table l5. Temporarily attached to the box H is a casing protector sleeve expander Hi. This is fitted with a threaded pin ll beneath which a frusto-conical section it is formed. The base of the cone i8 is presented uppermost and is of a diameter agreeing with the diameter Of the box ll. At the lower end of the section IS a cylindrical element I9 is formed. This cylindrical portion agrees susbtantially with the normal diameter of a central bore 20 formed through a casing protector sleeve 2!. This sleeve, as particularly shown in Fig. 5 of the drawing, is made of rubber, or a suitable equivalent, and has an upper convex end face 22-, for a purpose to be hereinafter described. The lower end face is substantially fiat, as indicated at 23, and carries a tubular projecting portion 24 which is of a diameter considerably less than the outer diameter of the sleeve. At the lower end of this portion an enlarged shoulder portion 25 is provided, for a purpose to be hereinafter explained. It is to be understood that the central bore 26 extends through the sleeve 2i, the tubular extension 24, and the shoulder 25.

It is necessary to expand the protecting sleeve 2| from its normal diameter so that it may pass over the enlarged box section ll of the drill string, after which the sleeve will contract onto the diameter of the drill string it. This is accomplished in the present instanceby providing a casing sleeve applicator, as indicated-generally at 26. This structure comprises a tubular cylindrical body 271 formed with a closed lower end wall 28. The end wall .28 has a central threaded opening 29 through it. The opening 29 receives a threaded extension 30 carried by an attaching box 3|. The box 3! is formed with a threaded socket 32 to receivethe upwardly projecting pin 52 of the tool joint carried by the drill string section It. Suitable transverse passageways 33 are formed through the box (H to receive a bar by which the member may be rotated to screw the box onto the pin 12. The upper end of the body member 2'! receives a cap 3%. Thiscap is formed with a central bore 35 terminating at its lower end in a counterbore 38. The outer diameter of the cap 34 is greater than th diameter of the body member El, and the counterboreagrees in diameter with that of the body member- 2? so that the body member may fit within the counterbore with its upper edge resting against a shoulder 3? in the cap. Fastening. means, such as cap-screws 38, are provided to hold the body member 2? and the cap 36 in an assembled relation to each other. The upper endof the cap M- is formed with a transverse pressure seat 39. .This seat has a central bore All which is concentric with the cap and is of smaller diameter than the inside diameter of the cap.. The upper. face of the pressure seat is outwardly and downwardly inclined, as-indicated at 4L. The face i! is designed to engage the face 23 of the casing. sleeve 2i and to act to force the. massof rubber of the sleeve outwardly in aiding in the expansion action-of the sleeve in the finaloperationof applying the sleeve to the drill string.-. This. fac isalso provided to 'receive a removable expander seat l2. As shown in Figs. 1 and 3 this member is formed in two semicylindrical pieces-=43 andtli which have'an annular groove 25- around them. Seated within this grooveare hinge members lii and 47 which arehinged. together at 48 and are latched together by a suitable latch generally indicated at 59. A pair of operating handles 50 are provided for swinging the structure to its open and closed position. The sections 33 and M are temporarily held within the members 4t and ll by any suitable means.

By reference to Fig. 1 it will be seen that the expander seat 42 has a relatively large upper cylindrical section formed at its lower end with an undercut shoulder 52, which rests upon the inclined face ll of the member 39, the abutting faces of the two members agreeing in angularity. The upper face of the expander seat 42 is outwardly and downwardly tapered, as indicated at 53, and provides a seat against which the face 230i the protector sleeveZl may rest in the initial expanding operation. A cylindrical portion of the seat %2- occurs below-th undercutface-52, as indicated at fi lg-and agrees-substantially in diameter with the bore 40 of the cap 34 so that the member 52 will be centrally positioned within the cap 3 3. A tubular extension 55 is formed integral with the portion 54 and provides a guide throat for the cylindrical end iii of the expander 26. A plurality of spring fingers 56am secured by their lower ends to the inner wall of the tubular portion 55 and are spaced circumferentially. These spring fingers extend upwardly and inwardly, and have free upper outturned ends 5? between which the cylindrical portion Q9 of the expander it may be guided as the expander moves downwardly through the protector sleeve 2i.

It will thus be seen that when the weight of the drill string section Ii] is applied to the expander it willforce the expander down through the protector 2i and a central bore 5'! of the member 42. It may be desirable to apply additional Weight to the "drill string, or in fact to apply hydraulic pressure to force the drill string iii longitudinally. Any of these expedients are contemplated as being within the scope of the present invention. In some instances it may be desirable to apply the casing sleeves while the drill string sections are lying horizontal in the rack. In that case mechanical means for applying pressure-are provided, as shown in Fig. 4 of the drawings. Here it will be seen that the expander ldis formed with a central bore 58 which is closed at its lower end by an end wall having a threaded bore 5%} therethrough. This borereceives a threaded screw 60 which is of a length to extend entirely through the applicator 26. Its outer end is fitted with an operating crank, and at a point adjacent thereto on the rod of the screw a threaded plug 62 is mounted. This plug is free to rotate but is held against longitudinal movement between collars 63 and (54, which are integral with the screw shaft. The threaded plug 32 i intended to b screwed into the threaded opening 2% in the end cap 28 of the applicator body 27. By this arrangement the expander H5 attached to the box ll of a drill string section it may be pulled through the protecting sleeve 2% rather than pushed through it, as'shown in Figs. 1 and 2.

