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.

Patents

  1. Advanced Patent Search
Publication numberUS1879226 A
Publication typeGrant
Publication dateSep 27, 1932
Filing dateJun 26, 1929
Priority dateJun 26, 1929
Publication numberUS 1879226 A, US 1879226A, US-A-1879226, US1879226 A, US1879226A
InventorsHeddy Edward H
Original AssigneeHeddy Edward H
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Magazine type of drilling tool
US 1879226 A
Abstract  available in
Images(4)
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

4 Sheets-Sheet E. H. H EDDY MAGAZINE TYPE OF DRILLING TOOL Filed June 2-, 1929 sept. 27, 1932.

m s 7 4 o 6 Tl M 8 4 lvl- W I f fllf 8 1 0 M 0 ll/ 7 3 m 4 The W2 A um om 3 W 7 n I H1 NIHII UWM MM 0. INV A 7 m .4 2 W Sept. 27, 1932. E. H. HEDDY MAGAZINE TYPE OF DRILLING TOOL Filed Jima 2s. 1929 4 sheets-sheet 2 Sept. 27, 1932.

E. H. HEDDY MAGAZINE TYPE OF DRILLING TOOL Filed June 2s, 1929l 4 Sheets-Sheet 3 Sept. 27, 1932. E H, HEDDY 1,879,226

MAGAZINE TYPE OF RILLING TOOL Filed Jupe 2s, 1929 4 Sheets-sheet 4 Patented Sept. 27, 1932 UNITED STATES PATENT or-FICE MAGAZINE TYPE 0F DBILLING TOOL Application led June 26, 1929. Serial No. 873,772.

My invention pertains to a magazine type of drilling tool or appliance for drilling deep wells. By magazine type I mean a tool in which the cutters may be changed without 5 withdrawing the tool from the well.

An object of my invention is a drilling tool in which sharp cutters may be substituted for cutters which have become dull in drilling, without removing the drilling tool from the bottom of the well.

A further object is a drilling tool or implement having sharp cutters to do the iirst work when the tool is introduced into the well and then having another set of cutters which may be substituted in drilling, for the first set when the iirst set becomes dull and this substitution taking place Without withdrawing the drilling tool or implement' from the well.

A still further object of my invention is having a first set of cutters on the bottom of a drilling tool having a second set mounted on `the drilling tool and positioned with their lower edge above the lower edge of the first set, and a construction whereby the second set may be lowered when the first set becomes dull and therefore the drilling operation may be carried on without removing the tool from the bottom of the Well.

In this connection a more detailed object is in having the first set of cutters forming a pair which may be bolted or otherwise secured to the drill tool to allow replacement at the top of the well and having a second 3,-, pair of cutters which are longitudinally slidable and transversely shiftable in regard to the drill tool, so that after the dulling ofthe first set the second setmay be lowered and then expanded laterally to bring the second pair of cutters into operation. When expanded 'or shifted laterally the second set of cutters are held'in their expanded position resisting the inward pressure and thus cutting a full size hole the same size as the first set of cutters.

y Another object of my invention is a tripping device which holds the second set of cutters in the elevated position while the i-rst 'set is in operation and in which the trip device may be operated by dropping a plunger or plug through the string of drill pipe and forcing it down with the slushing fluid. The pumping of the slushing iiuid has a positive action in forcing the second set of cutters downward to their cutting position and in expanding or pressing such cutters laterally to ll the hole. f

Another object of my invention is in rotary drilling by a hydraulic method in which the slushing fluid is fed to the first set of 60 .cutters while these are in operation and then this slushing iiuid is utilized to force the second set of cutters to their operative position, the slushing fluid being fed to thesecond set of cutters and cut oft from the leads or ducts o leading to the irst set, and also while the first set of cutters are in operation with the slushing fluid being led through special ducts thereto, the ducts which carry the iow to the second set being automatically cut oi. m

Al general object of my invention isI toy lessen the labor and wear and tear on machinery in drilling, in that at least two sets of cutters may be utilized to drill the hole before it is necessary to withdraw the drill- 7;, ing tool and the string of drill pipe from a well for changing the cutters and thus reduce the number of round trips necessary in withdrawing and inserting the cutting tools in the drilling of a well.

