US3552510A - Apparatus for rotary drilling of wells using casing as the drill pipe - Google Patents

Abstract

A drilling system employing casing as drill pipe and a bit section which is bodily insertable and removable through the casing and releasably attachable thereto for rotation with the casing.

Description

United States Patent Cicero C. Brown 1 c/o Brown Oil Tools, Inc., P.0. Box 19236, Houston, Tex. 77024 Oct. 8, 1969 Jan. 5, 1971 Continuation-impart of application Ser. No. 803,911, Mar. 3, 1969, Continuation-inpart of application Ser. No. 857,046, Sept. 11, 1969.

Inventor Appl. No. Filed Patented APPARATUS FOR ROTARY DRILLING OF WELLS USING CASING AS THEDRILL PIPE 12 Claims, 13 Drawing Figs.

U.S. Cl 175/261, 175/267, 175/284 Int. Cl. .Q F211) 9/26 Primary Examiner-James A. Leppink Attorney-R. Werlin ABSTRACT: A drilling system employing casing as drill pipe and a bit section which is bodily insertable and removable through the casing and releasably attachable thereto for rotation with the casing.

g es! PATENTED JAN 5 :sn

SHEET 2 OF 4CICERO 6. BROWN A TTORNE Y PATENTEU JAN. 5 |97l SHEET 3 BF 4 CIGERO C. BROWN I N VEN TOR.

A TTORNEY PATENIEUJAM 51971 v sum w 4 C/CERO aBRowN l N VEN'I OR.

A TTO RNEY APPARATUS FOR ROTARY'DRILLING or WELLS usnsc RELATEDYAPPLICATIONS' -This application is a continuation-in-part of my copending applications, Ser. :No. 803,91 1,'filed Mar. 3, 1969; and ser. No.857,046,filedS 'ept-.11,1969.

In the drilling of wells-for oil and gas,- for example by the rotary method, the drilling is convehtionallydone by the em ployment of'relatively smalldiameter string of drill pipe-to CASING AS THE mum. PIPE which a bit is secured, the entire string being rotated to drill the borehole. After'a suitable interval has been drilled, sometimes only a short distance'but at other times for the full depth of the well, casing larger in diameter than the drill pipe will be run into the'jborehole and subsequently cemented to seal off the formations through'whichfthe'borehole extends. This 1 necessarily involves the series of operations in which'the drill string must be extended asthe hole deepens, as by the addition of sections to the drill pipe, and also the entire drill string must be withdrawn whenever it'becomeneces'saryto replace the bit and then reinsert it toresume drilling. Thus making'of such sowith the-drill string outof the well, controlof the well becomes more'difficult. v

Heretofore numerous e, 'rtshavebeen made to provide a system employing the casing itself as the drill pipe in order to overcome some of the hazards enumerated, as well as time anchored to the landing shoe and with the underreamers in theirlextended position;

7 loss; However, thesepriori efforts have not'proven satisfactory l for-various reason well-knowntoithose skilled in the art. Y

The present invention, therefore, is directed to an improved arrangement by which 'theicasing "may'xbe employed as the drilling string andwhen used in combination with aretractable v or removable bit-sectionwillperforni all of the functions of drilling and casing of a well in a sequence-or series of operations which thereby greatly facilitates drilling operations. c

In accordance with 'tlie pr esent inventionja bit section is radially extendible and retractable underreamers, the entire bit section being arranged-and constructed to be insertable bodily through the bore of the 'casingand moved to'the lower end of the casing either on awire line or by simply dropping it into the casing, where, either by gravity alone or supplemented by pumped fluidfpressure, the bit section will be forced t'o'the bottom of the lower'end'of the casing string,

engageable with appropriate latch grooves or other anchorengaging structure in the landing shoe. The latter, in the illustrative embodiments, includes .a number of keys or splines which 'are adapted to engage appropriate spline slots or grooves in the bit section to lock the bit section to the casing against relative rotation whereby rotation of the casing string will be effective to rotate the bit for purposes of drilling the well.

