Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.


  1. Advanced Patent Search
Publication numberUS2105722 A
Publication typeGrant
Publication dateJan 18, 1938
Filing dateNov 20, 1935
Priority dateNov 20, 1935
Publication numberUS 2105722 A, US 2105722A, US-A-2105722, US2105722 A, US2105722A
InventorsBarrett George J, Sosthene Robichaux
Original AssigneeBarrett George J, Sosthene Robichaux
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Well-boring apparatus
US 2105722 A
Abstract  available in
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

Jn- 18 1938. G. J. BARRETT E-r AL 2,105,722

WELL BORING APPARATUS 5 Sheets-Sheet l Filed Nov. 20, 1935 it? ,HIII/ .hun.

G. J. BARRETT ET Al. 2,105,722

WELL BORING APPARATUS Filed NOV. 20, 1935 5 Sheets-Sheet 2 Jan. 18, 1938. y G. J. BARRETT r AL 2,105,722.

WELL BORING APPARATUS Filed Nov. `20. 1935 5 sheetsbsheet 3 43 A 33 fl ,/44 a5 45;. 4; W 45 rij; j '47 27 l5 30a. V 46/ \4 35 42 4L 49 50 5047 s4 45 Q 4/ 4a 85' O i .4/ O Sla.. 0

6 Y 3f '.f I 37 l l c?. l5, 41, o 46 jf 1f/4.

46 3 4/ 1 3? n 3mm/T004 4.5 40 504%4 x Jan- 18, 1938. G. J. BARRETT Er Al. 2,105,722

WELL BORING APPARATUS 5 Shets-Sheet 4 Filed NOV. 20, 1935 Jan- 18, 1933 G. J. BARRETT Er AL A 2,105,722

WELL BORING APPARATUS Filed Nov. 2o; 1935 5 sheets-sheet 5 52 `7.5 g'. gmc/wma Y Il TI ll Il i v Patented Jan. 18, 1938 WELL-BORING APPARATUS vGeorge J. Barrett and Sosthene Robichaux, Houston, Tex.

Application November 20, 1935, Serial No.' 50,729


This invention relates to a well boring appara.-


An object of the invention is to provide equipment of the character described whereby, in the process of completing a well, the well bore already formed may be side-tracked and deepened.

In well drilling the well bore sometimes becomes obstructed by pipe or tools, or other obstructions becoming stuck or lost in the bore. 0 In such -event the obstructed bore must be sidetracked in order to deepen the well; or for other reasonsl it might be desirable to sidetrack the bore, as, for example when it is desired to straighten a crooked hole. In order to side- ..15 track a bore already formed, it is common practice to locate a whipstock in the well at the point where it is desired to sidetrack, said whipstock having a sloping face at its upper end, and to then lower a milling tool into the well bore,

which is deflected by the whipstock and caused to cut through the side of the casing in the well, or, if no casing is in the well, to form a new bore in the walls of the bore alongside the original bore. At the present time during the milling operation the milling tool operates against the l sloping face of the whipstock as well as against the opposite siderof the casing or wall of the bore. The milling-tool often mills oi the upper end of the whipstock, forming an abrupt shoulder on which the milling tool rides, and in its operation Aagainst the whipstock, the milling tool not only cuts away the face of the whipstock, but

also becomes broken and dull, all seriously interfering withand impeding the proper operation of the milling tool.

' It is one of the principal objects of this invention to provide a whipstock whose upper or sloping face is formed with a track with a carriage mounted to move along the track as' the milling operation proceeds and to support the milling tool in spaced relation to the sloping face of the whipstock and out of contact therewith so that all of the work of the milling tool may be applied to cutting a side hole through the casing orto the formation of a new bore alongside the original bore through which drilling may thereafter proceed.

A further object of the invention is to provide a whipstock having novel meansl for anchoring the same in a bore having a casing therein, or in an open hole, that is, in a hole or bore which has not been cased up.

A still further object of the invention is to provide means for gradually feeding the milling tool to the Work to the end that the full weight (Cl. Z55-1) of the drill stem will not be sustained by the milling tool during the milling operation. 'I'he feeding means employed, however, may be used as- Well for feeding the drill to the work during ordinary operations. 5

With the above and other objects in view, the invention has particular relation to certain novel features of construction, operation and arrangement of parts. examples of which are given in. this specification and illustrated in the accomlo panying drawings, wherein:

Figure 1 shows aside view, vpartly in section, of a whipstock located in a Well casing, showing the milling tool in operation in the process of cutting through the casing. 15

Figure 2 shows a partial vertical sectional view y of the whipstock attached to the milling tool and the une 3 3 of Figure 2. 2oV

Figure 4 shows a cross-sectional view taken Aon the line 4-4 of Figure 1.

