US2756968A

US2756968A - Expansible well scraper

Info

Publication number: US2756968A
Application number: US422398A
Authority: US
Inventors: Emanuel Vincent; Virgil R Douglas
Original assignee: Grant Oil Tool Co
Current assignee: Grant Oil Tool Co
Priority date: 1954-04-12
Filing date: 1954-04-12
Publication date: 1956-07-31
Anticipated expiration: 1973-07-31

Description

July 31, 1956 v. EMANUEL ETAL 2,756,968

EXPANSIBLE WELL SCRAPER Filed April 12, 1954 y?, la J7?, g, 20 236 $5 JNVENToRs. VvcE/vr EMA/vue., Vies/z. l?. DOUGLAS, By

Arroz/vay- 2,756,968' nxPANsiLE WELL SCRAPER' Vincent Emanuel, Arcadia, and Virgil R. Douglas, Lynwoo'd, Calif., assignors to Grant Oil Tool Company, Los Angeles, Calif., a corporation of California Application April 12, 1954, seriaiNo. 422,398

'1o claims. (c1. 25a-76) nited States Pat the present invention, pivotally mounted for swinging movement within radial slots in the body and actuated in their swinging movement by and in response to axial movement of a mandril in the body. s

The invention may be further characterized as relating to a form of wall scraper in which the mandril is actuated during its movement in one direction by the pressure of circulating iiuid being conducted through the body, and actuation of the cutters occurs by virtue of an essentially geared relation between the mandril and inner end portions of the cutters. Illustrations of this general type of wall scraper appear in the Johnson Patents No. 2,049,450, issued August 4, 1936, and No. 2,116,898, issued May 10, 1938. The prior practice, as exemplified by these patents, has been to position the cutters in radial axial planes of the body and mandril and to locate the interengaging cutter and mandril actuating projections or teeth in the same planes, or to offset the cutter planes from the radial axial planes of the body and mandril, with the actuatingprojections or teeth also olfset. (As herein used, the term axial radial plane, means a plane intersecting both the longitudinal center line or axis of the body and mandril, and a radial line intersecting thataxis.) Experience has shown that when positioned in such radial axial planes, little mechanical advantage is available nnless the actuating teeth are extended into the wash pipe in which case uid erosion shortens the life of the teeth. With an offset actuating tooth arrangement, the actuating teeth are extended past the axis of the body, thereby increasing the mechanical advantage, the teeth are not 'exposed to detrimental fluid erosion, and the uid is conducted past the teeth to the bottom of lthe tool where it can clean and lubricate the pilot bit. The invention has for one of its major objects to provide for mounting of the cutters in radial axial planes of the body, while positioning the actuating teeth in a rack and pinion relation at locations offset from such planes and in a manner such that the teeth may be positioned and extended laterally of the mandril at its sides without being subject to any limitations otherwise imposed by the comparatively ,y 2,756,968 Patented yJuly 31, 1956 circulation through thel body and mandril, and under coni ditions s'uchithat the lluid ypressure actuates the mandril throughoutoneof its strokes. As to this feature, the invention is'concerned with the minimizing of 4abrasive wear of the mandril as a result of the iluid ilow velocity and the. presence of Vanyl abrasive particles in the uid. In Icontemplation of minimizing. Huid abrasion ofy the mandril, the latter is/pr'ovided with a hollow fluid control head containing'apertures through which the circul'ationfluid enters in separate streams which impinge within theihead and` thereby so dissipate their energy as to Vprevent the continuance'ofvelocity effects which otherwi'se would produce'wear. "(Ivt may be mentioned that mixingheads, as such, are known from such prior art as the Grant Patent' 2,072,859, and Santiago Patent 2,284,170.) Inthevpresentgtool'the iluid leaving the control head is vconducted in a course of How straight through" the bore ofthe mandril (in distinction tok llow outside the mandril) 'so as to further minimize the ex# istance of any high velocity lor other ow conditions that might result in seriouswear of the parts as well as Vto provide iiuid circulation through to the bottom of the tool. The invention hasuv'arious radditional features and objects, all of' ,whichl will be apparent from the following detailed description ofV an illustrative embodiment of the invention showirby` the accompanyingdrawing, in which Eig. ljisa vview'y showing the tool in longitudinal sec"- tionwith the cuttersV in 'expanded position;

