US3352593A

US3352593A - Well bore packer, milling and removing tool

Info

Publication number: US3352593A
Application number: US501287A
Authority: US
Inventors: Derrel D Webb
Original assignee: Houston Engineers Inc
Current assignee: Houston Engineers Inc
Priority date: 1965-10-22
Filing date: 1965-10-22
Publication date: 1967-11-14
Anticipated expiration: 1984-11-14

Description

Nov. 14, 1967 D. D. WEDD 3,352,593

WELL BORE PACKER, MILLING AND REMOVING TOOL Filed Oct. 22, 1965 2 Sheets-Sheet 1 wg? Ns INVENTOR.

Nov. 14, 1967 D. D. WEBB WELL BORE .PACKER, MILLING AND REMOVING TOOL Filed oct. 965

2 Sheets-Sheet 2 Danna. D. WEBB IN VENTOR.

Mfmm

United States Patent O 3,352,593 WELL BGRE PACKER, MILLING AND REMOVING TODL Derrel D. Webb, Houston, Tex., assignor to Houston Engineers, Inc., Houston, Tex., a corporation of Texas Filed Oct. 22, 1965, Ser. No. 501,287 7 Claims. (Cl. 294-8625) This invention is an improvement over that described and claimed in Patent 2,904,114 to D. D. Webb et al., issued Sept. 15, 1959, and the invention relates to well equipment and more particularly to a tool for milling away a packer holding means and packing member and thereafter removing the remainder of the packer from the bore of a well.

In the operation of wells such as those producing oil and gas, it has become relatively common practice to install packers in the bores of the wells in order to divide the same into two or more zones or sections, and such packers are normally installed in a substantially permanent manner in that no means is provided for permitting release of the packer and removal of the same to the surface. Conventional packers of the type here under consideration normally utilize a plurality of upper and lower tapered slips which operate to engage the inner wall of a well casing to securely hold the packer in place therein against a relatively high pressure and in addition the packer is provided with a yieldable packing member which is expanded into engagement with the inner wall of the well casing to prevent ow of iluid by the packer. Normally, the packer is installed in the well by use of a special tool which permits placing the packer in the desired location and thereafter expanding the slips as well as the packing member into engagement with the inner wall of the well casing to `securely fix the packer in place, after which the installing tool is withdrawn. Thereafter the packer remains in place permanently or until such time as it is necessary to remove the same which removal may become necessary for a variety of reasons which are not here important.

Heretofore, in the removal of packers from a well bore it has been common practice to simply lower a conventional rock drill bit on the lower end of a drill string and to drill or grind out the entire packer. This results in the chips or other material resulting from the drilling operation falling down the well to the top of a lower packer or to the 'bottom of the well which may result in plugging the bore and in the event there is a lower packer in the well these chips Vand other material further complicate removal of the lower packer. This method of removing packers is a slow and tedious job and also necessitates removing the chips and other material falling into the well as the result of the drilling operation before removal operations on a lower packer can be commenced. Since wells in which packers have been installed are normally relatively deep the use of fishing or other tools to recover chips or other parts which may have fallen into the well and become lodged in a lower packer requires considerable time since one or more trips of the fishing tool into the well are necessary and such trips require considerable time where the well is relatively deep.

While the packer removing tool disclosed and claimed in the above identified patent has been relatively successful in use, nevertheless, this tool does not provide for the interchangeability of dierent types of milling tools to accommodate the device to different conditions and furthermore the removing means which engages the portion of the packer remaining after the milling operation -cannot be engaged with the packer and thereafter released and reengaged. Since this latter operation is sometimes Patented Nov. 14, 1967 ICC very desirable, a packer removing tool such as that of the instant invention provides a definite step forward in the art.

It is accordingly an object of the invention to provide a tool for milling away the packer holding means and packing member to release the packer and furthermore incorporating means for engaging the remainder of the packer and removing the same from a well and in which all of the operations can be conveniently performed and controlled from the surface.

A further object of the invention is the provision of a tool for milling away a portion of a well bore packer and removing the same from a well which tool includes means for removing chips or other foreign material from the Well resulting from the milling operation.

