US2280076A - Pipe anchor - Google Patents

Description

April 21, 1942.

G. E. MuLLlNlx PIPE ANCHOR Filed Jan. 16, 1940 2 Sheets-Sheet 1 @d Emzmx lNvEN'roR' ATTO P11512: ANCHOR Filed Jan. 16, 1940 v 2 Sheets-Sheet 2 gyn f@ RNEY ATTO ythe event the tubing and catcher start tov fall .eringof the tubing, and the slips on` the catcher responds only sluggishly to a sudden free drop of .l they iinally take hold and interrupt the free fall tions `tending to lset the slips prematurely is an :1 l inverse function of that portion of the weight M unsupported Weight-that is, the stronger the actuator spring with relation to the total weight tubing when it falls freely. In the presentinf been'balanced `in such a manner that vthe possi- `sitivity to `free fall.

Patented Apr. 21, 1942 y 3f.

UNITED sTATEs PATENT oFFiCE PIPE ANCHOR? t y n Gini E.Mullinix,` Southgate, Calif., assignor to Byron Jackson Co., corporationof Delaware Huntington Park, Calif., a Y

Application January 16, 1940, serial No. `314,057

1 Claim. (Cl.

sists of a `minimum number oi. parts necessaryyi to accomplish its intended `functiomand which is therefore simple and positive in operation and economical to construct.

A further object is toprovide a device of the above type which is insensitive to minor forces, tending toset`the slips prematurely, but which automatically gripsrthe casing without delay in freely.` While a string oftubing is beinglowered into the well, it frequently` occurs that thea, tubing catcher is actuated byupwardsurges r,of gas through the well liquid,\or by toorapid` lowengage the casing and anchor the tubing prematurely. `On. the Aother hand, lf the catcher is con-r l `structed `sothat it isunail'ected by the above conditions tending to set itprematurely, it usually the tubing. in which case the tubing acquires sufiicient momentum to cause the slips on n the;` catcher to seriously damage the casing when of thetubing. 4 4 l l The sensitivity of a tubingcatcher to condiof the slips which is unsupported by the actuator springi. e., the greater the unsupported weight, the less `sensitive the device is to premature setlo ting. On the other hand, the sensitivity ofthe 1 device tofree fall ofthe tubingis a direct function of the ratio of spring-supported weight to of the slips,` the more nearly instantaneous willi; be theresponse` to gravity` acceleration of the stance "these mutually antagonistic factors have bility of inadvertent setting of the slips is re'. duced to a minimum, but without sacrificing sen- A still further object of the invention is to provide a `construction wherein the `minimum t around and through l retracted position;

l the slips inoperative manually set by the` i sleeve; and

casing-gripping total cross-sectional area of the iiuid passagesw).

`the tubing catcher is'great- `@ly increased over that of` prior tubing catchers. Anv increase `in `fluid passage varea serves a twofold purposeit facilitates the lowering of the tubing string and `catcher into the well by reducing the possibility. of premature setting of the slips by surges of gas,` and it lowers the frictional resistance `to flow of well fluid during pumping Y and thereby reduces the pumping head.

A stillfurther object is toprovide a simplied yand `irrnrove'd anchor mechanism for manually setting the slips toanchor` thetubing in the well at any desired `elevation therein.

Otherobjects and advantagesof the invention will .be apparent from the following detailed de, scription of a preferred embodiment, takenin conjunction with `.the accompanying drawings wherein:

Figi is a viewin 'side elevation, showing me' device being lowered into la well with the slipsv in Fig. 2 is a sideelevation` taken at right angles to Fig. 1; t

Figs; 3, 4 and 54 are cross-sectional views taken substantially on lines`3-3, 44and 5 5, respectivelyof `Fig.1; l

Fig. 6 is `a view similar to Fig. 1 but showing anchor mechanism; cross-sectional views taken 1-11 and 8 8, respectively.