- Figure 5 shows an end view of the sleeve bearing forming a tool carriage.'

Figure 6 shows a side elevation thereof. 25 Figure 'I shows an enlarged vertical sectional view of the lower end of one form of whipstock as anchored in the well casing.

Figure 8 shows a side view thereof taken at right angles to the view shown in Figure 7. 30

Figure v9 shows a cross-sectional view taken on the line 9 9 of Figure 7.

Figure 10 shows a cross-sectional view taken on the line Illl0 of Figure 7.

Figure 11 shows a side elevation of a type of 35 coupling `employed for seating the whipstock.

Figure 12 shows a side view, partly in section, of another type of whipstock specially adapted to be set in the open hole, showing a type of sidetracking tool employed therewith.

Figure 13 shows an enlarged fragmentary elevational view, partly in'section, showing the lower end of the whipstock disclosed in Figure l2.

Figure 14 shows a side view, partly in section thereof, taken at right'angles to the view shown in Figure 13.

Figure 15 shows a cross-sectional view taken on the line I5-I5 of Figure 13. Y

Figure 16 shows an elevational view of a well boring apparatus showing the feeding means for feeding the milling tool or drill to the work.

Figure 17 shows an enlarged vertical sectional view thereof.

.Figure 18 shows a fragmentary side view of a 55 drilling apparatus showing another form of feeding means, and

Figure 19 shows a fragmentary plan view of the apparatus shown in Figure 18.

Referring now more particularly to the drawings wherein like numerals of reference designate similar parts in each of the figures, the numerals I and 2, respectively, designate the deflector and the anchor forming a whipstock adapted to be located in a casing 3. set in a well. The anchor 2 is of approximately cylindrical contour and preferably has its lower end tapered, or of an inverted cone-shape, forming a guide 4 to guide the anchor in the casing. At one side the. anchor has the upwardly and outwardly tapering face 5, and the abrupt shoulder 6 beneath said face and mounted to ride against said face there is the pipe-engag-- ing jaw, 1 whose outer side has the downwardly pitched teeth and Awhose inner Iside is tapered'to conform to the pitch" of the face 5.

Pivoted to the upper end of the jaw 1, there is a latch 8 which is normally held inwardly'by-the at springJ 9vwhich presses inwardly thereagainst. The upper end of the latch has the outwardly turned lug III, and the inward extension II for a purpose to be hereinafter explained.

The .anchor 2 has the axial bore I2 extending downwardly from the upper end thereof and is also provided/with a lateral slot I3 leading outwardly from said bore wherein the latch 8 works.

When the anchor 2 is lowered into the well, as hereinafter explained, and reaches the point at which it is desired to set the whipstock, a downwardly tapering weight I4 may be dropped through the lowering string of pipe and will pass on down through the bore I2 and will engage the inward extension II of the latch and force 'the latch outwardly, and when the lug III registers with the joint between adjacent sections lof the casing 3, said lug will dropinto the joint and the jaw 1 will thereby be heldvstationary, and upon further downward movement of the anchor 2, the face 5 will'ride against the inner face of the jaw 1 and force said jaw outwardlywinto secure engagement with the casing 3 and the anchor 2 will thus be rmly secured into the cas ing against downward movement. 0

At the upper end of the anchor 2 the bore I2 is enlarged and formed with a side slot I5, and seated in this enlarged portion of the bore there 4is a tubular coupling I6 having an elongated lateralspline I1 which iits into the slot I 5v and which/is pinned therein by means of the frangible cross-pin I8. A string of tubing may be connected with the upper threaded end of the coupling I6 and the anchor thereby lowered to 'the desired point in the well and the anchor set as hereinabove explained. l

The anchor 2 is also provided with a downwardly and outwardly tapering face I9 whereon is mounted a wedge-shaped jaw 20 whose outer face has theupwardly pitched teethn and whose hereinabove explained, the -wight of the setting string above may be released, causing the coupling I6`f'to move on downwardly, shearing the pins I6 and `2I, and causing the jaw 20 to move This jaw 20 is normally held inr against downward movement in the casing 3, as

