US2758818A - Casing and drill pipe protectors - Google Patents

Description

Aug 14, 1956 A. w. KAMMERER, JR

cAsNG AND DRILL PIPE PRoTEcToRs Filed Aug. 9, 1954 0 2 i 4 5 a s 8 2 v d .5 www w m M D /f/ mm Y c AM v7 2 2 v/Lw C 3 a n I 7 8 L5 a 0 0 531 a e 2 ii; w 2 \\A\/ Alec/f5@ WnMMf/ee efe.

United States Patent() CA'sING AND DRILL PIPE PRorEcToRs Archer W. Kammerer, Jr., Fullerton, "Calif., assiguor to Rotary Oil Tool Co., Huntington Park, Calif., a cor` poration of 'California Application August 9, 1954, Serial No. 448,459

'2 Claims. (Cl. Z55- 28) The present invention relates to devices for protecting tubular drill strings during the rotary drilling of bore holes.

In the drilling of bore holes, rubber protectors have been mounted at spaced intervals on the exterior of strings of drill pipe, to prevent the latter from bearing against surface casing and other strings of casing in which the drill pipe is rotating. It is only desirable to have the protectors disposed along that length of the drill pipe located in the cased portion of the hole. Accordingly, in running drill pipe in the hole care must be exercised in accurately measuring the pipe, to insure that the pipe stands with protectors thereon will be incorporated in the drill string at the proper place, the protectors being located within the cased portion of the hole during the drilling operation.

Errors in measurement will result in the provision of inadequate protectors in the cased portion of the hole, or the disposition of rubber protectors in open hole, where the protectors are readily torn and inadvertently removed from the drill pipe by the open formation, which tends to restrict circulation of the drilling mud and possibly produces sticking of the drill pipe. Even with proper measurements, one or more of the protectors may be moved down below the cased hole and into open hole as drilling proceeds, produc-ing the aforementioned hazards.

The present practice of providing protectors on drill pipe is a time consuming and costly one. Not only must careful measurements be made of the unprotected drill pipe sections to be run in the open hole, but the drill pipe sections fitted with protectors must be handled and stored separately. The protectors are placed on the drill pipe by special tools and must be cut oft the drill pipe when the latter is to be used without protectors, or where a replacement protector is required.

Some bore holes are drilled by attaching a rotary drill bit to a string of well casing, rather than to drill pipe. Attempts to put rubber protectors on relatively large diameter drill casing would be comparatively costly, because of the size of the protectors, and such protected casing would be subject to the same disadvantages as drill pipe with protectors mounted thereon.

Accordingly, it is an Iobject of the invention to provide a protective device for a tubular drill string that eliminates the need for measurements of the drill string sections as they are being run in the hole, and the special storing and handling of the sections to be used in the cased portion of the hole. The sections or stands of drill string can be run in the hole with-out regard to the length of the cased hole.

Another object of the invention is to provide a protective device for a tubular drill string, in which the device cannot be disposed below the cased length of the hole, thereby preventing damage to the protect-ive device which would result were it disposed and used in Iopen hole.

A further object of the invention is to provide a protective device for a tubular drill string that provides a ice greatly increased bearing and protective service, increasing greatly the life of the protective device.

Yet another object of the invention is to provide a protective device that can be employed economically and with great effectiveness in conjunction with casing used as a drill string in drilling the bore hole.

This invention possesses many other advantages, and

.has other objects which may be made more clearly apparent from a consideration of several forms in which it may be embodied. Such forms are shown in the drawings accompanying and forming part of the present specification. These forms will now be described in detail, illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

Figure l is a longitudinal section, with parts shown in elevation, of a cased portion of the hole, embodying several forms of the invention, with a drill string disposed therein;

Fig. 2 is a greatly enlarged longitudinal section through a portion of the casing disclosed in Fig. l, illustrating one form of protective device;

Fig. 3 is an enlarged longitudinal section through a portion of the casing shown in Fig. l, disclosing another embodiment of the protective device.

As disclosed in the drawing, a string of casing 10, wh-ich may be surface casing, is disposed in a previously drilled bore hole 11. This casing string may constitute surface casing extending from the casing shoe 12, forming the lower terminus of the casing string, to the top of the well bore 11, and may include casing sections 13 threaded and coupled to each other. This string of casing 10 may be cemented in place by depositing cement in the annulus between it and the wall of the surrounding well bore 11.