A still further object of the invention is the provision of a tool which operates to mill or cut away the retaining slips and packing element of a packer installed in a well and also including a means for recovering the unmilled or uncut portion of the packer in a single unit and in a single operation.

Another object of the invention is the provision of a tool for removing well bore packers including means to cut a central hole entirely through the packer to permit engagement thereof by the packer removing mean-s forming a part of the tool whereby the packer may be removed from the well as a unit.

A further object of the invention is the provision of a tool for removing well bore packers including means for milling away a portion of the packer to release the same from the Well bore and also including means for engaging the remaining portions of the packer to remove the same from the well, such engaging mean-s being disposed a substantial distance below the packer during the milling operation in order to prevent damage to the engaging means.

A still further object of the invention is the provision of a Well packer removing tool including means for milling away a portion of the packer to release the same from the well and means for engaging the remaining portion of the packer to remove the same from the well, such engaging means being secured to the tool by a releasable locking means which permits convenient removal thereof but at the same time prevents inadvertent loss of the engaging means during the milling or recovery operation. Y

Another object of the invention is the provision of a tool for removing a well bore packer including means for milling away a portion of the packer to release the same from the -wellnbore and further including means to engage the remaining portions of the packer to remove the same from the wellsuch engaging means including means permitting selective engagement and disengagement between the engaging means and the packer and also auotmatic reengagement of the engaging means with the packer when desired.

A further object of the invention is the provision of a tool for removing a packer from the bore of a well and including means for milling away a portion of the packer to release the same from the well, such milling means being selectively interchangeable to provide dierent milling cutters for different conditions which may be encountered during well bore packer removing operations.

Further objects and advantages of the invention will be apparent from the following description taken in conjunction with the accompanying drawings wherein:

FIGURE 1 is a longitudinal sectional view showing the packer removing tool of this invention disposed in a Well with the milling device in position to commence the milling operation and with the packer engaging re- 3 moving means disposed a substantial distance below the packer;

FIGURE 2 is a longitudinal sectional view similar to FIGURE 1 but showing a different type of milling tool;

FIGURE 3, a sectional view taken substantially on the lines 3-3 of FIGURE 2, and showing the means for locking the recovery portion of the apparatus to the milling portion;

FIGURE 4, a sectional view taken substantially on the line 4-4 of FIGURE 1 and showing further details of the locking means of FIGURE 3;

FIGURE 5, a sectional view substantially on the line 5-5 of FIGURE l and showing details of the milling tool and particularly the passages for ilushing fluid;

FIGURE 6, a sectional view taken substantially on the line 6-6 of FIGURE 2 and showing the flushing fluid passages in the modied form of milling tool;

FIGURE 7, a fragmentary longitudinal sectional view showing the lower portion of the tool of this invention prior to passing downwardly through the packer to be removed;

FIGURE 8, a view similar to FIGURE 1 with the lower portion of the tool partially through the packer;

'FIGURE 9, a view similar to FIGURE 7, but with the packer removing engaging means in engagement with the packer for removal thereof;

FIGURE 10, a view similar to FIGURE 9 but showing a manner in which the packer engaging means may be released from the packer to ybe removed therefrom and subsequently reengaged therewith if desired; and

FIGURE 1l, a sectional view taken substantially on the line 11-11 of FIGURE 7.

With continued reference to the drawings there is shown in FIGURE 1 a well casing 10 in which has been installed a conventional well bore packer 11 which packer includes upper retaining slips 12 lower retaining slips 13 and a centrally located yieldable packing member 14. The

slips

12 and 13 may be serrated as shown in order to bite into and firmly engage the inner wall surface of the casing in order to hold the packer 11 in place, the upper slips 12 operating to prevent upward movement of the packer 11 and the lower slips 13 operating to prevent downward movement of the packer 11. The packing member 14 firmly engages the inner wall surface of the casing 10 in order to prevent uid ilow upwardly or downwardly in the casing 10 by the packer 11.

