U.S. patent application number 09/766793 was filed with the patent office on 2002-07-25 for mudsaver valve.
Invention is credited to LaFleur, Karl K..
Application Number | 20020096334 09/766793 |
Document ID | / |
Family ID | 25077554 |
Filed Date | 2002-07-25 |
United States Patent
Application |
20020096334 |
Kind Code |
A1 |
LaFleur, Karl K. |
July 25, 2002 |
Mudsaver valve
Abstract
A mudsaver valve for insertion into the upper end of a well
casing includes an elongated cylindrical valve body member having a
central bore for receiving an elongated generally tubular valve
closure member for movement in the body bore between valve closed
and open positions. Passages in the closure member open to the
outer surface thereof and spaced apart seal members mounted on the
closure member prevent fluid flow out of the valve when the closure
member is disposed in a closed position in the body. The body
supports plural circumferentially spaced spring biased drag blocks
or radially deflectable leaf or bow spring members which are
engageable with the casing to support the body stationary in the
casing so that the closure member may be reciprocated with respect
to the body between valve open and closed positions.
Inventors: |
LaFleur, Karl K.;
(Weatherford, TX) |
Correspondence
Address: |
CHRISTOPHER J. ROURK
AKIN, GUMP, STRAUSS, HAUER & FELD, L.L.P.
P O BOX 688
DALLAS
TX
75313-0688
US
|
Family ID: |
25077554 |
Appl. No.: |
09/766793 |
Filed: |
January 22, 2001 |
Current U.S.
Class: |
166/334.4 ;
175/218; 175/317 |
Current CPC
Class: |
E21B 21/106
20130101 |
Class at
Publication: |
166/334.4 ;
175/218; 175/317 |
International
Class: |
E21B 034/12; E21B
034/14 |
Claims
What is claimed is:
1. A mudsaver valve for use in well operations comprising: an
elongated valve body member including an axial cylindrical bore
therein; an elongated, generally tubular closure member disposed in
said bore in said body member, said closure member including an
elongated axially extending passage formed therein and passage
means opening to an outer surface of said closure member, said
closure member being movable axially in said bore in said body
member between valve open and closed positions; and at least one
drag member connected to said body member and engageable with a
wall of a well conduit upon insertion of said valve into said well
conduit for holding said body member substantially stationary with
respect to said well conduit to permit opening and closing said
valve by moving said closure member axially in said bore of said
body member.
2. The valve set forth in claim 1 including: spaced apart seals on
one of said body member and said closure member for preventing flow
of fluid from said passage means in said closure member in the
valve closed position of said closure member.
3. The valve set forth in claim 2 wherein: said seals comprise
annular seal members mounted on said closure member and engageable
with a borewall of said bore in said body member.
4. The valve set forth in claim 3 including: a tapered bore part
extending from one end of said body member and intersecting said
bore in said body member for engaging said seals when said closure
member moves from a valve open position to a valve closed
position.
5. The valve set forth in claim 1 wherein: said closure member is
connected at one end to an elongated conduit for conducting fluid
to said passage in said closure member from a source of said
fluid.
6. The valve set forth in claim 1 including: a tapered guide member
disposed on one end of said closure member for guiding said valve
into said well conduit.
7. The valve set forth in claim 1 wherein: said drag member
comprises plural circumferentially spaced drag blocks mounted on
said body member for limited movement relative to said body member
and operable to engage a wall of said well conduit.
8. The valve set forth in claim 7 including: resilient biasing
means for yieldably biasing said drag blocks radially outwardly
into forcible engagement with said wall.
9. The valve set forth in claim 8 wherein: said resilient biasing
means comprises spring means interposed said drag blocks and said
body member, respectively.
10. The valve set forth in claim 7 wherein: said drag blocks each
include an axially tapered outer surface formed thereon engageable
with said well conduit for camming said drag blocks radially
inwardly toward said valve body in response to urging said valve
body into said well conduit.
11. The valve set forth in claim 1 wherein: said drag member
comprises a drag assembly including plural circumferentially spaced
spring members supported on said body member and engageable with
said wall of said well conduit upon insertion of said valve into
said well conduit.
12. The valve set forth in claim 11 wherein: said spring members
comprise elongated cantilever spring fingers radially deflectable
in response to engagement with said wall of said well conduit and
operable to extend partially from an upper end of said well conduit
in response to insertion of said valve into said well conduit.
