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Патент USA US3071201

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Jan. l, 1963
J. E. HALL, sR., ETAL
3,071,191
cLosE TQLERANCE scRATcHERs
Filed Nov. 20. 1959
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Jan. l, 1963
J. E. HALL, SR., ETAL
3,071,19Í
CLOSE TOLERANCE SCRATCI-IERS
Filed NOV. 20. 1959
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Unite States Patent Oiitice
g
3,071,191
CLÜSE TÜLERANQE SCRATCHERS
.lesse E. Hall, Sr., and Lester A. Bailey, Weatherford, Tex.,
assignors to Abasteeedora Jefe, SA., Panama, Repub
lic of Panama, a corporation of Panama
Filed Nov. Ztl, 1959, Ser. No. 854,292
2 Claims. (£1. 165-173)
This invention relates to well bore scratchers of the
circular band or collar type utilizing angularly disposed
wire abrading elements and adapted to be mounted on
the exterior of a tubular casing and reciprocated there
with in a well bore.
The invention refers more par
3,671,191
Patented Jan. 1, 1963
2
tion prevents layover of the coils on reversal of rotation
of the scratcher in the Well. Referring generally to the
art, helical springs are sometimes employed, but are al
ways inadequate because of their inherent ability to handle
both winding and unwinding action. In the unwinding
action the coil above will get larger and expand to the
adjacent coil and lose etliciency of resilient action. Since
the helical spring is in contact with the next lower wrap or
coil, the tendency is to break off the tine. Additionally,
the tightness of `the last winding (top winding or coil)
tends to permit and produce snapping oif of the tine.
Therefore, an object of the invention is to provide
a close ‘tolerance seratcher wherein a minimum of ex
ticularly to such a scratcber `designed and adapted to fit
cessive diameter extension is created when the tine lays
into relatively small diameter well bores where there is a 15 down on the collar.
minimum distance or annulus between the well bore and
Another object of the invention is to provide a close
the outer surface of the casing.
tolerance scratcher with more resilience in the tines than
This invention is an improvement over the structure
one having uniform `diameter wraps.
shown in the Hall, Sr., Patent 2,735,495, issued February
Another object of the invention is to provide `a close
21, 1956, for “Well Bore Scratcher.”
20 tolerance scratcher with an absolute minimum of engage
Salient features of novelty of the instant invention
ment required interiorly of the collar of the abrading wire
reside in »the manner of fastening the wire abrading ele
units, yet wherein a `bracing action is provided against cir
ments to the collar, the type and arrangement of coil
cumferential reversing of the wires.
springs Wound into the wire abrading elements, `and the
Another object of the invention is to provide a close
construction of the wall of the collar itself whereby to pro 25 tolerance scratcher with secure internal engagement of
tect in the most effective manner the coil springs in op
the wires yet a minimum thickness of the collar produced
eration of the scratcher and, additionally, achieve a maxi
by said engagement.
mum rigidity and strength in the collar, while providing
Yet another object of the invention is to provide a
a minimum thickness thereof.
close tolerance scratcher with equal resilience, strength and
A major problem in well conditioning preparatory to 30 reversability compared to the uniform diameter wrap or
cementing where scratchers are used is the reduction of
coil type scratcher of the Hall Patent No. 2,671,515, yet
the thickness of the scratcher collar whereby to minimize
with no coil extension beyond the `collar or coil rub-olf
the obstmction and hindrance presented to the passage of
mud or circulated well fluid in the annulus between the
potential.
Another object of the invention is, in well bore scratch
casing and Well bore. In tight holes, where such annulus 35 ers, to reduce to a minimum the thicknes of the scratcher
is narrow, a condition often referred to as “close toler
collar and the operating thickness of the entire scratcher
ance” exists and the thicknes of the scratcher collar is of
assembly by providing a coil spring structure which, while
vital importance to the success of the operation. A fac
providing the necessary and desired flexibility to the
tor critical to operation of any collar type scratcher utiliz
abrading wires, at the same time restricts within the most
ing wire abrading elements is the capability of the 40 narrow limits the height of the spring coils and their
scratcher `collar to move through the plane of engage
projection above the peripheral surface of the collar.
Another object of the invention is to provide new meth
reversal of direction of movement of the casing during
ods and means of attaching the wires to the interior of the
reciprocation without hanging or fouling of the wires in
`collar which provides a secure, long lasting, cheap, easy to
the coil springs of adjacent wires occurring. The latter
manufacture attachment, while, at the same time, minimiz
problem is particularly critical in close tolerance situa
ing the thickness of the collar.
