CA1106355A - Dual concentric pipe joint - Google Patents
Dual concentric pipe jointInfo
- Publication number
- CA1106355A CA1106355A CA341,675A CA341675A CA1106355A CA 1106355 A CA1106355 A CA 1106355A CA 341675 A CA341675 A CA 341675A CA 1106355 A CA1106355 A CA 1106355A
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- CA
- Canada
- Prior art keywords
- pin
- box
- air
- members
- slots
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Abstract
ABSTRACT OF THE DISCLOSURE
Apparatus is disclosed for drilling a pilot hole and subsequently enlarging the pilot hole in earth formation. A
dual concentric pipe string is used for circulating air down-wardly through the outer pipe, a cross-over sub and through a pilot bit and upwardly through the bore hole outside the pipe string to bail cuttings, during drilling of the pilot hole. The air pressure expands the cutters of an expansible bit while a limited portion of the air supplied cools the cutters. The dual concentric pipe is made up by joints having pin and box structures which provide inner and outer flow passages and shoulders which abut between the outer members and which are resiliently sealed between the inner members.
Apparatus is disclosed for drilling a pilot hole and subsequently enlarging the pilot hole in earth formation. A
dual concentric pipe string is used for circulating air down-wardly through the outer pipe, a cross-over sub and through a pilot bit and upwardly through the bore hole outside the pipe string to bail cuttings, during drilling of the pilot hole. The air pressure expands the cutters of an expansible bit while a limited portion of the air supplied cools the cutters. The dual concentric pipe is made up by joints having pin and box structures which provide inner and outer flow passages and shoulders which abut between the outer members and which are resiliently sealed between the inner members.
Description
.. . .
In the forming of bore holes in the ear-th, more particularly enlarged bore holes, for example, blast holes used in bench mining or quarrying, it has become the practice to drill a pilot hole to a givendepth and enlarge the hole to form a .~ .
- 5 large chamber for receiving a blasting explosive. Such bore holes are also useful in connectlon with in-situ fragmentation for chemical mining and coal gas:ification techniques. In the drilling of other bore holes into or through the earth, such as oil or gas wells, it is sometimes necessary or desirable to enlarge the well bore for a given distance.
Accordingly, hole openers, including expansible drill bits have evolved. Some of the expansible drill bits have included a pilot bit in combination with expansible cutters to drill a pilot hole and also drill out an enlarged chamber. When drilling with liquid or mud as a drilling fluid to cool the cut-ters and flush cuttings from the bore hole, it is customary to . .
circulate the drilling fluld down a length of drill pipe or tubular conduit, and the fluid returns through the annulus between the pipe and the bore hole to flush cuttings from the hole.
In the case of certain bore hole drilling operations, both in the formation of blast holes and other bore holes, air .. , ~ .
or gas is employed as the drilling fluid to cool the cutters and remove the cuttings from the bore hole. However the effective removal of cuttings by air requires a relatively high bailing velocity as compa~ed with liquid drilling fluids. According to most authorities, air bailing velocities on the order of five thousand feet per minute of air are required.
When large bore holes are being drilled, using air as , .
a drilling fluid, therefore, it will be appreciated that such ,:
.`' ~
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, ... .... . .
6~S5 baiIing velocity of the air through the annulus, outside t.he drill pipe may be difficult to accomplish or may re~uire com--pressor capacity at the drilling rig in excess of that available :
or economically practical to obtain. Moreover, even if added compressors can supply sufficient air to cause the effective ~: bailing of cuttings through the bore hole annulus, the velocity of air returning to the reduced annular space above the enlarged chamber or bore hole would be ojectionably noisy at the outlet, and the abrasive nature of the cuttings and dust would be damag-. 10 ing to the drill pipe and the integrity of the enlarged bore hole. In the case of blast holes, particularly/ erosion of the shoulder at the beginning of the enlarged chamber is undesirable in that the blasting effectiveness is reduced.
. So called reverse circulation of drilling fluid has been - 15 resorted to in an effort to supply drilling fluid at adequate .~ bailing velocity. The reverse circulation involves circulating air downwardly through the bore hole annulus and upwardly through the bit and drill pipe, the velocity in the relatively small : bore of the pipe being quite high due to the small cross-; 20 sectional area of the flow passage.
In addition, circulation of the drilling fluid through `~ so-called dual concentricplpe strings has been resorted to in some drilling operations. Dual concentric pipe strings involve providing concentric inner and outer pipes having conne~ctions which provide flow passages establishing communication with the annular space between the.pipe sections, as well as through the central pipe bore. However, providing a good seal at the pipe connections and adequate wrench areas or tool slots for . .
making up and breaking out the connections, while maintaining adequ~ate flow area, are problems in dual concentric drill pipe.
In the forming of bore holes in the ear-th, more particularly enlarged bore holes, for example, blast holes used in bench mining or quarrying, it has become the practice to drill a pilot hole to a givendepth and enlarge the hole to form a .~ .
- 5 large chamber for receiving a blasting explosive. Such bore holes are also useful in connectlon with in-situ fragmentation for chemical mining and coal gas:ification techniques. In the drilling of other bore holes into or through the earth, such as oil or gas wells, it is sometimes necessary or desirable to enlarge the well bore for a given distance.
Accordingly, hole openers, including expansible drill bits have evolved. Some of the expansible drill bits have included a pilot bit in combination with expansible cutters to drill a pilot hole and also drill out an enlarged chamber. When drilling with liquid or mud as a drilling fluid to cool the cut-ters and flush cuttings from the bore hole, it is customary to . .
circulate the drilling fluld down a length of drill pipe or tubular conduit, and the fluid returns through the annulus between the pipe and the bore hole to flush cuttings from the hole.
In the case of certain bore hole drilling operations, both in the formation of blast holes and other bore holes, air .. , ~ .
or gas is employed as the drilling fluid to cool the cutters and remove the cuttings from the bore hole. However the effective removal of cuttings by air requires a relatively high bailing velocity as compa~ed with liquid drilling fluids. According to most authorities, air bailing velocities on the order of five thousand feet per minute of air are required.
When large bore holes are being drilled, using air as , .
a drilling fluid, therefore, it will be appreciated that such ,:
.`' ~
:, ~
, ... .... . .
6~S5 baiIing velocity of the air through the annulus, outside t.he drill pipe may be difficult to accomplish or may re~uire com--pressor capacity at the drilling rig in excess of that available :
or economically practical to obtain. Moreover, even if added compressors can supply sufficient air to cause the effective ~: bailing of cuttings through the bore hole annulus, the velocity of air returning to the reduced annular space above the enlarged chamber or bore hole would be ojectionably noisy at the outlet, and the abrasive nature of the cuttings and dust would be damag-. 10 ing to the drill pipe and the integrity of the enlarged bore hole. In the case of blast holes, particularly/ erosion of the shoulder at the beginning of the enlarged chamber is undesirable in that the blasting effectiveness is reduced.
. So called reverse circulation of drilling fluid has been - 15 resorted to in an effort to supply drilling fluid at adequate .~ bailing velocity. The reverse circulation involves circulating air downwardly through the bore hole annulus and upwardly through the bit and drill pipe, the velocity in the relatively small : bore of the pipe being quite high due to the small cross-; 20 sectional area of the flow passage.
In addition, circulation of the drilling fluid through `~ so-called dual concentricplpe strings has been resorted to in some drilling operations. Dual concentric pipe strings involve providing concentric inner and outer pipes having conne~ctions which provide flow passages establishing communication with the annular space between the.pipe sections, as well as through the central pipe bore. However, providing a good seal at the pipe connections and adequate wrench areas or tool slots for . .
making up and breaking out the connections, while maintaining adequ~ate flow area, are problems in dual concentric drill pipe.
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When expans:ible, pivoted cutter supporting arms on dLill bits are actuated outwardly by air pressure to ini-tiate an . enlarged bore hole, the flow of air to the cutters, in air cooled cutter bits, may be so great that inadequate pressure is 5 present to effect expansion of the cutters in a reasonably short period of drilling, so that a long tapered side wall is formed on which the back or outer surfaces of the pivoted cutter arms : may drag and wear. Thus, it is desirable that the expansive ~ force be maintained on the arms which carry the cutters, while ~ 10 not depriving the cutters of sufficient cooling air during the early sta~.es of bore hole enlargement.
. Air cooled expansible cutters currently available are both complicated in the structure permitting the flow of air . through the cutter support arms and inefficient in terms of the cleaning and cooling effect of the air on the cutter elements.
In the formation of blast holes in mining or quarrying operations, it has been found that a two-pass method of first drilling a pilot hole with a first drill bit and drilling stringt and then, in a second pass, enlarging the hole with an expansi-20 ble bit run on a second drill string, produces a superior blast hole shape, if the bore hole enlargement is con-tinued subs~
,.;
.~ tantially to the bottom of the pilot hole. Since the annular bore . hole space outside the drill string, when drilling the pilot .: .
;~ ~ hole is not large in cross-sectional flow area, the drilling fluid or air can be normally circulated down the drill string and up the annulus, and the bailing velocity of the fluid or . air in the annulus may be adequate. Thereafter, however, when .~ the second, hole enlarging pass is being made, the enlargement of the bore hole may so increase the annular flow area that the 30 necessary air bailing velocity may not be obtalned with existing. -3-' ' ' ' ' ~ 6~
1 compressors. If an expansible bit is used which is expanded by reverse circulation, even through a dual concentric pipe string, a different set up of equipment at the rig is nec-essary to supply the air through the annulus. On the other hand, the pilot bit could be used on the dual pipe with the dual pip]e rig equipment which supplies air through the dual pipe annulus. Thus, two separate pipe strings for the pilot drilling pass and the enlarging drilling pass would be re-quired in the case of existing equipment.
When forming blast holes by the two-pass method to pro-vide a more-or-less flat bottomed enlarged chamber, as more particularly disclosed in the United States Patent 4,189,165, issued February 19, 1980, it is desirable that the bottom of the hole be relatively free from cuttings and accumulated dust at the conclusion of the drilling. ~ccumulated debris at the bottom of the hole can cushion the explosive effect and interfere with bench removal or effective fragmentation. How-ever, residual cuttings and dust in the hole have continued to be a problem.
The present ivention relates to improved reverse circu-lation or dual pipe ]oints.
More particularly, the invention provides a dual pipe ~oint including a pin structure and a box structure; each of said structures icluding an inner tubular member hving a central passage therethrough; an outer tubular member dis-` posed about and connected to the inner tubular member; one of said members of each structure having longitudinal fluid pas-sages therein; said inner member of said pin structure having a threaded pin thereon; the inner member of said box structure 30 having transverse shoulders in abutting engagement with said '~' ~
: `
~; passages in communication; said inner members of said structure providing opposed transversely extended surfaces between said pin and box; sealing means between said transversely extended surfaces; and longitudinally extended concentric tubular members connected to the respective inner and outer tubular members and forming an annular space communicating with said fluid passages.
his invention possesses many other advnatages and has other purposes which may be made more clearly apparent from a consideration of a form and method embodying the invention. The form and method are shown and described in the present specifi-cation in connection with the drawings accompanying and cons-tituting a part thereof. Such form and method will now be described in detail, for the purpose of 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.
Referring to the drawings- Figs. la and lb, together, constitute a view diagrammatically showing the drilling of a ` pilot bore hole into earth formation, utilitzing the dual drill pipe string of the invention, Fig. lb being a downward conti-:
nuation of Fig. la;
Figs. 2a and 2b, together, constitute a view diagramma-tically showing the enlargement of the pilot bore hole of Figs.
