US2716542A

US2716542A - Flexible drill collars

Info

Publication number: US2716542A
Application number: US267810A
Authority: US
Inventors: Ralph W Goble
Original assignee: OILWELL DRAIN HOLE DRILLING CO
Current assignee: OILWELL DRAIN HOLE DRILLING Co
Priority date: 1952-01-23
Filing date: 1952-01-23
Publication date: 1955-08-30
Anticipated expiration: 1972-08-30

Description

Aug. 30, 1955 R. w. GOBLE FLEXIBLE DRILL COLLARS 5 Sheets-Sheet l Filed Jan. 25, 1952 .IH I/IN- INVENTOR.

a/N LMU LUW ATTO/CP/VEYJ Aug'. 30, 1955 R. w. GOBLE FLEXIBLE DRILL COLLARS I5 Sheets-Sheet 2 Filed Jan; 23, 1952 Aug. 30, 1955 R. w. GoBLE FLEXIBLE DRILL COLLARS 5 Sheets-Sheet 3 Filed Jan. 25. 1952 y f i Mm M 7% 6 A ww am zyf ii L h L i 5f/ www il -l H fw a ./LL LL MM w M Unite rates f atent Otice FLEXIBLE DRILL COLLARS Ralph W. Goble, Denver, Colo., nssignor, by mesne assignments, to Oilwell Drain Hole Drilling Company, Long Beach, Calif., a corporation of California Application January 23, 1952, Serial No. 267,810

4 Claims. (Cl. Z55-28) This invention relates to new and useful improvements in exible drill collars and relates particularly to the fluid conductors extending through such collars.

In the drilling of drain holes which are small diameter bores drilled outwardly from a main well bore, it has` been the practice to employ exible'drill pipe sections -f pipe to the drill bit and is ordinarily under considerable pressure. Obviously, to provide for eilicient circulation of the drilling fluid to the bit the iiuidconductor through the flexible pipe sections of the string must be capable of withstanding and holding such pressure.

It is one object of the present invention to provide an improved flexible drill pipe section or collar having a ilexible uid conductor mounted axially therein, whereby drilling tluid may be circulated downwardly through the pipe section or collar regardless of the ilexure or bending thereof.

An important object is to provide a flexible iluid conductor within a exible drill pipe section, together with an improved means for maintaining the seal at the ends of the fluid conductor throughout all bending movement of the pipe section. i

Still another object is to provide an improved fluid conductor assembly within a flexible drill collar, which conductor is constructed of a standard high pressure hose having fittings at each end thereof with means incorporated in the iittings to efciently seal between the ends of the hose and the bore of the drill collar.

A still further object is to provide a fluid conductor assembly wherein the end ttings on the ilexible conductor are capable of a sliding movement with respect to the drill collar or pipe section in which the conductor is mounted, with means for maintaining the seal between the ends of the fluid conductor and the drill collar throughout such sliding movement.

The construction designed to carry out the invention will be hereinafter described together with other features thereof.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown, and wherein:

Figure l is a view partly in section and partly in elevation of a drilling apparatus having a flexible pipe section or drill collar constructed in accordance with the invention connected therein,

Figure 2 is an elevation of the drilling apparatus showing the same operating to drill a drain hole or auxiliary bore,

Figure 3 is a view partly in section and partly in elevation and illustrating the mounting of the drilling iluid conductor within the exible pipe section or drill collar,

Figure 4 is a horizontal cross-sectional view taken on the line 4-4 of Figure 3,

Figure 5 is an exploded View of one of the end fittings for the tluid conductor,

Figure 6 is a view of the snap retaining ring which prevents displacement of the hose from the drill collar,

Figure 7 is a view partly in section and partly in elevation and showing the position of one of the end fittings of the fluid conductor when the drill collar or pipe section is exed, and v Figure 8 is a view partly in section and partly in elevation of the tool which is employed for actuating the end fittings.

In the drawings the numeral 10 designates a well bore from which inclined or offset drain holes or bores of reduced diameter 11 (Figure 2) are to be drilled. The drilling apparatus for forming the drain holes or auxiliary bores 11 is illustrated in Figure l and includes a whipstock 12 having an inclined face 13. A spiked footpiece 14 is connected by a tubular section 15 with the lower end of the whipstock and is adapted to engage the lower end of the main well bore 10; the length of the connecting element 15 may vary to properly locate the whipstock y,

12 at the desired elevation in the main well bore.

An elongate tubular guide 16 is connected by a coupling 17 with a collar 18 at the upper end of the whipstock. The usual drill pipe 19 extends downwardly from the surface of the well and has a sub 2t) connecting the lower end thereof with one or more lexible drill collars or pipe sections A. A drill bit 21 which is pref-v.

pipe is rotated, the ilexible drill collars A function to transmit rotation to the bit 21. Initially the sub 20 is connected by shear pins 22 to the tubular guide 16 and when so connected the drill bit 21 is in the position shown in Figure l. The parts are lowered into the well bore in this position and when drilling is to occur the pins 22 are sheared and thereafter the drill bit 21 will be guided at an inclination by the inclined face 13 of the whipstock in the manner illustrated in Figure 2. After drilling is complete, the drill pipe is raised and because the bit 21 has a larger diameter than the whipstock collar 13 the drill pipe functions to retrieve said whipstock.