A hole 14 is being drilled below the string of surface 10, or other cased portion of the hole 11. A tubular drill string 15 is run through the string of well casing 10, this tubular drill string having a rotary drill bit 16, `of any suitable type, secured to its lower portion for operation upon the bottom 17 of the hole 14. The drill bit 16 drills away the formation material, which is flushed from the drilling region by means of the usual rotary drilling mud pumped down through the drill string 15 and out through fluid passages 18 in the drill bit, the drilling mud mixing with the cuttings and carrying them upwardly around the outside of the drill string 15, and through the annulus between the drill string and the surface casing 10 to the top of the well bore. The tubular drill string 15 may consist of sections of drill pipe secured to one another. However, as disclosed in the drawings, a string of drill casing is attached to the drill bit 16, the drill casing including casing sections 19 suitably connected to each other, as through use `of intervening casing couplings 20.

It is desired to protect the `drill string 15 and the casing 10 already disposed in the well bore by preventing the drill string from rubbing against the inner wall of the well casing 10 during the drilling operation. Heretofore, it has been the practice to mount rubber protective sleeves or devices on the drill string 15 at longitudinally spaced intervals, the rubber protectors being disposed preferably only upon that portion of the drill string that is located within the cased portion of the hole. The rubber protectors would bear against the inner wall of the casing 10 and prevent the steel drill string 15 itself from bearing against the latter, thus preventing wear be- -tween the Idrill string 15 and the casing 10.

In the present instance, the protective devices are not mounted 'on the drill string 15, but are incorporated in the casing string which has already been disposed in the hole, and in which the drill string is operating.

The protective devices shown in the drawings may assume different forms. Thus, a protective device mayl be incorporated in yone or more of the casing lcouplings Zlythat secure adjacent casing sections 13 together.` Each casing coupling 21 is of a greater length Athan is usually provided, to form an extended coupling spaceZZ .between the lower end 23 of the upper casing section 13 and the upper end 24l of the next lower casing section 13 in which a'protective sleeve .25 may be disposed. This protective sleeve extends along substantially the entire length of the coupling space l22 and proiectslaterally into the casing stringhthe upper and .lower Yends 26, 2K7V of the sleeve preferably overlapping the inner walls 2850i `the upper and lower casingsections, respectively, to avoid gaps in which the drill bit ..16 might hang up or catch during, longitudinaly movement .of the latter through the casing string 10. To facilitate `guiding of the drill Abit 16 and other portions of the drill string 15 past each protective device, the upper end 2'6` ofthe sleeve-may flare, or be inclined, in an upward and outward direction, whereas the` lower end 17 of the sleeve may ilare, for be inclined, in a downward and outward direction. The ends. of each sleeve 25 `preferably terminate kclosely adjacent the inner walls 28 of the upper and lower casing section 13.

rEhe inside ydiameter of the protective sleeve 25 is materially less than the inside diameter of the casing sections y13 themselves. However, such inside vdiameter of the sleeve is still substantially greater than the outside diameter of the drill string couplings 20, to insure proper annular clearance therebetween .through which the drilling mud and cuttings can pass-in an upwarddirection through the surface casing 1"0. The protective sleeve -25 is preferably made of-readily drillable material, such asrubber, brass, bronze, or aluminum, and is suitably secured to the coupling member itself. If the sleeve-25 ismadeof rubber or -a'rubber-like material, it can be secured to the coupling 21byl aproper vulcaniz-ing operation. If it is=made of fbrass'onbronze, it ean'beattached to the coupling21 through the use of braiing material 30.

TheA protective .device 31 disclosed near thellower end of the casingstring`10 is secureddirectly to a casing section 13v`rather. than to a casing collar. This protective sleeve, which may be made ofany su-itable materiaL-such as rubber, brass, bronze or aluminum, as specied above, is secured to theinnerwall 28=of a .casing section,V as through the agency ofthe vulcanizing or brazing operationreferre'd to above, depending upon the particular material from which the protector sleeve 31 is made. This'sleevehasa lesser wallfthickness thanthe other form of 'protector sleeve '25, inasmuch as it is secured to the inner Ywall 28 oftheY casing section, and it is preferred that 'its inside diameter 'be substantially the same as the inside diameter of-theother protective device 25. Similarly, its upper 'and lower ends 32, 33'flare inupward and downward directions, respectively,to facilitate movement ofthed'rilll 'bit 16 andthe drill string 15 therethrough. As was described in connection with"the other formofprotective device-*there will be sufcient annular clearanceI between the drillstring land the inner wall 3d off the protective sleeve 31f for the passage of drilling mudand` cuttings therethrough. v