The bit section also includes connector means pivotally connected by crank meansthe the underreamers which will be actuatable from theupper end of the casing string by a suitable running tool by mechanical means or by hydrostatic force, as by drillingfluid circulating through the system, for purpose of extending or actuating the underreamers so as the enlarge the bore hole drilled-by the, pilot bit sufficiently to allow free downward movement of the casing behind the bit as the hole is to the movement of the connector means to the underreamer extending position to direct and confine fluid flow to the bit discharge passages while drilling. This valve arrangement assures high velocity wash fluid and minimizes wash fluid requirements. g

Novel lock means'are provided to lock the underreamers in extended position'contemporaneouslywith the closing of the bypass valve means.

To withdraw the bitsection a conventional fishing tool or -spear is run into the casing on a wire line connected to anchorreleasirig elements of the bit section, whereby an upward pull applied to the fishing tool will be efi'ec'tive to retract the underreamers and release the bit section from the landing shoe to which it has been anchored. The spacing arrangement between the underreamers and anchor elements is so designed as to assure that the underreamers are fully retracted before a the bit section is released, therebyavoiding damage to the unj iderr'eamers which might otherwise occur if they were not completely retractedwhen they pass through the lower end of the'landing shoe. v

Other and more specific object's'and advantages of this invention will become more readily apparent from the following detailed description when read in'conjunction with the accompanying drawing which illustrates a useful embodiment and modification thereof in accordance with the present invention.

'In the drawing: FIG. 1 is a longitudinal, sectional view showing the bit section inserted into the landing shoe preparatory to anchoring the bit section to the landing shoe;

FIG. 2 is a view similar to FIG. 1 showing the bit section FIG. 3 is apartial view generally similar'to FIG. 2 showing the bit section in drilling position with the running tool being withdrawn from the casing;

. "FIG. 4 is a partial longitudinal view similar to FIG. 3 with the' parts in drilling position and the running tool completely withdrawn; v FlG. 5 is a viewsimilar to FIG. 4 showing a retrieving tool inserted in the bit section preparatory to withdrawing the v I latter from the landing shoe; providedwhich includes both the primary bityand a plurality of FIG.6 is a view similar to FIG. 5 showing the parts in released position for withdrawal by the retrieving tool;

b FIG. 7 isa' partial longitudinal view generally similar to the preceding views showing a modifications of the underreamer latch structure;

' FIG. 8 is a longitudinal view of the drilling system in a well bore showing the casing string with the bit section in place in the landing shoe and the drive connections at the surface;

' FIGS. 9 and 10 are longitudinal quarter-sectional views showing, respectively,'the runningand drilling positions of a hydraulically-actuated modification of the bit section;

FIGS. 11 and 12 are cross-sectional views taken on lines 11-11 and 12-12 respectively, of FIG.'1; and

FIG. 13 is a cross-sectional view taken along line 13-13 of P16. 2.

Referring to the drawing and considering the first FIG. 8, there is shown a string of casing C carrying the bit section, designated generally by the letter B, showing the bit section in place in alanding shoe 10 connected to the lower end of casing C At its upper end casing C is connected to a power sub P which functions to rotate the casing string during drilling, as will be described. Power sub P is of the general form and construction. disclosed in my copending application, Ser. No. 736,179, filed June 11, 1968 nowU.S. Pat. No. 3,467,202. A suitable drive connection between the power sub and the casing is disclosed in my U.S. Pat. No. 3,467,202. Power sub P is I suspended from a swivel S carried on elevators E conventionally employed as part of the drawworks of a drilling rig. The swivel has a hose connection H by which conventional drilling fluid is pumped into the drill string of casing C, thence through the passages in the bit' section into the annulus defined by the bore hole surrounding the drilling string, the bore hole being designated by the letter W.

Returning now to FIGS. 1 and 2, the landing shoe and bit section B comprise the basic drilling structure which is secured to the casing. Shoe is provided with an internally, threaded socket '12 by which it is threadedly secured to the lower end of casing C. Adjacent itslower end shoe 10 is provided with two or more angularly spacedcylindrical pins 14 which project a short distance inwardly of the bore of the shoe and form male splines for purposes which will be explained shortly.