. ' . .
la and lb utilizing the expansbile bit of the invention and reverse circulation through the dual pipe string, Fig. 2b being a downward continuation of Fig. 2a;
Figs. 3a and 3b, together, constitute an enlarged longi-`~ tudinal section through the swivel structure, Fig. 3b being a downward continuation of Fig. 3a;
Fig. 3c is a fragmentary vertical section on the line , 30 3c-3c of Fig~ 3b;
-.
; j3 S, 5 ,, - ~` .
Fig. 4 is a transverse section through the swivel, as taken on the line 4-4 of Figs. 3a;
Figs. 5a and 5b, together, constitute an enlarged vertical section, as ta]cen on the line 5-5 of Fig. 1, showing a typical dual pipe joint, Fig. 5b being a downward continuation of Fig.
5a;
Fig. 6 is a transverse section as taken on the line 6-6 ; of Fig. 5a;
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Fig. 7 is a tran6verse sec-tion as taken on line 7-7 of Fig. 5b;
Figs. 8a and 8b, together, constitute an enlarged vertical section, as taken on the line 8-8 of Fig. 1, showing the cross-over unit in the~dual p:ipe string used -to drill the pilot bore hole; Fig. 8b being a downward continuation of Fig. 8a;
Fig. 9 is a transverse section as taken on the line ~-9 of Fig 8b;
Figs. lOa, lOb and lOc, together, constitute a vertical section, as taken on the line 10-10 of Fig. 2, showing the expan-; sible bit used to enlarge the bore hole with the cutters in retracted condition, ~igs. lOb and lOc being successive downward continuations of Fig. lOa;
Fig. 11 is a transverse section as taken on the line 11-11 of Fig. lOb;
Fig. 12 is a transverse section as taken on the line 12-12 of Fig. lOb;
Fig. 13 is a transverse section as taken on the line 13-13 of Fig. lOc;
Fig. 14 is a -transverse section as taken on the line 14-14 of Fig. lOc;
Flgs. 15a and 15b, together, constitute a vertical section corresponding to Figs. lOb and lOc, but showing the cutters expanded as in Fig. 2;
Fig. 16 is a bottom plan of the expansible bit, with the cutters expanded as in Flg. 15b; and Fig. 17 is an enlarged section, as taken on the line 17-17 of Fig. 16, showing the details of one of the air cooled cutters.
As seen in the drawings, referring first to Figs.la and lb, and Figs. 2a and 2b, apparatus is diagrammatical`y illustrated ., .
i35S
; for first drilling a pilot bore hole PH (Figs. la and lb) by drilling through -the earth formation F with the usual drill bit B, secured to the lower end of a string of rota-table drill pipe P, adapted to be rotated by a suitable rotary drive unit D, where-by the cutters C on the bit B progressively drill the bore or pllot hole PH as the drill pipe P is rotated, and drilling fluid is supplied through a swivel S from a suitable source of drilling fluid, such as a compressor for air in the case of drilling wi-th alr, via a supply conduit 10. As illustrated, the drill pipe string P is a dual concentric drill pipe having an inner pipe IP and an outer pipe OP made up in appropriate lengths or sections secured together at joints J and defining an annular space-A
therebetween communicating through the~respective joints, where-by drilling fluid or air supplied through the swivel S, from the pipe 10 through the annular spàce A to a crossover unit CO in ` which the annular spaoe A communlcates through lateral passages 11 with a central bore 12 at the lower end of the crossover unit.
The bit B is connected to the lower end of the crossover unit ~ ~ by the usual threaded connection 13 and has a central passage 14 `` 20 therethrough, through which the drilling fluid or air passes from the crossover passage 12, exiting into the bore hole PH
through the bit B and returning to the surface of the earth or i~ .
to the starting end of the bore hole through the annular space 15 defined between the bore hole wall and the drill pipe string P. The flow of the drilling fluid or air is operative to cool the cutters C of the bit B and to flush or bail cuttings from the bore hole as the drilling progresses.
It is generally known that the velocity of air upwardly through the annular space 15 between the drill pipe and the bore hole wall must be on the order of 5000 feet per minute in order ~8~-, .
.
to bail the cuttings from the bore hole. When as shown in : Fig. lb, the gauge of the bit B is only slightly larger than the diameter of the drill pipe string P, the annular cross-sectional area of the annulus 15 can enable the air to flow wi-th sufficient ` 5 velocity; for example, if air is suppliéd from a compressor through the annulus A of the drill pipe string at 1300 SCFM, the diameter of the drill pipe is 5 3/4" and the gauge of the bit .
is 7 7/8", and the bore hole is fairly regular, havlng no large . cavities or enlargements therein, the bailing velocity of the air returning through the annulus 15 will be on the order of in excess of 8000' per minute, or well in excess of the minimum - velocity required for removing the cuttings. With this in mind, the drilling of bore holes using air, generically including other : gas, as the drilling fluid supplied through the drill pipe string, either of the ordinary type or of the dual concentric type, has : , , been widely used as a drilling fluid in drilling bcre holes .~ into various earth formations, including bore holes for b~asting ~ ~........ or other mining operations, as well as in the drilling of well bores.
.
~ 20 As seen in Figs. 2a and 2b, the same drill pipe string P, .
. but without the crossover structure CO, has been connected to a - hole opener or bore hole enlarging bit EB of the expansible cutter type, having pivoted cutter supporting arms 16 provided with the cutters C at the lower free ends thereof, adapted to form the enlarged bore hole or chamber EH, as the expansible cutters are swung outwardly and the drilling progresses. If air were to be supplied through the swivel S to the drill pipe.
string.P in the same manner as described with respect to Figs.
la and lb in an effort to flush or bail the cuttings from the enlarged bore hole or chamber EH, the bailing velocity would be _9_ .
i35~
below the minimum value required. For example, if the enlarged bore hole EH is 13" in diameter, and drilling air is supplied at 1300 SCFM, the air velocity within -the enlarged bore hole ` would only be slightly more than 1700' per minu-te. In accordance with the present invention however, the air is supplied through the swivel S to the annulus A between the inner and outer pipes IP and OP, as shown by the arrows, flowing downwardly into the bore hole, and then entering the center pipe IP and flowing ~ upwardly therethrough, exiting from the top thereo. If it is :,'' .
assumed that the bore of the inside pipe is 2" in diameter, and all of the air returned to the surface through the 2" bore, ;:
supplied through the annulus A at 1300 SCFM, then the bailing velocity would be on the order of 60,000' per minute. Thus, if , merely 10% of the air entering the bore hole returns through the inner pipe, the bailing velocity would still be on the order of ~:.
6000' per minute, which is in excesss of the minimum velocity .~,.i~
~ required to bail the cuttings.
... . .
i~ As is known, baf~les between the pipe string P and the wall .. ~ .
of the bore hole PH may be employed to assure adequate flow of aix up the centre of the drill pipe string. However, in accor-dance with the present invention, as seen ln Fig. 2a, the flow of air up through the center pipe is enhanced by the provision of means ~ for drawing air through the inner pipe IP. The drive unit D is shown diagrammatically as having an inner drive pipe 17 driven by gearing 18 which is powered by suitable motors, such as hydxaulic motors M. Fluid and cuttings flow upwardly through the drive pipe 17 into a discharge chamber 17a in the drive unit housing, the pipe 17 having a packing 17b engaged therewith to prevent entry of dust into the drive unit housing. An outlet connection 19 is connected to the housing by fasteners l9a and 10, ' ~36355i .
establishes a flow path from the housing chamber 17a to a discharge hose l9b.
The venturi means V is associated with the discharge hose , l9b so as to induce flow through the hose and thus indwce flow upwardly through the center of the drill string. The venturi includes a housing l9c installed in the discharge hose l9b and having a flow passage l9d therethrough. A flange l9e on the housing l9c has an annular space or passage l9f to which air is supplied by an inlet conduit l9g. An annular yap l9h opens from the annular passage l9f into the flow passage l9d upstream of - the gap, thereby inducing fluid flow from the bore hole upwardly through the inner drill pipe and through the discharge hose, as . air is supplied through the swivel S and flows down -the annulus : A between the inner and outer pipes and enters the bore hole through the-bit.
The venturi or vacuum producing means V provides a ; further advantage after the completion of the enlargement of the bore hole, when the supply of drilling air is ~iscontinued. When the drilling operation is concluded, the bore hole will contain a quantity of cuttings and dust which have been lifted within the annular space within the bore hole outside of the drill pipe and which will settle to the bottom of the hole. The continued application of air to the venturi will induce flow through the discharge conduit which continues to draw air up~ the center pipe and wi~ continue to lift the cuttlngs from the bottom of the bore in a vacuuming operation. During the vacuuming operation, the drill pipe P can be rotated to cause the cutters on the bit to agitate the cuttings at the bottom of the holeO
Referring to Pigs. 3a, 3b, 3c and 4, the swivel structure S is shown in greater detail. Internally, the swivel structure '`; -11-,, includes ~n el~nc~atccl body or Inarlclrel 20 llavi.ncJ a c~ntral ~low , .
: passage 21 tllerethrough. ~t its upper end the body 20 ilas an .. externally threaded pin 22 threaded into an interllally t.hreacled box 23 of the rotary drive member 17, wh~cll i.s adaptc-d, a~s des-crlbed above, to be rotated by dr:Lve un.Lt D. The rotary drive member 17 has a central passaye 25 tileretllrough which communicates with the swivel passage 21 and with the discharge conduit and venturl means V. At its ].ower end, the swivel.body o.r rnandre]
20 has an internally tllreaded box section ~6connected to an .~ 10 externally threaded pin 27 forming a joinc3 J therewlth.
~ A tubular ou-ter body section 28 is dlsposed about the.
.... .
body of mandre:l 20 and welded thereto at appropriate locatlons to rlg.idly unite the inner and outer body sections toget}ler. As shown, the outer body 28 has an upper weld 29 securialg it to the upper portion of the inner body section, and a suitable number of longltudinally and circumferentially spaced wel.ds 30 formed in ~: drilled holes in the outer body sectlon are also provlded to secure the body sections toge-ther. Prlor to assembly of the ;~ .
. outer body section 28 on -the inner body, the inner body .is provided with a number of circumferentially spaced longitudinally extended milled slots 31 which communicate wi-th further down-wardly extending and circumferentially spacecl: slots 32 (Fig.3c), . . .
: througll which slots air is adapted to flow downwardly between the mandrel body sections. The .slots 32, as seen in Fig. 3c, :`' . . .
: 25 are narrower than the slots 31 and 33, bu-t of greater depth so .; as -to have approximately the same effecti.ve air flow areas.
.~ ~ .
Reduction ln the width of the slots 32 enables the .Eormatlon in the swlvel body at a number of clrcumferentially spaced loca-tions, . of outwardly openlng wrench slots 34 whlch extend longltudinally :: 30 of the body and provide a downwardly facing shoulder 35, ~ 12-., .
6;~5S
whereby a ver-tical supporting tool and hol.ding tool can be applied to the body by the drilling r1g, as is also well known.
