Note: Descriptions are shown in the official language in which they were submitted.
2~ 347 ~
STRAIGHT BORE METAL-TO-METAL WELLBORE SEAL APPARATUS
AND METHOD OF SEALING IN A WELLBORE
BACKGROUND OF ~l~il; INVENTION
1. Fleld of the Invention:
s The present invention relates generally to metal-to-metal seals for use in
oil and gas wellbores, and spe~ifi~lly to metal-to-metal seals which are run into
the wellbore and set against wellbore sl~rf~-es
2. De3~ tion of the Prior Art:
Wellbore col--p~ion operations frequently require the make-up of a high
quality, gas-tight seals, between a wo~ ing or production string and a
wellbore tubular string, such as a casing string, which are int~nded for long
service lives. Seals which include elastomeric colllponents are subject to
e~ ual deterioration after prolonged eA~o~ule to corrosive fluids and high
len~ es. Also, when energized, elastomeric colll~?onents are likely to flow
along extrusion p~ way;~ if lln.~
Furthermore, as prior art seal devices are lowered over great ~ t~nc~s
into oil and gas wellbores, elastomeric co---~nel-ts are e A~o~d to axial forcesfrom fluids in the well, which som~times cause the removal, or "swabbing-offn,
of the elaslu---~ic co---ponent, severely i---p~;-;n~ the operation of the seal.
Metal components can be used to obt~in gas tight seals, but are generally
suited for rather pristine environment~ other than wellbores. One problem with
metal sealing co---pon~;nts is that, like elastomeric co-..~nents, metal sealingco...pollen~ will eventually become degraded after prolonged eA~osu~ to
corrosive fluids.
.~
SUMMARY OF THE INVENTION ~ ~
It is an objective of an aspect of the present invention to provide a metal-
to-metal seal for use in se. ling against a straight bore tubular mPmbP,r disposed
5 in a wellbore.
It is an objective of an aspect of the present invention to provide a
wellbore seal which combines the advantages of elastomerdc and metal-to-met. l
seals.
It is an objective of an aspect of the present invention to provide a
10 wellbore seal which in~,1udes both met.,l-to-metal and elastomedc sealing
memhPrs which operate in co--.bination to provide a high quality, gas-tight sealin a wellbore.
It is an objective of an aspect of the present invention to provide a seal
app~dlus for use in a wellpore having a sealing surface which includes a
15 plurality of ~ d~r portions which define metal se~ points which engage a
wellbore surface during a se~ing mode of operation.
It is an objective of an aspect of the present invention to provide a seal
a~)l)alalus for use in a wellbore having a se. ling surface which in~ludes a
plurality of P tPnd~Pr portions which define metal seal points which engage a
20 wellbore surface during a sealing mode of operation, said sealing app~dlus
further in~lu-~ing a layer of resilient mqte~iql disposed over the sealing surf~ce,
whe.~;n the extender portions provide a skeletal structure for the layer of
resilient m,qt.e iql to prevent swabbing-off of the layer of resilient mqtPriql
during a running mode of operat,ion.
2s These and other objectives are achieved as is now described. A seal
ap~dlus is provided for use in a sub~~ ean wellbore having a wellbore
B
WO 94/20728 213 ~ 7 G 2 PCT/US94/00181
- 3 -
tubular disposed therein such as a casing string, which is of unknown
condition. The wellbore tubular defines a wellbore surface, which may have
irregularities or defects therein such as nicks, cuts, grooves, gouged regions,
corroded regions, and eccentricities and the like. Furthermore, the wellbore
5 tubular may have an inner diameter which varies over industry-accepted
tolerance range; for example, a conventional casing tubular having a nine and
five eighths (9 5/8) inches outer diameter may have a central bore with a
diameter which is in the range of 8.379 to 8.670 inches, which represents an
industry-accepted tolerance range for this type of tubular product.
The seal includes a number of components which cooperate
together. A conveyance tubular is provided, which is positionable within the
sul ler,anean wellbore at a selected location relative to the wellbore surface.
Typically, the conveyance tubular may col"~rise a workstring or a production
15 string which may extend several thousand feet or more. A sealing ring is
provided, and disposed about at least a portion of the conveyance tubular. The
sealing ring has a first surface proximate the conveyance tubular and a second
surface which is removed in distance from the conveyance tubular. The second
surface defines a sealing surface, and it includes a plurality of portions, with20 selected ones of the plurality of portions of the sealing ring extending radially
from the conveyance tubular in at least one radial dimension. The selected
portions define at least one metal seal point for selectively and sealingly
engaging the wellbore surface.
The seal apparatus is operable in a plurality of modes, including
a running mode of operation and a sealing mode of operation. In the running
mode of operation, the sealing ring is maintained in a radially-reduced position,
out of engagement with the wellbore surface. In this mode, the conveyance
tubular may be run deep into the wellbore. In the sealing mode of operation,
the metal seal point of the sealing ring is in sealing metal-to-metal engagementwith the wellL,ore surface of unknown, and in-fact unknowable condition,
providing a fluid-tight seal at a selected location between the conveyance
tubular and the wellbore tubular. The seal ap~ar~at~of the present invention
WO 94/20728 213 4 7 6 2 PCT/US94/00181
- 4 -
further includes an ~ctu~or member, which is selectively and remotely
actu~t~hle, for urging the sealing ring between the running and sealing modes
of operation. Preferably, the actuator member is responsive to set down weight
applied to the conveyance tubular string.
In the preferred embodiment of the present invention, the inner
surface of the wellbore tubular comprises the wellbore surface against which
the seal operates, and the first surface of the sealing ring comprises an inner
surface which is proximate an outer surface of the conveyance tubular, the
10 second surface of the sealing ring comprises an outer surface which sealinglyengages the inner surface of the wellbore tubular during the sealing mode of
operation. In the present invention, the sealing ring will deform sufficiently to
provide a gas-tight seal, even though the inner surface may have irregularities
or defects thereon.
Also, in the preferred embodiment, the inner surface of the sealing
ring at least in-part defines a clearance which is between the sealing ring and
the conveyance tubular. The actu~tor member includes a wedge compo,-ent
which is driven into this cavity to selectively radially expand the sealing ring20 between the radially-reduced running mode of operation and the
radially-expanded sealing mode of operation. Preferably, the sealing ring is
radially expanded in shape by deformation through the wedging action of the
actlJ~tor member.