The lower end of the deector I is approximately cylindrical, and it tapers upwardly, the tapering portion being formed with the deflectving face 26 which is arcuate in cross-sectional contour. The lower end of the'fdeiiectoiw is also formed with a flat tapering face 21 which is pitched so as to ride upon the tapering face 22 of the anchor when the deiiector is lowered into the well, as illustrated in Figure 1. The face 21 has a transverse notch 28 cut across it, forming the upwardly facing shoulder 29. `When the deiiector is lowered into the well, as hereinafter ex-` plained, and as the face 21 moves down over thel face 22, the dogs 24 will be depressed until they register with the notch 29, whereupon said dogs will engage over the shoulder 29 and lock the ydeflector in place.

The numerals 30, 3|, designate milling tools, of any conventional construction, and which are mounted upon, and connected by, the spindle 32, said milling tools being thereby' suitably spaced apart. The milling tools may be let down into the well and operated by a suitable tubular stem, or operating string 33. The spindle 32 is mounted to rotate in an elongated bearing 34.A This bearing is providedfat its lower end, with a dovetailed tenon 35 which is itted into and shaped to move along a correspondingly shaped dovetailed groove, or mortise 36 extending longitudinally along the tapering portion of the deflector I from its upper to its lower end. This tenon is preferably formed integrally with the bearing 34, and extends out far enough to hold the milling cutter 3| spaced away from the sloping face 26 so as not to contact therewith during the operation of said milling cutter.

When it is desired to lower the deector into the well, the tenon 35 is located in the upper end of the groove 36 and pinned therein by a frangible cross-pin 31, and as thus assembled, may be then let down into the well until the deiiector seats on and is latched to the anchor 2, as hereinabove explained, and the weight ofthe stem 32 will thereupon shear the pin 31, permitting the milling tools to move on downwardly; they will` be deflected outwardly into ccntact with the casf ing '3, and upon rotation of the stem 33, a side .opening will be cut through the wall of the casing 3 opposite the defiector face 26. The upper end of the bearing 34 has an outwardly extending guide 38 whose outer surface is curved to conform to the contour of and to ride against the face 26, ,and upon downward movement oi' the milling tool, this guide will ride against the face 26 and will hold the upper milling tool 39 out of contact 'with the whipstock face and firmly against the opposite side of the casing 3, as'is illustrated in Figure 1. The upper milling tool 30 is of somewhat larger diameter than the lowerr tool 3I, so that the upper milling tool will cut, through the casing rst before the lower tool 3I begins to opi crate on said casing and thereafter both tools will simultaneously operate to cut openings 'through the casing, and as thevtool progresses downwardly, the'material between the openings will be cut out by the upper tool 30 and the opening made by the lower tool wiil be enlarged by the one above. A long side opening may thus be cut through the casing 3 and the milling tools will not be injured or dulled by Coming intocontact with the whipstock and their efficiency willI all be'expended informing 4the side, opening through In the form shown in Figures 12 to 14 inclusive, the upper and lower tools 30a and 31a are earth boring tools and may be of any suitable design for sidetracking into the wall of the bore of an open hole, that is, a hole in which casing has not been set. In this form a delector la has the tapering arcuate lface26, and the channel or mortise 36, as in the form shown in Figures 1 and 2, and the sleeve bearing 34 has the tenon 35 which moves in the groove 36, and the guide 38 which moves along the face 26 n the manner and for the purposes hereinabove explained. In both forms the bearing 34, the tenon 35, and the guide 38, form a carriage to support the toolsv 30, 3l, or 30a, 3Ia, as the case may be, and to hold 'themrout of contact with the deflector fa'ce26 so that said tools will not be dulled or broken or have their elciency reduced by coming into contact with the whipstock.

'Ihe type of whipstock shown in Figures 12 and 15 is designed to be set on the bottom of the bore, or on an obstruction in the bore which it is necessary to sidetrack. In this form of whipstcck, the numeral 39 designates the anchor whose lower end is formed with the inverted conical shaped guide 40, and whose upper end is reduced on opposite sides and formed with an upstanding tenon 4I whose margins taper upwardly and at the upper end thereof are formed with the upwardly converging bearing faces 42, 42. 'I'he tenon 4l also has a row of vertically aligned openings 43. The lower end of the deector la. hasla transverse slot, or mortise, 44 to receive the tenon 4|.