`The. protective devices` 1.25, 2311 are incorporated iny the surface casing10 or other casing run in the hole, and through 'whichl the drill string 15 is-tol be run to Edrill a hole 142belowthe lower end of the casing string; the protective f devices '-being longitudinally fspaced from one another'and'being disposed-at suitable intervals-'along the length` of .Lthe casing stringI 10. fThe" ydrill v string 1 15 is lowered through. thislcasing 10, withthe drill bit16-'at'its lower'rend,i.=the"1hole -14L1belowthe easingi string'. 10 being tion, wear between the drill string 175 and the casing 10, is prevented, inasmuch as the drill string 15 can only move laterally into engagement with the protective devices 25, 31, and not into engagement with the casing string 10 itself. Since the protective devices are made of relatively soft material as compared the steel of which the drill string 15 is composed', the latter will not be subject to wea-r. Any wear that might take place will occur on the protective sleeve or sleeves themselves. It is to be noted that the sleeves 25, 31-are of a comparatively large inside diameter and will lhave a relatively large wearing surface against which the drill string 15 can bear, thereby insuring long 'life of, each protective device.

No problems are encountered in connection with the separate handling `of sections or stands of drill pipe or drill casing 15 with protectors thereon, inasmuch as the cased portion 10 of the hole 11 itself is provided with the protectors. Since they drillstring 15 has no protectors on it, there is no danger of protectors, being disposed ythe open hole 14 below the casing string llt), which might result in their being torn off, with resul-tant plugging or retarding Vof the circulation -of the drilling mud in` an upward direction around the annulus between the drill string 15 and the casing 10; The stands of drill string- 15 .can be rackedland -used without regard to the provision of protectors thereon, and it is unnecessary for careful measurements to be made whenV the drill string is being run into the hole, to insure the presence of drill string protectors at the proper location within the cased portion 10 of the hole. Actually, protective devices 25, 31 are disposed at they desiredv locations in casing 1t) already disposed in the holel itself.

i lt has been proposed to drill a well bore 14.- throughusc ofV casing 15` asa vdrill string rather than drill pipe. The casing would be run in :the well bore and no round trips would. ever be necessary, since the drill bit 16,is .of-.al

retrievableftype that can -be withdrawn through `the .drill casing 15 without the necessity .for withdrawing .the latter at all. A vnew bit can then be lowered through the Awell casing l5v and securedv to its .lower end. Accordingly,

sectionsof drill casing19 will be added at the top vofthe, hole .and the latter willbey lowered in the hole 14 until, the desireddepth `of holehas been produced. Thereafter,

the-drill bit l16`is. removed and retrieved from the .lower end ofthe casing .15 and` the latter all-owed to remain-in the'hole.

lf it were-necessary to-provide protectors on the exterior of sucha drill casing 15, the protectors would have to be incorporated thereon at the'proper spacedintervals along itsentire length, inasmuch as protectors di'sposedon the casing 415 within the previously cased portion '10 of the` hole will eventually be moved-down -below the ylatter as drillingproceeds. Accordingly, alarge number of rubber protectors would befoperating in o-pen hole, -where the rubberprotectors `would eventually be torn as a result of bearing against the ywall-offtheopen hole ,14. Thislarge mass of ytornrubber might. completely stop they circulation of fluid, which vwould prevent continueddrllingof the hole. Not only would sucha .condition be hazardous, but the number ofprotectors required would entail considerableexpense.

By using an internal type of protector secured to the casing'lt), applicant avoids the necessity for mountingan excessive Anumber of protectors on his drillcasing 1'52 The protectors are only required in the cased portion of the hole, and they can be `supplied, at'the desired intervals along-the casing length whenthe casing string 10 is run in the well bore 11.

yinasmuch as theprotective devices 25, 31 are made of readily drillable material, they can lbe removed by use of a suitable diameter drill bit -at anytime, which Ymight'be necessary-in the event :1an unrestricted bore-through the casing string is desired., *The drillbit will readily disintegrate the `rubber, brass, bronze yor aluminum 'from whichtheprotectorsleeves 25,531are made.

The inventor claims:

1. In combination: a string of casing disposed in a bore hole, including casing sections secured t-o each other, a pair of adjacent casing sections being secured to an intervening coupling, a readily drillable protective sleeve xedly secured to said coupling and having an inside diameter sub-stantially less than the inside diameter of said pair of casing sections to project laterally inwardly of the inner walls of said pair of casing sections, the upper and lower ends of said `sleeve aring in an upward direction and a downward direction, respectively, and loverlapping the walls of said pair of casing sections; a tubular d-rill string disposed in said casing string; and a drill bit attached to References Cited in the file of this patent UNITED STATES PATENTS 940,733 Sands Nov. 23, 1909 1,623,207 Poulsen Apr, 5, 1927 1,889,060 Dennie Nov. 29, 1932 2,126,575 Ranney Aug. 9, 1938

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