In the ~IJrefer~ed embodiment, the metal seal point of the sealing
ring comprises at least one circu"~fere"lial seal bead which is generally
triangular in cross-section, and which is urged to engage the wellbore surface
during the sealing mode of operation. In one embodiment of the present
invention, the metal seal points of the sealing ring are designed to be softer
than the material which con,~rises the sealing surface, and thus will deform if
sufficient force is applied to the sealing ring to expand it radially outward; in
another embodiment, the metal seal points are formed of a material which is
harder than the material which comprises the wellbore surface, and thus which
WO 94/20728 ' - i ' PCT/US94/00181
will penetrate the wellbore surface if sufficient force is applied to outwardly
radially expand the sealing ring. Also, preferably, the seal apparatus further
includes a layer of resilient malerial disposed over at least a portion of the
sealing surface of the sealing ring. The layer of resilient material has an inner
5 surface which is in engagement with the sealing surface of the sealing ring.
Selected ones of the plurality of portions of the sealing ring extend radially
outward and into the layer of resilient material, and are in gripping engagementtherewith. These radially-extended portions prevent the layer of resilient
material from swabbing-off during the running mode of operation. In the
10 preferred embodiment, the layer of resilient material includes an exterior surface
of substantially uniform radial dimension, which sealingly engages the wellbore
surface during the sealing mode of operation, in supplementation of the sealing
engagement between the metal seal point and the wellbore surface. In the
preferred embodiment, the layer of resiliel ll material further operates to prevent
15 entrapment of wellbore fluids between selected ones of the metal seal points
during the sealing mode of operation, while the seal points serve also to
prevent extrusion of the layer of resilient ",alerial.
rlereraL,ly, the portions of the sealing surface of the sealing ring
20 which define the extender memL,er~ extend into the layer of resilient i"alerial,
and provide a skeletal structure (that is, a structural framework) for the layer of
resilient " ldlerial~ to prevent swabbing-off of the layer of resilient material during
the running mode of operation. The plurality of extender members are oriented
at selected angles relative to the sealing ring to counteract directional forces25 acting on the layer of resilient material during the running mode of operation.
r,eferably, the plurality of extender members include at least one extender
member oriented generally outward and downward from the sealing surface of
~ the sealing ring to counteract upward axial forces acting on the layer of resilient
material during the running mode of operation, and at least one extender
30 member oriented generally outward and upward from the sealing surface of the
sealing ring to counteract downward axial forces acting on the layer of resilient
material during the running mode of operation.
-6- 2~347~2
As stated above, in the prcfellcd embodiment of the present invention,
the inner surface of sealing ring at least in-part defines a cavity bel~o~n the
sealing ring and the conveyance tubular, which is ~el~Pr~qlly triangular in cross-
section. The q~-tu-qtor member lç- .. in~t~s at a wedge portion which is alsogenPrqlly triangular in cross-~s~ctinn~ and which eYtPnds a ~Pl~ted dictq~ into
the cavity during the running mode of oper~q~tion, but which is urged deeper in
the cavity during the sealing mode of opPrqtion. The sealing ring is formed of as~Pl~Pct~Pd mqtPriql which yields to expand a s~lect~ ~1ist-qn~ relative to the
10 convey~ ce tubular in response to insertion of the wedge portion into the cavity.
In the prcf~led embodiment, the artn~tQr mçmbP~r includes an ~q~ctl~qtor sleeve
which circul,lr~l~,ltially en~qees the collveyance tubular, with the wedge ring
coupled to the lowermost end of the actuator sleeve, and means for applying
SPl~Pct~P~ axial force to the qçtll-qtor sleeve. A locking ",~l~qni~m is also
15 provided in the plef~lled embo limpnt which aUows only duwl~ward movement
of the actllqtor sleeve relative to the conveyance tubular to pr~ ient the met~-to-
met~l seal of the present invention from ~ dçntly ~iis~Pngqging from the sealingmode of operation.
Other aspects of this invention are as follows:
A seal app~lus for use in a s.ll)t~ll~can weUbore having a remotely-
located downhole wellbore tubular disposed therein, said wellbore tubular
~Pfinine a remotely-located downhole wellbore surface of unknown condition,
comrn~ing
a conveyance tubular po~iti~ nqhle within said s~l~ çqn wellbore on a
weUbore tubular string at a SPl~t~P~ location relative to sAid wellbore sllrf~
a sealing ring, disposed about at least a portion of said conveyance
tubular, said sealing ring having a first surface proximate said conveyance
tubular and a second surface, said second surface being a sealing surface with a
~2:
~ .
-6a- ~ ~ 3 47 ~ 2
plurality of portions, with sPl~ted ones of said plurality of portions of said
sealing ring eYten~ing radially from said conveyance tubular in at least one
radial dimencinn and defining at least one metal seal point for selective sealing
eng~ment with said wellbore surfaee;
whe~in said seal apl~alus is operable in a plurality of modes of
op~.ratinn, inclu(lir~
running mode of operation whele;il said sealing ring is ~ in~;n~ in a
radially-reduced position, out of engagement with said wellbore surface for
o coll~ance downward through said ~ubte~l~lean wellbore;
a sealing mode of operation, wherein said at least one metal seal point of
said sealing ring is in sealing metal-to-metal eng~m~nt with said wellbore
surf eP, providing a fluid-tight seal at a ~l~ted loc~tinn b~t~ said
conveyance tubular and said wellbore tubular; and
a conical wedge ring, the wedge ring being selectively and remotely
slidably insertable bel~oen the sealing ring and the conveyance tubular to
selectively cause the wedge ring to urge said sealing ring b~lw~n said running
and sealing modes of operation.
In a wellbore conl~inillg fluid therein and having a tubular member
2o ~icpo~, therein which includes a central bore which defines a wellbore surf~
the method of sealing compri.~ing:
providing a metal conveyance tubular with a cylindrical outer s~rf~e~;
providing a metal sealing ring with at least one circular metal eYtPnder
portion eYten-ling radially outward from an outer surface of said metal sealing
ring, and having a cor,loul~d inner surface;
E~
., '
-6b- 2 ~ 3 ~7 6 2
placing said metal sealing ring around said metal conveyance tubular so
that said con~uled inner surface at least in-part defines an annular cavity
around said metal conveyance tubular;
providing a metal conical wedge ring having a sloped outer surface;
placing said metal conical wedge ring around said meal conveyance
tubular and ~i~;posing at least a portion of it in said annular cavity;
lowering said metal conveyance tubular, said metal sealing ring, and said
metal conical wedge ring to a desired downhole remote location of unlmown
con-lition within said wellbore within said central bore of said tubular mPmbPr;
applying an axial load to said metal conical wedge ring to drive said
metal conical wedge ring belween said metal conveyance tubular and said metal
sealing ring and cause said metal sealing ring to deform by ex~n-ling radially
oulward to urge said at least one circular metal extender portion into sealing
metal-to-metal engagement with said wellbore surface of said tubular member;
and
whe~ein an annular region defined bel~ said conveyance tubular and
said tubular memhpr is ~l-lde~ by a gas-tight barrier which is composed
subst~nti~lly entirely of metal components.