Fig. 2 is a fragmentaryV sectional enlargement showing oneof the cutters in contracted position; and f f Figsy and 4 areenlarged cross-sections taken respectively on` lines 3v-3and 4-4 of Fig. 1V. 4 Referring rst to'thegeneral showing of Fig. 1, the tool comprises a tubular body 10 into the upper threaded box end 11"l of which may be screwed a service or tool joint V12 for connection vwith the drill string 13. The lower end 'of the bodyvltl may be connected to or formed integrally with any'appropriate tool such as the bit 14 which may for example be a pilot bit having a diameter less than that of ar pre-existing well hole 110, the bit being usable to remove'obstructions, cave-inv material andthe like' in 'theholeL As the drawing'illustrates, ythe body is formed with a succession of counterbor'es' 15, 16, 17, and 18, the latter communicating withv passage '19 through which circulating lluid is discharged from the narrow radial spacing between the cutters and mandril. l

Further contemplated is an arrangement of, the cutter and mandril teeth such that the cutters are positively actuated by the mandril displacement throughout the envtire swinging range of the cutters, all in a manner involving the use of a pair of teeth on each cutter which are successively engageable by and between three spaced shoulders or projections on the mandril so that there is continuous and progressive driving engagement of the mandril against the cutters.

The present tool embodies certain other features and improvements having to do with the maintenance of uid drill string through ,the tool to ther bit. The body 10 contains Va tubular mandril assembly, generally indicated at 20, which may be described as comprising a body portion 21 carrying at its lower end a wash pipe 22 extending within the body bore 18. Downward displacement ofthe mandril is resisted by a coil spring 23 confined between the body shoulder 24 and the mandril headk 25.'` The latter, working in bore 15, may carry anyJ appropriate type and form of packing 26 to serve as a fluid-tight plunger against which circulating fluid introduced from the drill string into the body bore 15, operates to displace the plunger downwardly against the resistance of spring23. The function of the spring is 'to keep the cutter members 33 illustrated as blades pivotally mounted to the body 10'in the collapsed posi# tion during transport and prior to scraping. The blades are closed primaiily by positive contact with the formation when the tool is raised vertically in the hole.v -This action forces the mandril to its uppermost positiony and the spring tends tol keep it there until suicient tluid presi sure is exerted to re-open the blades. The mandrilcarries a circulation control head, gen erally indicated at 27,` which comprises a lower tubular section 28 threaded into the mandril, and an upper 'sec` tion 29, the top 30 of which is essentially hemispherical in shape andcontains a pluralityy of openings 31 through which the circulating fluid flows from the body bore in separate streams into the mandril channel 32. Entering through the openings 31, the fluid streams merge and dissipate. their velocity energy, the uid thence assuming a straight course. of flow down through the mandril bore or channel, and wash pipe 22.

The body is shown typically to carry three cutters 33 which, as shown in Figs. 3 and 4, lie in radial axial planes P of the body, with the cutting sides or edges 33a o f the cutters offset from but substantially parallel to these planes. The blades are accommodated within the radial body slots 34 and are retained by pins` 35, for radial swinging movement between the Fig. 1 and Fig. 2 positions. At their inner angularly extending end portions 33b, the cutters carry a pair of spaced lugs or teeth 36 `which are offset from the plane P and extend along and in overlaping relation with the side of the mandril. Thus we have the bodies of the cutters 33 lying directly in the planes P with relatively narrow radial spacing at 38 from the mandril, while the teeth 36 are offset to the side of the mandril where they may be given such dimensions and extents for best structural and functional purposes without any limitations that would otherwise result from confinement within the narrow clearance at 38.

The portion 136 of the mandril 20 alongside which the toothed blade ends 33b extend in overlapping relation has an essentially triangular cross sectional shape forming outer sides or ats 236 extending longitudinally of the mandril between adjacent blades. The flats 236 preferably lie parallel to and adjacent the inner faces 133 of the three blade ends. 33h respectively in order to resist relative rotation between the mandril and blades about the mandril axis. j

The planes of the mandril flats 236 are offset from and extend generally parallel to the planes P so that as the cutter blades pivot about pins 35 their inner faces 133 sweep alongside the mandril flats 236.