13. The valve set forth in claim 11 wherein: said spring members
are mounted on a support collar adapted to be removably mounted on
said body member.
14. The valve set forth in claim 13 wherein: said collar includes
opposed arcuate collar members joined together by a hinge and by a
latch for mounting said collar on said body member and removing
said collar from said body member, respectively.
15. The valve set forth in claim 11 wherein: said spring members
comprise elongated bow springs radially deflectable in response to
engagement with said wall of said well conduit.
16. The valve set forth in claim 15 wherein: said spring members
are connected at one end to a first support collar adapted to be
mounted on said body member and said spring members are connected
at an opposite end to a second support collar mounted on another
body member moveable relative to said body member and relative to
an elongated mandrel connected to said closure member.
17. The valve set forth in claim 16 wherein: said collars each
comprise opposed collar members movable relative to each other for
mounting and demounting said drag assembly with respect to said
body members.
18. The valve set forth in claim 1 including: an indicator member
extending from said body member and operable to extend out of an
upper end of said well conduit when said body member is disposed in
said wall conduit.
19. A mudsaver valve for use in well operations comprising: an
elongated valve body member including an axial cylindrical bore
therein; an elongated closure member disposed in said bore in said
body member, said closure member including passage means opening to
an outer surface of said closure member, said closure member being
movable axially in said bore in said body member between valve open
and closed positions; and a drag assembly connected to said body
member and engageable with a wall of a well conduit upon insertion
of said valve into said well conduit, said drag assembly including
plural circumferentially spaced spring members supported on said
body member and engageable with said wall of said well conduit for
holding said body member substantially stationary with respect to
said well conduit to permit opening and closing said valve by
moving said closure member axially in said bore of said body
member.
20. The valve set forth in claim 19 wherein: said spring members
comprise elongated cantilever spring fingers radially deflectable
in response to engagement with said wall of said well conduit.
21. The valve set forth in claim 20 wherein: said spring members
are mounted on a support collar adapted to be removably mounted on
said body member.
22. The valve set forth in claim 21 wherein: said collar includes
opposed arcuate collar members joined together by a hinge and a
latch for mounting said collar on said body member and removing
said collar from said body member, respectively.
23. The valve set forth in claim 19 wherein: said spring members
comprise elongated bow springs radially deflectable in response to
engagement with said wall of said well conduit.
24. The valve set forth in claim 23 wherein: said spring members
are connected at one end to a first support collar adapted to be
mounted on said body member and said spring members are connected
at an opposite end to a second support collar mounted on another
body member moveable relative to said body member and relative to
an elongated mandrel connected to said closure member.
25. The valve set forth in claim 24 wherein: said collars each
comprise opposed collar members movable relative to each other for
mounting and demounting said drag assembly with respect to said
body members.
26. The valve set forth in claim 19 including: spaced apart annular
seal members mounted on said closure member and engageable with a
borewall of said bore in said body member for preventing flow of
fluid from said passage means in said closure member in the closed
position of said closure member.
27. The valve set forth in claim 26 including: a tapered bore part
extending from one end of said body member and intersecting said
bore in said body member for engaging said seals when said closure
member moves from a valve open position to a valve closed position.
Description
FIELD OF THE INVENTION
[0001] The present invention pertains to a mudsaver valve for use
in well drilling and casing installation operations.
BACKGROUND
[0002] In the art of well drilling operations, including operations
to install well casing, it is common practice to fill the tubular
casing with drill cuttings evacuation fluid, commonly known as
drilling fluid or "mud", and circulate such fluid through the
casing and the wellbore during casing installation procedures, in
particular. So-called mudsaver valves are usually connected to the
lower end of a hollow drill stem drive member or Kelly or to the
lower end of a circulating head to prevent spillage of the drilling
fluid or "mud" when the Kelly or circulating head are disconnected
from the drill stem or casing, as the case may be.
[0003] The use of a mudsaver valve is desirable to prevent the
aforementioned loss of drilling fluid, to prevent unsafe conditions
for rig operating personnel and also to minimize contamination of
the environment in the vicinity of the drilling operation.
[0004] Various types of mudsaver valves have been developed in the
prior art. A typical mudsaver valve design is characterized by a
poppet type closure member which is held against a valve seat by a
spring. In many instances, solid particulates are distributed
throughout the drilling fluid, such as lost circulation material or
unseparated drill cuttings, and these particulates become trapped
between the valve closure member and the valve seat resulting in
improper closure of the mudsaver valve and the loss of drilling
fluid out of the circulating head or conduits which supply the
fluid during operations.