Ad~itio~l objects, fealurGs and advantages will be al~pa~Gnt in the
written description which follows.
BRIEF DESCRIPIION OF 1~1~; DRAWINGS
The novel fealu~s believed char~teri~ti~ of the invention are set forth in
the appended claims. The invention itself, however, as well as a prefGllGd
. .
4 7 ~ ~
mode of use, further objects and advantages thereof, will best be understood by
~f~l~nce to the following det~il~ desc,iplion of an illustrative embo~im~-nt
when read in conjlm-;lion with the acco",pallying drawings, wherein:
Flgure 1 is a one-quarter iongi~u~lin~l section view of the pr~fe.,ed
c~ nt of the seal a~ s of the present invention in a running mode of
ope~ti~n~ po~d conce-l~;c~lly within a wellbore tubular;
WO 94/20728 213\ 4 7 6 ~ PCT/US94/00181
-- 7 --
Figure 2 is a one-quarter longitudinal section view of the prefer, ed
embodiment of the seal apparalus of the present invention in a sealing mode
of operation, in sealing engagement with an interior surface of a wellbore
tubular;
Figure 3a is a partial longitudinal section view of a prior art
mandrel with an elastomeric outer layer disposed thereon;
Figure 3b is a partial longitudinal section view of a prior art
10 mandrel with an elastomeric outer layer swabbing-off the mandrel in response
to axial forces applied thereto;
Figure 4 is a partial longitudinal section view of the preferred seal
apparatus of the present invention in a position intermediate that of the running
15 and sealing modes of operations;
Figure 5 is a partial longitudinal section view of the prefer~ed
embodiment of the seal apparatus of the present invention in a sealing mode
of operation;
Figure 6 is a partial longitudinal section view of an alternative
embodiment of the seal apparal.ls of the present invention in a sealing mode
of operation;
Figure 7 is a fragmentary longitudinal section view of the seal
apparatus of the present invention, depicting the actuator linkage which allows
a lra"srer of axial force in only one direction which serves to lock the seal
apparatus in the sealing mode of operation in sealing engagement with the
wellbore surface;
Figure 8 is a simplified partial longitudinal section view of the
preferred seal apparatus of the present invention depicting the geometric
configuration of the sealing surface of the sealing ring, which should be read
~, .. ,~ .
, , . ~". ., ~, .
WO 94120728 2 13 4 7 6 2 PCT/US94/00181
with reference to Tables 1 and 2 which provide actual dimensions of the
preferred embodiment;
Figures 9a, 9b, and 9c, depict wellbore tubulars which are in
5 poor conditions, and specifically depict tubulars which are (a) out-of-round,
(b) include gouges, and (c) have corrosion damage; and
Figure 10 schematically depicts the ulili~alion of the present
invention to seal a region between a conveyance tubular and a wellbore
10 tubular, which is of unknown condition.
DETAILED DESCRIPTION OF THE INVENTION
Figure 1 is a one-quarter longitudinal section view of the preferred
embodiment of the seal apparalus 11 of the present invention in a running
15 mode of operation, and disposed concentrically within wellbore tubular 13.
Conveyance tubular 17 is preferably coupled to force l,ans",illi"g sleeve 18
which is part of a tubular workstring (not depicted) which is used to lower
conveyance tubular 17 to a selected location within wellbore 25 relative to
tubular members 13. The seal apparatus 11 of the present invention may be
20 conveyed via a tubular workstring to a remote wellbore location, many
thousands of feet from the earth's surface, to a selected location within wellbore
25 relative to a tubular member 13, which has been maintained in wellbore 25
for a lengthy period of time, perhaps years, and which may be of an unknown,
and unknowable, condition. Therefore, seal apparatus 11 has great utility in
25 workover operations, wherein a wellbore is reengineered or reconditioned to
enhance production. Typically, such workover operations are directed toward
developing oil and gas production from one or more new production zones,
and/or ceasing production from a previous production zone. Since seal
apparatus 11 is intended to be conveyed many thousands of feet within a
30 wellbore, through the central bore of a wellbore tubular which is of unknown
condition, a substantial clearance must be provided to ensure that seal
apparatus 11 does not become stuck during running-in operations.
WO 94/20728 213 4 7 ~ ~ PCT/US94/00181
g
As is shown in Figure 1, seal apparatus 11 is adapted in radial
dimension for passage through central bore 27 of tubular member 13. Seal
apparatus 11 is depicted in Figure 1 in a radially-reduced running mode of
operation, during which seal apparatus 11 is out of wnld~l with wellbore
surface 15 which defines central bore 27 of tubular member 13. In the event
that seal apparatus 11 is run downward through the central bore of the casing
string, at least three-sixteenths (3/16) of an inch of radial clearance is provided
all the way around seal apparatus 11 to ensure that seal apparatus 11 does not
become stuck within the casing string. If, for other appliG~tions, seal apparatus
10 11 is intended to be run through the central bore of a production tubing string,
at least three-sixteenths (3/16) of an inch of radial clearance all the way around
seal apparatus 11 would be required in order to prevent it from becoming stuck
within the production string. In contrast, in Figure 2, seal apparatus 11 is
shown in a radially-enlarged sealing mode of operation, in which components
15 of seal apparatus 11 are in gas-tight sealing engagement with wellbore surface
15 of tubular member 13. In the present invention, seal apparatus 11 may
radially expand only a few thousandths of an inch or as great as three-
sixteenths (3/16) to fivo ei~hll ,s (5/8) of an inch. In the embodiment described
herein, such an expansion represents a five (5) to fifteen (15) percent expansion
20 of the outward diameter of the metal ring portion of seal apparatus 11.