. The wrench slots 34 are partially formed by external slots 36 formed in the exterior of the inner body section 20, and pre-ferably a bead of weld 37 is formed about the interace of the body parts within the wrench slot 34. Disposed about the rotat-able swivel body structure is an outer swivel housing structure -38, adapted to be held stationary in an appropriate suppo~ting arrangement which allows downward movement of the swivel assembly during the drilling operation. The supporting arrangement is not illustrated herein since it .is not germane to the present invention and various supporting arrangements can be utilized, as well known in the use of apparatus of the type here involved.
More particularly, the outer stationary swivel structure 38 comprises a central annular section 39 disposed about the . rotatable internal body structure and carrying suitable internal : side ring seals 40 and 41 in axially spaced relation. The seals 40 and 41 are preferably elastomer seals and are adapted to confine the air from the air inlet conduit 10 against leakage :`` 20 from the swivel assembly. As seen in Fig. 3a, the conduit 10 . opens into an annular space 42 defined by companion annular grooves 43 and 44 in opposed relation in the cylindrical walls . of the swivel member 39 and outer body secti.on 28 of`the swivel mandrel. Leading between the annulus 42 and the respective longitudinally extended flow passages or slots 31 in the mandrel :, is a number of circumferentially spaced radial ports 45. Upper bearing means 46 and lower bearing means 47 rotatably support the inner mandrel structure within the outer swlvel structure.
. The upper bearing means 46 includes an inner bearing race 48 ,,, seating on a shoulder 49 provided on the outer mandrel body ,:
s section 28and having an inwardly and upwardly inclined race or surface 50 engaged by bearing elements or rollers 51. An outer ,~:
"'~ race member 51' is engaged by the bearing rollers 51 and engages in a seat 52 provided within a bearing retainer and sealing sleeve 53. This sleeve 53 lS threaded at 54 onto an upwardly ex-tended annular flange 55 provided on the central swivel housing ' member 39 and has an upper circumferentially extended,and inwardly . . .
' projecting flange 55' which carries an internal sealing ringstructure 56 slideably and sealingly engaging with the outer cylindrical surEace of the mandrel body section 20, so as to pro-tect the bearing means 46 from erosive dust and dirt. Corres-pondingly, the lower bearing means 47 has an inner race 57 seating in a seat 58 provided on the mandrel body structure and having a downwardly and inwardly inclined surface or raceway 59 engaged by bearing elements or rollers 60 which also engage the opposing upwar.dly and outwardly inclined raceway 61 of an outer , . bearing race 62 disposed in a seat 63, which is provided by a .,~; .
. lower bearing retainer sleeve 64. This sleeve 64 is threadedly connec-ted at 65 to a downwardly extended annular flange 66 provided on the mandrel housing central member 39 and has a circumferentially extended and inwardly projecting lower flange 67, which carries an internal seal assembly 68 slideably and . sealingly engaging with the outer cylindrical surface of themandrel structure to prevent the entrance of foreign matter into the lower bearing assembly 47. It will be seen that the ou-ter :~' swivel housing structure 38 can be easily assembled about the swivel mandrel structure and disassembled for service or repair by threadedly disconnecting the respective bearing retainer sleeves 53 and 64 form the central housing member 39. In addi-: 30 tion, when the bearing retainers 53 and 64 are removed, the ~
`~ 6~5iS
;~ A central housing member 39 can be moved axially upwardly ~rom the end of the swivel mandrel to allow service and replacemen-t of the seal rings 40 and 41.
Referring to Figs. 5a and 5b, as well as -to the sectional views 6 and 7, a typical joint J is illustrated. Each joint J
includes a box end 70 and a pin end 71. The box ena 70 comprises an inner tubular member 72 having a suitable number of circum-ferentially spaced and longitudinally extended flow passages 73 milled therein and having a central flow passage 74 therethrough.
;~-` 10 At its lower end, the member 72 has a downwardly and outwardly . . .
, tapered internal thread 75 adapted to receive the complimental '~ external thread 76 on the pin section. At its upper end, the box member 72 has an annular seat 77 circumscribing the flow passage 74 and receiving a downwardly extended cylindrical end , ...
portion 78 of an elongated pipe section 79, which is welded to the box member 72 as by a circumferentially continuous weld 80.
Disposed about the pipe 79 and defininy~therewith the annular space A is an outer elongated pipe 81 which is welded by a suitable number of circumferentially spaced welds 82 in radial openings 83 to the upper end of the box body member 72. Also welded to the box body member 72 is a downwardly extended connector sleeve 84 which extends downwardly about the box body :;. .
72 and provides a downwardly facing end or shoulder 85 pro-jecting downwardly below the lower end 86 of the threaded box section. The sleeve 84 is welded to the box body section 72 by .,: ' . , means of a suitable number of circumferentially spaced welds 87 provided in radial openings 88 in the sleeve 84. In addition, a circumferentially continuous weld 89 is provided between the opposing ends of the upper pipe section 81 and the downwardly ; 30 extended sleeve 84. The outer connector sleeve 84 and the -15- _ .: .
.;'' .
. ~ 5 inner box member 72 are also united adjacen-t their lower ends by a weld 90 which extends circumferentially at the juncture of the lower end of the inner body 72 w:ith the internal periphery of the connector sleeve above the lower end shoulder 85. As seen in S Fig. 5b, the upper end of each length of pipe, having the pin end 71 of the respective joints J, has the external thread 76 on the upwardly and inwardly tapered pin section 91 which is provided on a pin body section 92 having a longitudinally extended bore or fluid passage 93 therethrough adapted to be aligned with the passage 74 through the box end 70 of the coupling. At its lower ~ end, the pin body section 92 has an internal annular seat 94 receiving an upwardly extended cylindrical end section 95 of the center pipe.79 which is welded to the body section 92 by a circum-ferentially continuous weld 96. Formed in the outer periphery ~ .
of the pin body section 92, adjacent the upper end thereof, is a number of circumferentially spaced longitudinally exte~nded slots 97 which communicate with relatively narrower but deeper longitudinally extended slots 98, which at their lower ends communicate with further longitudinally extended slots 99. The : 20 slots 97 communicate with an annular space 100 between the lower extremity of the box end 86 and an upwardly facing surface or shoulder 101 at the upper end of an outer pin connector sleeve 102. The lower slots 99 communicate with the annular space A
between the lower pipe 81 and the inner pipe 79 of the subjacent unit. As in the case of the slots 32 and 33 described above, the cross-sect:ional area of the slots 97 and 99, by reason of their relative:ly greater circumferential extent than the narrower slots 98, have substantially the same cross-sectional air flow area as the slots 98. The outerpin sleeve 102 is welded to the 30 inner pin body section 92 by a suitable number of circumferentially . . .
spaced welds 103 for~led in radial openings 10~ in the sleeve 102, as well as by a weld 105 formed at the upper end of the sleeve 102 and the upper outer edge of the pin body 92.
As seen in Fig~ 7, the relatively narrow circumferentially spaced slots 98 provide a substantial segment of the hody 92 wherein the circumferentially spaced or diametrically opposed wrench slots 106 can be formed, these slots 106 extending longi-tudinally and circumferentially to provide opposed longitudinally extended shoulders 107 and a downwardly facing horizontal face ^`10 108 engageable with the usual holding and supporting members of ~ ., the drilling rig. With the pin end held by the projections provided on the rig and engaged in the wrench slots, the super-jacent pipe length can be rotated by the rig to make up the threaded connection between the pin and the box.
- 15 Referring to Figs. 8a and 8b, the crossover sub or S! ' ., assembly CO is illustrated in detail. The assembly comprises an elongated center section having a flow passage 110 extending therethrough and including an upper inner body section 111 having . .
a threaded pin end 112 engaged in the box thread 75 at the lower end of the pipe section thereabove. At its lower end, the inner body member 111 has an annular seat 113 receiving the end pro-jection 114 of a lower, elongated crossover body section 115, welded to the body section 111 by a circumferentially continuous .
weld 116. The upper body section 111 has elongated slots 117 milled therein, opening at their lower ends into the annular space A between the inner body section 115 and the outer tubular body 118, which is welded at 119 to the upper, outer body section 120 which provides the upwardly facing shoulder 121 engageable with the downwardly facing shoulder 85 of the upper pipe section, when the connection is threaded together. Also, 6~5 as previously described, the pin 112 carries in its upper end surface an annular resiliently deformable or elastomeric seal ring 122 which prevents air flow from the annulus A in-to the central passage through the assembly. The upper, outer body 5 section 120 is welded to the inner body section 1l1 by a suitable number of welds 123 formed in holes 124 in the outer body section, and the lower outer body section 118 is also welded to the inner upper body section 111 by a suitable number of welds 125 formed in holes 126 in the body section 118 below the weld 119.
-~ 10 At the lower end of -the crossover assembly CO, the inner tubular body member 115 and the outer tubular body member 118 are joined to a crossover and connector member 127 which has an internally threaded box 128 connected to the externally threaded pin 129 of the bit B. The crossover and connector member 127 has a cylindrical body 130 providing an annular seat 131 which receivesl a downwardly extended cylindrical end portion 132 of -the inner body section 115, the two parts being welded together by circumferentially continuous weld 133. It will be seen that the connector body 130 blanks off the lower end of the fluid passage 110 in the center of the upper body section. The outer : tubular body 118 is rigidly connected to the crossover andconnector body 127 by a number of circumferentially spaced welds 134 formed in hole 135 in the portion of the body 118 which surrounds the cylindrical crossover body 130. Another circum-fentially continuous weld 136 ~s provided between the lower end of the body section 118 and the crossover connector 127.
A number of circumferentially spaced elongated milled . slots 137 in the side of the crossover body 130 communicate withthe annular space A and with a numbeF of radial ports 139 formed in the crossover body 130 and extending between the slots 137 and .
s a central bore 140 in the connec-tor body 130. The bore 140 opens downwardly into the central flow passage 141 through the bit B, ., .
:~ whereby air flowing downwardly through the annular space A finds access to the bit B and discharges into the bore hole, as pre-viously described with respect to Fig. la.
~` Referring to Figs. lOa through lOc, the expansible cutter , ., hole opener or hole enlarging bit of the invention is shown in detail. The bit EB includes an elongated tubular body 150 having an upper pin end 151 threadedly engaged in the thread 75 at the lower end o~ a length of the drill pipe P and shouldering at 152 with the lower end of the drill pipe section, the pin 151 carry-ing at its upper end an elastomeric or resilient seal ring 153 engagable within the box 70 to provide a seal between the outer `~ flow path and the inner flow passage 154 which extends through .~
.... .
the body of the hole opening bit.
Extending along the bit body 150 in circumferentially spaced locations is a number of elongated milled slots 155 which communicate through the connection at the upper end of the body with the annu~us of the drill pipe string, the outer body sleeve - 20 or member 156 of the bit body being welded at a number of cir cumferentially spaced locations by welds 147 formed in holes 148 in the body member 156 in angularly spaced relation to the slots 155.
At the lower end, the fluid passages 155 communicate through lateral openings 157 (Fig. 11) in the outer body member 156 with an annular piston chamber 158 provided by piston and cylinder means 159. This piston and cylinder means 159 is adapted to longitudinally shift an outer cutter carrying support section 160 of the bit upwardly with respect to an inner drive or mandrel section 161 of the bit, between the positions shown ' : in Fi~s. lOb and lOc, in which the cutter arms 16 are retrac-ted, and in Figs. 15a and 15b, in which the cutter arms 16 are expanded.