Bit section B comprises abody 16 having a bore 17, and is dimensioned to be insertable through the bore of casing C and into the bore ofshoe 10.Body 16 is provided about an intermediate portion thereof with a plurality of longitudinal keyways orspline grooves 18 adapted to receive the projecting ends of thepins 14, wherebybody 16 will be locked to shoe 10 against relative rotation so that rotation of casing C will function to rotatebody 16 and its appurtenances.Spline grooves 18 terminate inupper end walls 19 which form stops for engagement withpins 14 to limit downward movement of the bit body throughshoe 10. Anannular seal ring 20 is disposed about the exterior ofbody 16 aboveend wall 19 to seal with the bore wall ofshoe 10. At a point aboveseal 20,body 16 is provided with a plurality of radial windows oropenings 22 in which are mounted anchor dogs 24 of a generally conventional form which are adapted when projected outwardly to be received in anannular anchoring groove 26 formed in the bore wall ofshoe 10. The anchor dogs are positioned inbody 16 so that they will be in registration withgroove 26 whenbody 16 is fully inserted in the shoe withwalls 19 abuttingpins 14. The upper end ofbody 16 is screwed into a ring 28 which overhangs the upper end of the body to define a downwardly facingannular shoulder 30 projecting slightly into bore 17.

A settingsleeve 32, having anaxial bore 33, is coaxially slidably disposed in bore 17 and is provided a short distance below its upper end with an external upwardly facingannular shoulder 34 adapted to abutshoulder 30 in the running position of the tool. The exterior of settingsleeve 32 is provided with anannular recess 36 at a point belowshoulder 34 adapted to register withdogs 24 whenshoulder 34 abutsshoulder 30, as seen in FIG. 1, in which position anchor dogs 24 are free to retract fromanchor recess 24. The setting sleeve is also provided with a downwardly facinginternal shoulder 37 which projects intobore 33 at a point oppositeshoulder 34 for purposes to be described subsequently.

At a short distance belowrecess 36,sleeve 32 is provided with a plurality of radial windows oropenings 38 in which are mountedlock dogs 40 which at a certain stage of operation of the tool, as will be described hereinafter, are adapted to be projected into anannular lock recess 42 provided in the wall of bore 17.

Alock sleeve 44 having anaxial bore 45 is coaxially slidably disposed inbore 33 of the setting sleeve and is provided a short distance below its upper end with an external upwardly facingannular shoulder 46 adapted to abutshoulder 37 in the running position of the tool.Lock sleeve 44 is provided with an externalannular lock recess 48 adjacent its lower end spaced to be in registration withlock dogs 40 whenshoulder 46 is engaged withshoulder 37 in the running position so as to allowlock dogs 40 to be in retracted position during running of the tool.Bore 45 of the lock sleeve is provided with anannular recess 45a intermediate its ends which is adapted for engagement by retrieving tool as will appear subsequently.

The lower end ofbody 16 carries a downwardly facing internally threadedsocket 50 adapted to receive the externally threadedshank 51 of abit 52 which constitutes the primary or pilot bit and may be of any conventional design for drilling a bore hole to any desired nominal diameter determined by the dimensions of the bit. At a point between the lower ends ofsplines 18 andsocket 50,body 16 is provided with a plurality of longitudinally extending radially openingslots 53 in which are mounted underreamers 54 of any suitable and known design mounted toarms 55. The latter are pivotally mounted on pivot pins 56 which extend transversely of the respective slots for enabling the underreamers to be angularly moved as to be radially projected and retracted with respect to theslots 53. Atubular nozzle 57, having abore 58 is secured to the lower end oflock sleeve 32 and projects downwardly centrally of the tool. The lower end ofnozzle 57 defines asleeve valve 59 having anannular seal ring 60 seated in the bore thereof and arranged to telescopically receive atubular extension 61 secured to the upper end ofsocket 50, whennozzle 57 is moved downwardly relative toextension 61, as will be described subsequently. Each of theunderreamer arms 55 is fixedly connected to an angularly extending crankarm 62 having its free end secured to acrosshead pin 63 mounted in acrosshead groove 64 formed in the exterior ofnozzle 57 at a point above valve 57 (see FIG. 13). With this arrangement it will be seen that the movement ofnozzle 57 downwardly will act through crankarms 62 to rotate the underreamers outwardly and upwardly while reverse movement of the nozzle will act to retract the underreamers. The same movement ofnozzle 57 will simultaneously function to open the valve means formed bysleeve valve 59 and the upper end ofextension 61. The lower end portion 65 of the latter is conically enlarged to form the connection tosocket 50 and the sloping walls of portion 65 are provided with a plurality ofjet nozzles 66 positioned to direct a spray of high-pressure wash fluid against the underreamer cutters when the latter are in extended position (FIG. 2) to clean the surfaces of the cutters. The lower end of landingshoe 10 is provided with downwardly taperingslots 11 shaped to cooperate witharms 55 to limit the outward movement ofthe underreamers to the extent desired.