[0005] Another problem associated with prior art mudsaver valves
pertains to the inability to at least reliably and substantially
equalize the pressure between the casing or drill stem interior
passage and the fluid supply conduit to which the mudsaver valve is
connected. Fluid pressures in the so-called standpipe or conduit to
which the mudsaver valve is connected for supplying fluid to the
drill stem or casing should be reduced to substantially the same
pressure as the fluid in the drill stem or casing section at the
upper end thereof prior to disconnection and withdrawal of the
circulating head and mudsaver valve from the casing. However, if
fluid pressure should increase in the casing beyond a reasonable
value which would permit disconnection of the circulating head from
the casing, this pressure can be monitored by suitable instruments
connected to the fluid supply conduit or standpipe which is
connected to the circulating head. Accordingly, the mudsaver valve
should be operable to substantially equalize the fluid pressure in
the drill stem or casing with that in the standpipe or fluid supply
conduit before disconnecting the fluid circulating head or similar
casing installation equipment from the drill stem or casing.
[0006] Still another problem associated with prior art mudsaver
valves pertains to the rapid deterioration of the valve components
due to erosion caused by high fluid velocities between the closure
member and the valve seat or through flowports which are provided
in the closure member for certain types of mudsaver valve
configurations.
[0007] Accordingly, the desiderata in mudsaver valves includes (a)
reliable operation in moving the valve closure member between open
and closed positions to assure that there is negligible spillage of
drilling fluid onto the drilling rig floor, (b) assurance that
pressures in the casing and the fluid supply conduit are
substantially equalized before the fluid supply conduit and
mudsaver valve are withdrawn from the well casing and (c) provision
of a valve configuration that minimizes erosion and early failure
of the valve working parts. It is to these ends that the present
invention has been developed.
SUMMARY OF THE INVENTION
[0008] The present invention provides an improved mudsaver valve
for use in well drilling and casing installation operations.
[0009] In accordance with one important aspect of the present
invention, a mudsaver valve is provided which includes an elongated
tubular mandrel type closure member which is slidably disposed in a
generally cylindrical valve body and is movable between valve open
and closed positions wherein the mandrel moves relative to the body
out of a lower end thereof and substantially clear of any valve
seat or seal bore portions of the body which might suffer erosion
from high velocity fluid impinging thereon. In accordance with
another aspect of the present invention, a sliding mandrel type
mudsaver valve is provided which includes spaced apart annular
seals which seal off flow of fluid out of the valve when the
closure member is retracted into the bore of the valve body.
[0010] In accordance with yet another aspect of the invention, a
mudsaver valve is provided which includes members mounted on the
valve body which frictionally engage the inner borewall of a casing
or drill stem section into which the mudsaver valve has been
inserted to arrest movement of the valve body and to allow the
valve closure member to move relative to the valve body between
valve open and closed positions. The sliding mandrel type closure
member is movable to a valve open position only after it has been
inserted into the upper end of a casing section and the closure
member is movable to a valve closed position before the body is
forcibly removed from frictional engagement with the inner borewall
of the drill stem or casing member. In this way, there is assurance
that the mudsaver valve will be in a closed position before it is
withdrawn from the upper end of the casing or drill stem
section.
[0011] In accordance with still a further aspect of the present
invention, an improved mudsaver valve is provided which includes an
arrangement of resiliently deflectable members which frictionally
engage the inner borewall of a casing section to generally hold the
valve body stationary but to also allow the valve body to be moved
between a working position in the casing and a position retracted
out of the casing. Circumferentially spaced spring biased drag
blocks or resiliently deflectable leaf or bow type springs may be
mounted on the valve body for frictional engagement with the casing
borewall to retain the valve body within the casing and to allow
for movement of the valve closure member between valve open and
closed positions. Elongated flexible finger indicators may be
provided on the valve body to visually indicate to operating
personnel the position of the valve body in the casing.