Returning now to Figure 1, seal apparatus 11 of the preferred
embodiment of the present invention includes sealing ring 19 which is
circumferentially disposed about at least a portion of external surface 29 of
conveyance tubular 17. As is shown in Figure 1, sealing ring 19 includes
interior surface 31 and exterior surface 33, with interior surface 31 including
upper portion 35 and lower portion 37, with upper portion 35 at least in-part
~ defining an annular cavity 39 which extends circul11ferel1~ially about external
surface 29 of conveyance tubular 17 and sealing ring 19, and which is generally
triangular in cross-section. Interior surface 31 of sealing ring 19 further includes
lower portion 37 which circumferentially engages external surface 29 of
conveyance tubular 17.
WO 94/20728 21~ 4~ 6~ PCT/US94100181
- 10-
As shown in Figure 1 actuator member 21 extends downward
into annular cavity 39 and completely fills it. Actuator member 21 includes
conical wedge ring 41 force-transferring sleeve 18 and ~ctua~or linkage 43.
In the ~refer,ed embodiment wedge ring 43 and force-l,ailsrerlillg sleeve 18
5 are coupled by external threads 45 on the upper",osl end of wedge ring 41
and by internal threads 47 at the lowermost end of force-l, ans~erring sleeve 18Actuator linkage 43 further includes ratchet ring 49 and retainer ring 51.
Ratchet ring 49 is annular in shape and includes an interior surface upon which
are disposed inwardly-facing ratchet teeth 53 which are machined in the
10 "down" position. These inwardly-facing ratchet teeth 53 are adapted for
engaging outwardly-facing ratchet teeth 55 which are circu~ erenlially disposed
along a portion of external surface 29 of conveyance tubular 17 and which are
machined in the "up" position. Ratchet teeth 55 57 are adapted to allow only
downward movement of ratchet ring 51 and to oppose upward movement of
15 ratchet ring 49 relative to conveyance tubular 17.
Figure 2 is a one-quarter longitudinal section view of the preferred
embodiment of the seal apparatus 11 of the present invention in a sealing mode
of operation in sealing engagement with wellbore surface 15 of tubular member
20 13. As shown therein downward movement of force-~ransferti,lg sleeve 18 will
cause wedge ring 41 to be urged downward into annular cavity 39 which
applies a radial force to sealing ring 19 causing the material which forms
sealing ring 19 to deform by expanding radially outward and into contact with
wellbore surface 15 of tubular member 13. Downward movement of
25 force-l,ansfer,i,lg sleeve 18 also causes ratchet ring 49 to travel downward
along external surface 29 of conveyance tubular 17. As stated above the
orientation of ratchet teeth 53 55 ensure that movement of ratchet ring 49 is
limited to one direction namely downward relative to conveyance tubular 17.
Sealing ring 19 is prevented from moving downward in response
to downward dis~lLcement of force-transferring sleeve 18 by operation of
buttress member 57 which is secured in a fixed position relative to conveyance
WO 94/20728 - 2 I 3 ~ ~ 6 2 PCT/USg4/00181
tubular 17 by threaded coupling 63 and the mating of internal shoulder 59 of
buttress member 57 and external shoulder 61 of conveyance tubular 17.
The potential leakage pathway at the interface of force-transferring
sleeve 18 and conveyance tubular 17 is sealed by operation of O-ring seal 65
which is disposed in O-ring cavity 67 at external surface 29 of conveyance
tubular 17, which operates to provide a dynamic, gas-tight seal with interior
surface 69 of force-transferring sleeve 18.
As shown in Figure 2, sealing ring 19 includes a layer of resilient
material 71, which is in the preferred embodiment an elastomeric layer which
is formed upon, or bonded, by conventional means, to exterior surface 33 of
sealing ring 19.
Figures 3a and 3b are partial longitudinal section views of a prior
art mandrel with an elastomeric outer layer disposed thereon, with Figure 3b
depicting the swabbing-off of the ela~lo",eric layer from the mandrel in
response to axial forces applied thereto. Figure 3a is a simplified depiction ofa design which is common in wellbore completion equipment, in which
elastomer band 72 is bonded to an exterior surface of mandrel 73 by use of
adhesive 75 (which is not visible in either Figure 3a or 3b). During running
modes of operation, mandrel 73 will be lowered into a wellbore having fluids
disposed therein. Fluid flow within the well in combination with the pressure
di~ere"lial created by the occlusion of a portion of the wellbore by mandrel 73
will create axial force 77 which may detach elastomer band 72 from mandrel
73, resulting in "swabbing-off" of elastomer band 72. Of course, the loss or
displ~cement of elastomer band 72 could seriously impair the operation of a
wellbore tool, which, for example, may be depending upon elasloi"er band 72
to supply a sealing engagement with other wellbore components.
- 30
Seal apparatus 11 of the present invention is designed to avoid
the swabbing-off of a layer of resilient material 71, but also functions to provide
a seal which combines many of the attractive features of metal-to-metal seals
t
WO 94/20728 2 13 ~ 7 6 2 PCT/US94/00181
- 12 -
and elastomeric seals, as will be described now with referer,ce to Figures 4
and 5.
Figure 4 is a partial longitudinal section view of the preferred seal
5 apparatus 11 of the present invention in a position intermediate that of the
running and sealing modes of operations which are depicted in Figures 1 and
2. Figure 5 is a partial longitudinal section view of the ~.refer,ad embodiment
of seal apparatus 11 of the present invention in a sealing mode of operation,
in gas-tight and fluid-tight sealing engagement with wellbore surface 15 of
tubular member 13. As shown, wedge ring 41 includes inner surface 83 which
slidably engages external surface 29 of conveyance tubular 17. The potential
leak path at the interface of inner surface 83 and external surface 29 is sealedagainst leakage by operation of O-ring seal 81 which is disposed in O-ring
cavity 79, which is formed in conveyance tubular 17 at external surface 29.
Wedge ring 41 further includes outer surface 85 which slidably
engages interior surface 31 of sealing ring 19. The potential leak path at the
interface of interior surface 31 and outer surface 85 is sealed against fluid
leakage by operation of O-ring seal 87 which is disposed in O-ring cavity 89
which is formed in sealing ring 19 at interior surface 31. O-ring seal 87
provides a gas-tight and fluid-tight dynamic seal at the sliding interface of the
surfaces.
As is shown in Figure 4, inner surface 83 of wedge ring 41 is
parallel with the central longitudinal axis of conveyance tubular 17. In contrast,
outer surface 85 of wedge ring 41 is disposed at an angle from the central
longitudinal axis of conveyance tubular 17. As shown, the taper in wedge ring
41 which is defined by the inclination of outer surface 85 ensures that upper
portions of wedge ring 41 will be thicker in radial dimension than the lower
portions of wedge ring 41. In the preferred embodiment of the present
invention, wedge ring 41 includes outer surface 85 which is disposed at three
(3) degrees of inclination from the longitudinal central axis of conveyance
tubular 17.