Each drill pipe section or collar A is constructed of a plurality of interconnected elements which will transmit rotation therebetween while permitting free ilexure or bending of the section or collar. The particular construction of the type of connection between the elements of the collar A is subject to variation and so long as the collar is capable of easy flexing the purposes of the invention will be accomplished.

During the drilling operation it is necessary to conduct drilling liuid to the drill bit 21, and it is apparent that since each ilexible drill collar or section A is formed of a plurality of interconnected jointed elements, the flexible collar is not capable of conducting pressure iiuid therethrough. For the purpose of conducting pressure fluid downwardly through the jointed flexible section or collar a Huid conductor assembly as shown in Figure 3 is provided. The upper end element 23 of the flexible collar A is formed with a reduced pin section 24 for' connection with the sub 20. An axial bore 25 is formed within the element 23 and beneath said bore is a counterbore 216 whereby an internal shoulder 27 is provided within the element 23. An end iitting generally indicated at F in Figure 3 is mounted within the bore 25 of the element 23 lgaaiersted Aug. 30, 1955 and is connected to one end of a fluid conductor 28, which conductor may be a standard high pressure hose. The fitting F provides a seal between the end of the hose or conductor 2S and the wall of the upper element 23 of the flexible drill collar A.

The hose 26 has a similar fitting F' at its lower end, which fitting is slidable within the bore 29 of the lowermost element 3l) of the flexible drill collar. The element 30 has a counterbore 31 which forms an internal shoulder 32 therein. At its extreme lower end the ele ment 31B of the flexible drill collar is formed with a box 33 whereby connection through a sub 34 may be made with the drill bit 21. The lower fitting F' provides a seal between the lower end of the hose 2S and the lowermost element 3l) of the flexible drill collar, and thus when tluid is circulated downwardly through the drill pipe 19 such fluid enters the upper end of the fitting F, flows through the hose 28 and through the fitting F' to the drill bit. As will be hereinafter described, the fittings F and F are slidable axially within the respective bores 2S and 29 of the

end elements

23 and 30 of the `flexible drill collar and such sliding motion permits free flexing of the drill collar A without any loss of the seal.

The fittings F and F are identical in construction and a description of one will suffice. In Figure 5 an exploded view of the fitting F is illustrated, and such fitting cornprises a tubular mandrel 46 having an axial bore 41 extending entirely therethrough. The upper end of the mandrel is enlarged at 42 and externally threaded at 43 whereby a collar 44 may be secured thereon. The upper end of the mandrel has a pair of diametrically opposed wrench notches dfi while the collar 44 has similar wrench notches 46 in its upper end. The external surface of the collar has an annular groove 47 therein for receiving a sealing ring 4S which is preferably of the O ring type. An annular enlargement 49 is formed intermediate the ends of the mandrel to provide an external shoulder S and beneath said shoulder the mandrel is externally threaded at i, whereby an outer sleeve member 52 may have its upper end threaded onto the mandrel. As clearly shown in Figure 5, the sleeve 52 has internal threads 53 engageable with the threads 51, and obviously the upper end 54 of the sleeve may be connected to the mandrel in abutting relationship to the shoulder 5l). Below the threads 53 the bore of the sleeve 52 is slightly enlarged as indicated at 55, and the lower portion of the bore is formed with annular grooves S6. The contour or crosssection of the grooves is such that when the end of the flexible hose 2S is pressed therein, displacement of said hose from the grooves by longitudinal movement is prevented.

When the sleeve 52 is connected to the threads 51, the portion a of the mandrel below said threads projects downwardly through the bore of the sleeve 52. The extreme lower end of the mandrel is reduced as indicated at 5'7, and above this reduced portion is a beveled shoulder 58.

In the assembly of the fitting the end of the hose 28 is inserted into the sleeve S2 so as to be opposite the annular projections 56a formed by the annular grooves 56. The end Lilla of the mandrel is then inserted; into the bore 23a of the hose and the reduced end 57 of said mandrel facilitates such insertion; as the portion 40a of the mandrel enters the bore the flexible mandrel of the hose 23 is deformed into the annular grooves 56 in the manner illustrated in Figure 3. As the mandrel threads 5i engage the threads 53 of the sleeve a relative rotation of the parts screws the sleeve upwardly into abutting relationship to the shoulder S0 on the mandrel, and at this time the end of the hose is firmly clamped between the portion 46a of the mandrel and the mandrel 42.

Thereafter, the collar dd having the O ring 48 within its groove is connected to the threads 43 of the mandrel to complete the assembly as shown in Figure 3. For the purpose of tightening the collar 44 upon the mandrel, a-

fil)

(ill

wrench 60 which is illustrated in Figure 8 is provided. This wrench includes an inner tubular member 61 having Wrench lugs 62 on its lower end and these lugs are engageable with the wrench notches 4S in the mandrel 42. An outer sleeve 63 having wrench lugs 64 is rotatable about the member 6l and its lugs are arranged to engage the notches 46 of the collar 44. The member 61 may have a handle 61a while the sleeve 63 is provided with a handle 63a to facilitate operation of these parts. lt will be evident that the lug 62 of the inner member may be engaged with the notches 45 of the mandrel, while the lug 64 of the sleeve may be engaged with the notches d6 of the collar. Thereafter a relative rotation of the sleeve 63 with respect to the member 61 will tighten the collar upon the mandrel.