The embodiment illustrated in FIGS. 1 to 6, inclusive, is designed to be run on a suitable running tool, designated generally by the letter R, which may, in turn, be run on a conventional sand or wire line string, or on a string of tubing (not shown). As illustrated tool T includes atubular body 70 having alower end portion 71 designed to be inserted in an annular space between the upper end portions of settingsleeve 32 and locksleeve 44 and to seat against ashoulder 72 in the bore of the setting sleeve. Ashear pin 73 initially securesportion 71 to the upper end portion of settingsleeve 32. Acollar 74 surrounds the exterior of the lower portion ofbody 70 and the exterior of the upper end portion of settingsleeve 32 and is secured tobody 70 at a point aboveshear pin 73 by means ofasecond shear pin 75. In this position the lower end of collar bears against the upper end of body 16 (FIG. 1). The upper end ofcollar 74 has an inwardly turnedlip 76 abuttable by anexternal shoulder 77 onbody 70 at a point slightly aboveshear pin 75. Atubular plunger 78 is mounted in the bore ofbody 70 and is biased downwardly against the upper end oflock sleeve 44 by means of aspring 79 held in compression against the upper end ofplunger 78 by means of abackup collar 80 mounted in the bore ofbody 70.Backup collar 80 is provided with radially extending adjustment pins 81 which project through longitudinally extending slots 82 formed in the upper end ofbody 70 into anannular recess 83 formed in the bore of a threadedcoupling 84 which serves to connect the running tool to a runningconnection 85 which forms a part of the running string.Plunger 78 is provided with anexternal shoulder 78a with an opposed shoulder 78b in the bore ofbody 70 for purposes which will be made apparent subsequently.

In operation, the bit section secured to running tool R will be inserted into the upper end of easing C and will be lowered through the bore of the casing until the bit is brought to a stop by the engagement ofpins 14 withend walls 19 ofspline grooves 18. At this stage, as the bit section is lowered into place,sleeve valve 59 will be separated from the upper end ofextension 61, permitting free bypassing of well bore fluids through the bore of bit section which might otherwise hinder the movement of the bit section through the casing. The parts of the bit section will be positioned as illustrated in FIG. 1 in which the setting sleeve is held in its retracted position byshear pins 73 and 75. Anchor dogs 24 will thus be free to retract and are effectively retracted intorelief groove 36.

whereby, to allow the free movement of the bit section through the casing and into landingshoe 10. At the same time, lock dogs 40 will be in their retracted position effectively holdinglock sleeve 45 in its upper or inactive position, as seen in FIG. 1.

With the bit section thus in place in the landing shoe, upward jarring force is applied through the running string to breakshear pin 75. Thereupon springs 79 will driveplunger 78 downwardly and bringshoulders 78a and 78b into engagement so that the downward force will be transmitted to settingsleeve 32, as well as to locksleeve 44. The resulting downward movement of both sleeves will drive anchor .dogs 24 intoanchor groove 26 effectively locking the bit section to the landing shoe and simultaneously drive lock dogs 40 into lockinggroove 42, thereby effectively; locking the Setting sleeve to bit.body 10, .being held inthis :position by the downward movement oflock sleeve 45 as seen in FIG. 2. 1

The downwardmovement of the setting sleeve will also be transmitted vianozzle 57 through the crosshead pins 63 and crank arms 62.,to underreamer arms 55-to swing the underreamers to their extended positions. I

Runningtool R may, now:be released by jarring upwardly with sufficient force to break shear pins 73 (FIG. 3), whereupon the running tool'may be removed from the well leaving the ,bit" section secured to the landing shoe with the underreamers in extendedoperating position (FIG. 4).