[0012] Those skilled in the art will further appreciate the
above-mentioned features and advantages of the invention together
with other important aspects thereof upon reading the detailed
description which follows in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a side elevation, in somewhat schematic form, of a
casing circulating system including a mudsaver valve in accordance
with the present invention;
[0014] FIG. 2 is a longitudinal central section view of the
mudsaver valve shown in FIG. 1 partially inserted in the upper end
of a well casing section;
[0015] FIG. 3 is a detail section view taken generally from the
line 3-3 of FIG. 2;
[0016] FIG. 4 is a longitudinal central section view of the
mudsaver valve shown in FIG. 2 fully inserted within the casing
section and in the valve open position;
[0017] FIG. 5 is a longitudinal central section view of a first
alternate embodiment of the mudsaver valve of the present invention
shown within a casing section and in the valve open position;
[0018] FIG. 6 is a top plan view of a removable spring finger drag
assembly for the mudsaver valve shown in FIG. 5;
[0019] FIG. 7 is a side elevation of the spring finger drag
assembly shown in FIG. 6;
[0020] FIG. 8 is a longitudinal central section view of a second
alternate embodiment of a mudsaver valve in accordance with the
invention, shown in the valve closed position;
[0021] FIG. 9 is a section view showing the valve of FIG. 8 in an
open position;
[0022] FIG. 10 is a side elevation of the drag assembly for the
valve shown in FIGS. 8 and 9; and
[0023] FIG. 11 is a bottom plan view of the drag assembly shown in
FIG. 10.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] In the description which follows, like parts are marked
throughout the specification and drawing with the same reference
numerals, respectively. The drawing figures are not necessarily to
scale and certain features may be shown in somewhat schematic form
in the interest of clarity and conciseness.
[0025] Referring to FIG. 1, there is illustrated a portion of a
well drilling rig including an arrangement adapted for circulating
drilling fluid into and through drill stem or casing sections, in
particular, while inserting such casing sections into a wellbore.
FIG. 1 shows the upper end of a conventional well casing section 10
which is adapted to be supported by suitable slips, not shown,
prior to insertion of the casing section into a wellbore, also not
shown. The circulating assembly includes a rig swivel assembly 12,
a lifting bail 14 adapted to be connected to the rig traveling
block, not shown, and a conventional casing elevator assembly 16
connected to the swivel 12. An elongated fluid conducting conduit
18 is connected to the swivel 12, depends therefrom and is in
communication with a drilling fluid supply conduit 20 connected to
the swivel in a conventional manner and to a source of drilling
fluid, such as high pressure pumps, not shown. Conduit 18 is
connected to a generally inverted can shaped seal member 24 of a
type known in the art. The seal member 24 may be a commercially
available external or internal seal, fillup and circulating tool
such as an Autoseal tool available from Weatherford or an FC fillup
and circulating tool available from Frank's International.
[0026] A somewhat flexible, thick walled, reinforced hose type
conduit 26 depends from the casing seal member 24 and is in
communication with the conduit 18 for receiving drilling fluid
therefrom. However, conduit 26 may in certain operations be
connected directly to conduit 18 and seal member 24 omitted. The
lower end of conduit 26 is connected to a coupling 27 which is
connected to a mandrel member of a mudsaver valve in accordance
with the invention, which valve is generally designated by the
numeral 28. Prior to insertion of casing section 10 fully into a
wellbore, the mudsaver valve 28 is lowered into the casing section
10 sufficiently to allow the valve to open, as will be fully
understood from reading the description of the valve hereinbelow.
When conduit 26 is lowered sufficiently to cause valve 28 to be
fully inserted in casing section 10 and the valve caused to open,
drilling fluid is pumped into the casing section or sections to
fill same with such fluid. Subsequently conduit 26 and seal 24 are
lowered further until the seal 24 engages the upper end 10a of the
casing section in a known manner so that drilling fluid can
continue to be pumped from conduit 20 through conduits 18 and 26
and through the mudsaver valve 28 into and also through the
interior of the casing section. When the casing section 10 has been
lowered into a wellbore to a point just above the floor of the
drilling rig, not shown, pumping of drilling fluid ceases and after
equalization of fluid pressure in the casing section 10 and the
conduit 26, the seal member 24 and mudsaver valve 28 are moved
upwardly and withdrawn from the interior of the casing section in a
known manner. The process described above is repeated, also in a
known manner, as additional casing sections are added to a casing
string being inserted into the aforementioned wellbore.