In constructing my invention I utilize a tubular drilling tool with a. pair of cutters bolted atl the bottom. These cutters are attached to the tool at the top'of the well and have a bottom cutting edge and also a side 35 cutting edge to round out the hole. A second pair of cutters are positioned in thetool with their lower or cutting edge above the edge of the first set and with their lateral or side cutting edge drawn in out of contact 90 with the hole. The second set of cutters are vpositively held in an elevated position by a tubular plug which is suspended in the tubular drilling tool by dog-like catches and when inthis upper position the slushing fluid may ns be pumped down through a string of drill pipe, preferably through a sub, through the tubular plug and out of openings into ducts which discharge in a suitable position to lead -the fluid to the irstset of cutters. After the 100 first set of cutters are worn and are no longer through the string of drill pipe and this plunger has a fiexible gasket or packing thereon so that the slushing fiuid will act on such gasket and forcibly cause the plunger to release the dogs or latches and force the tubular plug and the second set of cutters downwardly, the cutting tool in the meantime having been lifted off the bottom of the well.

The plunger is also provided with a pair of abutment dogs which preferably engage the sub and hold the plunger with the tubular plug in its lowermo-st position. This tubular plug has a portion which holds the second set of cutters pressed out laterally and these cutters obtain an upward thrust against shoulders formed in the tubular cutting tool. The slushing fluid is fed through ducts communicating with the tubular plug and discharging adjacent said second set of cutters.

An application of my invention is illustrated in the accompanying drawings, in which,

Figure 1 is an elevation partly in section, showing the first set of cutters in full view;

Fig. 2 is an elevation taken partly in section, in the direction of the arrow 2 of Fig. 1, showing the second set of cutters in full view and in operative position;

Fig. 3 is a vertical section taken substantially on the line 3-3 of Fig. 1, in the direction of the arrows, showing the second set of cutters in their elevated and contracted position;

Fig. 4 is a. view similar to Fig. 3 with the second set of cutters in their` lowered or operative position, the first set being illustrated as dulled and showing the tubular plug in its lowermost position with the plunger fitting therein;

Fig. 5 is a section substantially on the line 5-5 of Fig. 4 in the direction of the arrows, to illustrate the passage for slushing fiuid through the upper plug and illustrating the mounting of the first set of cutters;

Fig. 6 is a horizontal bottom view taken in the direction of the arrow 6 of Fig. 2, on an enlarged scale; I

Fig. 7 is a horizontal section on the line 7 7 of Fig. 2in the direction of the arrows;

Fig. 8 is a horizontal section on the line 8 8 of Fig. 3 in the direction of the arrows;

Fig. 9 is a transverse section on the line 9-9 of Fig. 1, showing the leads for the slushing fluid feeding the first set of cutters;

Fig. 10 is a horizontal section on the line 10-1() of Fig. 2, showing the leads for the slushing fluid feeding the second set of cutters; Fig. 11 is an elevation of the tubular plug taken in the direction of the arrow 11 of Fig. 12; p

Fig. 12 is an elevation of the tubular plug,

Fig. 13 is an elevation of the plunger; Fig. 14 is a perspective view of one of the second set or shiftable cutters;

Fig. 15 is a perspective view of oneof the first set or fixed set of cutters.

In my invention I employ a tubular drill tool 11 which has a first set of cutters 12 secured at the bottom and a second set of cutters 13 which may belowered and pressed outwardly into position. A sub 13 is secured to the upper end of the drill tool and a string of drill pipe 14 is connected to the sub. Fitting inside of the upper drill tool I employ a tubular plug 15, to control the operation of this plug I have a plunger 16 which is dropped through the drill pipe.

In detail the upper drill tool has a lower pair of transverse slots 17 which slots have an upper horizontal shoulder 18 with a curved shoulder 19 extending downwardly and inwardly, a vertical backing section 20 and a horizontal shoulder 21 at the bottom. The first set of cutters 12 which fit in said slots are provided with a fiat upper end 22 fitting against the shoulder 18, a curved inner edge 23 fitting against the curved portion 19, an inner vertical edge 24 fitting against the vertical edge 20 and a shoulder 25 fitting against the shoulder 21. The outer edge 26 has a forwardly turned cutting edge 27 (note particularly Figs. 7 and 15) and provided with a bottom cutting edge 28. The lower edge 28 merges with the side 26 and with the vertical inner edge 29. These first or fixed set of cutters have a perforation 30 therethrough which pass bolts 31 holding them in place.