Another object of the invention is to provide a mini
tions.
mum thickness scratcher collar construction which never
The art encompasses the scratcher of Hall, Sr., as
theless protects the coil springs from the reversing motion
exemplified in United States Patent No. 2,671,515, issued
March 9, 1954, yfor “Well Bore Cleaning Scratcher” in 50 of the abrading wires to the maximum extent in operation
of the scratcher on a reciprocating casing in the well bore.
addition to the Hall Patent No. 2,735,495, previously
Other and further objects of the invention will appear
noted. Other various efforts at close tolerance scratchers
in the course of the following description thereof.
to enable scratchers to be used in decreased diameter
In the drawings, which ‘form Ia part of the instant
holes, particular `at great depths are `also known. it should
be noted that a number of critical objections arise when 55 specification and 4are to be read in conjunction therewith,
embodiments of the invention are shown and, in the
considering the Hall scratcher of Patent No. 2,671,515 in
various views, like numerals are employed to indicate like
relation to close tolerance holes. In the first place, in a
ment of the wire ends with the well bore wall upon
parts.
uniform diameter coil spring, at least .three or four con
FIG. l is an end on, axial view of a scratcher em
volutions or wraps are required to permit the required
60 bodying a iirst preferred form of the inventive construc
up and `down travel of the free wire ends with suitable
tion.
resilience of the tines. This number of wraps requires
FIG. 2 is a side elevation, with parts cut away and
quite a thick collar to provide any protection whatso
in section to better illustrate the scratcher construction
ever. However, even with the thick coHar, when the tines
of the construction of FIG. 1.
are bent toward the collar, the wraps or coils rise up
above the surface of the collar and permit snagging of the 65
FIG. 3 is a View ta'ken along the line 3_3 of FIG. 2
coils with adjacent tines or rubbing off of the coils against
in the direction of the arrows.
the Well bore, etc. Additionally, the uniform diameter
FIG. 4 is a view taken along the line 4-«4 of FIG. 2
Wraps or :coils require a quite complex engaging struc
inthe direction of the arrows.
FIG. 5 is an enlarged perspective detail of a scratcher
ture interiorly of the collar including a U-bend in the 70
wire unit adapted to be mounted upon the inside of the
center portion thereof between coils with at least three
lances engaging the center portion. This latter construc
collar of the inventive scratcher.
3,071,191
3
4
bodying a second form of the inventive construction.
FIG. 7 is a side elevation, parts cut away and in sec
tion, of a portion of a second form of the inventive con
struction.
FIG. 8 is a View taken along the line 7-7 of FIG. 7
tially the depth of the inwardly formed rib or groove
10b. The first coil of the lesser diameter spring por
tion is substantially received within the said larger partial
coil. The second coil of the lesser diameter spring por
tion is received within the thickness of the collar it
self circumferential to the openings 10a. The third and
in the direction of the arrows.
final coil is substantially received within and matched
FIG. 6 is an end on axial view of a scratcher em
FIG. 9 is a view taken along the line 9~-9 of FIG. 7
by the thickness of the outwardly formed or dimpled
in the direction of the arrows.
portions 12. In the case of a two complete coil lesser
FIG. l0 is a fragmentary interior perspective of the 10 diameter spring, even lesser extension of the wire units
scratcher band of FIG. 6 without attachments.
relative t-o the collar is achieved and thus this form is
Referring to the drawings and particularly to the pre
ferred modification of FIGS. 1e5, inclusive, at 10` is gen
optimum.
erally designated a band or collar which serves as a
of the collar as exemplified at 10b and 10c provides an
It should be noted that the triple grooving or ridging
support for abrading wire units of FIG. 5 designated as 15 exceedingly strong and rigid, though exceedingly nar
a whole by the numeral lll. These units comprise free
row collar with full protection to each segment of the
end portions 11a, coil springs 11b for inside collar band
wire unit on each side of the central ridge. This is an
advantage not previously achieved.
attachment, coil springs 11e for outside collar attach
ment and cross-over portions llld by means of which the
It should be appreciated that the scratchers as illus
wire units are fixed to the collar, whether the units are
trated, are mounted at intervals along the length of cas
mounted within the collar or outside the collar.
