US1841500A - Perforator knife - Google Patents

Description

Jan. 19, 1932. D. sHULL PERFORATOR KNIFE 2 Sheets-Sheet 1 Filed Nov. 2l, 1928 mmw hu//////%//%/////% a 4 5 7 @ov HW/4 .f M 5,37 www ,5

Jan. 19, 1932.

` D. 1 SHULL PERFORATOR KNIFE Filed' Nov. 2l, A.1928 2 SheetS-Shet 2 M 5,. Y m5. F "wlw @a @sm s 1v, .4 //,II\\*W,

Patented Jan. 19, 1932 STATES' PATENT BANIEL L. SHULLOF ONG` BEACH, CALIFORNIA rnitronnroii KNIFEv l Appiieation filed November 2l, 1928. SeraiNo. 320,939.l

My invention relates to oilwell equipment and vmore particularly to casing perforators and is an improvement on my prior invention, application entitled Double casing perforator, No.256,178,-led February '23, 1928.

After A a well has been drilled, f a casing called the water string is inserted therein, and there is Vextended in this water string a l casing lrnown as the oil spring. The oil Aio string is provided with `a screen pipe which extends through the oil sands'andv the screen pipe is adapted for the purpose of straining from the inward seeping oil gravel and sand which might injure the oil pump. The screen pipe is either formed prior to the installation of the oil-'string or else the oil string is perforated at the levelof the oil sands after installation by a perforator provided for this .2 purpose. It is sometimes desirable to perforate the waterk string also,l as when the latter has been cemented off below the oil bearing strata which itis desired to drain,.and`it is inconvenient or impossible to raise the lower end of the water stringto this strata.

' It is an object of myinventionto provide a novel casing perforator adapted to perforate one or morecasings, and likewise, thecement aroundthe water string before i communication is established between the oil string andthe oil bearing strata.

Since those perforators now in use are not adapted to givethe operator a positive indication of the completion of the perforation, the operation oftentimes continues until perforations are in the form of long slits which materially weaken the casing and decreases the efficiency of the straining action.

it' is another object of my invention to pro- 1- vide a perforator of the class described which will give aV positive indication to the operator when the casings have been perforated.

in the casing perforator shown in mypapplication Serial No. 256,178, referred to heretofore, much trouble is had with the breaking of the cutter blade of the perforator. When the blade is forced into the casing to be cut,

it is moved outward'and tends to pivot around the upper gripping portion which engages the casing. Y Since the blade is iny clined upward and inward the upper face of casing.

the

f the blade engages the upper edge of the slot beingrformed. At this time thereis a down force on the blade where it engages the upper edge of the slot, tending to move the blade downward, but this downward movement' is resisted by the engagement of the gripping portion and the casing.` kEither of two actions will occur-fthe casing will be torn at the upper end of the slot being formed or thejblade will break. My experience has been` Vthat thel blade will break after a few slots have been cut. y n

, It is one of the important objects of my inventionV to provide y a casing perforator in whichY thei cutter is free to move vertically; that is, to move along the casing as the blade yis forcedthroughthe casingso that the cutter maybe moved or guided'by the blade in order that shearing strains in the blade will .1...

be eliminated.`

' A still further object of my invention is to provide a casing perforator in which the cutter engages the casing adjacent lthe place whererthe blade thereof is cutting lthe slot,

and in which friction reducing means is pro- Y vided at .the rengagement point of the cutter and the casing, so that the cutter is free to move up or down as the blade is being forced outward or moved inward relative to the A still further object `ofmy invention is to provide friction reducingmeans in the form of roller means.

it :is a further object of my` invention to provide a casing perforator with a cutting member having friction reducing'means Vso lustrated by the accompanying drawings, in which:

Fig. 1 is an enlarged vertical section of the perforator of my invention with the cutter member in retracted position.

Fig. 2 is a vertical section similar to Fig. 1, except that the cutter member is released and in cutting position.

Fig. 3 is an enlarged cross-sectional view indicated by line 3 3 of Fig. 1.

Fig. 4 is a vertical section of part of the body portion of my perforator showing the position of the cutter at the completion of the perforation.