These bolts have their heads and the nuts 32 fitting in recessed sections 33 at the base of the drill tool; the body of the drill tool otherwise is preferably circular in cross section.

The tubular drill tool 11 has vertical slots 34 at the bottom for the second set of tools 13. The inner portion of the drill tool is provided with shoulders 35, 36 and 37 connected by vertaken inthe direction of the arrow 12 of Fig.. efficient, a tapered plunger is dropped 11 tical sections 38 and 39, there being an out- A ward bulge as indicated at 40 adjacent the bottom of the tubular drill tool. (Note particularly Figs. 3 and 4.) The shiftable drilling tools 13 are constructed with steps 41, 42 and 43 and with vertical sections 44, 45 and 46 making these steps. There is also a vertical outer edge 47 and a fiat top 48 with a cut` out section 49 leaving a hook 50. A tapered section 51 leads downwardly from the hook on the inside ed e, terminating in a shoulder 52 and below this shoulder there is an inner edge 53. This vertical edge 47 has a forwardly extending cutting edge 54 to cut the side walls of the hole and is provided with a bottom cutting edge 55 doing the main cutting. The vertical edge of the portions of the drill tool adjacent the slot 34 have a bevelled edge 56 to accomodate the edge 54 when these cutters 13 are retracted in the position shown in Figs. 1 and 3, when the cutters 13 are in their elevated position of Fig. 3.

There is a space 57 at the bottom of the groove 34 which may become compacted with dirt so that I provide a. shearing edge 58 on the rear face of each of the cutters 13 so that when such cutters are forced downwardly in the manner hereunder set forth this edge will displace such dirt and will allow the forcing of such cutters downwardly. These cutters are provided with an L-shaped slot 59 having a vertical portion 60 and a horizontal portion 61. The bolts 62 extend through these slots,-

such bolts having heads and nuts 63 which fit on the outside of the lower portion of the drill tool having the slots.

The drill tool at its upper end has a tapered thread 64 which engages the internal thread of the sub, which sub has a large opening or recess 65 which is somewhat dcmeshaped so that there is an outwardly tapering annular surface 66 exposed on the upper portion of the drill tool inside of this recess. The sub has a passage 67 therethrough which aligns with the passage through the drill pipe for pumping down -slushing fluid.

The cutters and the drill tool are assembled at thetop of the well with the second set or replaceable cutters held in their upper position by the tubular plug 15. This plug it will be noted has a hollow section 68 (note particular Figs. 3, 4, 11 and 12) and a solid section 69 at the bottom. This solid section has an annular shoulder 70 with an annular groove 71 above the shoulder. This groove engages the hooks formed above the recess 49 of the cutters 13 and holds these in the position shown in Fig. 3 in which position the bolts 62 are at the bottom of the vertical leg 60 of the L-shaped slots 59. The tubular plug 16 is itself held in its upper positionl by means of latches or triggers designated generally by 72. These are illustrated as having a hook end 73 engaging the annular shoulder 66, being pivoted on pintles 74 in slots 75 in a tubular 'extension 76 in the upper part of the tubular plug 15. These triggers have a straight lower end 77 pressed outwardly by a flat spring 78 (note Fig. 3). The extension 76 has an open top as indicated at 79 and a tapered interior surface 80. This extension 76 is only secured on two sides of the main bod)T portion of the tubular plug, leaving openings 81 on opposite sides for the slushing mud to flow downwardly when the plunger 16 is in its seated position as hereunder detailed.

When thea second set of cutters are in their elevated position, such as shown in Figs. 1

, and 3, the slushing fluid passes downwardly through the sub. the upper'extension 7 6, the hollow portion 68 ofthe tubular plug and outwardly through the ports 82 into the annular grooves 83 formed on the exterior of the plugs. It then fiows through sloping ducts 84 into vertical ducts 85 form-ed on the body portion ofthe drill tool.' These vertical ducts are formed by having a vertical semi-circular groove 86 cut or formed in the body portion and with semi-circular half pipes 87 welded thereto; thus making circular ducts. These discharge as indicated at 88 adjacent the tops of the fixed first set of cutters and slightly in front of such cutters as indicated in Fig. 9.