The outer, cutter arms supporting structure 160 comprises :':
~:` 5 a tubular member 162 having at circumferen-tially spaced locations elongated fluid passages or slots 163 milled therein and then . closed by elongated closure strips 164 welded into an elongated seat 165. At alternate angularly spaced locations about the , member 162 are additional passage ways are slots 166 which are . 10 somewhat.shorter than the slots 163 and which are closed by elongated closure strips 167 welded in seats 167' in the member . 162. As wi~ be described hereinafter, the passage ways 163 are adapted to supply air to the cutters C on the cutter arms 16, and the passages 166 communicate with passages 168 in the lower end . 15 section 169 of the outer body member 162, these passages 168 leading to no~zles 170 which are carried in the lower end of the body and are directed towards the bits' cutters, whereby the air discharging from the nozzles is caused to blow over the cutters . to remove cuttings therefrom and assist in maintaining the bit 20 - in a cool operating condition.
~ Carried by the lower end section 169 of the body member ~ 162 in a plurality of circumferentially spaced elongated slots. 171 are the respectlve cutter support arms 16. Pivot pins 172 : ~ extend.through the upper ends 173 of the cutter arms 16 and into ~- 25 aligned bores 174 at opposite sides of the slots. The pins ................ ...... engage at one end with a stop 175 and are retained in place by suitable screw members 176 threaded into the body as seen in :
Fig. 14.
.. As previously indicated, air from passages 163 in the body member 162 is adapted.to be directed to the cutters C.
. -20-'~ ' ' . ' ' . , `- Thus, the passayes 163, at the lower ends, open in-to a bore 177, and a flexible, preferably metallic, fluid connector 178 has a fitting 179 connected in the bore 177 and another fitting 180 which communicates with an elongated passage 181 formed in the bit support arm 16. In the illustrated embodiment, the - ~ bit arm 16 is a two part structure, including the pivot end 16a and the cutter support end 16b joined together by a weld 16c with ~ a tubular insert 16d providing for continuity of the fluid ; passage 181. Air supplied to the passages 181 is adapted to cool the cutters C ln a manner to be describee below.
The inner body or drive member 161 extends reciprocably ; within the outer member 162 and has at its lower end a tubular member 182 having a head 183 disposed in a seat 184 at the lower end of the body member 161 and retained in place by a suitable means such as a split retainer ring 185, which is in turn re-tained in place by balls 186 engaging in opposed arcuate surfaces provided about the outer periphery of the split ring 185 and :;
;~ about the inner peripheral wall of the seat 184. The tubular ; ~
member 182 extends downwardly within the center of the outer body . . .
section 162 and through a bushing 187, which is retained in place by snap rings 188 within a bore 189 provided in a web 190 at the lower end of the outer body member 169. Extending through the tubular member 182 is a fluid passage 191 which is in communi-, :
cation with the central passage 154 through the inner bit body . ~ .... .
; ~ 25 member 161. Since the air flowing through the tubular member - 182 is laden with cuttings and abrasive dust, the member 182 is preferably provided at its lower end with a wear resistant ring insert 192.
In the operation of the structure to expand the cutter supporting arms outwardly from the position of Fig. lOc to the -21-~
' .
:, , '. : , . :
~63S5 .
When expans:ible, pivoted cutter supporting arms on dLill bits are actuated outwardly by air pressure to ini-tiate an . enlarged bore hole, the flow of air to the cutters, in air cooled cutter bits, may be so great that inadequate pressure is 5 present to effect expansion of the cutters in a reasonably short period of drilling, so that a long tapered side wall is formed on which the back or outer surfaces of the pivoted cutter arms : may drag and wear. Thus, it is desirable that the expansive ~ force be maintained on the arms which carry the cutters, while ~ 10 not depriving the cutters of sufficient cooling air during the early sta~.es of bore hole enlargement.
. Air cooled expansible cutters currently available are both complicated in the structure permitting the flow of air . through the cutter support arms and inefficient in terms of the cleaning and cooling effect of the air on the cutter elements.
In the formation of blast holes in mining or quarrying operations, it has been found that a two-pass method of first drilling a pilot hole with a first drill bit and drilling stringt and then, in a second pass, enlarging the hole with an expansi-20 ble bit run on a second drill string, produces a superior blast hole shape, if the bore hole enlargement is con-tinued subs~
,.;
.~ tantially to the bottom of the pilot hole. Since the annular bore . hole space outside the drill string, when drilling the pilot .: .
;~ ~ hole is not large in cross-sectional flow area, the drilling fluid or air can be normally circulated down the drill string and up the annulus, and the bailing velocity of the fluid or . air in the annulus may be adequate. Thereafter, however, when .~ the second, hole enlarging pass is being made, the enlargement of the bore hole may so increase the annular flow area that the 30 necessary air bailing velocity may not be obtalned with existing. -3-' ' ' ' ' ~ 6~
1 compressors. If an expansible bit is used which is expanded by reverse circulation, even through a dual concentric pipe string, a different set up of equipment at the rig is nec-essary to supply the air through the annulus. On the other hand, the pilot bit could be used on the dual pipe with the dual pip]e rig equipment which supplies air through the dual pipe annulus. Thus, two separate pipe strings for the pilot drilling pass and the enlarging drilling pass would be re-quired in the case of existing equipment.
When forming blast holes by the two-pass method to pro-vide a more-or-less flat bottomed enlarged chamber, as more particularly disclosed in the United States Patent 4,189,165, issued February 19, 1980, it is desirable that the bottom of the hole be relatively free from cuttings and accumulated dust at the conclusion of the drilling. ~ccumulated debris at the bottom of the hole can cushion the explosive effect and interfere with bench removal or effective fragmentation. How-ever, residual cuttings and dust in the hole have continued to be a problem.
The present ivention relates to improved reverse circu-lation or dual pipe ]oints.
More particularly, the invention provides a dual pipe ~oint including a pin structure and a box structure; each of said structures icluding an inner tubular member hving a central passage therethrough; an outer tubular member dis-` posed about and connected to the inner tubular member; one of said members of each structure having longitudinal fluid pas-sages therein; said inner member of said pin structure having a threaded pin thereon; the inner member of said box structure 30 having transverse shoulders in abutting engagement with said '~' ~
: `
~; passages in communication; said inner members of said structure providing opposed transversely extended surfaces between said pin and box; sealing means between said transversely extended surfaces; and longitudinally extended concentric tubular members connected to the respective inner and outer tubular members and forming an annular space communicating with said fluid passages.
his invention possesses many other advnatages and has other purposes which may be made more clearly apparent from a consideration of a form and method embodying the invention. The form and method are shown and described in the present specifi-cation in connection with the drawings accompanying and cons-tituting a part thereof. Such form and method will now be described in detail, for the purpose of 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.
Referring to the drawings- Figs. la and lb, together, constitute a view diagrammatically showing the drilling of a ` pilot bore hole into earth formation, utilitzing the dual drill pipe string of the invention, Fig. lb being a downward conti-:
nuation of Fig. la;
Figs. 2a and 2b, together, constitute a view diagramma-tically showing the enlargement of the pilot bore hole of Figs.
. ' . .
la and lb utilizing the expansbile bit of the invention and reverse circulation through the dual pipe string, Fig. 2b being a downward continuation of Fig. 2a;
Figs. 3a and 3b, together, constitute an enlarged longi-`~ tudinal section through the swivel structure, Fig. 3b being a downward continuation of Fig. 3a;
Fig. 3c is a fragmentary vertical section on the line , 30 3c-3c of Fig~ 3b;
-.
; j3 S, 5 ,, - ~` .
Fig. 4 is a transverse section through the swivel, as taken on the line 4-4 of Figs. 3a;
Figs. 5a and 5b, together, constitute an enlarged vertical section, as ta]cen on the line 5-5 of Fig. 1, showing a typical dual pipe joint, Fig. 5b being a downward continuation of Fig.
5a;
Fig. 6 is a transverse section as taken on the line 6-6 ; of Fig. 5a;
... ~
~ 10 . ' / ~
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,.: /
,' /
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, /
'': /
. /
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/
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,. ~ /
-~ 25 /
., / , ~,. /
`~ 35S
Fig. 7 is a tran6verse sec-tion as taken on line 7-7 of Fig. 5b;
Figs. 8a and 8b, together, constitute an enlarged vertical section, as taken on the line 8-8 of Fig. 1, showing the cross-over unit in the~dual p:ipe string used -to drill the pilot bore hole; Fig. 8b being a downward continuation of Fig. 8a;
Fig. 9 is a transverse section as taken on the line ~-9 of Fig 8b;
Figs. lOa, lOb and lOc, together, constitute a vertical section, as taken on the line 10-10 of Fig. 2, showing the expan-; sible bit used to enlarge the bore hole with the cutters in retracted condition, ~igs. lOb and lOc being successive downward continuations of Fig. lOa;
Fig. 11 is a transverse section as taken on the line 11-11 of Fig. lOb;
Fig. 12 is a transverse section as taken on the line 12-12 of Fig. lOb;
Fig. 13 is a transverse section as taken on the line 13-13 of Fig. lOc;
Fig. 14 is a -transverse section as taken on the line 14-14 of Fig. lOc;
Flgs. 15a and 15b, together, constitute a vertical section corresponding to Figs. lOb and lOc, but showing the cutters expanded as in Fig. 2;
Fig. 16 is a bottom plan of the expansible bit, with the cutters expanded as in Flg. 15b; and Fig. 17 is an enlarged section, as taken on the line 17-17 of Fig. 16, showing the details of one of the air cooled cutters.
As seen in the drawings, referring first to Figs.la and lb, and Figs. 2a and 2b, apparatus is diagrammatical`y illustrated ., .
i35S
; for first drilling a pilot bore hole PH (Figs. la and lb) by drilling through -the earth formation F with the usual drill bit B, secured to the lower end of a string of rota-table drill pipe P, adapted to be rotated by a suitable rotary drive unit D, where-by the cutters C on the bit B progressively drill the bore or pllot hole PH as the drill pipe P is rotated, and drilling fluid is supplied through a swivel S from a suitable source of drilling fluid, such as a compressor for air in the case of drilling wi-th alr, via a supply conduit 10. As illustrated, the drill pipe string P is a dual concentric drill pipe having an inner pipe IP and an outer pipe OP made up in appropriate lengths or sections secured together at joints J and defining an annular space-A
therebetween communicating through the~respective joints, where-by drilling fluid or air supplied through the swivel S, from the pipe 10 through the annular spàce A to a crossover unit CO in ` which the annular spaoe A communlcates through lateral passages 11 with a central bore 12 at the lower end of the crossover unit.
The bit B is connected to the lower end of the crossover unit ~ ~ by the usual threaded connection 13 and has a central passage 14 `` 20 therethrough, through which the drilling fluid or air passes from the crossover passage 12, exiting into the bore hole PH
through the bit B and returning to the surface of the earth or i~ .
to the starting end of the bore hole through the annular space 15 defined between the bore hole wall and the drill pipe string P. The flow of the drilling fluid or air is operative to cool the cutters C of the bit B and to flush or bail cuttings from the bore hole as the drilling progresses.
It is generally known that the velocity of air upwardly through the annular space 15 between the drill pipe and the bore hole wall must be on the order of 5000 feet per minute in order ~8~-, .