Pivotally mounted at their upper ends in this slot`4| are the wall hooks 45, 45, whose lower ends are outwardly turned and formed with the wall-engaging prongs 46, 46, having the downwardly converging at faces 41, 41, arranged to ride against the corresponding faces 42, 42. The

Y wall hooks 45 are normally held retracted, or in inner position, by' the flat springs 48 which'bear against the outer sides-thereof.

There are the oppositely arranged spring- 'seated dogs 49, 49, mounted on opposite sides of the slot 44, and in the lower end of the deflector la. Ihe inner ends olfv these dogs are upwardly and inwardly beveled, as at 5D, 50, so that upon downward movement of the deiiector la relative to the anchor 39, the dogs .49 will be successively forced outwardly so thaty they Vmay engage in the openings 43 successively from above downwardly.

` In order to lower a whipstock of this type into the well, the upper end of the tenon may be inserted into the slot 44 and the dogs 49 engaged vin the upper opening 43 with the faces 42 bear-V until the anchor 39 rests on the bottom of the bore, or upon an obstruction in the bore. The deflector la will move on downwardly by its own weight, the faces 42 cooperating with the faces 41 to force the prongs 46 of the wall hooks 45 outwardly causing them to penetrate into the walls of the bore, as shown in Figure l2, and the dogs 49 will successively engage in the openings 43 as the deector la moves downwardly, and when it has reached the limit of its downward movement, said dogs 49 will thereafter secure the deflector and anchor rmly together. The wall hooks 46 will hold the whipstock against turning in the bore during the succeeding operation of the tools 30a, 31a.

When a whipstock of this type is located in the bore, upon downward movement of the stem 33, the pinv 31 will be sheared, as hereinabove stated, and as the stem is further lowered and rotated, the tools 30a, 31a, will be gradually deflected against the side wall cf the bore opposite the sloping face 26 and will form a new bore, sidetracking the original bore.

The carriage, hereinabove referred to, will hold the tools 30a, 31p', out of contact with the whipstock during the sidetracking operations. Upon completion of the. sidetracking operations, the stem 33 may be withdrawn and a drill attached to the lower end of the stem and let down into lhe bore, and the well thus vdeepened to the desired depth.

It is desirable that the milling tools, or other tool, attached to the lower end of the drill stem be` fed to the work gradually so that said tools will not be subjected to too severe work. Means for gradually lowering the drill stem so as to graduallyfeed the milling tools, or other tools, to the work, have been provided,

As shown in Figure 16, there l'is the usual derrick 5I` on the floor of which is mounted the usual rotary drilling machine 52 through which the drill stem extends, and by means of which it is'rotated. Attached to the upper end of the A drill stem, there is the conventional swivel 53 which is connected to the traveling block 54. Y This traveling block is suspended from the crown which works through a stuing box 6l in the' upper end'of the cylinder. This piston rod is connected to the cable 56 by means of the cable 62. The cylinder 58 is filled with a liquid and is provided with a leak pipe 63 leading downwardlyy from the upper end thereof and controlled by a valve 64. Upon beginning milling operations or drilling operations, with the piston 59 at the lower end of the cylinder, the valvel 64 may be slightly opened 'so as to allow 'the liquid in the cylinder above the piston to gradually leak out, and this will control the 'rate of descent of the drill stein 33 and the tool at the lower end thereof and the amount of leakage may be regulated by the valve 64 so as to obtain the desired feed of the milling tool or drilling tool.

A modified form of feed-controlling apparatus is shown in Figure 18. In this form, a sprocket wheel 65 is xed on theshaft of the drum 51 and operating over 'this 'sprocket wheel is the sprocket chain 66 which also operates over the sprocket wheel 61 fixed on the shaft 68. This 75 ates.

shaft 68 also has a. larger sprocket wheel 69 ilxed thereon over which the sprocket chain 'I0 oper- During milling, or drilling, operations, the' lcable 1I is gradually unwound from the drum 12 at a uniform rate of speed, and the rotation of the drum 51 in unwinding the cable i6 is thus 'controlled so as to gradually allow the drill stem l33 to be lowered, and so as to gradually feed the tool at the lower end of said drill -stem to the work. Should the weight of the drill stem 33 be suflicient to cause the cable 56 to unwind from the drum 51 too fast and thus speed up the motor 16, the movement-of the drill stem' downwardly can be additionally controlled by the brake 15.