The plug 16 has a body portion 89 (note Figs. 4 and 13) which is tapered for the main portion thereof, having a short cylindrical section 90 atthe top and a smaller cylindrical section 91 at the bottom with a conical point 92. The upper end has a threaded pin 93 on which is threaded a stem 94, the stem having internal threads engaging the pin 93. A fiexible cup washer or bushing 95 of leather or the like, is caught at the lower end of the stem on the shoulder 96 on the upper end of the body portion 89. A pair or dogs 97 are secured by apivot pin 98 between ears 99 on the upper part of the stem. These dogs have a projecting finger 100 engaging inside of the sub as shown in Fig. 4 and a shoulder 101 engaging the curved recess 65 of the sub. Small pins 102 prevent these dogs from tilting in the wrong direction.

After the drilling tool has been operated on the first or fixed set of cutters, until these become dull and worn off somewhat as shown in Fig. 4, the drill tool is hoisted ofll the bottom of the hole and the plug 16 is dropped through the string of drill pipe. This is designed so that the washer 95 has a snug fit in the cylindrical bore 67 of the sub and so that the tapered portion 89 fits in the tapered portion 80 of the extension 76 of the tubular plug.v When the plug strikes this extension 76 and is guided therein by the point 92 it hits the straight ends 77 of the triggers, shifting these from the position shown in Fig. 3 to that shown in Fig. 4. The

pumping action of the slushing mud spreads the washer 95 in the cylindrical portion 67 of the sub and should there be anv tendency of the second set of cutters tosti ck. these are bodily forced down so that the slushing ports 81 having the annular groove 83 are brought out of registry with the ducts 84 and 85, thus no mud can be forced out of the device until the tubular plug is moved bodilv downwardlv from the position shown in Fig. 3 to that shown in Fig. 4. The plugis provided with a plurality of grooves 103, 104 and 105 inl which there are packing rings frming a tight seal with the inner cylindrical surface of the drill tool.

The downward movement thereof of the tubular plug with, the plunger forces the shiftable cutters downwardly, the bolts 62 arising in the vertical section 60 of the L- shaped slots 59. The downward movement releases the hooks 49 from the annular shoulder 70 and the tapered sections 106 of the plug force the cutters outwardly until the bolt 62 comes into the position at the inner end of the horizontal section 61 of the L- shaped slots 59 as shown in Fig..4. In this position it will be noted that the shoulders on the cutters bear against the horizontal shoulders at the lower portion of the drill tool and have an internal backing by the taper 106 fitting against the sloping surface 51 and the cylindrical section 107 fitting against the vertical section 53 of the cutters. This prevents the cutters from being thrust upwardly or forced inwardly in the drilling operation and holds them in firm position. When the cutters are thus forced down their cutting edge is below the dull cutting edge of the first set of cutters and as above mentioned if there is any dirt caught in the lower part of the groove or slot which holds this second set of cutters, it is sheared off by the shearing edge -58 of the rear face of the cutters.

In this lowered position the slushing fluid passes downwardly through the o en portions 81 on each side of the extension 76 of the plugs, through the hollow central section and throughthe ports 81 to the annular groove 83, from which it enters the lateral sloping ducts 108 and'vertical ducts 109 leading to a point in front of the shifting cutters the fixed cutters.

13 as shown in Fig. 10. These vertical ducts are made in the outside portion of the drill tool in the same manner as the vertical ducts for discharging from the upper position to It will be noted that unless the plug has its ports in registry with the upper orlower set of ducts, that no slush# ing fluid can be forced through the tool and hence a considerable pressure may be generated to bodily force the shiftable cutters downwardly should they stick and to force them outwardly and also that when slushing fluid is being forced to one set of ducts for either the fixed or the shiftable cutters, that it cannot be by-passed through the other set of ducts.

When the plunger and the plu are in their lowermost position, the dogs 9 engage the sub as shown in Fig. 4 and prevent the upward movement or shifting of the tubular plug and the plunger.- Should any dirt flowing with the slushing mud stick in the ports,

'this is sheared off by a downwardly turning cutting edge on the upper edge of the annular groove 83 adjacent the ports 82. It will be noted that it takes a very slight movement of the tubular plug 15 to cut ofi:l the flow through the upper ducts 84 and 85 so that should the shitable cutters for any reason stick or bind, av positive hydraulic pressure is brought to bear to force the tubular plug downwardly.