Fig. 5 is a detailed enlarged perspective view of my perforator cutter detached from its operative mechanism.

F ig. 6 is a fragmentary view of Fig. 1, showing an alternative type of cutter with one large guide roller and showing two different positions of the cutter element.

Fig. 7 is a fragmentary sectional view showing the lock means provided on the cutter actuating device.

Referring to the drawings and particularly to Fig. 1, an outer casing or water string 10 has been inserted in a well and is cemented off at its lower end in the usual manner. The upper end of the casing 10 is provided with a casing head not illustrated, forming a tight fit between the water string 10 and an oil string 11 which is extended inside the water string. Vhen it is desired to permit oil4 to flow into the oil string 11 at a level above that at which the water string is cemented off, as at an oil stratum, a perforator 12 of my invention is attached to the lower end of a jar and lowered on a cable through the oil string 11 in the ordinary manner. The jar and weight mechanism connected therewith may be of the conventional type known in the art, comprising two interlocking links with a ram or weigh attached to the upier link.

The perforator 12 includes a body 13 cylindrical in cross-section, as illustrated in Fig. 3 with a coupling 14 at its upper end adapted to threadedly receive the lower end of a link of the jar mechanism not illustrated. T he lower end of the body 13 has a cylindrical hub 15 of lesser diameter than the body 13, and this hub is provided with external threads 16 for a purpose to be described later.

Formed diametrically in the body 13 and with its axis parallel to the axis of the perforator 12 is a cutter slot 17 having a vertical, an inclined, and an arcuate wall, as indicated by the numerals 18, 19, and 20 respectively in Figs. 1, 2, 4, and 6. At right angles to the cutter slot 17 a cam slot 21 ex tends through the body 13, this cam slot comprising a portion 22 and a portion 23 substantially parallel to the vertical wall 18 and the inclined portion 19 of the cutter slot 17.

Positioned in the cutter slot 17 a cutter element 24 non-rotatably mounted on a cutter shaft 25 slidably disposed in the cam slot 21, the cutter shaft 25 being of a length which prohibits its projection outside the body 13 at any position in the cam slot 21 for obvious reasons. The cutter element comprises a rectangular body portion 26 and a blade 27 disposed at approximately right angles to the body portion. The blade 27 is provided with a lower edge 28 and a forwardly curved cutting edge 29 forming a continuation of the edge 28. T he cutter elementen bloc is preferably forged from relatively hard metal and the body portion thereof is provided with flat sides 30 and 31 and fiat edges 32 and 33. The blade 27 is centrally disposed on the edge 3 at the lower end and thereby forms with the body 26 the shoulders 34 t the opposite sides of said blade. A flange 35 is centrally disposed on the edge 32 of the body portion 26 and forms with the said body the oppositely disposed shoulders 3G. The shoulders 36 adacent the base of the cutter body diverge inwardly towards the shoulders 34 and form a stop 37. The flange 35 extends from a point adjacent the upper end of the edge 32 of the body portion and dually tapers outwardly and increases in thickness towards the lower end of the body portion as at 38 and then in ".Jardly, the lowerA surface thereof merging into the lower edge 28 of the blade 27.

The upper end of the body portion of the cutter element 24 is bifurcated for the reception of upper and lower friction rollers 39 and 40, the upper rollers 39 being mounted on a stub shaft 41 having bearings in bosses 42 formed on the outer edge portions of the bifurcations 43 and 44, while the lower friction roller 40 is mounted below but in advance of the roller 39 on a stub shaft 45 having bearings in the bifurcations 43 and 44. Resultant of mountingl the upper roller 39 in the bosses 42, the same is projected forwardly of t-he flange 35 and upwardly from the bifurcations 43 and 44. The roller 4() projects outwardly from the bifurcated portions 43 and 44 on the edge 33 and is adapted for engagement with the inner surface of the casing 11.

rlhe cutter element 24 is so mounted on the cutter shaft 25 as to permit the flange 35 to fit within a groove 46, Figs. 3 and 4, formed in the rear wall of the cutter slot 17 and the shoulders 33 of the cutter to slide upon the eppositely disposed Ishoulders 47 formed resultant of the placement of said groove 46.