The packer 11 is installed in the casing by a special tool which operates to expand the

slips

12 and 13 as well as the packing member 14 into engagement with the inner wall surface of the casing 10 and normally the packer 11 is permanently installed in the well. Since` it is frequently necessary to remove a packer from a well bore, the tool of this invention has been developed to expeditiously accomplish this purpose.

With particular reference to FIGURES 1 and 2 of the drawings, the packer milling and removing tool of this invention may well comprise an elongated hollow mandrel 15 having an enlarged upper portion 16 and a reduced lower portion 17. The lower portion 17 terminates in a shoulder 18 merging into the upper portion 16 intermediate the length of the mandrel 15. Means such as screw threads 19 are provided at the upper end of the mandrel 15 to facilitate detachably connecting same to the lower end of a conventional drill string 20.

The enlarged portion 16 of the mandrel 15 is provided on the lower end thereof adjacent the shoulder 18 with screw threads 21 which serve for detachably connecting a hollow end mill 22 to the mandrel 15 with screw threads 23 on the end of mill 22 threadedly engaging the screw threads 21 on the enlarged portion 16 of the mandrel 15s As clearly shown in FIGURE 1 the end mill 22 extends downwardly around the reduced portion 17 of the mandrel 15 and suitable cutting elements 24 are provided on the lower edge of the end mill 22. The cutting elements 24 are so disposed on the lower edge of the end mill 22 as to engage and mill away the entire packer 11 including the

slips

12 and 13, the packing means 14 and also at least a portion of the lbody 25 of the packer 11. I'he specific operation of the end mill 22 in connection with the packer removing operation will be later described.

In order to provide for the circulation of uid to remove chipsand cuttings resulting from the milling operation there is provided a longitudinal passage 26 in the mandrel 15 and such passage 26 communicates with a plurality of branch passages 27 which extend outwardly through the wall of the mandrel 15 and terminate at the shoulder 1S and in this manner fluid may be delivered v into the space 28 between the end mill 22 and the lower reduced portion 17 of the mandrel 15. As shown in FIG- URE 5, the end mill 22 is provided with a plurality of longitudinal internal grooves 29 which serve to premit passage of fluid from the space 28 downwardly and around the cutting element 24 on the lower edge of the end mill 22 and in order to permit upward flow of the fluid from the cutting element 24, the end mill 22 is provided with exterior longitudinally extending grooves 30.whereby the fluid together with chips or cuttings entrained therein may flow upwardly through the grooves 30iand through the casing 10 to the surface of the well.

With particular reference to lFIGURE 2, there is shown a structure which is substantially identical with that shown in FIGURE 1 and described above with the exception of the fact that a different type of end mill is shown which is utilized for a slightly different operation during removal of the packer 11. In FIGURE 2, there is shown an end mill 31 which is attached to the upper portion 16 of the mandrel 15 by means of the screw threads 21 as in the structure previously described above and the end mill 31 extends downwardly a greater distance than the end mill 22, and furthermore the cutting elements 32 provided on the lower edge of the end mill 31 are of a character to only mill away the flange 33 on the upper end of the body 25 of the packer 11 together with the upper slips 12, the packing means 14 and the lower slips 13. This milling operation consequently leaves a portion of the body 25 to be removed by a later operation as described below. Fluid for removing chips and cuttings flows downwardly to the passage 26 in the mandrel 15 and outwardly through the passages 27 into the space 34 between the end mill 31 and the lower portion 17 of the mandrel 15. Since the inner diameter of the end mill 31 is appreciably greater than the inner diameter of the 'end mill 22 there is a greater space 34 for ow of uid downwardly and consequently it is not necessary to provide grooves in the inner surface of the end mill 31. However, as shown in FIGURE 6, longitudinal grooves 35 are provided in the exterlor surface of the end mill 31 in order to facilitate upward flow of fluid from around the cutting element 32 and upwardly through the casing 10. Y In order to position the remaining parts of the removmg tool of this invention, a suicient distance below the end mill 22, there may be provided oneV or more exten.- slon mandrels 36 detachably secured to the lower 4end of the mandrel 15 and the manner of attaching the extension mandrel 36 to the mandrel 15 in order to transmit tensile forces therebetween and also to prevent relative rotation therebetween is best shown in FIGURES 1, 3 and 4. With particular reference to these ligures the lower end of the portion 17 of the mandrel 15 may be provided with internal screw threads 37 which serve to threadedly engage screw threads 38 on the upper end ofthe extension mandrel 36. The lower end of the portion 17 of the mandrel 15 is also provided with a plurality of downwardly projecting fingers 39 separated by notches 40. A collar 41 is slidably received on splines 42 on the upper end 43 of the extension mandrel 36 and the collar 41 is provided with upwardly projecting lingers 44 separated by notches 45. As shown in FIGURE 1 with the collar 41 in uppermost position the ngers 44 on the collar 41 engage in the notches 40 on the mandrel 15 and 'the fingers 39 on the mandrel 15 engage in the notches 4S in the collar 41. Consequently, since the collar 41 is prevented from rotation with respect to the extension mandrel 36 by reason -of the splincd connection 42, relative rotation between the extension mandrel 36 and the mandrel will be prevented when the coll-ar 41 is in uppermost position. The collar 41 may be releasably locked in this position by a suitable set screw 46. When it is desired to remove the extension mandrel 36 from the mandrel 15 it is only necessary to loosen the set screw 46 to permit downward movement of the collar 41 which serves to disengage the iingers and notches on the collar 41 and the mandrel 15, and thereafter the mandrel 36 may be rotated with respect to the mandrel 15 to disengage the threaded