W0 94/20728 213 ~ 7 6 2
- 13-
As is shown in Figure 4, sealing ring 19 includes raised portions 91, 93,
95, 97, 99, 101, and 103 which extend radially outward from the body portion
105 of sealing ring 19 a plurality of differing radial dimensions, and which define
a plurality of extender members which extend from body portion 105, and which
5 serve a variety of functions including: engaging in a metal-to-metal sealing
engagement with wellbore surface 15, to provide back-up resilient seals which
supplement the sealing action of the metal-to-metal seals, preventing the
entrapment of corrosive or other wellbore fluids between selected metal seal
points, and to provide a skeletal framework for a layer of resilient material 7110 which extends over most of the exterior "sealing" surface 33 of sealing ring 19
and which prevents ~'swabbing-off~ of the layer of resilient material 71 due to
axial forces applied to the layer of resilient material 71 during the running mode
of operation. As shown in Figure 4, layer of resilient material 71 defines a
substantially uniform sealing surface 107, which is generally cylindrical in shape,
which completely covers raised portions 93, 95, 97, 99, 101, and partially
covers raised portions 91, 103.
The functions of raised portions 91, 95, 97, 99, 101, 103, and the layer
of resilient material 71 can best be explained with reference to Figures 5 and
20 6 which depict, in partial longitudinal section view, two embodiments of the seal
apparatus 11 of the present invention in sealing modes of operation. The
embodiment shown in Figure 5 is the prerer~ed embodiment of the present
invention, while the embodiment shown in Figure 6 is an alternative
embodiment of the present invention. The dirrerences between these
25 embodiments is easily explained with rererence to Figures 5 and 6. As shown
in Figure 5, metal seal points 109, 111, and 113 are composed of a material
which is softer than the material which forms wellbore surface 15 of tubular
member 13; therefore, the outermost extents (that is "tips") of metal seal points
109, 111, and 113 are blunted or slightly deformed after coming into
30 engagement with wellbore surface 15 of tubular member 13. While blunted,
they still provide a zero extrusion gap and a gas-tight seal between sealing ring
19 and wellbore surface 15 of tubular member 13. In contrast, in the
embodiment of Figure 6, metal seal points 115, 117, and 119 are composed
WO 94/20728 2134 7 62 PCT/US94/00181
- 14 -
of a material which is harder than that which forms wellbore surface 15 of
tubular member 13; therefore, metal seal points 115, 117, and 119 will in fact
penetrate the material which forms wellbore surface 15 of tubular member 13,
also providing a zero extrusion gap for a gas-tight seal.
In the preferred embodiment of Figure 5, metal seal points 109,
111, 113 are formed of 1020 steel, which has a known, industry-sta,)c~afd
modulus of elasticity and Poisson ratio; while tubular member 13, in one
embodiment, may comprise a polished seal bore which is formed of 4140 steel.
In the alternative embodiment of Figure 6, metal seal points 115, 117, and 119
should be formed of a harder steel. Of course, the seal apparatus 11 of the
present invention may also function to provide a metal-to-metal sealing
engagement with conventional wellbore tubulars, such as tubing and casing
strings, which are for a particular well, of known hardness, but unknown
15 condition, and may include nicks, gouges, and corroded regions or which may
be out of round.
Returning once again to Figure 5, the cooperation of the metal
and resilient sealing components will be described in detail. This desc,i~JIion
20 is equally applicable to the embodiment of Figure 6. The principal functions of
sealing ring 19, with layer of resilient material 71 disposed thereon, include
providing a high quality, gas-tight metal-to-metal seal between sealing ring 19
and wellbore surface 15 of tubular member 13, providing a back-up resilient
seal between the layer of resilient material 71 and wellbore surface 15 of tubular
25 member 13, preventing the extrusion of portions of the layer of resilient material
71 from between selected metal seal points, and preventing the accumulation
or entrapment of corrosive or other wellbore fluids around or between selected
metal seal points.
As is shown in Figure 5, as wedge ring 41 is wedged downward
into annular cavity 39, thicker portions of wedge ring 41 are urged between
conveyance tubular 17 and sealing ring 19 (which are both stationary). Sealing
ring 19 is maintained in a fixed position relative to both conveyance tubular 17
WO 94/20728 213 ~ 7 62 PCT/US94/00181
_~ -15 -
and tubular member 13 by operation of buttress member 57. Wedge ring 41
will apply a force to sealing ring 19 which includes both axial and radial forcecomponents. Force is provided to wedge ring 41 by conventional means, such
as applying set down weight from a drilling or work-over rig to a workstring
which includes force-translating sleeve 18. Aller"alely, the axial force can
originate from conventional power charge setting tools. The axial force
component provided by wedge ring 41 serves to overcome the frictional
resistance to the insertion of wedge ring 41 into annular cavity 39. The radial
force component (which is a sine function of the axial force component, and
which depends upon the angle of inclination of outer surface 85 of wedge ring
41) serves to work against the material which comprises sealing ring 19,
causing deformation of sealing ring 19 by outwardly radially expanding sealing
ring 19 between the radially-reduced position of the running mode of operation
and the radially-expanded position of the sealing mode of operation.
In the ~reter, ed embodiment of the present invention, conveyance
tubular 17 is formed of 4140 steel, having known and industry standard
modulus of elasticity and Poisson ratio, in to the form of a cylinder having an
outer diameter of 7 inches and an inner diameter of 6.25 inches. In the
preferred embodiment, sealing ring 19 is formed of 1020 steel. (The
dimensions of the preferred sealing ring 19 of the present invention will be
described in greater detail herebelow with reference to Figure 8.) Conveyance
tubular 17 will not collapse or yield in response to radial force applied to sealing
ring 19 by operation of wedge ring 41; instead, conveyance tubular 17 will
provide a firm buttress to wedge ring 41.
Accordingly, sealing ring 19 will expand radially outward in
response to the radial component of the axial force applied thereto by operationof wedge ring 41. The operational result is that metal seal points 109, 111, and113 will be urged radially outward into engagement with wellbore surface 15 of
tubular member 13. In the prete"ed embodiment, since metal seal points 109,
111, 113 are formed of a material comparable in hardness to wellbore surface
15, they will become blunted and deformed and may in-fact extend slightly into
~, ,
WO 94/20728 213 4 7 6 2 PCT/US94/00181
- 16-
welibore surface, yet will provide a gas-tight, extrusion resislant metal-to-metal
seal with wellbore surface 15 of tubular member 13.