As has been-previously explained, one of the difficulties encountered in the satisfactory use ofcasing protectors is that they do nothave sufficientinherentcontractile strength to insure that the protecting sleeves will remain in a set position on the drill string. In order to positively hold the casing protector in a set positionon the drill pipe a clamping. collar 65 is provided. Thiscollar, .asshownin Fig. 6 of the drawings, is made in two semicircu1ar halves 65 and 65 each of whichshavev a threaded bore Edto receive a. cap screw. 8?. The. head. of each cap screw is concealed within an indentation 68 in the outer surface of the elements 65 and 65 sothat these heads Will not engage the casing. The diameter of the clamping collar 65 is materially less than the outside diameter of the protecting sleeve 2!. It is formed with a central bore which has a wickered surface so that the collar will positively engage the surface of the drill string to prevent it from moving in any direction thereon after it has been clamped. At the upper end of the wiclzered bore 59 an enlarged annular recess is formed to accommodate the shoulder portion 25 of the casing protector 2 l. Asmaller bore occurs beyondthis recess to grip 'around'the' tubular portion 24 of the casing protectorr Thus; the collar interlocks with one end of the casing protector so that when the collar is fixed on the drill string the casing protector will be held likewise.

In operation of the present invention it will be assumed that a portion of the drill string has been assembled and lowered into a well so that its upper section It projects above the rotary table l and is held by the slips I4. This will cause the tool joint carrying the pin |2 to be presented upwardly above the rotary table. The applicator has been previously assembled so that it carries the box 3| at its lower end. This box is then screwed onto the pin I2 so that the applicator will be supported in an upright position with its face 4| presented upwardly to receive the expander seat 42. This will provide a face 43 against which the lower face '23 of a casin projector 2| may rest. It will be understood that the bore 51 in the upper end of the member 42 is of suificient diameter to permit the tubular extension 24 and the shoulder member 25 of the protector sleeve to extend downwardl therethrough. The drill string section H] at this time will be appropriately supported above the rotary table so that the expander iii may be connected therewith. This is done by threading the pin ll into the box Thus the cylindrical end IQ of the expander It will extend downwardly. As pressure is applied to the expander It by the weight of the drill string section It or other pressure applying means, the cylindrical portion |9 of the expander will be forced into and through the central bore 20 of the protector sleeve. As Weight is continuously applied the frusto-conical section I9 of the expander will force its way into the bore 20 to stretch the sleeve. Attention is directed to the fact that when the upper face of the protector sleeve is flat there will be a tendency for surplus rubber to accumulate directly against the tapered face of the portion Hi. This will act to retard the entrance of the expander into the bore of the sleeve. In order to eliminate this condition the upper end face of the sleeve 2| is here shown as being concave, as indicated at 22. Due to this arrangement when the entrance of the expanding cone into the bore 20 causes the rubber of the sleeve to stretch and flow it has been found that a mass of rubber does not accumulate objectionably around the mouth of the bore into which the expanding tool is being forced. As the expander i6 is forced downwardly and the diameter of the sleeve increases it will be seen that the surface 53 will continually provide a pressure face against which the casing sleeve will be held. After the cylindrical end |9 of the expander has been forced entirely through the central bore 20 of the sleeve 2| it will move to a position between the yieldable fingers 56 and will be held centrally to insure that pressure exerted by the expander I6 will be applied uniformly to the protector sleeve 2|. Attention is directed to the fact that the diamete of the expander seat 42 is substantially greater than the diameter of the sleeve. This permits the expander It to be forced a desired distance through the sleeve while the lower face 23 of the protector sleeve is adequately supported.

In designing the device care is taken to see that the bore 51 in the face 53 is small enough to insure support of the sleeve 2| at all times but is not large enough to allow the complete application of the protector sleeve to the drill string in one continuous operation. In other words, the base diameter of the conical section It of the expander I6 is greater than the diameter of the bore 51. However, the bore 40 within the upper end of the cap 34 is greater than thediameter of the expander I6 andthe box ll of the tool joint, for a purpose to be hereinafter set forth.