The triangular portion 136 of the mandril also has three sets of longitudinally spaced

projections

40, 41 and 42. preferably formed integrally with the mandril to extend outward from the at sides 236 thereof. The sets of

projections

40, 41 and 42 are formed alike in section or plan as exemplified by the showing in Fig. 3 of the three projections 40 extending outwardly respectively from the three flat mandril sides 236. Each of the. pro.-

jections

40, 41 and 42 has a vertical planar surface 13S (see upper projection in Fig. 4) received in closelyy spaced relation to a cylindrically extending surface 23.8 on an associated cutter blade 33, and has a smaller relatively angular vertical planar surface 139 in closely spaced relation to a frusto conical surface 239 on the cutter. Also, each projection has an outer vertical arcuate surface 338 engageablewith bore 17, and has an inwardly extending vertical surface 339,

Spaces

43 and 44 are formed between

projections

40 and 41 and between

projections

41 and 42 respectively for receiving the spaced teeth 36 of the cutter blades which interfit within the

spaces

43 and 44 when the teeth are engaged bythe

projections

40 and 41 on downward displacement of the mandril.

In considering the operation of the cutters, assume the parts first to be in the Fig. 2 position with the cutters fully contracted by virtue of the spring urged upward thrust of the mandril projection 42 against the lower cutter tooth 36. As fluid pressure is applied to its plunger head, the mandril is displaced downwardly, first causing the mandril projection 41 to engage the top surface of the lower cutter tooth 36 and initiate outward swinging movement of the cutter. As the mandril continues its downward movement, the upper cutter tooth 36 is swung inwardly to a position at which it is engageable by the upper mandril projection 40, enabling the latter to continue the exertion of expanding thrust against the cutter until just before the latter reaches its fully expanded condition of engagement with the body shoulder 45, as

shown in Fig. l. At the limit of the cutter movement as determined by shoulder 45, mandril projections 40 and blade teeth 36 are spaced apart a short distance at 145, to prevent vibration and wear of the mandril and associated parts as a result of vibration of the blades in use. In order to allow for such spacing of projections 40 and the blade teeth, the downward movement of the mandril is limited at the position shown in Fig. l by engagement of shoulders on the mandril and body at 125. Upon release of the fluid pressure, the spring 23 causes the mandril to swing the cutters by a reverse sequence of engagement between the mandril projections and cutter teeth, until the cutters are restored to the Fig. 2 contracted position.

We claim:

l. An improved oil well tool comprising a tubular body, a plurality of cutter blades pivotally mounted in slots in the body for radial swinging movement, a mandril movable axially within the body, said mandril having a plurality of outer flats extending between adjacent cutter blades, each of said cutter blades lying in an axial radial plane of the body and mandril and having an inner toothed end portion offset from said plane and extending alongside one of said flats, and projections on the mandril engageable with said end portions of the cutter blades to swing the cutter blades upon axial movement of the mandril.

2. An improved oil well tool comprising a tubular body, a plurality of cutter blades pivotally mounted in slots in the body for radial swinging movement, a mandril movable axially within the body, said mandril having a polygonal cross section portion forming a plurality of outer ats extending between the cutter blades, each of said cutter blades lying in an axial radial plane of the body and mandril and having an inner toothed end portion offset from said plane and extending alongside one of said flats, and projections on the polygonal cross section portion of the mandril engageable with said end portions of the cutter blades to swing the cutter blades upon axial movement .of the mandril.

3. An improved oil well tool comprising a tubular body, three cutter blades pivotally mounted in slots in the body for` radial swinging movement, a mandril movable axially within the body, said mandril having a substantially triangular cross section portion forming outer flats extending between the cutter blades, each of said cutter blades lying in an axial radial plane of the body and mandril and having an inner toothed end portion offset from said plane and extending alongside one of said flats, and projections on the substantially triangular cross section portion of the mandril engageable with said end portions of the cutter blades to swing the cutter blades upon axial movement of the mandril.

4. An improved oil well tool comprising a tubular body, a plurality of cutter blades pivotally mounted in slots in the body for radial swinging movement, a mandril movable axially within the body, said mandril having a plurality of outer ats extending between adjacent cutter blades, each of said cutter blades lying in an axial radial plane of the body and mandril and having an inner end portion offset from said plane and carrying a pair of spaced teeth adjacent the mandril and extending alongside one of said flats, and means forming on the mandril a plurality of spaced shoulders receiving said teeth between them and progressively engageable with the teeth to swing the cutter blades inwardly and outwardly of the body upon axial movement of the mandril.

5. An improved oil well tool comprising a tubular body, a plurality of cutter blades pivotally mounted in slots in the body for radial swinging movement, a mandril movable axially within the body, said mandril having a substantially triangular cross section portion forming outer ats extending between the cutter blades, each of said cutter blades lying in an axial radial plane of the body and mandril and having an inner end portion offset from said plane and carrying a pair of spaced teeth adjacent the mandril and extending alongside one of said ats, and means forming on the substantially triangular cross section portion of the mandril a plurality of spaced shoulders receiving said teeth between them and progressively engageable with the teeth to swing the cutterA blades inwardly and outwardly of the body upon axial movement of the mandril.