As sealing ring 19 and layer of resilient material 71 are urged
radially outward, wellbore fluids, including corrosive fluids, which would
otherwise have been trapped between metal seal points 109, 111, and 113, are
expelled by displacement either upward or downward relative to sealing ring 19.
The layer of resilient material 71, which in the prefer, ed
embodiment comprises an elastomeric band, will itself come into sealing
engagement with wellbore surface 15 of tubular member 13, providing a back
up seal to the seals provided by metal seal points 109, 111, and 113. The
sealing action of the layer of resilient material 71 can be quite good, providedwellbore temperatures in the vicinity of seal apparatus 11 are below 450
degrees Fahrenheit. Temperatures above 450 degrees Fahrenheit will quickly
impair the sealing function of the layer of resilient material 71, which is
preferably formed of an elastomeric material. However, thermoplastic or other
materials can be used to form the layer of resilient material 71, which have still
higher operating temperature ranges, and which are thus useful in wellbore
regions which have temperatures which exceed 450 degrees Fahrenheit.
Irrespective of the range of temperatures encountered in the
wellbore, the sealing engagement between metal seal points 109, 111, and 113
also serve to provide an extrusion barrier to portions 121, 123 of the layer of
resilient material 71 which is trapped between seal points 109, 111, 113
respectively. Thus, when wellbore temperatures are high, portions 121, 123
serve primarily as a mechanism for evacuating wellbore fluids from between
seal points 109, 111, 113; however, when temperatures encountered in the
wellbore are within the range of operating temperatures associated with the
material which comprises the layer of resilient material 71, portions 121, 123
serve as back-up elastomeric-type resilient seals, and cooperate with the
metal-to-metal seals of metal seal points 109, 111, 113 and wellbore surface 15
of tubular member 13. As shown in Figure 5, at a low temperature range, seal
wo 94/20728 2 13 i ~ 6 2
apparatus 11 of the present invention provides three metal-to-metal seals and
two resilient seals.
As explained above with regard to Figures 3a and 3b, during
5 running modes of operation, seal apparatus 11 may be run thousands of feet
into a wellbore, during which wellbore fluids create axial forces which act uponthe layer of resilient material 71, and which tend to cause the material to
swab-off. The design and orientation of raised portions 91, 93,95,97,99,101,
and 103 (of Figure 4) define a structural framework upon which the layer of
10 resilient material 71 iS formed or bonded, which deters and resists the axialforces which would otherwise urge the layer of resilient ",aLe,ial 71 to swab-off
sealing ring 19.
For example, with rererence now to Figure 4, raised portions 91,
103 provide a leading edge for sealing ring 19 which respectively shield the
layer of resilient material 71 from axial forces encountered during downward
and upward displacement within the wellbore. Raised portion 93 defines an
extender member which is oriented generally outward and upward from the
sealing surface 33 of sealing ring 19, which extends into the layer of resilient20 material 71, and counteracts or resists downward axial forces acting on the
layer of resilient material 71 during the running mode of operation. Conversely,raised portion 101 defines an extender member which is oriented generally
outward and downward from sealing surface 33 of sealing ring 19, which
extends into the layer of resilie,)t material 71, and which resists or counteracts
25 upward axial forces acting on the layer of resilient material 71.
Likewise, the raised shoulder defined by raised portion 95 extends
into the layer of resilient material 71, and is oriented generally outward and
upward from the sealing surface 33 of sealing ring 19, to resist or counlerac~
downward axial forces acting on the layer of res ';ent material 71. Conversely,
the shoulder defined by raised portion 99 extends into the layer of resilient
malerial 71 and is oriented generally outward and downward from sealing
surface 33 of sealing ring 19, and serves to resist or counteract upward axial
WO 94120728 ~ 21317 ~ 2 PCT/US94100181
- 18 -
forces acting on the layer of resilient material 17 during the running mode of
operation.
Raised portion 97 defines an extender member which is oriented
5 directly radially outward, and which is thus equally resistive to both upward and
downward axial forces, and cannot be considered a directional-specific
extender member. In this manner, raised portions 91, 93, 95, 97, 99, 101, and
103 cooperate together to minimize the opportunity for swabbing-off of the layerof resilient material 71 from sealing surface 33 of sealing ring 19.
Figure 8 is a cross-section view of sealing ring 19 of the preferred
embodiment of the present invention, and is used to provide a precise physical
descri,c lion of the various components which together comprise sealing ring 19.Physical dimensions, including distances and angles are indicated on the figure
15 by single letters for length and width dimensions, and double letters for angles.
Please note that lateral dimension lines on Figure 8 indicate diameter of the
portion, unless specifically indicated otherwise. For example, the letter "L"
indica~es the outer diameter from the outermost radial surface of raised portion103 of sealing ring 19. Other measurements, such as "I", indicate the distance
20 between the dimension lines which are provided as an overlay on the
cross-section view of sealing ring 19. Length and width dimensions are
provided in Table 1, and angle measurements are provided in Table 2.
As can be determined from Figure 8, table 1, and table 2, in the
25 preren ed embodiment of the present invention, seal ap~,aralus 11 has an outer
diameter of 8.210 inches, and an inner diameter which ranges from 7.45 inches
to 7.780 inches, and which is thus suited for conveyance into a wellbore on a
conveyance tubular which has an outer diameter of 7.45 inches or less. Of
course, Figure 8 depicts seal apparatus 11 in an undeformed condition. For
30 this particular embodiment of seal apparatus 11, outward radial deror" ,alion is
expected to be in the range of three-sixteenths (3/16) to five-sixteenths (5/16)of an inch, to close an expected clearance between the outer diameter of seal
apparatus 11 and an adjoining wellbore tubular, such as a casing string, which
WO 94/20728 21 3 4 7 6 ~ PCT/US94/00181
- 19 -
in this case, will have an outer diameter of nine and five-eights (9 5/8) inches,
and an inner diameter somewhere in the acceptable range of 8.379 inches to
8.670 inches. The wellbore tubular may have been in the wellbore for an
extended period of time, and thus exposed to corrosive wellbore fluids, high
5 temperatures, high pressures, and may have been subjected to mechanical
damage during the running in or out of other wellbore tools. Therefore, as
depicted in Figures 9a, 9b, and 9c, the wellbore tubular 13 may include
substantial defects, such as an eccentric (out-of-round) central bore, which is
depicted in Figure 9a, a gouge or nick, such as depicted in Figure 9b, or a
10 corroded surface, such as depicted in Figure 9c. In other applicalions, seal
apparatus 11 may be designed to seal against different sizes of tubular
products, including other sizes of casing. Conventional casing ranges in outer
diameter from four inches to sixteen inches. Seal apparatus 11 would be
scaled upward or downward to allow (1) a running clearance between the seal
15 apparatus 11 and the wellbore tubular of about three-sixteenths of an inch all
the way around seal apparatus 11, and (2) radial expansion of the metal ring
component of seal apparatus 11 which is at least large enough to span the
running clearance. Such expansion can be as small as a few thousandths of
an inch to as much as fifteen percent (15%) of the outer diameter of the metal
20 ring component of seal apparatus 11. r, e~erably, the metal ring component ofseal apparatus 11 will be expanded radially in an amount which is in the range
of five percent to fifteen percent (5% -15%) of the outer diameter of the metal
ring component.