The external threads 16 of the cylindrical hub 15 are adapted to screw into internal threads of a hollow cylindrical sleeve 48 of a trip cage 49. Threadedly secured in the lower end of the sleeve 48 is an end plate 50 with a central cylindrical bore 51 through which a trip shaft 52 is adapted to slidably extend.

Retained in threaded engagement with the upper end of the trip shaft 52 as by a lock nut V cylindrical bore 56 in the body-13 of the cutjso ' lows ter 12 which communicates with the cutter slot 17, is an operatingpin 55. The operating pin 55fis provided with a hub 57 at its lower end head S at its upper end, both of which are of greater diameterthan the bore 56 so that the movement -of the l:pin in the bore is limited. l Y

Referring particularly to Figs. land 7, the trip plate 54 carries a pin 75 which projects outward into a slot 7 6 carried bythe tube 48. The upper end of the slot which is indicated by the numeral 7 7 is so located that when the pin 75 rests in the slot the trip plate 54 is'prevented form moving upward in the yLube 4 and consequently cannot move the operating pin upward. The lower end of the slot 76 is open at 78 and-below the slot is an in,- clined wall 79. When, the trip plate 54 is moved downward tothe bottom end of the slot 7 6 the pin 75 will engage the inclinedwall 79, thus causing the trip plate to rotate relative to the tube 43. This willmove the pin fromthe lower end of the slot 78 so that when the body 12 is subsequently lowered the pin 7 5 will notprevent the trip plate 54 from moving upward into the position shown in Fig. 2. in which position the operating pin 55 is elevated so as to operate the perforator cutter. e

rlhreadedly secured to the lower end of the trip shaft 52 is a cylindrical stop member slidably disposed in a cylindrical sleeve- 6'0 which is threadedly attached at its lower endto a spring-retaining shaft 61. Disposed between the cylindrical stop member 59 and the spring-retaining shaft 61 in the cylindri' cal sleeve is a coil spring 62 which acts as a shocl absorbing member fortheftrip shaft lt should be obvious that the trip shaft 52 is free to rotate relativek to the springretaining shaft 61.. Attached as by screws 63 are flat springs 64 here shown fragmen-A tary, the said springs being preferably four in number, adapted to frictionally and re- .iliently engage the inner surface of the oil string 11. f l

rlhe operation of my invention is as fol- The cutter is placed in the position shown inFig. 1 fand the apparatus with'its associated viar and weight is lowered by the cable into the oil string` llto the level at which it is i desired toperforate the casings.

lVhen the apparatus is at the level at which .it is desired to operate the cutter, the cable is subjected to an upward pull. Because of the engagement of the fiat springs 64 with the casing` 11, this causes a relative movement between the bodv 13 and the spring-retaining shaft 61 so that the spring-retaining shaft 61, the trip shaft 52, and the trip plate 54 move downwardlyrelative to the body 13. 'lJVhen the trip plate moves to the lower end of the tube 48 thepin 75 engages the inclined wall 79, causing the trip plate and shaft 52 to rotate relative to the body 12 and the tube43. This moves the pin from alignment with thev slot 76. Then the body and associated partsare then lowered the trip plate 54 is free to move upward into such a position that the operating pin 55 willbe actuated. When the operating pin 55 is actuated. by raising it the head 5S thereof engages the lower edge of the blade 27 and swings the cutter on its pivot so that theblade is moved into engagement with the casing to be perforated, as shown in As the weight is raised and dropped by the cable the cutting edge 29 of the cutter blade 27 is forced into the casing 11. Each successive blow on the perforator causes the cutter to move upward relative to the body 13 in the cam slot 21. Because of the inclined portion 23 of the cam' slot 21 this relative movement forces the cutter blade 27 further into thecasing 11. VTheroller 40 on the cutter element engages the inner surface of the casing 11 to retain the blade portion 27 in proper cutting posi-Jion. The pounding act1 on is continued until both casings and the vformation immediately adjacent are l perfo- It should be noted that because of the f rated. fact that the cutter 24 is operating through a circular swing, the cutter blade has an eX- ceptionally long throw so that any cement or non-porous formation .adjacent kto the outer casing can also be perforated.

l/Vhen the cutter blade 27 has finished the perforation, the cutter shaft 25 will be at the top of the inclined portion 23 of the cam slot 21 as illustrated in Fig. k4. At this time the body 13 and j ar and weight will drop kuntil the cutter shaft 25 reaches the top of the vertical portion 22 of the cam slot 21, thus giving the operator a positive indication of the completion of the perforation.