.
to bail the cuttings from the bore hole. When as shown in : Fig. lb, the gauge of the bit B is only slightly larger than the diameter of the drill pipe string P, the annular cross-sectional area of the annulus 15 can enable the air to flow wi-th sufficient ` 5 velocity; for example, if air is suppliéd from a compressor through the annulus A of the drill pipe string at 1300 SCFM, the diameter of the drill pipe is 5 3/4" and the gauge of the bit .
is 7 7/8", and the bore hole is fairly regular, havlng no large . cavities or enlargements therein, the bailing velocity of the air returning through the annulus 15 will be on the order of in excess of 8000' per minute, or well in excess of the minimum - velocity required for removing the cuttings. With this in mind, the drilling of bore holes using air, generically including other : gas, as the drilling fluid supplied through the drill pipe string, either of the ordinary type or of the dual concentric type, has : , , been widely used as a drilling fluid in drilling bcre holes .~ into various earth formations, including bore holes for b~asting ~ ~........ or other mining operations, as well as in the drilling of well bores.
.
~ 20 As seen in Figs. 2a and 2b, the same drill pipe string P, .
. but without the crossover structure CO, has been connected to a - hole opener or bore hole enlarging bit EB of the expansible cutter type, having pivoted cutter supporting arms 16 provided with the cutters C at the lower free ends thereof, adapted to form the enlarged bore hole or chamber EH, as the expansible cutters are swung outwardly and the drilling progresses. If air were to be supplied through the swivel S to the drill pipe.
string.P in the same manner as described with respect to Figs.
la and lb in an effort to flush or bail the cuttings from the enlarged bore hole or chamber EH, the bailing velocity would be _9_ .
i35~
below the minimum value required. For example, if the enlarged bore hole EH is 13" in diameter, and drilling air is supplied at 1300 SCFM, the air velocity within -the enlarged bore hole ` would only be slightly more than 1700' per minu-te. In accordance with the present invention however, the air is supplied through the swivel S to the annulus A between the inner and outer pipes IP and OP, as shown by the arrows, flowing downwardly into the bore hole, and then entering the center pipe IP and flowing ~ upwardly therethrough, exiting from the top thereo. If it is :,'' .
assumed that the bore of the inside pipe is 2" in diameter, and all of the air returned to the surface through the 2" bore, ;:
supplied through the annulus A at 1300 SCFM, then the bailing velocity would be on the order of 60,000' per minute. Thus, if , merely 10% of the air entering the bore hole returns through the inner pipe, the bailing velocity would still be on the order of ~:.
6000' per minute, which is in excesss of the minimum velocity .~,.i~
~ required to bail the cuttings.
... . .
i~ As is known, baf~les between the pipe string P and the wall .. ~ .
of the bore hole PH may be employed to assure adequate flow of aix up the centre of the drill pipe string. However, in accor-dance with the present invention, as seen ln Fig. 2a, the flow of air up through the center pipe is enhanced by the provision of means ~ for drawing air through the inner pipe IP. The drive unit D is shown diagrammatically as having an inner drive pipe 17 driven by gearing 18 which is powered by suitable motors, such as hydxaulic motors M. Fluid and cuttings flow upwardly through the drive pipe 17 into a discharge chamber 17a in the drive unit housing, the pipe 17 having a packing 17b engaged therewith to prevent entry of dust into the drive unit housing. An outlet connection 19 is connected to the housing by fasteners l9a and 10, ' ~36355i .
establishes a flow path from the housing chamber 17a to a discharge hose l9b.
The venturi means V is associated with the discharge hose , l9b so as to induce flow through the hose and thus indwce flow upwardly through the center of the drill string. The venturi includes a housing l9c installed in the discharge hose l9b and having a flow passage l9d therethrough. A flange l9e on the housing l9c has an annular space or passage l9f to which air is supplied by an inlet conduit l9g. An annular yap l9h opens from the annular passage l9f into the flow passage l9d upstream of - the gap, thereby inducing fluid flow from the bore hole upwardly through the inner drill pipe and through the discharge hose, as . air is supplied through the swivel S and flows down -the annulus : A between the inner and outer pipes and enters the bore hole through the-bit.
The venturi or vacuum producing means V provides a ; further advantage after the completion of the enlargement of the bore hole, when the supply of drilling air is ~iscontinued. When the drilling operation is concluded, the bore hole will contain a quantity of cuttings and dust which have been lifted within the annular space within the bore hole outside of the drill pipe and which will settle to the bottom of the hole. The continued application of air to the venturi will induce flow through the discharge conduit which continues to draw air up~ the center pipe and wi~ continue to lift the cuttlngs from the bottom of the bore in a vacuuming operation. During the vacuuming operation, the drill pipe P can be rotated to cause the cutters on the bit to agitate the cuttings at the bottom of the holeO
Referring to Pigs. 3a, 3b, 3c and 4, the swivel structure S is shown in greater detail. Internally, the swivel structure '`; -11-,, includes ~n el~nc~atccl body or Inarlclrel 20 llavi.ncJ a c~ntral ~low , .
: passage 21 tllerethrough. ~t its upper end the body 20 ilas an .. externally threaded pin 22 threaded into an interllally t.hreacled box 23 of the rotary drive member 17, wh~cll i.s adaptc-d, a~s des-crlbed above, to be rotated by dr:Lve un.Lt D. The rotary drive member 17 has a central passaye 25 tileretllrough which communicates with the swivel passage 21 and with the discharge conduit and venturl means V. At its ].ower end, the swivel.body o.r rnandre]
20 has an internally tllreaded box section ~6connected to an .~ 10 externally threaded pin 27 forming a joinc3 J therewlth.
~ A tubular ou-ter body section 28 is dlsposed about the.
.... .
body of mandre:l 20 and welded thereto at appropriate locatlons to rlg.idly unite the inner and outer body sections toget}ler. As shown, the outer body 28 has an upper weld 29 securialg it to the upper portion of the inner body section, and a suitable number of longltudinally and circumferentially spaced wel.ds 30 formed in ~: drilled holes in the outer body sectlon are also provlded to secure the body sections toge-ther. Prlor to assembly of the ;~ .
. outer body section 28 on -the inner body, the inner body .is provided with a number of circumferentially spaced longitudinally extended milled slots 31 which communicate wi-th further down-wardly extending and circumferentially spacecl: slots 32 (Fig.3c), . . .
: througll which slots air is adapted to flow downwardly between the mandrel body sections. The .slots 32, as seen in Fig. 3c, :`' . . .
: 25 are narrower than the slots 31 and 33, bu-t of greater depth so .; as -to have approximately the same effecti.ve air flow areas.
.~ ~ .
Reduction ln the width of the slots 32 enables the .Eormatlon in the swlvel body at a number of clrcumferentially spaced loca-tions, . of outwardly openlng wrench slots 34 whlch extend longltudinally :: 30 of the body and provide a downwardly facing shoulder 35, ~ 12-., .
6;~5S
whereby a ver-tical supporting tool and hol.ding tool can be applied to the body by the drilling r1g, as is also well known.
. The wrench slots 34 are partially formed by external slots 36 formed in the exterior of the inner body section 20, and pre-ferably a bead of weld 37 is formed about the interace of the body parts within the wrench slot 34. Disposed about the rotat-able swivel body structure is an outer swivel housing structure -38, adapted to be held stationary in an appropriate suppo~ting arrangement which allows downward movement of the swivel assembly during the drilling operation. The supporting arrangement is not illustrated herein since it .is not germane to the present invention and various supporting arrangements can be utilized, as well known in the use of apparatus of the type here involved.
More particularly, the outer stationary swivel structure 38 comprises a central annular section 39 disposed about the . rotatable internal body structure and carrying suitable internal : side ring seals 40 and 41 in axially spaced relation. The seals 40 and 41 are preferably elastomer seals and are adapted to confine the air from the air inlet conduit 10 against leakage :`` 20 from the swivel assembly. As seen in Fig. 3a, the conduit 10 . opens into an annular space 42 defined by companion annular grooves 43 and 44 in opposed relation in the cylindrical walls . of the swivel member 39 and outer body secti.on 28 of`the swivel mandrel. Leading between the annulus 42 and the respective longitudinally extended flow passages or slots 31 in the mandrel :, is a number of circumferentially spaced radial ports 45. Upper bearing means 46 and lower bearing means 47 rotatably support the inner mandrel structure within the outer swlvel structure.
. The upper bearing means 46 includes an inner bearing race 48 ,,, seating on a shoulder 49 provided on the outer mandrel body ,:
s section 28and having an inwardly and upwardly inclined race or surface 50 engaged by bearing elements or rollers 51. An outer ,~:
"'~ race member 51' is engaged by the bearing rollers 51 and engages in a seat 52 provided within a bearing retainer and sealing sleeve 53. This sleeve 53 lS threaded at 54 onto an upwardly ex-tended annular flange 55 provided on the central swivel housing ' member 39 and has an upper circumferentially extended,and inwardly . . .
' projecting flange 55' which carries an internal sealing ringstructure 56 slideably and sealingly engaging with the outer cylindrical surEace of the mandrel body section 20, so as to pro-tect the bearing means 46 from erosive dust and dirt. Corres-pondingly, the lower bearing means 47 has an inner race 57 seating in a seat 58 provided on the mandrel body structure and having a downwardly and inwardly inclined surface or raceway 59 engaged by bearing elements or rollers 60 which also engage the opposing upwar.dly and outwardly inclined raceway 61 of an outer , . bearing race 62 disposed in a seat 63, which is provided by a .,~; .
. lower bearing retainer sleeve 64. This sleeve 64 is threadedly connec-ted at 65 to a downwardly extended annular flange 66 provided on the mandrel housing central member 39 and has a circumferentially extended and inwardly projecting lower flange 67, which carries an internal seal assembly 68 slideably and . sealingly engaging with the outer cylindrical surface of themandrel structure to prevent the entrance of foreign matter into the lower bearing assembly 47. It will be seen that the ou-ter :~' swivel housing structure 38 can be easily assembled about the swivel mandrel structure and disassembled for service or repair by threadedly disconnecting the respective bearing retainer sleeves 53 and 64 form the central housing member 39. In addi-: 30 tion, when the bearing retainers 53 and 64 are removed, the ~
`~ 6~5iS
;~ A central housing member 39 can be moved axially upwardly ~rom the end of the swivel mandrel to allow service and replacemen-t of the seal rings 40 and 41.
Referring to Figs. 5a and 5b, as well as -to the sectional views 6 and 7, a typical joint J is illustrated. Each joint J
includes a box end 70 and a pin end 71. The box ena 70 comprises an inner tubular member 72 having a suitable number of circum-ferentially spaced and longitudinally extended flow passages 73 milled therein and having a central flow passage 74 therethrough.
;~-` 10 At its lower end, the member 72 has a downwardly and outwardly . . .
, tapered internal thread 75 adapted to receive the complimental '~ external thread 76 on the pin section. At its upper end, the box member 72 has an annular seat 77 circumscribing the flow passage 74 and receiving a downwardly extended cylindrical end , ...
portion 78 of an elongated pipe section 79, which is welded to the box member 72 as by a circumferentially continuous weld 80.
Disposed about the pipe 79 and defininy~therewith the annular space A is an outer elongated pipe 81 which is welded by a suitable number of circumferentially spaced welds 82 in radial openings 83 to the upper end of the box body member 72. Also welded to the box body member 72 is a downwardly extended connector sleeve 84 which extends downwardly about the box body :;. .