This significant expansion allows for a good metal-to-metal seal,
even though the wellbore tubular may have defects on its central bore, or may
vary in inner diameter size over an acceptable tolerance range. Therefore, seal
ap,l)aral.ls 11 may operate to provide a gas-tight, metal-to-meal seal with a
wellbore tubular of (1) unknown condition and/or (2) unknown inner diameter.
The present invention allows for a high-integrity, and long-service-life seal with
tubulars of a wide range of conditions and a wide range of diameter sizes. The
condition and size OT Ule wellbore tubular need not be known or investigated;
WO 94/20728 2 1 3 ~ ~ 6 ~ PCT/US94/00181
- 20 -
this is a significant benefit since it may be impossible to know the condition or
exact inner diameter of remotely-located, permanently placed wellbore tubulars.
Figure 7 is a fragmentary longitudinal section view of a portion of
seal apparatus 11 of the present invention, depicting actuator linkage 43 which
allows a transfer of axial force in only one direction to urge the seal apparatus
11 into sealing engagement with wellbore surface 15. Actuator linkage 43 was
discussed above generally in connection with Figure 2. As shown in Figure
7, external threads 131 of the upper portion of wedge ring 41 engage internal
threads 133 of the lowermost portion of force-transferring sleeve 18. Wedge
ring 41 includes interior inclined surface 135 which engages exterior inclined
surface of ratchet ring 49. Ratchet ring 49 includes inwardly-facing ratchet
teeth 53 which engage outwardly facing ratchet teeth 55 of conveyance tubular
17, as axial force 139 is applied to force-transferring sleeve 18. Retaining ring
51 comprises, in the ~,refer,ed embodiment, a snap ring. O-ring 141 is
disposed between retainer ring 51 and ratchet ring 49 and functions as a
rubber spring to hold the retainer ring in place.
Actuator linkage 43 of the present invention operates to lock
wedge ring 41 in a fixed position relative to sealing ring 19 once the sealing
mode of operation of obtained. This ensures that the metal-to-metal seal
obtained by seal apparatus 11 of the present invention is permanently
energized and ,nainlai, led in the sealing mode of operation to prevent
accidental, or unintentional, release of the sealing engagement between sealing
ring 19 and wellbore surface 15 of tubular member 13.
The present invention may also be characterized as a method of
sealing in a wellbore having a tubular member disposed therein which defines
a wellbore surface. The method includes steps of providing a metal
30 conveyance tubular with a cylindrical outer surface, and providing a metal
sealing ring with at least one circular metal extender portion extending radially
outward from the outer surface of the metal sealing ring. The metal sealing ringshould also be provided with a contoured inner surface. The metal sealing ring
WO 94120728 213 4 7 62 ' ~ ~ ' PCTtUS94/00181
._
- 21 -
is placed around the metal conveyance tubular so that the contoured inner
surface at least in-part defines an annular cavity around the metal conveyance
tubular. A metal conical wedge ring is provided which has a sloped outer
surface. The metal conical wedge ring is placed around the metal conveyance
5 tubular and disposed at least in-part within the annular cavity between the metal
conveyance tubular and the metal sealing ring.
The metal conveyance tubular, metal sealing ring, and metal
conical wedge ring are lowered into the wellbore to a desired location within the
10 central bore of the tubular member. Then, an axial load is applied to the metal
conical wedge ring to drive it between the metal conveyance tubular and the
metal sealing ring, causing the metal sealing ring to deform by expanding
radially outward. At least one circular metal extender portion which is disposedon the outermost surface of the metal seal ring is urged into sealing
15 metal-to-metal engagement with the wellbore surface of the tubular member.
In this manner, the annular region which is defined between the
conveyance tubular and the tubular member is occluded by a gas-tight barrier
which is composed substanlially entirely of metal components. Since the
20 sealing barrier is composed of metal, preferably steel, the metal-to-metal seal
apparatus of the present invention can provide a seal which can withstand
extremely high pressure differentials, as opposed to conventional seals which
form an annular barrier which at least in-part includes subsLa,1lial elastomericcomponents.
Figure 10 is a simplified schematic view of utilization of work-over
rig 201 to create and lower production string 203 within wellbore 215. As is
shown, work-over rig 201 includes conventional hoisting equipment 207 for
raising and lowering production string 203 within wellbore 215, power tongs
30 205 for making-up and breaking-down the production tubing string, as needed,
and gripping equipment 209 which serves to engage production string 203
during make-up operations. As is shown, wellbore 215 includes casing string
213 with interior ~urface 211 which defines a central bore. Typically, casing
WO 94120728 PCT/US94/00181
2134762
- 22 -
213 may have been installed within wellbore 215 many years prior to the
workover operation, and may be composed of a known grade of steel, which
is in an unknown, and quite possibly unknowable condition, and may include
nicks, cuts, gouges, corroded regions, and out-of-round regions. Additionally,
5 casing 213 may have an inner diameter which is within a range of acceptable
inner diameter for particular casing type and size. As is shown, seal apparatus
11 may be aligned next to a particular region 219 of wellbore 215 which may
have these and other defects in the interior surface which defines the central
bore. Region 219 may be located several hundred or several thousand feet
from work-over rig 201. In the present invention, seal apparatus 11 is utilized
to seal annular region 217 between production string 203 and casing 213,
notwithstanding the fact that region 219 of casing 213 may have many of the
above-identified defects which would normally pose a severe problem for
sealing operations. In the present invention, seal apparatus 11 has a
sufficiently small radial dimension during running operations to pass through
hundreds or thousands of feet of wellbore without becoming stuck, but expands
radially outward in an amount which is sufficient to forcefully engage region 219
of casing 213 in a manner which either (1) deforms selected ones of the raised
portions, or (2) urges selected ones of the raised portions to penetrate into
casing 213 at region 219, to provide a gas-tight, metal-to-metal seal which
effectively seals annular region 217.