The perforator12 is then Vpulled upward, the cutter shaft 25 slidingl in the inclined poreoy tion 23 of the cam slot 21 and removing the f cutterblade 27 from the perforation. The frictional engagement of the flat springs 64 withthe casing 11 causes the spring-retaining shaft 61, thetrip shaft 52 and thetrip plate 54 to move downward relative to the body 13 when the whole apparatus moves upward as a unit. f

'The downward movement` of the trip plate 54 relative to the body 13 permits the operating pin 55 to assume the position shown in Fig. 1 so that'the movement of the cutter shaft 25 in the inclinedfportion 23 of the cam slot 21 may continue untilthe cutter 24 assumes the position shown in 1, in which it ofersno resistance to the-upward movement of the perforator. This upward movement of the apparatus is continued until that level is reached at whichanother perforation is made. The cutter 24 is moved into operating position in this second location by simply lowering the weight. rl`he flat springs 64e retain the trip plate 5d in the same position while the body 13 is lowered until the trip plate causes the operating pin to move the cutter 2- into cutting position. Thereafter trie operation is identical with that already described.

It will be noted that when the blade has been brought into engagement with the casing to be perforated and when the body is lowered there will be a relative vertical movement between the cutter and the body. By reason of the inclined portion of the slot the entire cutter will be moved outward from the body and the cutter will be so swung that the blade and the anti-friction means in the form of the roller l0 both engage the casing. Upon furtl er downward movement of the body 13 the inclined slot 19 operating on the pin 25 exerts a force against the cutter which tends to pivot it around the anti-friction means l0. The blade I? theref re is caused to penetrate the casing. In vies of the fact that the blade when it starts its cutting operation is inclined and is higher its inner end than at its outer end, as the blade is forced inward, the upper face of the blade the upper wall of the slot being formed and as the outward or cutting movement of the blade continues, this pressure becomes greater due to the fact that the blade is inclined. lfhen the pressure of the upper face of the blade against the upper wall of the slot being formed reaches a certain amount the entire cutter will move downward so that the blade may pass through the opening being formed without tearing the upper wall of the slot being formed, and preventing excessive shearing strains from bein@r placed on the blade. It will 'therefore be seen that the anti-friction means not only acts as a fulcruin for the cutter but in addition acts as a means which permits the critter' to move vertically anc acts as a means which permits the cutter to be guided by the blade as it passes through the slot being formed. lhen the casing is perforated, as shown in Fig. fl, the upper face of the blade 27 is in substantially a horizontal position. It has reached this horizontal position not by the lower portion or the outer portion of the upper edge when in the position shown in Fig. l moving upward to the level of the upper portion or inner portion of the upper edge but by the cutter moving bodily downward so that he blade 27 will pass through the perforations without tearing away the upper end of the perforation and without placing excessive strains on the blade which would result in a breakage. ldfhen the cutter 24 has assumed the position illustrated in Fig. e, the roller 39 engages with and rotates on the rear wall of the groove 415 and takes up the friction encountered by it with the body 13.

In the modification illustrated in Fig. 6,

the construction is the same as in the preferred form, with the exception, that a single relatively large roller 61a on the cut-ter element 62 takes the place of the two rollers 39 and 10. In this form the roller 6l functions to reduce the friction by engaging at one side the inner surface of a casing 63a and at the other side the inner wall of a groove 64;a in the cutter slot G5. In this form the cutter element 62 is likewise formed with a blade 66.

In this manner a direct long thrust is imparted to the cutter blades 27 and 66. Likewise, a resultant of the use of the rollers 39, 40 and 61a, the friction which would normally be encountered between the upper part of the cutter body and the casing wall and the perforator body, is taken up by the rollers. It is likewise obvious, that resultant of the novel construction and mounting of thc cutter element in the perforator body the shearing stress on the blade member is minimized and consequently the shearing or breaking olf of the cutter blades is prevented.

lVhile the preferred forms of embodiment of my invention above illustrated and described are fully capable of fulfilling all of the purposes primarily stated, I do not wish to be specifically limited to them, for it is to be understood that my invention may be embodied in various other forms, all coming within the scope of the claims which follow.