72 and provides a downwardly facing end or shoulder 85 pro-jecting downwardly below the lower end 86 of the threaded box section. The sleeve 84 is welded to the box body section 72 by .,: ' . , means of a suitable number of circumferentially spaced welds 87 provided in radial openings 88 in the sleeve 84. In addition, a circumferentially continuous weld 89 is provided between the opposing ends of the upper pipe section 81 and the downwardly ; 30 extended sleeve 84. The outer connector sleeve 84 and the -15- _ .: .
.;'' .
. ~ 5 inner box member 72 are also united adjacen-t their lower ends by a weld 90 which extends circumferentially at the juncture of the lower end of the inner body 72 w:ith the internal periphery of the connector sleeve above the lower end shoulder 85. As seen in S Fig. 5b, the upper end of each length of pipe, having the pin end 71 of the respective joints J, has the external thread 76 on the upwardly and inwardly tapered pin section 91 which is provided on a pin body section 92 having a longitudinally extended bore or fluid passage 93 therethrough adapted to be aligned with the passage 74 through the box end 70 of the coupling. At its lower ~ end, the pin body section 92 has an internal annular seat 94 receiving an upwardly extended cylindrical end section 95 of the center pipe.79 which is welded to the body section 92 by a circum-ferentially continuous weld 96. Formed in the outer periphery ~ .
of the pin body section 92, adjacent the upper end thereof, is a number of circumferentially spaced longitudinally exte~nded slots 97 which communicate with relatively narrower but deeper longitudinally extended slots 98, which at their lower ends communicate with further longitudinally extended slots 99. The : 20 slots 97 communicate with an annular space 100 between the lower extremity of the box end 86 and an upwardly facing surface or shoulder 101 at the upper end of an outer pin connector sleeve 102. The lower slots 99 communicate with the annular space A
between the lower pipe 81 and the inner pipe 79 of the subjacent unit. As in the case of the slots 32 and 33 described above, the cross-sect:ional area of the slots 97 and 99, by reason of their relative:ly greater circumferential extent than the narrower slots 98, have substantially the same cross-sectional air flow area as the slots 98. The outerpin sleeve 102 is welded to the 30 inner pin body section 92 by a suitable number of circumferentially . . .
spaced welds 103 for~led in radial openings 10~ in the sleeve 102, as well as by a weld 105 formed at the upper end of the sleeve 102 and the upper outer edge of the pin body 92.
As seen in Fig~ 7, the relatively narrow circumferentially spaced slots 98 provide a substantial segment of the hody 92 wherein the circumferentially spaced or diametrically opposed wrench slots 106 can be formed, these slots 106 extending longi-tudinally and circumferentially to provide opposed longitudinally extended shoulders 107 and a downwardly facing horizontal face ^`10 108 engageable with the usual holding and supporting members of ~ ., the drilling rig. With the pin end held by the projections provided on the rig and engaged in the wrench slots, the super-jacent pipe length can be rotated by the rig to make up the threaded connection between the pin and the box.
- 15 Referring to Figs. 8a and 8b, the crossover sub or S! ' ., assembly CO is illustrated in detail. The assembly comprises an elongated center section having a flow passage 110 extending therethrough and including an upper inner body section 111 having . .
a threaded pin end 112 engaged in the box thread 75 at the lower end of the pipe section thereabove. At its lower end, the inner body member 111 has an annular seat 113 receiving the end pro-jection 114 of a lower, elongated crossover body section 115, welded to the body section 111 by a circumferentially continuous .
weld 116. The upper body section 111 has elongated slots 117 milled therein, opening at their lower ends into the annular space A between the inner body section 115 and the outer tubular body 118, which is welded at 119 to the upper, outer body section 120 which provides the upwardly facing shoulder 121 engageable with the downwardly facing shoulder 85 of the upper pipe section, when the connection is threaded together. Also, 6~5 as previously described, the pin 112 carries in its upper end surface an annular resiliently deformable or elastomeric seal ring 122 which prevents air flow from the annulus A in-to the central passage through the assembly. The upper, outer body 5 section 120 is welded to the inner body section 1l1 by a suitable number of welds 123 formed in holes 124 in the outer body section, and the lower outer body section 118 is also welded to the inner upper body section 111 by a suitable number of welds 125 formed in holes 126 in the body section 118 below the weld 119.
-~ 10 At the lower end of -the crossover assembly CO, the inner tubular body member 115 and the outer tubular body member 118 are joined to a crossover and connector member 127 which has an internally threaded box 128 connected to the externally threaded pin 129 of the bit B. The crossover and connector member 127 has a cylindrical body 130 providing an annular seat 131 which receivesl a downwardly extended cylindrical end portion 132 of -the inner body section 115, the two parts being welded together by circumferentially continuous weld 133. It will be seen that the connector body 130 blanks off the lower end of the fluid passage 110 in the center of the upper body section. The outer : tubular body 118 is rigidly connected to the crossover andconnector body 127 by a number of circumferentially spaced welds 134 formed in hole 135 in the portion of the body 118 which surrounds the cylindrical crossover body 130. Another circum-fentially continuous weld 136 ~s provided between the lower end of the body section 118 and the crossover connector 127.
A number of circumferentially spaced elongated milled . slots 137 in the side of the crossover body 130 communicate withthe annular space A and with a numbeF of radial ports 139 formed in the crossover body 130 and extending between the slots 137 and .
s a central bore 140 in the connec-tor body 130. The bore 140 opens downwardly into the central flow passage 141 through the bit B, ., .
:~ whereby air flowing downwardly through the annular space A finds access to the bit B and discharges into the bore hole, as pre-viously described with respect to Fig. la.
~` Referring to Figs. lOa through lOc, the expansible cutter , ., hole opener or hole enlarging bit of the invention is shown in detail. The bit EB includes an elongated tubular body 150 having an upper pin end 151 threadedly engaged in the thread 75 at the lower end o~ a length of the drill pipe P and shouldering at 152 with the lower end of the drill pipe section, the pin 151 carry-ing at its upper end an elastomeric or resilient seal ring 153 engagable within the box 70 to provide a seal between the outer `~ flow path and the inner flow passage 154 which extends through .~
.... .
the body of the hole opening bit.
Extending along the bit body 150 in circumferentially spaced locations is a number of elongated milled slots 155 which communicate through the connection at the upper end of the body with the annu~us of the drill pipe string, the outer body sleeve - 20 or member 156 of the bit body being welded at a number of cir cumferentially spaced locations by welds 147 formed in holes 148 in the body member 156 in angularly spaced relation to the slots 155.
At the lower end, the fluid passages 155 communicate through lateral openings 157 (Fig. 11) in the outer body member 156 with an annular piston chamber 158 provided by piston and cylinder means 159. This piston and cylinder means 159 is adapted to longitudinally shift an outer cutter carrying support section 160 of the bit upwardly with respect to an inner drive or mandrel section 161 of the bit, between the positions shown ' : in Fi~s. lOb and lOc, in which the cutter arms 16 are retrac-ted, and in Figs. 15a and 15b, in which the cutter arms 16 are expanded.
The outer, cutter arms supporting structure 160 comprises :':
~:` 5 a tubular member 162 having at circumferen-tially spaced locations elongated fluid passages or slots 163 milled therein and then . closed by elongated closure strips 164 welded into an elongated seat 165. At alternate angularly spaced locations about the , member 162 are additional passage ways are slots 166 which are . 10 somewhat.shorter than the slots 163 and which are closed by elongated closure strips 167 welded in seats 167' in the member . 162. As wi~ be described hereinafter, the passage ways 163 are adapted to supply air to the cutters C on the cutter arms 16, and the passages 166 communicate with passages 168 in the lower end . 15 section 169 of the outer body member 162, these passages 168 leading to no~zles 170 which are carried in the lower end of the body and are directed towards the bits' cutters, whereby the air discharging from the nozzles is caused to blow over the cutters . to remove cuttings therefrom and assist in maintaining the bit 20 - in a cool operating condition.
~ Carried by the lower end section 169 of the body member ~ 162 in a plurality of circumferentially spaced elongated slots. 171 are the respectlve cutter support arms 16. Pivot pins 172 : ~ extend.through the upper ends 173 of the cutter arms 16 and into ~- 25 aligned bores 174 at opposite sides of the slots. The pins ................ ...... engage at one end with a stop 175 and are retained in place by suitable screw members 176 threaded into the body as seen in :
Fig. 14.
.. As previously indicated, air from passages 163 in the body member 162 is adapted.to be directed to the cutters C.
. -20-'~ ' ' . ' ' . , `- Thus, the passayes 163, at the lower ends, open in-to a bore 177, and a flexible, preferably metallic, fluid connector 178 has a fitting 179 connected in the bore 177 and another fitting 180 which communicates with an elongated passage 181 formed in the bit support arm 16. In the illustrated embodiment, the - ~ bit arm 16 is a two part structure, including the pivot end 16a and the cutter support end 16b joined together by a weld 16c with ~ a tubular insert 16d providing for continuity of the fluid ; passage 181. Air supplied to the passages 181 is adapted to cool the cutters C ln a manner to be describee below.
The inner body or drive member 161 extends reciprocably ; within the outer member 162 and has at its lower end a tubular member 182 having a head 183 disposed in a seat 184 at the lower end of the body member 161 and retained in place by a suitable means such as a split retainer ring 185, which is in turn re-tained in place by balls 186 engaging in opposed arcuate surfaces provided about the outer periphery of the split ring 185 and :;
;~ about the inner peripheral wall of the seat 184. The tubular ; ~
member 182 extends downwardly within the center of the outer body . . .
section 162 and through a bushing 187, which is retained in place by snap rings 188 within a bore 189 provided in a web 190 at the lower end of the outer body member 169. Extending through the tubular member 182 is a fluid passage 191 which is in communi-, :
cation with the central passage 154 through the inner bit body . ~ .... .
; ~ 25 member 161. Since the air flowing through the tubular member - 182 is laden with cuttings and abrasive dust, the member 182 is preferably provided at its lower end with a wear resistant ring insert 192.
In the operation of the structure to expand the cutter supporting arms outwardly from the position of Fig. lOc to the -21-~
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` position of Fig. 15b, an outward projec-tion 193 a-t one side of the tubular member 182 is formed to engage a downwardly and inwardly, arcuately extended camming surface 194 provided on the inside of -the respective support arms 16. At the lower end of the camming surface 194 is a locking surface 195 which, when the arm 16 is fully pivotally extended as seen in Fig. 15b is engaged by the cam member 193 to mechanically lock the arms in the expanded positlons until reverse motion of the bit body members ~ occurs. Upon such reverse motion of the bit body sections, a shoulder 196 projecting outwardly and facing upwardly on the ...
' - tubular member 182 is provided for engagement with a downwardly facing lug or projection 197 upon the upper end 173 of the res-pective support arm 16, whereby to pivotally shift the support arms 16 from the extended position of Fig. 15b back to the retracted position of Fig. lOc, enabling the bit structure to be removed from the hole on the drlll pipe.
As previously indicated, the inner bit body member I61 :-: . ,is a rotary drive member which is adapted to rotatably drive the outer bit body section 162 in response to rotation of the drill pipe string, so that the bit cutters are rotated or revolved :- : .
about the axis of the bit. The rotary drive between the bid ~;j body sections is provided as shown in Fig. 13, whereln it will ~ be seen that at opposite sides of the inner body section 161 are - chordal flats 198 disposed in opposed relation and slidably engageable with segmental torque transmitting members 199, which - are carried within the outer body member 162 and suitably fixed in place as by weldments.