Figs. `7 and 8` are substantially on lines Fig..9is a central longitudinal sectional View of theanchor cage; f l Fig. 10 is a View inside `elevation of the anchor ig. 11, isa development ofthe outer surface of the anchor sleeve. Y

Referringto the drawings, it will be observed that the tubing catcher comprises generally a `plurality of. pipe-gripping slips A and A movably mounted on a mandrel head B which is rigidly secured to a nipple`C`a slip actuator D slid- I, ably mounted on `the ,nipple CK and connected with the ,upper `endshof` the` slips, and anchor mechanism E mountedonthe nipple belowthe slips and having V means frictionally contacting the well casingF. This general arrangement `of the essential elements of` the catcher is similar "to that shown` in U.` S. Letters Patent No. 1,921,547 issued` August `8, 1933,'to N. K. Smith and R. K. Hertel."` i

In the aforementioned `patent there are three slips, equallyl spaced circumferentially-about the body of ,thel tubing catcher,

`position afterhaving been faces 21 and 28 with the shoulders 25 and and, as will be more fully explained hereinafter,

distribution of pressure applied to the casing. In some instances four slips are employed. In the instant case, however, only two slips are provided, and are mounted for movement upwardly and radially outwardly in diametrically opposite directions.- Referring to Figs. 2 and 3, it will be observed that the outer surface of the slip A has two circumferentially spaced series of downwardly directed serrations I and II, longitudinally extending groove I2. In a similar manner, slip A' is provided with serrations I9' and II' separated by a groove I2. Each slip thus constitutes in effect two separate slips, and the two slips A and A' provide 4 spaced pipegripping portions simulating the gripping action of a four-slip catcher.

The slips are adapted to be moved .upwardly and `outwardly into engagement with the well casing F, and to this end each slip is provided with stepped tapered wed'ging surfaces I5 and I6 formed on the lateral edges thereof. These surfaces are adapted to engage corresponding wedging surfaces I1 and I8, respectively, on the head B. As shown, most clearly in Fig. 6, the head B comprises upper and lower .downwardly converging wedge portions I9 and 20, secured to the nipple C as bywelding at 2I, 22, and 23. The lower wedge portion 20 terminatesat its upper extremity in a pair of shoulders 25 and 26 converging downwardly and inwardly at a relatively flat angle, and forming kseats adapted to be engaged respectively by the downwardly facing seating surfaces 21 and 28at the lower extremities of the WedgesurfacesflS on the' slips. When the slips are retracted into the `position shown in Fig. l, they yare supported against further downward movement by the engagement of the seating surthe downward and inward taper of the shoulders 25 and 26 assists in maintaining the slips retracted from the Wallof the casing. v

Formed integral with and extending upwardly from each slip is a suspension rein 3l, on the upper .extremity of which is a pair of laterally extending. lugs 32 (Fig. 2) forming a T-head engaging a T-slot'33 in thevside wall of the actuator D. An upwardly and inwardly beveled projection 34 extends upwardly from the T-head in telescopic relation to a similarly beveled inner wall 'portion 35 on the actuator to limit the Voutward movement of the rein and hence of the slip. As is customary in tubing catchers of this generaltype, the actuator D ismounted on a coil compressionspring 31 of a strengthsuflicient to support a portion of the weight of the slips. The spring is kinterposed between a shoulder on the actuator and a collar 38 formed at the upper end `of theyhead B. Slots v39 are provided in the collar',` through which the reins 3|' extend and by which they are laterally guided.

1 The slips A4 and A are adapted to be manually actuated from the inoperative position shown in Figsgl,` 2 and V3 into the casing gripping position shown in Figs. 6, 7 and 8 by engagement of the anchor E with depending fingers or tail-pieces 42 formed integral with and extending downwardly from thersli'ps. It will be observed that one such tail-*piece depends from eachv side of each slip, and that they are tapered downwardly and inwardly at the same angle with respect to the pipe axis as they wedging faces I5, I6, I1 `and I8. As shown most clearly in Fig. 4, each pair of adjaseparated by a ,outwardly of the outer wall of the anchor sleeve 45, whereby the lower extremities of the tailpieces are disposed in the path of upward move- .ment of the upper surface 41 of an -anchor cage 48 forming part of the anchor mechanism E. When the tubing nipple C and the stationary parts of the' catcher are manipulated from the surface in a predetermined manner, to be described in detail hereinafter, the nipple C, head B, and slips A and A are moved downwardly relative to the anchor sleeve 48 until the tail-pieces 42 engage the upper surface 41 of the anchor cage. Thereafter, continued downward movement of thenipple and head B results in relative movement between the head and the slips since further ldownward movement of the slips is arrested by the anchor cage. The slips are thus constrained to move outwardly by the wedge portions I9 and 20 on the head B into the casinggripping position shown in Fig. 6.