[0027] Referring now to FIG. 2, the mudsaver valve 28 is shown in a
position wherein it has just entered the upper end 10a of the
casing section 10 but is not yet completely in its intended working
position for circulating drilling fluid into the bore 11 of the
casing section. The casing section 10 includes an upper collar
portion or box 13 forming part of the upper end 10a and having
internal threads 13a of larger inside diameter than the casing bore
11. The casing section 10 is of conventional construction.
[0028] Mudsaver valve 28 includes a generally cylindrical elongated
valve body 30 having a longitudinal, central cylindrical bore 32
extending therethrough between an upper transverse endface 34 and a
lower transverse endface 36. Cylindrical bore 32 intersects a
conical bore part 38 which opens to the lower endface 36. Valve
body 30 is also provided with three circumferentially spaced
elongated rectangular cross section slots 40, see FIG. 3 also, for
receiving three circumferentially spaced respective so-called drag
blocks 42, as shown in FIGS. 2 and 3, which drag blocks project
radially outwardly and are operable to forcibly engage the borewall
11 of casing section 10. The section view of FIG. 2 has been
rotated into the plane of the paper to show two of the drag blocks
42. Each of the drag blocks 42 is characterized as a generally
rectangular member preferably formed of a urethane composition and
is provided with an axially sloped outer surface portion 43, as
shown in FIG. 2. Each of the drag blocks 42 is retained in its slot
40 by a suitable threaded fastener 44, FIG. 2, having a head
portion 46 disposed in a recess 47. The drag blocks 42 are also
each provided with spaced apart spring receiving bores 49, as shown
in FIG. 2, for receiving respective coil biasing springs 50
therein. Biasing springs 50 are engageable with the valve body 30
and are sleeved over suitable guide pins 52 mounted on the body 30
and projecting radially outwardly therefrom. Guide pins 52 are
slidably disposed in cooperating bores 54 formed in the drag blocks
42, as shown, to assist in guiding and centralizing the blocks so
that the blocks may move radially inwardly and outwardly with
respect to a longitudinal central axis 55. Accordingly, the drag
blocks 42 are adapted to frictionally engage the borewall 11 as the
mudsaver valve 28 is inserted into the upper end of casing section
10, and may be urged radially inwardly as the surfaces 43 engage
the borewall 11 and remain forcibly engaged with the borewall for a
purpose to be described further herein.
[0029] Referring further to FIGS. 2 and 3, the mudsaver valve 28
includes an elongated, generally cylindrical closure member 60
disposed in bore 32 and suitably secured to a conically shaped
guide nose 62 disposed on the lower end of the closure member. The
closure member 60 is provided with an externally threaded upper end
part 63 suitably connected to an elongated cylindrical tubular
mandrel 61, as shown. Mandrel 61 is connected to conduit 26 via
coupling 27, see FIGS. 1 and 4. The closure member 60 includes a
central longitudinal flow passage 65 in fluid flow communication
with mandrel 61 and extending from the upper end 63 to axially
inclined fluid discharge ports 66 which open to the outer
cylindrical surface 67 of the closure member between spaced apart
annular, elastomer lip type seals 69. The seals 69 are disposed in
suitable annular grooves 70 and 72 on the closure member 60 spaced
apart on opposite sides of the points at which the ports 66
intersect the surface 67 of the closure member 60.
[0030] In the position of the mudsaver valve 28 shown in FIG. 2,
the closure member 60 is in a valve closed position and fluid flow
out of the mudsaver valve is blocked by the position of the closure
member 60 relative to the valve body 30. There are no substantial
resultant pressure fluid forces acting on the closure member 60
tending to bias it in the open position or in the closed position
shown, due to the configuration of the ports or passages 66 and the
arrangement of the seals 72 when the closure member is in the valve
closed position. However, when the mudsaver valve 28 is inserted
into a casing section, such as the casing section 10, the drag
blocks 42 will forcibly engage the borewall 11 permitting only
limited entry of the body 30 past the intersection of the borewall
11 with the enlarged diameter bore which includes internal threads
13a. Continued downward movement of the conduit 26 and the
structure connected thereto will cause the closure member 60 to
move downward to the position shown in FIG. 4 wherein the ports 66
are open to the interior passage 11a of the casing section 10.
Drilling fluid may then flow down through conduit 26, mandrel 61
and closure member 60 into casing section 10.
[0031] As shown in FIG. 4, the valve body 30 has entered the casing
section 10 only a relatively short distance below the intersection
of the bore 11 with the bore formed by the internal threads 13a of
the upper end 10a of the casing section. Valve body 30 is
preferably provided with one or more upwardly extending elongated
spring steel position indicator or "telltale" fingers 73, FIG. 4,
to indicate when the body 30 is sufficiently inserted in casing
section 10. Indicator fingers 73 are suitably connected to the
upper end of body 30 adjacent end face 34, as shown in FIG. 2.