connection

37 and 38 therebetween.

A packer engaging and removing device 47 may be detachably secured to the lower end of the extension mandrel 36 and the means for connecting the packer engaging and removing device 47 to the extension mandrel 36 may be the same as that described above for connecting the extension mandrel 36 tothe mandrel 15.

With particular reference to FIGURES 7 to 1l, the packer engaging and removing device 47 may comprise and elongated bony 48 round in cross section and having a reduced upper section 49 and enlarged intermediate' section 5) and a still larger lower section 51, there being a shoulder 52 between the lower section 51 and the intermediate section S, and the shoulder 52 serves to provide an upwardly facing abutment. A hollow packer engaging member 53 is slidably received on the body 48 above the lower section 51 and the packer engaging member 53 is slotted as at 54 to provide resilient radially

movable jaws

55 and 56 which are normally biased toward outermost position as shown in FIGURE 7. The reduced upper section 49 of the body 48 is provided with longitudinal grooves 57 and oset recesses 5S intermediate the length of the grooves 57 but communicating therewith. Internal lugs or keys 59 are provided on the packer engaging member 53 and such lugs or keys 59 are slida-bly received in the grooves 5'7 in the reduced upper portion 49 of the body 48. The

jaws

55 and 56 may `be provided with

serations

59 and 60 thereon, and furthermore the jaws 55 yand 56 may be provided adjacent the lower ends thereof with

enlarged portions

61 and 62, the purpose of which will presently appear. A suitable cutting tool 63 may be attached to the lower end of the body 4S of the packer engaging device 47.

In operation, the tool of this invention is lowered into a well until the cutting tool 63 on the lower end engages the central portion of the packer 11 at which time the cutting tool 63 is rotated to bore a passage through the packer 11 to permit movement of the tool of this invention downwardly therethrough. At this time the packer engaging member 53 will engage the upper end of the packer 11 and move upwardly on the upper section 49 of the body 43 to the position'shown in FIGURE 7. Further downward movement will result in engagement with the lower

enlarged portion

61 and 62 of the

jaws

55 and 56 with the edges of the bore in the packer 11 resulting in squeezing the

jaws

55 and 56 inwardly to the position shown in FIGURE 8 thereby permitting downward movement of the

jaws

55 and 56 through the packer 11 to the position shown in FIGURE 9 or, if desired, to a yposition below the packer 11 lat which time the

jaws

55 and 56 due to the resilient construction thereof will be biased outwardly to outermost position.