Referring now to the details of the anchor mechanism E, it will be observed that it is in all essential respects generally similar to that shown and described in the copending application of Richard K. Herteh Serial No. 208,225, filed May 16, 1938, Patent No. 2,221,797 of Nov. 19, 1940, and particularly the embodiment shown in Figs. 12 and 13 therein. The anchor cage 48 is in the form of a cylindrical shell having a plurality of lateral openings 56 in the side wall thereof (herein three in number), as shown most clearly in Fig. 9. An anchor shoe 5I is mounted in each of the openings 50 for radial movement relative to the cage, each shoe being resiliently urged outwardly into frictional engagement with the inner wall of the Well casing F by a slightly bowed steel spring 52 having its ends received in recesses 53 in the outer wall of the cage above and below the openings 50. I

A plurality of guide lu'gs 55 are formed` on the inner wall of the anchor cage 48 adjacent the upper end thereof, and, as shown in Figs. 5 and 9, in the present instance four lugs are provided, being equi-angularly spaced about the inner periphery of the cage. The lugs 55 are adapted to be selectively received within relatively short channels 56, 56a', 56h, and 56, or to engage relatively lcng channels 51, 51a, 51h, and 51c formed in the outer wall of the anchor sleeve 45 secured to the nipple C, to selectively retain the anchor cage 48 out of operative engagement with the tailpieces 42 on the slips, or to permit the anchor sleeve to engage the tail-pieces to move the slips into gripping engagement with the well casing.

As shown most clearly in Fig. 11, which is a development of the outer surface of the anchor sleeve 45, the short channels 56, 56a, 56b and 56 valternate with the long channels 51, 51a, 51b and 51, the channels of each group being angularly lspaced apart to correspond to the spacing of the guide lugs 55 on the anchor cage 48. Two of the long channels 51 and 51b merge into the downwardly converging recesses 43 in which the tail-pieces 42 on Ithe slips are confined, while the The above-described anchor mechanism enables 1 theslips to be b'othset andreleased by rotation of the tubing in one direction, accompanied by rais- ,lng and lowering of the tubing. This is a decided advantage over prior anchor mechanisms requiring rotation of Vthetubing in one direction to set i the slips and rotation in the opposite direction to releasel them, since in the latter case there is always the danger of. unscrewing a tubing coupiing. v

the well with `the tubing catcher incorporated therein, the anchor cage 48 tends to move upwardly relative to the anchor sleeve and slips, due to the frictional engagement'of the anchor shoes "5| with the well casing resisting downward movement ofthe anchor cage. This relative upward movement of the anchor cage is prevented, however,` by engagement ofthe guide lugs 55 on the anchor cage with the short channels 56, 56a, 56h and 56 on the anchor sleeve. The cage is thus When the string of tubing being lowered into i sleeve move to the left, as viewed'in Figs.' 10 and i 11, into engagement with the'guide lugs'and thus held in the position shown in Figs. 1 and 2. It

will be observed that inthis position the upper surface 41 of the anchor cage is spaced down-` wardly from the lower ends of the slip tail-pieces 42, and the slips are supported in their lowermost position by engagement of the seating surfaces 21 and 28 on the vslips with the upwardly facing shoulders 25 and 26 on the lower wedge portion 20 of the head B.

In the event the string of tubing should part above the catcher or should be accidentally released at the surface while being run in or pulled from the well, the acceleration of the nipple C and head B due to gravity will relieve the actuator spring 31 of the weight of the slips, and the spring forces the actuator D and the slips upwardly relative to the head, causing the slips to move outwardly into gripping engagement with the casing and bringing the tubing string to rest.Y I have found that by making the slips relatively heavy and by supporting only a small proportion of their weight bythe spring 31, the possibility of inadvertent setting of the slips while running in is greatly reduced without decreasing their sensitiveness to free fall of the tubing. Itwill be understood, however, that any desired proportion of the weight of the slips may be supported by the n spring. n

When it is desired to anchor the tubing in the well at a pre-selected elevation therein, the tubing is raised slightly and rotated in a right-hand direction through a partial revolution and then lowered. During the raising operation the anchor cage 48 remains` stationary due to frictional engagement withthe casing, causing the guide lugs 55 on the cage to move downwardly in the channels56, 56a, 56b and 56. The downward move` ment of the cage .relative to the anchor sleeve is limited by engagement of inwardly projecting shoulders 6| on the cage with the upper surface of the lower tubing coupling 62, the relation between these elements being such as to position the guide lugs between the lower stop lugs 58, 58, 58b and ping surfaces on the slips afford adequate grip-A 58 on the anchorsleeve when the latter is raised.