It is considered desirable to have the cup `force the plug and the shiftable cutters downwardly should the latter stick. However, this may not be always necessary, for in operation when the plug 16 is inserted in the drill pipe at the top, it is desirable to .run the mud pumps sufliciently opened up in order to force the plug 16 down quickly and to give a type of impact blow when the plunger seats in the tubular plug 16 and thus have the function of giving a ar to loosen the shiftable cutters' should they in any manner stick. It is to be understood that the free or open spaces as between the tapered portion 106 of thefbody structure 69 ofthe plug will be packed with grease as will be any other free spaces, to prevent entrance of the slushing mud and also of the cuttings from the formation in which the drill is working. A small wooden plug may also be placed in the lower portion 57 of the slots carrying the' od of drilling, in that a rotary drilling tool may be introduced into a well with the first set of cutters operating and when these cutters become dull a second set of cutters may be brought into use without removing the first set of'cutters and without removing the drill tool and the drill string from the hole.

VThe slushing fluid also plays an important part in the operation, this first has a flow from an upper position in the drill tool to the first set of cutters and then from a lowered position in the drill tool to the second set of cutters, and is prevented from by-passing from one set to the other so that the slushing mud will not flow through both sets of ducts at the same time. The slushing fluid also has an important operation in positively forcing the shiftable cutters downwardly and causing the expansion laterally of such cutters.

It will'be noted that an important feature of my invention is that the second set of cutters during the drilling operation by the first set are held in a position considerably above the bottom cutting edge of the first set-of1l cutters and also retracted inwardly from the walls of the hole so that the secondary cutters are not subjected to a cutting actionv into operative position they are positively forced downwardly and outwardly so that thebottoms of the second cutters engage the bottom of the hole and also the side walls of the hole, thus maintaining the hole of a true side.

Another important feature of my invention is that the secondary cutters are positively held upwardly into an inoperative position until they are brought into use and then after being forced downwardly and outwardly they are positively and rigidly held in this drilling position. y

Another characteristic of my invention is that the slushing fluid first feeds directly to .the first set of cutters and when the second set are brought into use the fiow of the slushing fluid to the first set is cut out and directed entirely to the second set.

Another feature of my invention is that the second set of cutters cannot be brought into operation by the accidental dropping of foreign objects in the drill pipe or by solid material being carried down by the slushing fluid and .blocking the passage of such slushing fluid.

Various changes may be made in the principles of my invention without departing from the spirit thereof as set forth in the description, drawings and claims.

I claim: 3o l. A drilling appliance comprising in combination a string of drill pipe, a drilling tool having afirst set of cutters rigidly connected thereto, a second set of cutters downwardly and outwardly shiftably mounted on the tool, means to suspend thesecond set of cutters out of operative position while the first set is operating, a tripping device adapted to be introduced through a drill string and trip the means suspending the second set of cutters whereby the second set of cutters shift p downwardly into an' operative drilling position.

2. A drilling appliance as claimed in claim 1, the tripping device being adapted to be a forced downwardly by a slushing fluid, means to flow the slushing fiuid to the first set of cutters, means to shut off said fiow, and means to fiow the fiuid to the second set of cutters.

3. A drilling appliance comprising a string of drill pipe, a tubular drilling tool having a first set of cutters rigidly connected thereto, a Second set of cutters downwardly and outwardly slidably mounted in slots at the bottom of the tool to cut on the bottom of the hole made by the first set of cutters, a plug mounted in the tool and having means to suspend the plug in the tool, the plug having means to non-shiftably retain the second set of cutters out of operative position, and a plunger insertable through the string of drill pipe into the tool, said plunger releasing the means suspending the plug to allow downward movement of the plug and the second set of cutters.

4. A drilling appliance as claimed in claim 3, the tool being constructed to allow lateral movement of the second set' of cutters, the said plug forcing said cutters outwardly laterally and forming a center support for the inward thrust of said cutters in operation.

5. A drilling appliance comprising a drilling tool having a first set of cutters rigidly connected thereto, a second set of cutters shiftably mounted ,in the tool and means to press the second set of cutters laterally outwardly to bring said second set of cutters into operation on the'bottom and side walls of the hole "on dulling of the first set.

6. A drilling appliance comprising in combination a drilling tool having a first set of cutters rigidly connected thereto at the lower end, a second set of cutters shiftably mounted in the lower end of the tool, means to retain the second set of cutters out of operative position, while the first set is used for drilling, means to lower and to shift the second set of cutterslaterally to bring them into position for drilling on dulling of the first set, and co-actingstructures between the second set of cutters and the tool to carry the upward thrust of the tools and means engaging the second set of cutters to take the inward thrust of said cutters.