Power sub P may now be connected tothe upper end of the casing and rotation of .the latter as the drill string will be effected to drill the well as indicated in FIG. 8.

The drilling fluid circulation will be through hose connecbore of easing C. Thence, through the bit section, the fluid flowing through the bores ofsleeves 44 and 32 to bore 58 and through the now-closed bypass valve to the discharge passages in the pilot bit and thejet nozzles 66. The 'mud flush will return to the surface through the annulus between well bore W and casing C. Y I

When necessary to withdraw the bit section from the casing in order to replace or repair the pilot bit, underreamers or any other part of the bit section, a. fishing tool, designated generally by the letter T, of the form illustrated and described in my copending application," Ser. No. 869,563, filed Oct. 27, 1969, or of any other generally conventional form, the details of which do not form a part of this invention, will be run into the casing bore on a wire line, or tubing string if desired, and will be 'latched'into groove 45a of-loclrsleeve 44, as seen in FIG. 5. On application of upward pull to the fishing string, the lock sleeve will be drawn upwardly bringing shoulders37 and 46 in abutment and placing lock recess 48in registration withlock dogs 40, freeing the latter fromrecess 42. This same upward movement, now transmitted through abuttingshoulders 37 and 46 will raise settingsleeve 32 sufficiently to placerecess 36 in registration withanchor dogs 24 which will thus be free to retract fromanchor groove 26. Additionally, the upward movement ofthe setting sleeve will be transmitted tonozzle 57 which will, in turn, raisesleeve valve 59 off of the end ofextension 62 opening the bypass valve to allow fluid to dump back into the well as the bit section is raised. Further the upward movement ofnozzle 57 will rotate the underreamers back to their retracted position insideslots 53. The parts will now be in the same positions as when running into the casing (FIG. 6) and theentire bit section may now be withdrawn through the casing.

iii. drilling is to be resumed, the bit section, with the parts in the original retracted positions, will be returned through the bore of the casing to its lodgment inshoe 10, the bit section anchored and the underreamers extended as described, and drilling will be resumed. a

Fig. 7, illustrates a modification in which the setting sleeve and lock sleeve are effectively combined. In thismodification body 16 is provided with an externalannular recess 90 at a point spaced betweenshoulder 30 andrecess 36. Settingsleeve 32 is provided with a plurality of angularly spaced previouslydescribed embodiment, will close valve 5961 and I .tion I-l, swivel S and through a conduit in power sub P into the openings or windows 138 (one shown) in which are mounted pivotedlatches 140 which are biased by means ofsprings 91 to urge the upper ends of the latches to swing outwardly ofwindows 138. With this arrangement it will be seen that when settingsleeve 32 moves downwardly relative tobody 16 sufficient to bring the upper end positions of the latches oppositerecess 90, the spring pressure on the lower ends of the latches will swing the upper ends of the latches outwardly ofwindows 138 into recesses 'causing them to abut theshoulder 128 forming the upper wall ofrecess 90 and thereby locking the setting sleeve in the position at which anchor dogs 24 will be anchored inrecess 26. This downward movement, as in the hold the underreamers in their extended positions.

. Running tool R will be slightly modified, as shown, but in general will operate in substantially the same way as the earlier described tool. Similarly, the retrieving tool will be modified so as to swing latches out ofrecess 90 when effecting release of the bit body from the landing shoe. These modificatons will be readily apparent to those skilled in the relevant art.

FIGS. 9 and 10 illustrate a further modification in which the use of a running tool is dispensed with and the bit section run and set by a combination of gravity and hydrostatic pressure. As-seen in these FIGS., the only structural changes are the provision at the lower end oflock sleeve 44 of abottom closure plate 92 having acentral orifice 93 of relatively restricted dimensions. Alsobody 16 is provided with anextension 16a which is secured directly to asetting sleeve extension 32a by means of ashear pin 73a to hold the parts in the relatively retracted positions.