Continued movement of the tool of this invention downwardly results in engagement of the cutting elements 24 on the lower edge of the end mill 22 with the upper end of the packer 11 and rotation of the end mill 22 will result in cutting or milling away the upper portions of the packer 11 including the upper slips 12, the packing means 14 and the lower slips 13, as well as a portion of the packer -body 25. This milling operation results in freeing the packer 11 from the casing 10 and thereafter in order to remove the remaining portions of the packer 11 from the casing 19, it is only necessary to move the device of this invention upwardly at which time the abutment provided by the shoulder 52 on the body 48 of the packer engaging device 47 will engage at the lower ends of the

jaws

55 and 56 and at the same time the intermediate enlarged section 50 will move inwardly of the

jaws

55 and 56 to prevent retraction thereof. Further upward movement will result in engaging the

jaws

55 and 56 with the lower part of the packer 11 and continued upward movement of the tool will result in withdrawing the packer 11 from the casing 10 to the surface of the well.

In the event the packer is not free and it is desired to disengage the

jaws

55 and 56 from the packer 11 and withdraw the device from the packer 11 to wash cuttings from the packer top, it is only necessary to lower the tool a suiicient distance to align the lugs or keys 59 on the packe-r engaging member 53 with the offset recesses 58 in the body 4S. At this time rotation of the tool to move the lugs or keys 59 into the offset recesses 58 and subsequent upward movement of the tool will result in Withdrawing the packer engaging member 53 from within the packe-r since at this time the packer engaging member 53 is disposed opposite the reduced upper section 49 of the body 48 and will be retained in this position by reason of the engagement of the lugs or keys 59 in the Offset recesses 5S, in which position the engaging means may -be `removed from the packer. After Washing for a time, it may be desirous to again lower the engaging means back through the packer, and the rotating cam action of the upper tapered portion of recess 58 will automatically put the slip element in the engaging position without rotation in the opposite direction.

The operation of the form of the invention shown in FIGURE 2 is identical with that described above, the only dierence bei-ng that only the upper ange 33 of the body Z5 of the packer 11 is removed together with the slips and packing member with the remainder of the body 25 being removed from the well by the packer engaging device.

It will -be obvious that by the above described invention there has been provided a relatively simple, yet highly effec-tive tool for removing packers from well bores and in which the holding means of the packer are milled or cut away to free the packer from the well casing, and at the same time the device provided for engaging and removing the remaining portions of the packer from the well may be positioned a suicient distance lbelow the packer and the milling cutter to provide for freedom of operation and prevent damage to the packer engaging means. The entire operation may be carried out and controlled from the surface of the well merely by raising or lowering the drill string and by rotating the same, and furthermore if desired, the packer engaging means may be disengaged from the packer and removed from the well if for any reason it is desired to discontinue the operation. There has furthermore been provided a convenient means for detachably connecting parts of the tool together which will serve to transmit -all necessary tensile forces and at the same time prevent relative rotation between the connected parts and by reason of the novel structure and manner of operation of the tool of this invention the same may be conveniently removed from the well if necessary during the course of the operation in order to repair or renew the end mill or the cutting elements thereon.

It will be obvious to those skilled in the art, that various changes may be made in the invention without departing from the spirit and scope thereof, and therefore the invention is not limited by that which is shown in the drawings and described in thespecication, but only as indicated in the appended claims.

What is claimed is:

1. A tool for milling and removing a well bore packer of the type having holding means and a packing member engaging the inner wall of a well casing t-o prevent flow of iiuid by the packer, said tool comprising an elongated hollow mandrel having an enlarged upper portion and a reduced lower portion, said lower portion terminating in a shoulder merging into said upper portion intermediate the length of said mandrel, means on the upper end of said mandrel for detachably connecting the same to a drill string, screw threads on said enlarged portion `adjacent said shoulder, a hollow end mill threadedly engaging said screw threads to detachably secure said mill on said mandrel with said mill extending downwardly around said reduced portions and having cutting elements on the lower edge, at least one extension mandrel detachably connected to the lower end of said reduced portion, means for preventing relative rotation between said mandrel and said extension mandrel, a packer engaging and removing device detachably secured to the lower end of said extension mandrel, means for preventing relative rotation between said device and said extension mandrel, said device comprising an elongated -body round in cross section having a reduced upper section, an enlarged intermediate section and a still larger lower section, there being Ia shoulder between said intermediate and lower sections providing an upwardly facing abutment, a hollow packer enga-ging member slidably received on said body above said lower section, said engaging member having resilient radially removable jaws biased toward outermost position, said reduced upper section having a vertical groove and an offset recess intermediate the length of said groove communicating therewith, and an internal lug on said engaging `member slidably received in said groove, whereby upon lowering said tool into a well said engaging member will engage the upper end of a packer and move upwardly on said body to a position opposite said reduced upper section, further downward movement causing said jaws to retract and permit downward movement of said device through the packer with said jaws expanding below said packer, upward movement of said tool and body serving to move said intermediate enlarged section into said engaging member to prevent retraction of said jaws and engage the same with the packer and said abut-ment engaging the lower end of said engaging member to withdraw the packer from the well after removal of said holding means and packing member by said end mill.

2. A tool as defined in claim 1 in which said mandrel is provided with outwardly and downwardly inclined passages communicating with the interior thereof and with the interior of said end mill adjacent to shoulder offset mandrel, said end mill having internal and external vertical grooves, whereby uid may flow downwardly through said mandrel, said passages and said internal grooves, aroundy the lower edge of said end mill to remove chips `and upwardly through said external grooves.

3. A tool as defined in claim 1 in which the lower cutting edge of said end mill is of a size to engage and cut away the entire packer.

4. A tool as dened in claim 1 in which the lower cutting edge of said end mill is of a size to engage and cut away only the packer holding means and packing member.

5. A tool as defined in cla'im 1 in which the means for securing said extension mandrel to said mandrel and preventing relative rotation therebetween comprises a screw kthreaded connection between said mandrel and said extension mandrel, a collar slidably and nonrotatively mounted on said extension mandrel, said mandrel and collar havin-g meeting interengaging lingers and slots, and means for releasably retaining said collar in position with said fingers and slots engaging to prevent relative rotation between said mandrel and extension mandrel, said screw threaded connection serving to transmit tensile forces from said mandrel to said extension mandrel.

6. A tool for milling and removing a well bore packer .of the type Nhaving holding means and a packing member engaging the inner wall of a' well casing to prevent ow o iiuid by the packer, said tool comprising an elongated hollow mandrel having an enlarged upper portion and a reduced lower portion, said lower portion terminating in a shoulder merging into said upper portion intermediate the length of said mandrel, means on the upper end of said mandrel for detachably connecting the same to a drill string, a hollow end mill detachably secured on said mandrel adjacent said shoulder with said mill extending downwardly around said reduced portion and having cutting elements on the lower edge, at least one extension mandrel detachably connected to the lower end of said reduced portion, a packer engaging and removing device detachably secured to the lower end of said extension mandrel, said device comprising an elongated body round in cross section having a reduced upper section, an enlarged intermediate section and a still larger lower section, there being a shoulder between said intermediate and lower sections providing an outwardly facing `abu'tment, a hollow packer engaging member slidably received on said body above said lower section, said engaging member having resilient radially movable jaws biased toward outermost position, said reduced upper section having a vertical groove and an offset recess intermediate the length of said groove communicating therewith, and an internal lug on said engaging member slidably received in said groove, whereby upon lowering said tool into a' well said engaging member will engage the upper end of a packer and move upwardly on said body and be cammed rotatably on said body to a position opposite said reduced upper section, further downward movement causing said jaws to retract and permit downward movement of said device through the packer with said jaws expanding below said packer, upward movement of said tool and body serving to move said intermediate enlarged section into said engaging member to prevent retraction of said jaws and engage the same with the packer and said abutment engaging the lower end of said engaging member to withdraw the packer from the well after removal ofsaid holding means and packing member by said end mill.