Accordingly, when it is desired to circulate drilling fluid through
the casing section 10, the mudsaver valve 28 and conduit 26 are
inserted in the upper end 10a and move downwardly until indicator
fingers 73 disappear within the casing section. Conduit 26 is moved
further downward to assure that valve 28 has moved to the open
position and conduit 26 may also, when fluid circulation is to
commence, be moved downward until the seal 24 extends over the
upper end of the casing section 10 in a known manner. At this time,
the body 30 has only moved a short distance into the casing section
10, as shown in FIG. 4, but the closure member 60 has extended to
the position shown to allow free flow of drilling fluid through the
passage 65, the ports 66 and into the casing bore.
[0032] When it is desired to withdraw the mudsaver valve 28 from
the interior of the casing section 10, the aforementioned traveling
block raises the swivel 12 and the conduit assembly connected to
the mudsaver valve whereby the closure member 60 will move upwardly
relative to the body 30 until flange 62a of nose 62 engages the
lower end face 36 of the body and the closure member is fully
seated within the body.
[0033] Thanks to the conically tapered bore 38, the seals 69 are
guided into fluid tight sealing engagement with the body 30 at bore
32 as the closure member 60 moves into the bore from the valve open
position to the valve closed position shown in FIG. 2. Accordingly,
since the body 30 is frictionally engaged with the casing section
10 by way of the drag blocks 42, the closure member 60 moves to the
valve closed position before the mudsaver valve 28 is withdrawn
from the casing and only a negligible amount of drilling fluid may
spill out of the upper end of the casing section 10 as the
circulating assembly shown in FIG. 1 is withdrawn from the casing
section.
[0034] Still further, once circulation of drilling fluid from
conduit 20 down through conduits 18 and 26 has ceased and while the
closure member 60 is still in the position shown in FIG. 4,
pressures in the casing bore 11 and the conduits of the circulating
assembly are essentially equalized so that when the seal 24 is
moved off of the upper end 10a of the casing section, there is no
rapid discharge of pressure fluid from the casing. Of course, if
rig operating personnel detect substantial pressure in the conduits
leading to the casing section 10 prior to withdrawal of the mud
circulating assembly from the casing section, the seal 24 and
mudsaver valve 28 will not be removed from the casing section until
pressures can be substantially reduced and equalized between the
conduit 26 and the casing section 10, for example.
[0035] Referring now to FIG. 5, a first alternate embodiment of a
mudsaver valve in accordance with the invention is illustrated and
generally designated by the numeral 128. The mudsaver valve 128 is
shown inserted within a casing section 10 and includes a closure
member 60 slidably disposed in a modified valve body 130 and
connected to a tubular mandrel 161 which is connected to conduit 26
via a coupling 27. Valve body 130 is configured generally like
valve body 30 and includes a cylindrical longitudinal central bore
132 extending between an upper endface 134 and a lower endface 136.
Bore 132 intersects a conical bore 138 which opens to the lower end
face 136 of the valve body 130 for the same purpose as the conical
bore 38. Valve body 130 includes a cylindrical reduced diameter
recessed section 135 between the upper end face 134 and the lower
end face 136 for supporting a friction or drag assembly, generally
designated by the numeral 140.
[0036] The drag assembly 140 includes four, circumferentially
spaced longitudinally extending cantilever spring fingers 142 which
are mounted on a hinged collar 144, see FIGS. 6 and 7 also. The
collar 144 comprises opposed arcuate collar members 144a and 144b
which are hinged together at a hinge pin 148. Collar members 144a
and 144b include spaced apart interfitting latch members 145 and
147 which are alignable to receive a latch pin 150. Collar members
144a and 144b may be latched in a collar closed position by pin 150
when fitted snugly over the reduced diameter section 135 of body
130. The friction or drag assembly 140 may be selected in
accordance with the diameter of the casing bore 11 so that the
mudsaver valve 128 may be used with various casing sizes and
requiring only that the drag assembly 140 be substituted for a drag
assembly having spring fingers of suitable dimensions to provide
the requisite resistance to movement through the casing section so
as to allow the closure member 60 to move relative to the body 130
in the manner generally as described for the mudsaver valve 28.