As previously indicated, the piston and cylinder means 159 which form the piston chamber 158 act to move the outer body structure 160 upwardly with respect to the inner body structure .,. ~ , . .
. . . . . . .
' ' ~6~355 161 when the cu-t-ter arms 16 are -to be extended~ Re~erring to Fig~ lOb, it will be noted that the piston and cylinder structure : . comprises an upper annular head 200 secured within the upper end of the outer body member 162 by means such as retainer screws 201 carried by the body member 162 and extending into an opening or groove 202 ~ormed about the outer periphery of the head 200.
An external sealing ring 203 is disposed between the body member . 162 and the outer periphery of the head 200, and an in*ernal side .~ ring seal or piston ring 203' is carried by the head and slid-.: 10 ably and sealingly engaged with the outer cylindrical surface of ,:.
the upper and outer body member 156. Another wiper or resilient . seal 204 is carried by the upper end of the head 200 and slidably engages the cylindrical outer surface of the body member - 156. I.n addition, a lubricant is adapted to be supplied to an ~; 15 annular space 205 above the piston ring seal 203' and the wiper ring seal 204 through a suitable grease fitting 206 to lubricate the slidable connection between the head 200 and the body member ;.: 156. Below the head 200, and carried by the inner body member .,, ~ ~- .. .
161, is another head member or ring 207 disposed about the outer 20 periphery of the body member 161 and seating on a stop ring 208, the ring being held in place by means of a number of circum-. ferentially spaced retainer screws 209 threaded into the inner body member 161. A static seal ring 210 is disposed between the body member 161 and the inner periphery of the head 207, and a . 25 sliding and resllient ring seal 211 is carried by the head ring 207 adjacent its lower end and slidably and sealingly engaging within the inner cylindrical surface of the outer body member 162. Another external ring seal 212 is carried by the head ring 207 and slidably engages the inner periphery of the outer body 30 member 162 at the upper end of the head ring 207. Thus, it will ., be seen that air supplied through the swivel to the annular space A between the inner and outer pipe sections can Elow downwardly through the respective joints finding access to the air passages 155 provided in the bit mandrel. Ports 157 at the lower end of the passages 155 provide communication between the passages 155 and the piston chamber 158, so that the pressure of air in the piston chamber acts upwardly across the annular cross-sectional area of the head 200 between the outer periphery of the bit mandrel 156 and the inner periphery of the outer bit member 162, providing an upward force to lift the outer body member 162 and consequently the bit support arms 16 upwardly with respect to the inner body member 161 and the camming member 193 on the mandrel tube 182. Such upward movement causes the pro-gressive expansion of the bit arms 16 outwardly, as ro-tation of the drill pipe causes the cutter C to form the downwardly facing upper shoulder within the enlarged bore hole EH.
A suitable number of circumferentially spaced small ports 213 communicate between the piston chamber 158 immediately below the head 200 and the air passages 163 in -the outer body member 162, whereby a portion of the air supplied to the piston chamber finds access to the passages 163, and then through the flexible connectors 178 to the air passages 181 in the bit arm 16.
Referrin~ to Fig. 17, it will be seen that the cutter ;; .
: arm passages 181 are adapted to supply alr to the cutters C to cool the same. The passages 181 communicate via passage 181a with a bore 181b, and from the bore 181b air can flow through a further passage 181c, which extends through the journal or mount 220 for . the rotary conical cutter element 221, which carries suitable : hard cutting inserts 222 arranged in an appropria~e cutting pattern, as is well known. Between the journal or hub 220 of : -24- -:
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the cutter and the conical cutter element 221 are sultable roller bearings 223 engaging opposed parallel bearings surfaces . .
224 within the conical member 225 on the hub. In addition, .
ball bearing elements 226 are disposed between opposed arcuate seats 227 on the hub and 228 within the conical cutter element 221, these balls being supplied initally through the bore 181b and serving to rotatably retain the cutter element 221 on the hub. After the bearing balls 226 are installed, they are retained in place by a retainer 229 disposed in the bore 181b and pro-viding an inner arcuate surface 230 corresponding to the surface 227 within the journal, and retainer 229 is then secured in place as by-a weld 231. In addition, an end bearing or sleeve 232 is disposed between the reduced end of the journal 220 and the end bore within the conical member 221. The air passage 181c ... .
opens through the inner end of the journal 220, so that all of - the air supplied through the passage 181 passes about the bearings 232r226 and 223 as the air exits between the cutter cone and the journal.
While, as previously indicated, the relatively small ports 213 leading from the piston chamber 158 to the fluid passages 163 and thence to the cutters allow sufficient flow to effectively cool the cutters during the initial hole opening operation, it is desired that after expansion of the cutters to the positions of Fig. 15b, where they are mechanically locked in the outwardly extended position, a largé volume of air be supplied to the cutters to cool them. Accordingly, again re-. . .
ferring to Fig lOb, it will be seen that additional fluid ports 213a are provided in the body member 162 and communicating with the air passages 163 therein. These ports 213a are initially closed by virtue of the lower side ring seal 211 and the upper :
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side ring seal 21~ between the head member or sleeve 207 and the inner periphery of the body member ]62. However, as the body member 162 moves upwardly, to the position of Fig. 15a, it will be seen -that the relatively larger ports 213a communicate with the piston chamber 158 after the por-ts 213a pass above the ,. .
upper head seal 212, whereby additional air is supplied to the passage ways through the cutter supporting arms and to the cutters.
In addition, it will be seen, again referring to Fig. lOb, that the body member 162 has additional circumEerentially spaced ports communica-ting with the passage ways 166 extending there-through and leading to the nozzles 170 at the lowerend of the .... . .
outer bit body secti:on 169. These additional ports 213b are also initially located between the lower seal 211 and the upper seal 212 between the body 162 and the head rlng 207, so that communication between these ports 213b and the fluid passage 155 is initially precluded. Here again, however, as the outer body .
~ of the bit moves upwardly and the bit arms 16 are fully expanded, , .
these additional ports 213b are also in communication with the piston chamber 158 so that a share of the air supplied to the piston chamber can now flow to the nozzles which are, as seen in ig. 16, directed towards the cutters C so as to create an air ., blast against the cutters to blow cuttings therefrom and also , assist in maintaining the cutters cool.
.
In the use of the apparatus described above to first form a pilot hole PH as in Fig. 1 and to form the enlarged bore hole EH, the components of the apparatus are preferably carried by a drill-ing rig havlng a compressor for supplying air to the drilling ` operation, suitable supports for the various components so that they can be made up in a string during the drilling operations, -~6-,; , -``
and engaging and holdin~ tools for -the respective components so that they can be tor~ued together. Initially, the crossover sub CO is made up together with the usual drilling bit B and the swivel S, together with an appropriate length of intermediate dual concentric pipe. Rotation is applied to the pipe string as the drilling air is supplied to the conduit lO. The air flows down the annulus A of the pipe string, cr~ossing over through the crossover to the central bit passage and returns to the surface through the annulus 15 outside of the drill pipe. This is, except for the use oE the dual concentric pipe and crossover, a fairly standard bore hole drilling operation which could be conducted with ordinary drill pipe instead of the dual concentric pipe.
After -the pilot hole PH has been drilled to the desired depth, the drilling string is removed from the bore hole and the bit and crossover assembly removed. Then the expansible bit EB is applied to the pipe string and lowered in the bore hole to the location at which the formation of the enlarged chamber or hole . . .
EH is to commence.
Air is supplied simultaneously to the drilling fluid conduit lO as well as to the venturi V, and rotation of the drill pipe string is effected to commence the cutting action of the ,:. .
cutter C against the pilot hole wall. The cut-tings, together with the portion of the air circulated to the cutter C through the ex-pansible arms will reversely flow upwardly through the center pipe ~ 25 assisted by the induced flow produced by the venturi device V.
- ~ Since the flow of drilling air to the cutter C is initially res-tricted by the relatively small ports 213 communicating between the cutter expandlng piston chamber 158 and the cutters, high air pressure is available to forcefully move the cutters outwardly to rapidly undercut the formation, preventing the outer surfaces '' ' ' ' ' ~ ' 6~
of the cutter arm :L6 from drayging on the formation at -the under-cut shoulder. When the expansible cutters are Eully expanded ` and locked in place by the camming action of the mandrel onthe support arms and more air is allowed to circulate through 5 the cutters to cool and cleanse them, the balance of the air is jetted through the nozzles 170 in the direction of the bits to further blow the bits clean and further cool them. The drilling ., - operation can then be continued until, for example, the enlarged - hole is drilled to the same depth as the depth of the original pilot hole, as in the two pass blast hole forming method of the above-identiEied copending application. Then the circulation of air through the drill pipe and the application of drilling thrust can be ceased while the application of air to the venturi continues. Any cu-ttings and dust which have-been carried up-wardly through the bore hole annulus in the air which returns to the surface through the annulus will then settle to the bottom ; of the bore hole. The continued rotation of the drill pipe can cause the cutters to agitate the settling dust and cuttings, and the flow of air downwardly through the annulus and upwardly through the center of the drill pipel under the influence of the venturi will vacuum the hole relatively clean.
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` position of Fig. 15b, an outward projec-tion 193 a-t one side of the tubular member 182 is formed to engage a downwardly and inwardly, arcuately extended camming surface 194 provided on the inside of -the respective support arms 16. At the lower end of the camming surface 194 is a locking surface 195 which, when the arm 16 is fully pivotally extended as seen in Fig. 15b is engaged by the cam member 193 to mechanically lock the arms in the expanded positlons until reverse motion of the bit body members ~ occurs. Upon such reverse motion of the bit body sections, a shoulder 196 projecting outwardly and facing upwardly on the ...
' - tubular member 182 is provided for engagement with a downwardly facing lug or projection 197 upon the upper end 173 of the res-pective support arm 16, whereby to pivotally shift the support arms 16 from the extended position of Fig. 15b back to the retracted position of Fig. lOc, enabling the bit structure to be removed from the hole on the drlll pipe.
As previously indicated, the inner bit body member I61 :-: . ,is a rotary drive member which is adapted to rotatably drive the outer bit body section 162 in response to rotation of the drill pipe string, so that the bit cutters are rotated or revolved :- : .
about the axis of the bit. The rotary drive between the bid ~;j body sections is provided as shown in Fig. 13, whereln it will ~ be seen that at opposite sides of the inner body section 161 are - chordal flats 198 disposed in opposed relation and slidably engageable with segmental torque transmitting members 199, which - are carried within the outer body member 162 and suitably fixed in place as by weldments.
As previously indicated, the piston and cylinder means 159 which form the piston chamber 158 act to move the outer body structure 160 upwardly with respect to the inner body structure .,. ~ , . .
. . . . . . .
' ' ~6~355 161 when the cu-t-ter arms 16 are -to be extended~ Re~erring to Fig~ lOb, it will be noted that the piston and cylinder structure : . comprises an upper annular head 200 secured within the upper end of the outer body member 162 by means such as retainer screws 201 carried by the body member 162 and extending into an opening or groove 202 ~ormed about the outer periphery of the head 200.
An external sealing ring 203 is disposed between the body member . 162 and the outer periphery of the head 200, and an in*ernal side .~ ring seal or piston ring 203' is carried by the head and slid-.: 10 ably and sealingly engaged with the outer cylindrical surface of ,:.
the upper and outer body member 156. Another wiper or resilient . seal 204 is carried by the upper end of the head 200 and slidably engages the cylindrical outer surface of the body member - 156. I.n addition, a lubricant is adapted to be supplied to an ~; 15 annular space 205 above the piston ring seal 203' and the wiper ring seal 204 through a suitable grease fitting 206 to lubricate the slidable connection between the head 200 and the body member ;.: 156. Below the head 200, and carried by the inner body member .,, ~ ~- .. .