7. A tool for milling and removing a well bore packer of the type having holding means and a packing member engaging the inner wall of a well casing to prevent flow of iiuid by the packer, said tool comprising an elongated hollow mandrel having an enlarged upper portion and a reduced lower portion, said lower portion terminating in a shoulder merging into said upper portion intermediate the length of said mandrel, means on the upper end of said mandrel for detachably connecting the same to a drill string, a hollow end mill detachably secured on said mandrel adjacent said shoulder with said mill extending downwardly around said reduced portion and having cutting elements on the lower edge, at least one extension mandrel detachably connected to the lower end of said reduced portion, a packer engaging and removing device detachably secured to the lower end of said extension mandrel, said device comprising an elongated body round in cross section having a reduced upper section, an enlarged intermediate section and a still larger lower section, there being a shoulder between said intermediate and lower sections providing an outwardly facing abutment, a hollow packer engaging member slidably received on said body above said lower section, said engaging member having radially movable jaws biased toward outermost position, said reduced upper section having a vertical groove, and an internal lug on said engaging member slidably received in said groove, whereby upon lowering said tool into a well said engaging member will engage the upper end of a packer and move upwardly on said body and be cammed rotatably on said body to a position opposite said reduced upper section, further downward movement causing said jaws to retract and permit downward movement of said device through the packer with said jaws expanding below said packer, downward movement of said engaging member serving to place said intermediate enlarged section into position with said engaging member to prevent retraction of said jaws and engage the same with the packer and said abutment engaging the lower end of said engaging member to Withdraw the packer from the Well after removal of said holding means and packing member by said end mill.

References Cited UNITED STATES PATENTS 1,776,989

Miller 294-8625 X Webb et al 294-8624 X Crowe et al. 166-55 Kennard 294-8624 Clark 294-8622 Lee et al 294-8622 CHARLES E. OCONNELL, Primary Examiner.

.L 9/1930 Baimbridge eta1. 294 86.25 X 10 JAMESA EPPINKExam'n"

Claims

1. A TOOL FOR MILLING AND REMOVING A WELL BORE PACKER OF THE TYPE HAVING HOLDING MEANS AND A PACKING MEMBER ENGAGING THE INNER WALL OF A WELL CASING TO PREVENT FLOW OF FLUID BY THE PACKER, SAID TOOL COMPRISING AN ELONGATED HOLLOW MANDREL HAVING AN ENLARGED UPPER PORTION AND A REDUCED LOWER PORTION, SAID LOWER PORTION TERMINATING IN A SHOULDER MERGING INTO SAID UPPER PORTION INTERMEDIATE THE LENGTH OF SAID MANDREL, MEANS ON THE UPPER END OF SAID MANDREL FOR DETACHABLY CONNECTING THE SAME TO A DRILL STRING, A SCREW THREADS ON SAID ENLARGED PORTION ADJACENT SAID SHOULDER, A HOLLOW END MILL THREADEDLY ENGAGING SAID SCREW THREADS TO DETACHABLY SECURE SAID MILL ON SAID MANDREL WITH SAID MILL EXTENDING DOWNWARDLY AROUND SAID REDUCED PORTIONS AND HAVING CUTTING ELEMENTS ON THE LOWER EDGE, AT LEAST ONE EXTENSION MANDREL DETACHABLY CONNECTED TO THE LOWER END OF SAID REDUCED PORTION, MEANS FOR PREVENTING RELATIVE ROTATION BETWEEN SAID MANDREL AND SAID EXTENSION MANDREL, A PACKER ENGAGING AND REMOVING DEVICE DETACHABLY SECURED TO THE LOWER END OF SAID EXTENSION MANDREL, MEANS FOR PREVENTING RELATIVE ROTATION BETWEEN SAID DEVICE AND SAID EXTENSION MANDREL, SAID DEVICE COMPRISING AN ELONGATED BODY ROUND IN CROSS SECTION HAVING A REDUCED UPPER SECTION, AN ENLARGED INTERMEDIATE SECTION AND A STILL LARGER LOWER SECTION, THERE BEING A SHOULDER BETWEEN SAID INTERMEDIATE AND LOWER SECTIONS PROVIDING AN UPWARDLY FACING ABUTMENT, A HOL-