FIG. 2
shows the assembled unit, with the coil springs 11b
located in aperture 10a punched in the collar.
ing or pipe and so located as to clean the bore of the
well of accumulated mud where a cement column is to
be placed. The annulus between the casing and well
The abrading wire unit construction as shown in FIG.
bore being relatively narrow, causes the free ends or
5 comprises a single enlarged partial coil or convolution 25 abrading wires lla to drag against the well wall and bend
of relatively large diameter at the bottom of the coil,
upwardly as the casing is run into the hole or during
surmounting and contained within this large partial loop
the downstroke when reciprocated.
On the upward
at least two loops or convolutions of wire of smaller
movement of the casing, since the scratchers are mount
internal diameter than the large convolutions but sub
ed upon the casing between stops, the movement of
30
stantially the same internal diameter amongst themselves.
the free ends of the wires are reversed, at which time
From the upper convolution of each of the coil springs
the scratcher collars must pass through the wires as they
extend the free ends 11a. The coils of relatively smaller
are closely wrapped about the collar due to the narrow
diameter and the free ends 11a are not inclined with
space within which they operate.
respect to the axis of any one of the lesser diameter
projections of any sort, such as the tops of the coil
If prominences or
coils, but the entire assembly is inclined with respect to 35 springs, extend beyond the outer surfaces of the scratch
the larger diameter base coils 11b as seen in FIG. 4.
ers and are not protected, the free ends of the wires are
Cross-over portions 11d extend between the larger partial
apt to hang upon these projections, thus fouling the wires
coils 11b substantially at a diametric position intermedi
upon the _springs and, in some instances, carrying them'
ate therebetween. In the construction of FIG. 2, the
from their attachment to the collar. When this occurs,
diameter of the larger partial coils 11b is greater than 40 the effectiveness of the abrading wires and scratchers is
the inside diameter of openings lila, while the outer
materially reduced. It is for this reason that, in the con
diameter of the larger partial coils 1lb is greater than
structions shown in FIGS. l~5, and in the modified struc
the inside diameter of openings 10a, while the outer
tures of FIGS. 6-10, the Wire units are attached to the
diameter of the smaller coils llc is less than the openings
collar by an inside mounting, the height of the coil
10a inside diameter. Thus the inner partial large coils 45 springs, carefully regulated and reduced to a minimum,
may lie circumferential to said openings with the smaller
and outward indentations E2 are provided. Guard mem
coils extending thereinto and therethrough.
bers l2 are provided particularly to permit the abrad-l
The collar 10 has a circumferential groove 10b in
ing ends of the wires to pass freely over the surface of
dented or formed inwardly therein preferably centrally
the collar and prevent hanging or fouling of the wires
thereof or intermediate the openings 10a, the latter paired 50 with the coils.
opposite one another at upper and lower portions of the
With the provision of the partial large convolution of
collar. Upper and lower grooves or ribs 10c are formed
FIG. 5, it has been found that three full lesser diameter
in the upper and lower edges of the collar and are of
convolutions are sufficient, although essential, in the coil
greater depth than the center groove or rib 10b. The
springs to provide the required resiliency and reversability
-outer diameter of the extreme upper and lower edges 55 of the free ends of the wires during reciprocation. This
of the collar are less than the outer diameter of the
is a marked improvement over the construction of the Hall
collar portions which are not grooved or ribbed. Sec
Patent No. 2,735,495, which projected a minimum of four
ondary grooves or openings 10d are formed, cut or
convolutions with at least one full convolution in the larger
punched in the central rib or groove 10b between open
internal coil. Even when four convolutions are employed
60
ings ltla to receive the cross-over wire portions lid. The
in the instant construction, with only the partial -convolu
edges or walls of the openings 10d are punched, pressed
tion present in the large internal construction, yet a marked
or formed inwardly over the cross-over portions after
reduced width or thickness of the wire unit is achieved.
the insertion of the latter therein to ñx the wire units to
Referring to FIGS. 6-10, inclusive, therein is shown
the collar.
a construction identical in all ways to that of FIGS. l-S,
Referring particularly to FIG. 4, raised portions or
dimples 12 are outwardly formed, attached to or other
wise provided along a portion of the periphery of open
ings 10a in a direction opposite the extension of the end
portions 11a in their normal direction of extension. The
raised portions 12 are limited in extent to the maximum
of one-quarter the circumferential distance of the open
ings 10a.
In a case of a three coil central spring as
inclusive, with the exception of the method of attachment
of the cross-over portions to tr e central ridge or groove.
Thus, identical parts in FIGS. 6-10 to FIGS. 1-5 have
been numbered the same, but primed.
Referring then to FIGS. 6-10, inclusive, and the novelty
therein, secondary grooves r3 are formed in ridge or
groove 10b’ whereby to receive cross-over portions lld’.