In operation, the bit section will be inserted into the casing and allowed to fall of its own weight to lodgment onmale splines 14. Pumped fluid may be employed to assist the bit section to move through the casing to its seat. As soon as the bit section is in place onpins 14, pump pressure will be increased and pressure will build up insidelock sleeve 44 by reason of the restrictedorifice 93, the variousseals including seal 20 preventing leakage of the pressure about the outside of the bit section. When the hydrostatic pressure has built up sufficient force to breakshear pins 73a, bothsleeves 32 and 44 will be caused to moved downwardly to position drivinganchor dogs 24 intoanchor recess 26 and lockdogs 40 intolock recess 42. Also, sleeve valves 59'-6l will be closed and the underreamers extended to their operative position where rotation of the casing from the surface will permit drilling ahead.

To remove the bit section when required, a retrieving tool such as that previously described may be run and operated to raiselock sleeve 44 and then settingsleeve 32, with opening of the bypass valve and retraction of the underreamers.

From the foregoing it will be evident that a drilling system is provided in which the casing itself which is ordinarily required to line the bore hole will be used as the drilling string and will be continuously fed into the hole as the drilling proceeds, thereby obviating all of the additional operations conventionally required in rotary drilling and for casing the well. The hazards accompanying the conventional drilling and casing operations, including those arising from round trips" of the drill string, will be obviated, drilling operations greatly facilitated, and time of operation substantially reduced.

Landingshoe 10 may be employed to land conventional tools required for cementing the casing or performing other operations commonly required in completing the well.

It will be understood that various changes and modifications may be made in the details of the illustrative embodiment within the scope of the appended claims but without departing from the spirit of this invention.

I claim:

1.-Apparatus for rotary drilling of wells using casing as the drill pipe, comprising in combination with a string of casing and means for rotating the same:

a. a bit section bodily insertable and removable through the bore of the casing;

b. cooperating means on the bit section and the lower end portion of the casing for landing the bit section therein in nonrotative relation to the casing;

c. said bit section comprising:

i. a generally tubular body;

ii. radially movable anchor means mounted on the body for releasably anchoring the body to said casing portion;

iii. a main bit carried by the lower end of the body having an upwardly extending tubular shank defining a fluid passage through the bit;

iv. a plurality of angularly space underreamers mounted on the body above said bit for radial movement between extended and retracted positions relative to said body;

v. a sleeve member coaxially disposed in said body cooperable with said anchor means and reciprocable between upper and lower positions respectively releasing and actuating said anchor means;

vi. connector means pivotally connecting said sleeve member to said underreamers reciprocable with said sleeve member between said positions for simultaneously respectively retracting and extending said underreamers;

vii. valve means carried by the sleeve member cooperable with said shank for opening and closing communication between the interior of said sleeve member and said fluid passage respectively at said upper and lower positions of said sleeve member; and

vii. releasable means initially securing said sleeve member to said body in said upper position.

2. ln apparatus according toclaim 1, wherein said bit section includes lock means carried by said sleeve member operable in response to movement of said sleeve member to said lower position to lock said sleeve member to said body in said lower position.

3. Apparatus according toclaim 1 wherein said valve means comprises a tubular nozzle defining a sleeve valve disposed to telescopically receive the upper end portion of said shank.

4. Apparatus according toclaim 1 including means responsive to mechanically applied force for releasing said releasable means.

'5. Apparatus according toclaim 1 including means responsive to hydrostatic force for releasing and said releasable means.

6. Apparatus according to claim 2 wherein said lock means includes:

a. radially movable lock elements mounted on said sleeve member for releasably anchoring the same to said body; b. a lock sleeve coaxially disposed in the bore of said sleeve member cooperable with said lock elements and reciprocable between upper and lower positions respectively releasing and actuating said lock elements; and c. means actuable in response to the release of said releasable means to simultaneously move said lock sleeve to said lower release position. 7. Apparatus according toclaim 1 wherein said cooperating means includes:

a. a tubular landing shoe secured to the lower end of the casing string; b. inwardly projecting male splines in the bore of said shoe;

and c. spline grooves in the bit body open at their lower ends for receiving the male spline in response to relative downward movement of the bit body. 8. Apparatus according toclaim 7 wherein said anchor means includes:

a. a plurality of angularly spaced anchor dogs disposed in openings in the wall of said body; and b. an annular anchor groove in the wall of said landing shoe arranged for anchoring engagement with said dogs. 9. Apparatus according to claim 2 wherein said lock means includes:

a. a plurality of angularly spaced latching dogs disposed in openings in the wall ofsaid sleeve member; and b. an annular latching groove in the interior. wall of said body arranged for latching engagement with said latching dogs. 10. Apparatus according toclaim 3 wherein said connector means includes:

a. a crank arm angularly secured to each underreamer; and b. a crosshead pin-and-slot connection between the free end of each crank arm and said nozzle. 11. Apparatus according toclaim 6 wherein said lock sleeve includes:

a. a closure plate across the bore thereof; and b. an orifice of restricted area through said closure plate. 12. Apparatus according toclaim 1 wherein said shank has mounted through the walls thereof a plurality ofjet nozzles arranged to direct wash fluid toward said underreamers.

Claims (12)

1. Apparatus for rotary drilling of wells using casing as the drill pipe, comprising in combination with a string of casing and means for rotating the same: a. a bit section bodily insertable and removable through the bore of the casing; b. cooperating means on the bit section and the lower end portion of the casing for landing the bit section therein in nonrotative relation to the casing; c. said bit section comprising: i. a generally tubular body; ii. radially movable anchor means mounted on the body for releasably anchoring the body to said casing portion; iii. a main bit carried by the lower end of the body having an upwardly extending tubular shank defining a fluid passage through the bit; iv. a plurality of angularly space underreamers mounted on the body above said bit for radial movement between extended and retracted positions relative to said body; v. a sleeve member coaxially disposed in said body cooperable with said anchor means and reciprocable between upper and lower positions respectively releasing and actuating said anchor means; vi. connector means pivotally connecting said sleeve member to said underreamers reciprocable with said sleeve member between said positions for simultaneously respectively retracting and extending said underreamers; vii. valve means carried by the sleeve member cooperable with said shank for opening and closing communication between the interior of said sleeve member and said fluid passage respectively at said upper and lower positions of said sleeve member; and vii. releasable means initially securing said sleeve member to said body in said upper position.

2. In apparatus according to claim 1, wherein said bit section includes lock means carried by said sleeve member operable in response to movement of said sleevE member to said lower position to lock said sleeve member to said body in said lower position.

3. Apparatus according to claim 1 wherein said valve means comprises a tubular nozzle defining a sleeve valve disposed to telescopically receive the upper end portion of said shank.

4. Apparatus according to claim 1 including means responsive to mechanically applied force for releasing said releasable means.

5. Apparatus according to claim 1 including means responsive to hydrostatic force for releasing and said releasable means.

6. Apparatus according to claim 2 wherein said lock means includes: a. radially movable lock elements mounted on said sleeve member for releasably anchoring the same to said body; b. a lock sleeve coaxially disposed in the bore of said sleeve member cooperable with said lock elements and reciprocable between upper and lower positions respectively releasing and actuating said lock elements; and c. means actuable in response to the release of said releasable means to simultaneously move said lock sleeve to said lower release position.

7. Apparatus according to claim 1 wherein said cooperating means includes: a. a tubular landing shoe secured to the lower end of the casing string; b. inwardly projecting male splines in the bore of said shoe; and c. spline grooves in the bit body open at their lower ends for receiving the male spline in response to relative downward movement of the bit body.

8. Apparatus according to claim 7 wherein said anchor means includes: a. a plurality of angularly spaced anchor dogs disposed in openings in the wall of said body; and b. an annular anchor groove in the wall of said landing shoe arranged for anchoring engagement with said dogs.

9. Apparatus according to claim 2 wherein said lock means includes: a. a plurality of angularly spaced latching dogs disposed in openings in the wall of said sleeve member; and b. an annular latching groove in the interior wall of said body arranged for latching engagement with said latching dogs.

10. Apparatus according to claim 3 wherein said connector means includes: a. a crank arm angularly secured to each underreamer; and b. a crosshead pin-and-slot connection between the free end of each crank arm and said nozzle.

11. Apparatus according to claim 6 wherein said lock sleeve includes: a. a closure plate across the bore thereof; and b. an orifice of restricted area through said closure plate.

12. Apparatus according to claim 1 wherein said shank has mounted through the walls thereof a plurality of jet nozzles arranged to direct wash fluid toward said underreamers.

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