When the tubing is rotated, the stop lugs on the 51a, 51In and 51. 'move upwardly to `enable the u-pper surface 41 of position the latter directly beneath the downwardly facing cam surfaces 63 on the ribs 64 which separate the channels 56 and51 formed on the anchorsleeve. Upon subsequent lowering of the n tubing, the guide lugs 55 move upwardly relative tothe sleeve 45 and contact the cam surfaces 63 and are guided thereby into the long channels 51,

In this position they are free to the anchor cage to engage the lower ends of the slip tail-pieces `v42 and force the slips upwardly and outwardly intogripping engagement with the well casing.

When it is desired to pull the tubing from the well, it is only necessary to raise the tubing to cause the head B to release the slips and allow them to drop back to the retracted position shown in Figs. 1 and 2. If, however, it is desired to lower Vthe tubing and reset the slips at a lower elevation in the well, itis only` necessary to first raise the tubing a slight distance and then lower it to the desired elevation `and repeat the sequence of steps described above. During the raising operation, the guide lugs 55 move downwardly-out of the channels 51, 51a, 51b and 51c andinto contact with Vtl'ie upwardly facing cam surfaces 55 on the stop lugs 58, 58a, 58b and 58. It will be observed from Fig. 9 that the guide lugs 55 are substantially diamond-shaped, and, as shown in Figs. 10 and 11, the upper extremities of the stop lugs 58 are `disposed to the left of the center of the channels 51, whereby the guide lugs 55 necessarily engage the cam surfaces 59 when they move downwardly from the channels 51. The guide lugs are thus cammed to the right and into a position directly beneath the short channels 56, 56a, 56b and 56, into which they move upon subsequent lowering of the tubing. The tubing string may then be lowered to the new setting and again anchored.

It will be observed with particular reference to Fig. 1 that so long as the tail-pieces 42 on the slips are engaged in the recess 43 the outward movement of the upper reins 3l on the slips is limited by engagement of the projections 34 with the wall 35 of the actuator D. To disassemble the slips from the head they must be raised sufficiently to disengage the tail-pieces 42 from the recesses 43, and then the lower ends of the slips are swung outwardly about the T-heads 32 on the upper reins to permit the projections 34 to clear the wall 35. When the slips are assembled, however, the

upward movement of the slips is limited by en- `by surges of gas while running the tubing into the well is greatly reduced, and the long gripfour substantially equally spaced points, thereby avoiding distortion of the casing. The advantages oi a four-slip catcher are thus embodied in a twoslip catcher with a consequent reduction in the number of parts and a substantial increase in fluid passage area.

The provision in-the slips of the center groove is particularly useful when the catcher is employed in casing of larger inside diameter than normal. Thus when an ordinary 2-slip catcher is used in casing of slightly larger diameter than that for which the catcher was designed, the slips engage the casing only at their centers so that force is applied by the catcher to the casing substantially at two diametrically opposite points. This has a marked tendency to distort the casing. On the other hand, with my construction when the catcher is used in casing of oversize internal diameter, each half of each slip will engage the casing, giving a 4-point contact instead of a 2-point contact, and the distortion effect on the casing is greatly reduced.

While I have shown and described in detail what is now considered to be a preferred embodiment of the invention, it is to be understood that this is solely for illustrative purposes, and that various changes may be made therein Without departing from the spirit of the invention or the scope of the appended claim.

I claim:

A pipe anchor comprising a body; pipe-gripping slips mounted thereon for movement relative thereto from contracted to expanded positions; slip-actuating means comprising an anchor cage slidably and rotatably mounted on said body and having an upper plane surface adapted to operatively engage said slips; friction means associated with said cage and frictionally resisting sliding and rotary movement of said cage relative to an extraneous object; and cooperating means on said body and cage for selectively either maintaining said cage out of engagement with said slips or permitting said upper plane surface on said cage to engage and actuate said slips into expanded positions, said last-named means comprising a first channel and a second channel in the outer wall of said body, said first channel opening downwardly and terminating in a shoulder at its upper end at a point below the lower extremities of said slips when the latter are in contracted position, said second channel also opening downwardly but extending upwardly a substantial distance above the upper end of said rst channel, and a guide lug projecting inwardly from said anchor cage below said upper plane surface thereon, said guide lug being selectively engageable with said first channel or said second channel by axial movement of said body and rotation thereof in a single angular direction.

GIRD E. MULLINIX.

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