6. An improved oil well tool comprising a tubular body, a plurality of cutter blades pivotally mounted in slots in the body for radial swinging movement, a mandril movable axially within the body, said mandril having a plurality of cuter flats extending between adjacent cutter blades, each of said cutter blades lying inan axial radial plane ofthe body and mandril and having an inner toothed end portion odset from said plane and extending alongside one of said ats, and projections on the mandril engageable with said end portions of the cutter blades to swing the cutter blades upon axial movement of the mandril, each ot' said cutter blades having an outer cutting edge lying in the plane of its said inner toothed end portion.

7. An improved oil well tool comprising a tubular body, a plurality of cutter blades pivotally mounted in slots in the body for radial swinging movement, a mandril movable axially within the body, said mandril having a plurality of outer flats extending between adjacent cutter blades, each of said cutter blades lying in an axial radial plane of the body and mandril and having an inner end portion oiset from said plane and carrying a pair of spaced teeth adjacent the mandril and extending alongside one of said flats, and means forming on the mandril a plurality of spaced shoulders receiving said teeth between them and progressively engageable with the teeth to swing the cutter blades inwardly and outwardly of the body upon axial movement of the mandril, each of said cutter blades having an outer cutting edge lying in the plane of its said teeth.

8. An improved oil well tool comprising a tubular body, a plurality of cutter blades pivotally mounted in slots in the body for radial swinging movement, a mandril movable axially within the body, said mandril having a plurality of outer flats extending between adjacent cutter blades, each of said cutter blades lying in an axial radial plane of the body and mandril and having an inner toothed end portion offset from said plane and extending alongside one of said ats, and projections on the mandril flats engageable with said end portions of the cutter blades to swing the cutter blades upon axial movement of the mandril, and means for axially displacing the mandril in one ldirection by the pressure of fluid exertible against said means, said means allowing uid passage through an imperforate -axial bore in the mandril at the inside of said cutter blades.

9. An improved oil well tool comprising a tubular body,

` a plurality of cutter blades pivotally mounted in slots in the body for radial swinging movement, a mandril movabley axially within the body, said mandril having a pluv pressure of iluid exertible against said means, said means allowing fluid passage through an imperforate axial bore in the mandril at the inside of said cutter blades.

10. An improved oil well tool comprising a tubular body, a plurality of cutter units pivotally mounted in slots in the body for radially outward swinging movement and each swinging in essentially an axial radial plane of the body, a mandril movable axially within the body and having -a plurality of outer flats extending between adjacent cutter units, each of said cutter units having an inner toothed end portion oiset from said plane and extending alongside one of said flats, and projections on the mandril engageable with said end portions of the cutter units t0 swing the cutter units upon axial movement of the mandril.

References Cited in the le of this patent UNITED STATES PATENTS 1,478,306 Sweetman Dec. 18, 1923 1,981,262 Burt Nov. 20, 1934 2,049,450 Johnson Aug. 4, 1936 2,072,859 Grant Mar. 9, 1937 2,116,898 Johnson May 10, 1938 2,238,998 Grant Apr. 22, 1941 2,284,170 Santiago May 26, 1942

Claims

1. AN IMPROVED OIL WELL TOOL COMPRISING A TUBULAR BODY, A PLURALITY OF CUTTER BLADES PIVOTALLY MOUNTED IN SLOTS IN THE BODY FOR RADIAL SWINGING MOVEMENT, A MANDRIL MOVABLE AXIALLY WITHIN THE BODY, SAID MANDRIL HAVING A PLURALITY OF OUTER FLATS EXTENDING BETWEEN ADJACENT CUTTER BALDES, EACH OF SAID CUTTER BLADES LYING IN AN AXIAL RADIAL PLANE OF THE BODY AND MANDRIL AND HAVING AN INNER TOOTHED END PORTION OFFSET FROM SAID PLANE AND EXTENDING ALONGSIDE ONE OF SIAD FLATS, AND PROJECTIONS ON THE MANDRIL ENGAGEABLE WITH SAID END PORTIONS OF THE CUTTER BLADES TO SWING THE CUTTER BLADES UPON AXIAL MOVEMENT OF THE MANDRIL.