7. A drilling appliance comprising in combination a string of drill pipe, a' sub, a l

drill tool, a first set of cutters rigidly connected to the tool, a second set of cutters slidably mounted in the tool, a plug in the tool. means to non-shiftably suspend the plug in the tool, means on the plug to retain 'the second set of cutters out 4of operative position, a plunger insertable through the drill ipe and the sub, means to flow a hydraulic fiuid through the pipe, the sub, the plug to the first set of cutters, the plunger having means engaging the sub to prevent flow of such fluid, the plunger at the same time engaging the plug and releasing the suspending means, the hydraulic Huid being adapted to positively force the second set of cutters into operative position should said cutters stick to engage the bottom of the hole made by the first set of cutters.

`8. A drilling appliance comprising in combination a string of drill pipe., a tubular drill tool having slushing ducts therein, a

`first set of cutters rigidly connected to the tool, a second set of cutters shiftably mounted in the tool, means to How a slushing iuid through an upper set of ducts in the drilling tool to the first set of cutters, means to bring the second set of cutters into operative position to engage. the bottom of thc hole made by the first set of cutters, means to cut ofi' the flow from the upper ducts and means to flow the fluid from a lower set of ducts to the second set of cutters, said means preventing fiow of the fluid through one set of ducts when the other set of ducts is in operation.

9. A drilling appliance comprising in combination a string of drill pipe, a sub, a drilling tool having a first set of cutters rigidly connected thereto cutters shiftably mounted in said tool, a plug in the tool having retaining means to hold the second set of cutters out of operative position, a plunger insertable through the drill pipes and the sub to engage the plug and by movement of the plug bring the second set of cutters into operative position, and means on the plunger engaging the sub to prevent upward shifting of the plunger and plug.

and a second set of' l0. A drilling apparatus comprising a drilling tool having a first set of cutters and second set of cutters, means to shift the second set of cutters downwardly and outwardly into drilling position after dulling of the first set of cutters, said drilling position of the second set of cutters engaging said cutters with the bottom and the side of the hole made by the first set of cutters, and means to operate said second set of cutters without enlarging the diameter of the hole made by the first set, the said shifting means for the cutters being operable without withdrawing the drilling tool from a well.

11. A drilling appliance comprising in combination a rotary drilling tool having a first set of cutters rigidly connected thereto, aV second set of cutters shiftably mounted on the tool, means actuated by a slu'shing fluid to shift the second set of cutters downwardly and outwardly into operative drilling position after dulling of -the first set, said second set of cutters when in the drilling position engaging the bottom and sides of the hole made by the first set without enlarging the diameter of said hole, and said means being operative without withdrawing the tool from a well. l

12. A drilling appliance as claimed in claim 11, a connection for flow of the slushing fluid from the drill -tool to the said cutters, the flow to the first set of cutters being shut off when the flow to the second set is established.

13. A drilling apparatus comprising a drilling tool having a first set of cutters, a second set of cutters, means t0 positively non-shiftably suspend the second set of cutters in inoperative position, means to force said second set of cutters downwardly and outwardly to operate on the bottom and contact the sides of the hole on dulling of the' first set and without removal of the first set from the tool or from the well, and means to positively retain the second set of cutters in operative position, the second set of cutters having bottom cutting edges to cut on the bottom of the hole within a circle cut by the first set of cutters.

los

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2754089 *Feb 8, 1954Jul 10, 1956Rotary Oil Tool CompanyRotary expansible drill bits
US5758725 *May 6, 1996Jun 2, 1998Streetman; FoyMethod and device for enhancing oil and gas flow in a well
US6131675 *Sep 8, 1998Oct 17, 2000Baker Hughes IncorporatedCombination mill and drill bit
US6142250 *Apr 24, 1998Nov 7, 2000Camco International (Uk) LimitedRotary drill bit having moveable formation-engaging members
EP0874128A2 *Apr 22, 1998Oct 28, 1998Camco International (UK) LimitedRotary drill bit having movable formation-engaging members
Classifications
U.S. Classification175/268, 175/271, 175/317, 175/379, 175/288, 175/287, 175/421
International ClassificationE21B10/32, E21B10/62, E21B10/00, E21B10/26
Cooperative ClassificationE21B10/322, E21B10/62
European ClassificationE21B10/32B, E21B10/62