161, is another head member or ring 207 disposed about the outer 20 periphery of the body member 161 and seating on a stop ring 208, the ring being held in place by means of a number of circum-. ferentially spaced retainer screws 209 threaded into the inner body member 161. A static seal ring 210 is disposed between the body member 161 and the inner periphery of the head 207, and a . 25 sliding and resllient ring seal 211 is carried by the head ring 207 adjacent its lower end and slidably and sealingly engaging within the inner cylindrical surface of the outer body member 162. Another external ring seal 212 is carried by the head ring 207 and slidably engages the inner periphery of the outer body 30 member 162 at the upper end of the head ring 207. Thus, it will ., be seen that air supplied through the swivel to the annular space A between the inner and outer pipe sections can Elow downwardly through the respective joints finding access to the air passages 155 provided in the bit mandrel. Ports 157 at the lower end of the passages 155 provide communication between the passages 155 and the piston chamber 158, so that the pressure of air in the piston chamber acts upwardly across the annular cross-sectional area of the head 200 between the outer periphery of the bit mandrel 156 and the inner periphery of the outer bit member 162, providing an upward force to lift the outer body member 162 and consequently the bit support arms 16 upwardly with respect to the inner body member 161 and the camming member 193 on the mandrel tube 182. Such upward movement causes the pro-gressive expansion of the bit arms 16 outwardly, as ro-tation of the drill pipe causes the cutter C to form the downwardly facing upper shoulder within the enlarged bore hole EH.
A suitable number of circumferentially spaced small ports 213 communicate between the piston chamber 158 immediately below the head 200 and the air passages 163 in -the outer body member 162, whereby a portion of the air supplied to the piston chamber finds access to the passages 163, and then through the flexible connectors 178 to the air passages 181 in the bit arm 16.
Referrin~ to Fig. 17, it will be seen that the cutter ;; .
: arm passages 181 are adapted to supply alr to the cutters C to cool the same. The passages 181 communicate via passage 181a with a bore 181b, and from the bore 181b air can flow through a further passage 181c, which extends through the journal or mount 220 for . the rotary conical cutter element 221, which carries suitable : hard cutting inserts 222 arranged in an appropria~e cutting pattern, as is well known. Between the journal or hub 220 of : -24- -:
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the cutter and the conical cutter element 221 are sultable roller bearings 223 engaging opposed parallel bearings surfaces . .
224 within the conical member 225 on the hub. In addition, .
ball bearing elements 226 are disposed between opposed arcuate seats 227 on the hub and 228 within the conical cutter element 221, these balls being supplied initally through the bore 181b and serving to rotatably retain the cutter element 221 on the hub. After the bearing balls 226 are installed, they are retained in place by a retainer 229 disposed in the bore 181b and pro-viding an inner arcuate surface 230 corresponding to the surface 227 within the journal, and retainer 229 is then secured in place as by-a weld 231. In addition, an end bearing or sleeve 232 is disposed between the reduced end of the journal 220 and the end bore within the conical member 221. The air passage 181c ... .
opens through the inner end of the journal 220, so that all of - the air supplied through the passage 181 passes about the bearings 232r226 and 223 as the air exits between the cutter cone and the journal.
While, as previously indicated, the relatively small ports 213 leading from the piston chamber 158 to the fluid passages 163 and thence to the cutters allow sufficient flow to effectively cool the cutters during the initial hole opening operation, it is desired that after expansion of the cutters to the positions of Fig. 15b, where they are mechanically locked in the outwardly extended position, a largé volume of air be supplied to the cutters to cool them. Accordingly, again re-. . .
ferring to Fig lOb, it will be seen that additional fluid ports 213a are provided in the body member 162 and communicating with the air passages 163 therein. These ports 213a are initially closed by virtue of the lower side ring seal 211 and the upper :
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side ring seal 21~ between the head member or sleeve 207 and the inner periphery of the body member ]62. However, as the body member 162 moves upwardly, to the position of Fig. 15a, it will be seen -that the relatively larger ports 213a communicate with the piston chamber 158 after the por-ts 213a pass above the ,. .
upper head seal 212, whereby additional air is supplied to the passage ways through the cutter supporting arms and to the cutters.
In addition, it will be seen, again referring to Fig. lOb, that the body member 162 has additional circumEerentially spaced ports communica-ting with the passage ways 166 extending there-through and leading to the nozzles 170 at the lowerend of the .... . .
outer bit body secti:on 169. These additional ports 213b are also initially located between the lower seal 211 and the upper seal 212 between the body 162 and the head rlng 207, so that communication between these ports 213b and the fluid passage 155 is initially precluded. Here again, however, as the outer body .
~ of the bit moves upwardly and the bit arms 16 are fully expanded, , .
these additional ports 213b are also in communication with the piston chamber 158 so that a share of the air supplied to the piston chamber can now flow to the nozzles which are, as seen in ig. 16, directed towards the cutters C so as to create an air ., blast against the cutters to blow cuttings therefrom and also , assist in maintaining the cutters cool.
.
In the use of the apparatus described above to first form a pilot hole PH as in Fig. 1 and to form the enlarged bore hole EH, the components of the apparatus are preferably carried by a drill-ing rig havlng a compressor for supplying air to the drilling ` operation, suitable supports for the various components so that they can be made up in a string during the drilling operations, -~6-,; , -``
and engaging and holdin~ tools for -the respective components so that they can be tor~ued together. Initially, the crossover sub CO is made up together with the usual drilling bit B and the swivel S, together with an appropriate length of intermediate dual concentric pipe. Rotation is applied to the pipe string as the drilling air is supplied to the conduit lO. The air flows down the annulus A of the pipe string, cr~ossing over through the crossover to the central bit passage and returns to the surface through the annulus 15 outside of the drill pipe. This is, except for the use oE the dual concentric pipe and crossover, a fairly standard bore hole drilling operation which could be conducted with ordinary drill pipe instead of the dual concentric pipe.
After -the pilot hole PH has been drilled to the desired depth, the drilling string is removed from the bore hole and the bit and crossover assembly removed. Then the expansible bit EB is applied to the pipe string and lowered in the bore hole to the location at which the formation of the enlarged chamber or hole . . .
EH is to commence.
Air is supplied simultaneously to the drilling fluid conduit lO as well as to the venturi V, and rotation of the drill pipe string is effected to commence the cutting action of the ,:. .
cutter C against the pilot hole wall. The cut-tings, together with the portion of the air circulated to the cutter C through the ex-pansible arms will reversely flow upwardly through the center pipe ~ 25 assisted by the induced flow produced by the venturi device V.
- ~ Since the flow of drilling air to the cutter C is initially res-tricted by the relatively small ports 213 communicating between the cutter expandlng piston chamber 158 and the cutters, high air pressure is available to forcefully move the cutters outwardly to rapidly undercut the formation, preventing the outer surfaces '' ' ' ' ' ~ ' 6~
of the cutter arm :L6 from drayging on the formation at -the under-cut shoulder. When the expansible cutters are Eully expanded ` and locked in place by the camming action of the mandrel onthe support arms and more air is allowed to circulate through 5 the cutters to cool and cleanse them, the balance of the air is jetted through the nozzles 170 in the direction of the bits to further blow the bits clean and further cool them. The drilling ., - operation can then be continued until, for example, the enlarged - hole is drilled to the same depth as the depth of the original pilot hole, as in the two pass blast hole forming method of the above-identiEied copending application. Then the circulation of air through the drill pipe and the application of drilling thrust can be ceased while the application of air to the venturi continues. Any cu-ttings and dust which have-been carried up-wardly through the bore hole annulus in the air which returns to the surface through the annulus will then settle to the bottom ; of the bore hole. The continued rotation of the drill pipe can cause the cutters to agitate the settling dust and cuttings, and the flow of air downwardly through the annulus and upwardly through the center of the drill pipel under the influence of the venturi will vacuum the hole relatively clean.
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Claims (4)
PRIVILEGE IS CLAIMED ARE DERFINED AS FOLLOWS:
1. Dual concentric drill pipe structure comprising: a pin structure and a box structure; each of said structures including an inner tubular member having a central passage therethrough; an outer tubular member disposed about and connected to the inner tubular member; one of said inner and outer tubular members of each pin and box structure having longitudinal fluid passages therein; said inner tubular member of said pin structure having a threaded pin thereon; the inner member of said box structure having a threaded box receiving said pin; said outer members having transverse shoulders in abutting engagement and with said longitudinal fluid passages in communication with each other; said inner members of said structures providing opposed transversely extended surfaces between said pin and box; sealing means between said transversely extended surfaces to prevent fluid flow between the central passages of said structures and said longitudinal fluid passages; and longitudinally extended concentric tubular bodies connected to the respective inner and outer tubular members and forming an annular space communicating with said fluid passages; at least one of said pin and box structures having longitudinally extended, outwardly opening radial slots offset from said longitudinal fluid passages defined by walls on both said inner and outer members for receiving a tool.
2. Dual concentric pipe structure comprising: a pin structure and a box structure; each of said structures including an inner tubular member having a central passage therethrough; an outer tubular member disposed about and connected to the inner tubular member; one of said members of each structure having longitudinal fluid passages therein; said inner member of said pin structure having a threaded pin thereon; the inner member of said box structure having a threaded box receiving said pin; said outer members having transverse shoulders in abutting engagement and with said longitudinal fluid passages in communication with each other; said inner members of said structures providing opposed transversely extended surfaces between said pin and box; sealing means between said transversely extended surfaces to prevent fluid flow between said central passages and said longitudinal fluid passages; and longitudinally extended concentric tubular bodies connected to the respective inner and outer tubular members and forming an annular space communicating with said fluid passages;
said fluid passages being slots formed in the respective inner member and covered by said outer members, said slots being angularly spaced from each other and having a relatively narrow but deep intermediate portion and relative broad and shallow end portions in the region of said transverse shoulders providing substantially uniform flow area though said portions.
said fluid passages being slots formed in the respective inner member and covered by said outer members, said slots being angularly spaced from each other and having a relatively narrow but deep intermediate portion and relative broad and shallow end portions in the region of said transverse shoulders providing substantially uniform flow area though said portions.
3. Dual concentric drill pipe structure as defined in claim 2, having wrench portions on said pin and box structures in the region of and offset from said the intermediate portion of said slots narrow slot portions.
4. Dual concentric drill pipe structure as defined in claim 3, said wrench portions having outwardly opening wrench slots in said inner and outer members between the intermediate portion of said slots forming said fluid passages.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA341,675A CA1106355A (en) | 1979-12-11 | 1979-12-11 | Dual concentric pipe joint |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA341,675A CA1106355A (en) | 1979-12-11 | 1979-12-11 | Dual concentric pipe joint |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1106355A true CA1106355A (en) | 1981-08-04 |
Family
ID=4115810
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA341,675A Expired CA1106355A (en) | 1979-12-11 | 1979-12-11 | Dual concentric pipe joint |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1106355A (en) |
-
1979
- 1979-12-11 CA CA341,675A patent/CA1106355A/en not_active Expired
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| Date | Code | Title | Description |
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| MKEX | Expiry |