After the fittings F and F have been assembled in the manner above described, the fitting F is inserted into the bore 25 of the upper element 23 of the flexible drilling collar. The external diameter of the collar 44 is such that the collar has a sliding fit within the bore 25, and'- inward displacement is limited by the shoulder 27 within element 23. Outward displacement of the collar 44v from the bore is prevented by a snap ring 65 (Figure 6) which engages within a groove 66 provided in the outer portion of the bore of the end element 23. The collar 44 of the lower fitting is inserted within the bore 29 of the lower element 36 of the flexible drill collar, and its inner movement is limited by the internal shoulder 32. Outward displacement of the tting F is prevented by one ot the snap rings 65 which is mounted in an annular groove 67 provided for the purpose within the lower end element 3@ of the drill collar.

With the parts assembled as shown in Figure 3, it will be evident that the ends of the hose 28 are firmly clamped to the fittings F and F and a tight sealing of the ends of the hose with the mandrels of the fittings is effected. The provisie-n or" the O rings 48 in the collars 44 or" the fittings effects a sliding seal between the collars and the bore of the flexible drill pipe section. It is thus apparent that as drilling iiuid is circulated downwardly from the drill pipe l@ into the iiexible pipe sections A, said fiuid will flow downwardly through the high pressure hose 2S and be conducted to the drill bit therebelow. Upon a liexure or bending movement of the sections A, it is apparent that the collars 44 of the fittings F and F' may slide within their respective bores to compensate for the bending movement and still maintain the seal. ln Figure 7 the upper fitting F is illustrated as having slid or moved downwardly Within its bore 25 upon a bending movement or iiexure of the iiexible pipe section A. The O ring d3 maintains the seal with the wall of the upper element 23 ot' the flexible pipe section A throughout all movements of the collar within its bore. Each fitting is relatively simple in construction and comprises a minimum number of parts which may be readily disassembled in the event that replacement of the hose or O rings is necessary.

Although the invention has been described above in its preferred form, as having fittings F and F axially slidable within the elements 23 and 3l), respectively, in some instances it may be desirable to secure the fittings F and F' to the elements 23 and 3i), respectively, by threads or any other suitable means, so that the fittings are stationary in the flexible drill collar. When the iittings F and F are thus made stationary, the hose 28 must vbe sufficiently flexible to stretch axially upon flexing ofthe drill collars A in a path such as shown in Figure 2.

Using such construction of the fittings F and F and.

attached hoseZS, the G rings d3 could be eliminated since the rigid connection of fitting F to element 23 and fitting F' to element 3% would seal off any fluid and direct it through the hose 28,

The foregoing disclosure and description of the invenv tion is illustrative and explanatory thereof, and various changes in the size, shape and materials, as wellY as-in the details of the illustrated construction may be made, within the scope of the appended claims, without departing from the spirit of 'the invention.

Having described the invention, I claim:

1. A flexible drill pipe section including, a plurality of elements, means for connecting the elements to each other to permit limited detlection of each element relative to its adjacent elements, whereby the drill pipe section may undergo a flexing movement, said connecting means also securing the elements to each other so that rotation may be transmitted through said elements, a flexible hose extending axially through said section, a tting connected to each end of the hose and slidable within the end portion of the bore of the pipe section, and means providing a seal between each fitting and said bore of the pipe section.

2. The combination with a flexible drill collar of a exible conductor extending axially within said collar, a fitting at each end of the conductor having sliding and sealing contact with the bore of the drill collar, and

means for limiting the sliding movement of each fitting with respect to said collar.

3. The combination with a flexible drill collar of a fluid conductor assembly comprising a ilexible hose extending axially within the bore of said flexible drill collar,

a ltting at each end of said hose, said fitting comprising a mandrel having a portion thereof engageahle within the bore of the hose, an outer clamping sleeve encircling the hoseand clamping the same between said sleeve and the mandrel, and a collar of a diameter larger than the mandrel secured to its outer ,end and having a sealing ring mounted on its exterior surface, said last-named collar being slidably disposed within the bore of the exible drill collar and having its sealing ring in sealing engagement with said bore.

4. The sub-combination set forth in claim 3, wherein the sealing ring is an O ring.

References Cited in the lile of this patent UNITED STATES PATENTS 487,893 Schimper et al, Dec. 13, 1892 1,314,601 McCaskey Sept. 2, 1919 2,198,016 Rogers et al. Apr. 23, 1940 2,296,161 Hall Sept. 15, 1942 2,344,277 Zublin Mar. 14, 1944 2,485,976 Main Oct. 25, 1949 2,515,366 Zublin July 18, 1950 2,521,127 Price Sept. 5, 1950 2,551,536 Harvey May 1, 1951