Laboratory tests have revealed that the metal-to-metal seal
ap,uara~us of the present invention can withstand pressure dir~erer,lials of
between 10,000 and 16,000 pounds per square inch, at extremely high
temperatures. It is believed that the metal-to-metal seal of the present invention
can provide a gas-tight barrier to pressure di~erenlials of 20,000 pounds per
square inch or greater. It can thus be appreciated that the seal apparatus and
method of the present invention can provide a high quality, gas-tight sealing
engagement, which may find many commercial uses in wellbore drilling and
completion operations.
WO 94/20728 213 ~ 7 6 2 PCT/US94/00181
- 23 -
The present invention represents a significant advance over prior
art devices. The clearance provided around the seal apparatus, which can be
identified as the "running clearance," is sufficiently large to allow the seal
apparatus to be run into remote locations within a wellbore which may be
5 thousands and thousands of feet away from the earth's surface. The seal
apparatus is then subjected to a large amount of force, causing the metal ring
component of the seal apparatus to deform radially outward to span the
running clearance between the seal apparatus and a remotely-located wellbore
tubular member. In the embodiment described herein, the radial running
10 clearance between the seal apparatus and the wellbore tubular is approximately
three-sixteenths (3/16) of an inch. In the embodiment shown herein, the
outward radial expansion of the metal ring component of the seal apparatus
can be only a few thousandths of an inch, or as great as three-sixteenths
(3/16) of an inch to five-sixteenths (5/16) of an inch. This rather large range
15 of radial expansion of the metal ring component ensures that the seal apparatus
will provide a gas-tight, long-service-life, metal-to-metal seal with the wellbore
tubular, even though the condition of the wellbore tubular is entirely unknown.
The wellbore tubular may have nicks, gouges, corroded regions,
20 or irregularities in the shape of the inner bore. Furthermore, even if the
wellbore tubular is not damaged in any respect, it may have an inner diameter
which falls within an industr,v-accepted range of acceptal,le inner diameters.
The variance of the inner diameters of undamaged tubulars spans a significant
distance range. The present invention provides a seal ap~,aral,Js which will
25 provide a gas-tight, long-service-life, metal-to-metal wellbore seal which will seal
against the wellbore tubular, irrespective of the actual inner diar"eler of the
wellbore tubular, provided it is within the total expansion range of the metal seal
component of the wellbore tubular.
In the present invention, expansion of the metal seal component
can represent a five to fifteen percent (5%-15%) radial expansion of the metal
ring component. Although greater percentages of expansion are possible,
particularly if dir~re,1t ma~erials are selected to form the metal ring component,
~i~, ,.
WO 94/20728 PCT/US94/00181
21347 ~2 - 24
in the present invention the amount of radial expansion must be at least as
great as the running clearance between the seal apparatus and the wellbore
tubular against which it is intended to seal. In the embodiment described
herein, radial expansion can be as large as five-sixteenths (5/16) of an inch,
5 which exceeds the preferred running clearance between the seal apparatus and
the wellbore tubular by two-sixteenths (2/16) of an inch. This significant rangeof possible maximum expansion of the metal ring component allows the seal
apparatus to seal against wellbore tubulars which have significant damage,
shape irregularities, and inner diameter dimensions.
In the embodiment described herein, the running clearance is
completely spanned by expansion of the ring, but an additional sixty to seventy
percent of the running clearance may also be spanned. This allows for tight
seals against seriously damaged or deformed wellbore tubulars, without
15 requiring the operator to determine the condition of the tubular or dimensions
of such tubulars. The operator need only have knowledge of the ~nominal~
(that is, the stated) dimension of the wellbore tubular. For example, engineering
records of a particular well may indicate that nine and fivc ei~hls (9 5/8) inches
outer diameter casing is disposed at a region of interest within the wellbore.
20 The operator may select a seal apparatus in accordance with the present
invention which is sized and constructed to allow for unobstructed running-in
operations through all intermediate tubulars between the surface and the nine
and five-eights ( 9 5/8) inches casing. Furthermore, the selected seal
apparatus will be capable of sufficient outward radial ex~ansion to engage the
25 nine and five eigl,l:j inches casing in a gas-tight seal, even though the inner
diameter of the casing varies over an acceptable range, or includes deformities
or damage such as corroded regions, gouges, nicks and eccentricities. The
significant range of possible expansions of the metal ring component of the sealapparatus ensures that a great number of types of deformities and irregularities,
30 as well as a great range in degree of deformities and irregularities, may be
effectively sealed by the present invention.
WO 94/20728 PCT/US94/00181
~213476~
2 5 -- ;~ 1
The present invention may be sized upward or downward to allow
for running-in operations through either production tubing or casing, as long asa sufficient running clearance is provided between the tool and the tubular
strings between the earth's surface and the desired setting location. All that is
5 further required is that the metal ring component of the apparatus be
expandable to an extent which is sufficient to entirely bridge the running
clearance, and prererably additional clearance which may be provided by
gouges, nicks, corroded regions, eccentricities, or variance of the inner
diameter within an acceptable range of diameters.
While the invention has been shown in only one of its forms, it is
not thus limited but is susceptible to various changes and modifications withoutdeparting from the spirit thereof.
WO 94t20728 PCT/US94/00181
213~ 762 -26-
TABLE 1 TABLE 2
A3.5 inches M 75 degrees
B1.75 inches AB 60 degrees
C1.50 inches AC 60 degrees
D1.00 inches AD 60 degrees
E0.10 inches AE 60 degrees
F0.015 inches AF 75 degrees
G0.015 inches AG 75 degrees
H0.015 inches AH 75 degrees
1.50 inches Al 3 degrees
J1.00 inches
K0.75 inches
L8.125 inches
M7.75 inches
N7.45 inches
O0.18 inches
P7.803 inches
Q7.90 inches
R1.84 inches
S7.780 inches
T8.00 inches
U8.125 inches
V8.210 inches