After the conical portion l8 of the expander It has been forced a sufficient distance through the bore 20 of the protector sleeve 2| it is necese sary to provide a new pressure seat against which to operate. This is done by lifting the drill string section III, the expander Hi, and the partially expanded protector ring which is held by its own friction upon the tapered portion |8 of the expander. When the portion is of the expander has been lifted clear of the upper end of the expander seat 42 the expander seat may be lifted by the handles 50 so that it will be removed from its seated position on the upper end of the cap 34. The latch 49 may be unlocked to allow the parts 43 and 44 to spread so that the structure may be removed. The operation is then continued by lowering the drill string section if! and the expander 6 so that the lower face '23 of the protector sleeve 2| will rest against the face ll of the cap 34. As previously explained, the diameter of the bore 40 is sufficient to accommodate the expander IB and the box The circumferential face ll therearound is of suficient dimensions to propertly support the protector casing 2| as it rests upon this face initially, and to give it adequate support as the protector sleeve is expanded further. After the member t2 has been removed and the sleeve disposed upon the face 4| the cylindrical end it of the expander It will extend downwardly into the applicator 26 and between a plurality of spring fingers H the lower ends of which are fixed within the body portion 27 of the applicator. This allows the upper free ends to form centering guides for the expander. As pressure is then applied to the expander Hi the protector sleeve 2| will be stretched further until its bore 20 is of a diameter to accommodate the box and to thereafter be moved over onto the drill string section H) to a desired point in the length of the drill string section. After the casing protector has been properly positioned upon the drill string section it can be fastened securely by the collar 6-5. This is done by placing the two halves 65 and 65 of the collar around the casing with the recess 7|] in register with the shoulder portion 25. The cap screws 67 are then applied and tightened so that the wickered faces of the bore 69 will be forced against the surface of the drill pipe In to engage the same positively and to prevent rotation of the casing protector 2| upon the drill pipe section It or longitudinal movement of the casing protector with relation to the drill pipe section Hi.

It is well known that casing protectors have been provided which were of the sectional sleeve type and where a plurality of metal elements carried rubber buffer sections while the metallic parts embrace the drill string directly and were clamped thereagainst. In many instances this clamping action did not prove to be positive and would not give the result here obtained, where an annulus of rubber is placed upon a. drill string and carries a portion embracing the drill string but which may receive metallic clamping members acting to engage the surface of the drill string directly as well as to compress the projecting portion into firm frictional gripping relation to the drill string. The present structure, therefore, provides the normal gripping action produced by the contraction of the rubber sleeve, the mechanical gripping action produced by 7 tightening-the projecting portion of-the'sleeve against the drill string, and the positive gripping action by causing impingement ofthe wickered surface of the metallic collar with the outer surface of the drill string.

It will thus be seen that by the use of the present device it is possible to easily and quickly apply a rubber casing protector to a drill string and to set it at a desired position therealong without danger of breakage of parts or injury toworkmen. It will be noted further that by the use of the present device it is not necessary to thread a drill string through an applying structure but that the applicator may be applied easily and may be removed quickly.

While I have shown the preferred form of my invention as now known to me, it will be understood that various changes may be made in combination, construction and arrangement of parts by those skilled in the art, without departing from the spirit of my invention as claimed.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A casing protector sleeve, comprising a resilient annular sleeve adapted to be placed upon a, cylindrical pipe, the bore of said sleeve being normally of lesser diameter than the diameter of the pipe, an extension formed at one end of said sleeve and embracing the pipe, the outer diameter of said extension being less than the outer diameter of the main body of the sleeve and having a circumferential groove, and clamping means adapted to embrace said. extension and to engage said groove and a portion of the pipe adjacent thereto whereby the pipe will be mechanicallygripped to hold the sleeve in position.

2. The structure of claim 1 in which the-surface f the portion of the clamping means physically engaging the pipe is wickered.

3:- An oil; well. casing protector to be mounted upon adrill'string in a fixed position, said protector including a tubular resilient sleeve made with a normal bore of lesser diameter than the diameter of the drill string whereby it will contract therearound, a tubular extension formed as a continuation of one end of the sleeve and being of 'lesser outside diameter than the sleeve, said' extension being formed with a circumferential groove in the outer face thereof, and clamping means adapted to be disposed around the tubular extension and being of a length greater than the tubular extension, said clamping means having a portion extending into said circumferential groove and a portion beyond the end thereof which may be drawn in positive clamping engagement with the surface of the pipe upon which the sleeve is mounted.

JOHN T. PHIPPS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,024,344 Langevin Apr. 23, 1912 1,029,950 Schulz June 18, 1912 1,167,758 Hess Jan, 11, 1916 1,854,339 Lamb Apr. 19, 1932 2,197,531 Smith Apr. 16, 1940 2,252,692 Barnes et al Aug. 19, 1941 2,291,251 Norris July 28, 1942 2,299,978 Hall Oct. 27, 1942 2,308,147 Ballagh Jan. 12, 1943 2,318,878 Miller May 11, 1943 2,320,553 Barnes et a1 June 1, 1943

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