I claim as my invention:

1. In a casing perforator, the combination of: a body; a cutter carried by said body and movable relative to said body, said cutter having a blade adapted to penetrate a casing, and engaging means adapted to engage s casing near the place where said blade penetrates said'casing, said engaging means permitting said cutter to move along said casingl and to be guided by said blade as it moves through said casing; and operating` means whereby said cutter is operated by said body.

2. In a casing perforator, the con'ibination of: a body; a cutter carried by said body and movable relative to said body, said cutter having a blade adapted to penetrate a casing, and roller means adapted to engage said casing near the place where said blade ocuftratcs said casing, said roller means permitting., said cutter to move along said casing and to be guided by said blade as it moves through said casing; and operating means .vhereby said cutter is operated by said body.

3. In a casing perforator, the combination of a cutter having a blade adapted to penctrate a casing, and fulcrum means at apted to engage said i adjacent to said blade. said fulcrum means beii p; der ned to pe mit relative movement of id cutter alon,v casing; and inechanisi or forcing said cut ter outward against said casing around f id fulcrum means., said blad-e being caixrd penetrate said casing, said fulcrum means moving along said casingV as said blade moves through said casino.

4. In a casing perforator, the combination of: acutter having a cutter body, a. blade extending at an angle to said body and a fulcruin means on said cutter body adapted to engage said casing adjacent to said blade, said fulcruin means being designed to permit relative movement of said cutter along said casing; and mechanism for forcing said cutter outward against said casing around said fulcrum means, said blade being caused to penetrate said casing, said fiile-rum means moving along said casing as said blade moves through said casing.

5. In a casingperforator, the combination of: a cutter having a blade adapted to penetrate a casingand roller means adapted to engage said casing adjacent to said blade, said roller means being designed to permit relative movement of said cutter along said casing; and mechanism for forcing said cutter outward against said casing around said roller means, said blade being caused to penetrate said casing, said roller means moving along said casing as said blade moves through said casing.

6. In a casing perforator, the combination of: a cutter having a cutter body, a-blade extending at an angle to said body and a roller means on said cutter body adapted to engage said casing adjacent to said blade, said roller Y means being designed to permit relative movement of said cutter along said casing; and mechanism for forcing ,said cutter outward against said casing around said roller means,

said blade being caused to penetrate said Vcasing, said roller means moving along said casinfr as said blade moves through said casing;

In a casing perforator, the combination of: a shell having a cutter receiving cavity a cutter in said cavity, said cutter having a body and a blade extending therefrom; operating means connected to the lower part of said body and to said shell whereby said cutter is operated so that said blade penetrates a casing; and friction reducing means at the upper endof. said body for engagement with the bottom of said cavity.

8. As a new article of manufacture, a cutter for a casing perforator consisting of a body; a blade extending from said body at an angle thereto; and means associated with said body for reducing the friction between said body andthe casingjbeing perforated, said means tending to move said blade into cutting engagement with said casino.y y

9. As a new article of manufacture, a cutterk for a'casing perforator consisting of: a

body; a blade extending from one end of said body at an angle thereto; and means associated with said body for reducing the friction blade into cutting engagement with said casy ing. Y

Y l0. As a new article of manufacture, a cutter for a casing perforator consistingk of; a body; a blade extending from said body at a right angle thereto; and means associated with said body for reducing the friction between said body and the casing being perforated, said means tending to move said blade into cutting engagement with said casing.

11. As a new article of manufacture, a cutter for a casing perforator consisting of: a body; a blade extending from said body at an anglethereto; and a. roller associated with said body for reducing the friction between said body and the casing being perforated, said roller tending to move said blade into cutting engagement with said casing.

InA testimony whereof, I have hereunto set my hand at Los Angeles, `California, this 15th day of November, '1928.`

` DANIEL L. SHULL.

between said body and the casing being pery Y forated, said means tending to movesaid

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