The drawings and description disclose what is now considered to be preferred forms of the invention by way of illustration only, While the broad principle of the invention will be defined by the appended claims.

What we claim is:

-1. A whipstock comprising an anchor shaped to be lowered into a well, means for fixing the anchor to the Wall of the well, a deflector shaped One end of the chain is attached to a This cable is wound about the drum ing face and also having a longitudinal track, and a toolguide mounted to move along the track.

3. A whipstock shaped to be lowered into a. Welland comprising an anchor, means on the anchor adapted to be projected outwardly into the wall of the well, a deiiector, means carried by the anchor and deflector for attaching the deflector'to the anchor in the well, said deiiector having a sloping, deilecting face, and a tool guide connected to the deilector and movable along said face. I

4. A whipstock shaped to be lowered into a well and comprising an anchor, means on the anchor adapted to be engaged with the wall of the well, a deector, means carried by the anchor and deector for attaching the deector to the anchor in the well, said deflector having a sloping deflecting face and a tool guide movable along said'face, and arranged tc hold the tool out of contact with said face.

5. A whip stock whose upper end is upwardly and outwardly tapered forming a deecting face, a carriage movable along said face and having a bearing, a spindle rotatable in the bearing on the carriage, a tool on the spindle above and beneath said bearing.

6. In combination a whip stock whose upper end is upwardly and outwardly tapered forming a deecting face, a carriage movable along said face, spaced boring tools, a shaft connecting said tools and mounted to rotate on the carriage.

"7. In apparatus of the character described a whipstock anchor shaped to be lowered into a pipe and having outwardly converging faces, pipe engaging jaws on said faces, a normally retracted member connected to one jaw and engageable with the pipe to anchor said jaw against downward movement whereby the corresponding face actuates said jaw into engagement with the pipe upon downward movement of the anchor and frangible means normally maintaining the other jaw retracted into inactive position.


Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2555462 *Nov 3, 1947Jun 5, 1951Beck Julius SWhipstock
US2839270 *Jun 1, 1954Jun 17, 1958Oilwell Drain Hole Drilling CoReleasable connections for drain hole drilling equipment
US2882015 *Jun 10, 1957Apr 14, 1959J E HillDirectional window cutter for whipstocks
US3029874 *Dec 18, 1958Apr 17, 1962Sprague & Henwood IncBases for mounting deflecting wedges of earth-boring or drilling equipment
US3397746 *Dec 30, 1965Aug 20, 1968Directional Service Co Of PeruCirculating mill guide
US3908759 *May 22, 1974Sep 30, 1975Standard Oil CoSidetracking tool
US4153109 *May 19, 1977May 8, 1979Baker International CorporationMethod and apparatus for anchoring whipstocks in well bores
US4397360 *Jul 6, 1981Aug 9, 1983Atlantic Richfield CompanyMethod for forming drain holes from a cased well
US4767100 *Aug 31, 1981Aug 30, 1988Gearld PhilpotDrilling rig with hoist transportable by a vehicle
US5109924 *Dec 17, 1990May 5, 1992Baker Hughes IncorporatedOne trip window cutting tool method and apparatus
US5297638 *Dec 8, 1992Mar 29, 1994Atlantic Richfield CompanyDrivepipe guide and installation method for wells
US5361833 *Nov 18, 1993Nov 8, 1994Triumph*Lor, Inc.Bottom set, non-retrievable whipstock assembly
US5409060 *Apr 4, 1994Apr 25, 1995Weatherford U.S., Inc.Wellbore tool orientation
US5425417 *Sep 6, 1994Jun 20, 1995Weatherford U.S., Inc.Wellbore tool setting system
US5425419 *Feb 25, 1994Jun 20, 1995Sieber; Bobby G.Whipstock apparatus and methods of use
US5452759 *Sep 10, 1993Sep 26, 1995Weatherford U.S., Inc.Whipstock system
US5494111 *May 13, 1994Feb 27, 1996Baker Hughes IncorporatedPermanent whipstock
US5535822 *Sep 8, 1994Jul 16, 1996Enterra CorporationApparatus for retrieving whipstock
US5620051 *Jun 3, 1996Apr 15, 1997Weatherford U.S., Inc.Whipstock
US5657820 *Dec 14, 1995Aug 19, 1997Smith International, Inc.Two trip window cutting system
US5727629 *Jan 24, 1996Mar 17, 1998Weatherford/Lamb, Inc.Wellbore milling guide and method
US5730221 *Jul 15, 1996Mar 24, 1998Halliburton Energy Services, IncMethods of completing a subterranean well
US5769166 *Oct 10, 1996Jun 23, 1998Weatherford/Lamb, Inc.Wellbore window milling method
US5785133 *Aug 29, 1995Jul 28, 1998Tiw CorporationMultiple lateral hydrocarbon recovery system and method
US5787978 *Nov 19, 1996Aug 4, 1998Weatherford/Lamb, Inc.Multi-face whipstock with sacrificial face element
US5803176 *Jul 15, 1996Sep 8, 1998Weatherford/Lamb, Inc.Sidetracking operations
US5806600 *Oct 10, 1996Sep 15, 1998Halford, Sr.; Hubert E.Whipstock system
US5813465 *Jul 15, 1996Sep 29, 1998Halliburton Energy Services, Inc.Apparatus for completing a subterranean well and associated methods of using same
US5826651 *Jul 30, 1996Oct 27, 1998Weatherford/Lamb, Inc.Wellbore single trip milling
US5833003 *Jul 15, 1996Nov 10, 1998Halliburton Energy Services, Inc.Apparatus for completing a subterranean well and associated methods of using same
US5836387 *Aug 13, 1997Nov 17, 1998Weatherford/Lamb, Inc.System for securing an item in a tubular channel in a wellbore
US5862862 *Jul 15, 1996Jan 26, 1999Halliburton Energy Services, Inc.Apparatus for completing a subterranean well and associated methods of using same
US5871046 *Aug 11, 1997Feb 16, 1999Halliburton Energy Services, Inc.Orienting, retrievable whipstock anchor
US5878818 *May 28, 1998Mar 9, 1999Smith International, Inc.Mechanical set anchor with slips pocket
US5909770 *Aug 13, 1997Jun 8, 1999Baker Hughes IncorporatedRetrievable whipstock
US5911275 *Sep 25, 1995Jun 15, 1999Mcgarian; BruceApparatus for milling a well casing
US6024168 *Oct 31, 1997Feb 15, 2000Weatherford/Lamb, Inc.Wellborne mills & methods
US6035939 *Nov 9, 1998Mar 14, 2000Weatherford/Lamb, Inc.Wellbore anchor system
US6056056 *Jan 18, 1998May 2, 2000Durst; Douglas G.Whipstock mill
US6059037 *Jun 30, 1998May 9, 2000Halliburton Energy Services, Inc.Apparatus for completing a subterranean well and associated methods of using same
US6076602 *Jul 1, 1998Jun 20, 2000Halliburton Energy Services, Inc.Apparatus for completing a subterranean well and associated methods of using same
US6092601 *Jun 30, 1998Jul 25, 2000Halliburton Energy Services, Inc.Apparatus for completing a subterranean well and associated methods of using same
US6112812 *Jan 6, 1998Sep 5, 2000Weatherford/Lamb, Inc.Wellbore milling method
US6116344 *Jul 1, 1998Sep 12, 2000Halliburton Energy Services, Inc.Apparatus for completing a subterranean well and associated methods of using same
US6135206 *Jul 1, 1998Oct 24, 2000Halliburton Energy Services, Inc.Apparatus for completing a subterranean well and associated methods of using same
US6155349 *Mar 3, 1998Dec 5, 2000Weatherford/Lamb, Inc.Flexible wellbore mill
US6302198Nov 29, 1999Oct 16, 2001Canadian Downhole Drill SystemOne trip milling system
US8307890 *Aug 21, 2008Nov 13, 2012Its Tubular Services (Holdings) LimitedWhipstock assembly
US20110308785 *Aug 21, 2008Dec 22, 2011Its Tubular Services (Holding) LimitedWhipstock assembly
WO1995023273A2 *Feb 21, 1995Aug 31, 1995Sieber Bobby GWhipstock apparatus and methods of use
WO1995023273A3 *Feb 21, 1995Nov 16, 1995Bobby G SieberWhipstock apparatus and methods of use
WO2001031159A1 *Oct 20, 2000May 3, 2001Canadian Downhole Drill Systems Inc.One trip milling system
U.S. Classification175/81, 175/203, 166/117.6, 175/392, 175/82, 166/55.3
International ClassificationE21B7/04, E21B7/08, E21B7/06
Cooperative ClassificationE21B7/061
European ClassificationE21B7/06B