A circumferential band of metal is then fixed by welding
shown in the figures, the following relationships accrue.
or other means of attachment to the ridge or groove lltìb
The thickness of the partial large coils 1lb is substan 75 in such fashion as to rigidly ñx the cross-over portions
6
cross-over portion comprising a groove circumferentially
formed centrally of said collar with the wall thereof ex
tending inwardly ofthe collar, said circumferential groove
11d’ in the secondary grooves 13‘. The thickness of the
band 14 is preferably a minimum and is partially com
pensated for by the greater inward extension of ridges or
wall having a secondary groove formed therein to receive
each cross-over portion, and a circumferential metal ring
fixed interiorly of said band to said groove wall and over
grooves 10c' of collar 10’ over ridge or groove 10b’.
Band 14 also protects the cross-over portions to a greater
extent, although requiring a slightly greater total thick
ness of the collar. If the band is of sufficient width to
overlie some portion of the enlarged partial coils 11b', it
aids in rigidifying these coils against layover during re
versal of rotation of the scratcher on the pipe.
From the foregoing it will be seen that this invention
is one well adapted to attain all of the ends and objects
hereinabove set forth together with other advantages
lying said cross-over portions, and a freel end portion
projecting from each of the said respective smaller diam
eter coil springs outwardly away from the outside surface
10 of the collar.
2. In a well bore scratcher, the combination with a
circular collar band support adapted to be fitted over a
casing, said collar band support having a plurality of
which are obvious and which are inherent to the structure.
paired openings therethrough disposed circumferentially
It will be understood that certain features and sub
combinaions are of utility and may be employed without
reference to other features and subcombinations. This is
contemplated by and is within the scope of the claims.
As many possible embodiments may be made of the
invention Without departing from the scope thereof, it is 20
thereof, of a plurality of wire .abrading units attached to
the collar, said units each comprising a central straight
cross-over portion disposed against the collar and extend
ing between a pair of said openings, an enlarged partial
coil of greater than 180° and less than 360° arc wound
into the Wire at the extremities of the cross-over portion,
to be -understood that all matter herein set forth or shown
each -said enlarged partial coil disposed flat against the
in the accompanying drawings is to be interpreted as illus
collar and of greater diameter than said openings, no more
trative and not in a limiting sense.
than three lesser `diameter full coil springs Wound into
the wire at the extremity of the larger coil and of such
Having thus described our invention, We claim:
l. In a well bore scratcher, the combination with a 25 diameter as to ñt into said openings, the inner one of said
lesser diameter coils fully received within the larger diam
circular collar band support adapted to be ñtted over `a
casing, said collar band support having a plurality of
eter partial coil, said cross-over portion extending be
paired openings therethrough disposed circumferentially
tween said larger partial coils substantially at a diametric
position intermediate therebetween, the said cross-over
thereof, of a plurality of wire abrading units attached to
the collar, said units each comprising a central straight
portions and enlarged partial coils of said wire units lying
cross-over Iportion disposed against the collar and extend
ing between a pair of said openings, an enlarged partial
against the interior surface of the collar with the lesser
diameter coils positioned in the openings in said collar,
said wire units being attached to said collar by means en
gaging said cross-over portion, said means engaging said
each said enlarged partial coil disposed llat against the 35 cross-over portions comprising a circu-mferential groove
formed in said collar with the wall thereof extending in
collar and of greater diameter than said openings, no more
wardiy of the collar, said circumferential groove wall hav
than three lesser diameter >full coil springs wound into the
ing a secondary groove formed therein to receive each
wire at the extremity of the larger coil and of such diam
cross-over portion of said wire units, the portions of said
eter as to lit into said openings, the inner one of said
lesser diameter coils fully received within the larger diam 40 ygroove wall next to said secondary grooves formed over
said ‘cross-over portions in such manner `as to positively
eter partial coil, said `cross-over portion extending be
tween said larger partial coils substantially at a diametric
engage them and attach the wire units to said collar.
position intermediate therebetween, the said cross-over
References Cited in the ñle of this patent
portions and enlarged partial coils of said wire units lying
against the interior surface of the collar with the lesser
UNITED STATES PATENTS
coil of greater than 180° and less than 360° arc wound
into the wire at the extremities of the `cross-over portion,
diameter coils positioned in the openings in said collar,
said wire units being attached to said collar by means
engaging said cross-over portion, said means engaging said
2,735,495
2,808,112
Hall _________________ __ Feb. 2'1, 1956
Hall __________________ __ Oct. l, 1957
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