Moreover, the spring fingers 142 serve as their own telltale or
position indicators for determining if the body 130 is sufficiently
inserted within the casing section 10.
[0037] Referring further to FIGS. 6 and 7, the drag assembly 140 is
shown with a configuration of the cantilever spring fingers 142
which project upwardly and radially outwardly and have somewhat
reentrant distal end parts 143. The spring fingers 142 may be
formed of spring steel and are preferably covered or coated with a
suitable plastic overlay, such as a urethane coating 146, to
minimize any chance of damage to the threads 13a of the casing
section 10 when the mudsaver valve 128 is inserted into the casing.
Preferably the body 130 may be inserted only to the extent that the
spring fingers 142 forcibly engage the internal threads 13a of the
casing section and are thus partially visible from the upper end
10a of the casing section during operation of the mudsaver valve
and the circulating assembly.
[0038] In other words, as the mudsaver valve 128 is inserted into a
casing section, such as the casing section 10, the valve body 130
is inserted until the upper ends 143 of the spring fingers 142 are
visible just above the upper end 10a of the casing section. Then,
under operating conditions using the seal 24, as the seal is
lowered and engaged with the upper end of the casing section, the
operator of the circulating assembly is assured that the closure
member 60 has moved downward to the position shown in FIG. 5
relative to the body 130.
[0039] Alternatively, the valve 128 may be inserted to the position
shown in FIG. 5. The mudsaver valve 128 is thus operated in
substantially the same manner as the valve 28 and is easily
withdrawn from the casing section 10 by merely pulling up on the
circulating assembly, including the swivel 12, until the closure
member 60 moves to the closed position relative to the body 130 and
further upward movement results in the cantilever spring fingers
142 sliding upward in frictional engagement with the casing section
so that the valve 128 can be withdrawn from the casing in its
closed position.
[0040] Referring now to FIGS. 8 and 9, a second alternate
embodiment of a mudsaver valve in accordance with the invention is
illustrated and generally designated by the numeral 228. The
mudsaver valve 228 utilizes the closure member 60 and the mandrel
61 suitably connected to the conduit 26, not shown, by way of the
coupling 27. A modified body 230 includes a suitable central axial
bore 232 for receiving the closure member 60 in the same manner
that the body 30 receives the closure member 60 of the embodiment
of FIGS. 1 through 4. Valve body 230 includes central axial bore
232 and a tapered bore portion 238 at the lower end thereof, as
illustrated in FIGS. 8 and 9. Accordingly, when the closure member
60 moves to a valve closed position, as shown in FIG. 8, from a
valve open position, as shown in FIG. 9, the seals 69 are operable
to provide fluid tight engagement with the bore 232 in the same
manner as for the embodiments of the mudsaver valve previously
described.
[0041] As shown in FIG. 8, the body 230 includes spaced apart
circumferential flanges 231 and 233 between which is secured a
hinged collar 144 for a modified drag assembly 240. Drag assembly
240 further includes a second hinged collar 144 secured to a
generally spool-shaped body member 245 which includes a central
axial bore 246 for receiving the mandrel 61 in axial sliding
engagement therewith. The upper hinged collar 144 is disposed on
the body 245 between opposed circumferential flanges 245a and 245b.
The upper and lower hinged collars 144 are suitably connected to
opposite ends of circumferentially spaced elongated spring steel
drag members 242, similar to the spring finger drag members 142,
but secured at their opposite ends to the respective hinged collars
144 and adapted to retain a somewhat radial outward projecting bow
shape, as shown. Accordingly, a selected drag assembly 240 may be
mounted on the mudsaver valve 228, depending on the diameter of
casing in which the mudsaver valve is to be inserted, so that the
drag members 242 may engage the bore wall of the casing with
sufficient frictional drag to allow the closure member 60 to move
downward out of the body 230 sufficiently, as shown in FIG. 9, to
uncover the ports 66 so that fluid may flow into a casing section,
not shown in FIGS. 8 and 9, in which the mudsaver valve 228 has
been inserted.
[0042] Referring also to FIGS. 10 and 11, further details of the
drag assembly 240 are illustrated. Each of the hinged collars 144
is secured in its closed position by pins 148 and 150, as shown,
and each of the drag members 242 may include a suitable elastomer
coating 246 formed thereon, such as the aforementioned urethane
coating used for the spring fingers 142 of the drag assembly
140.
[0043] When the mudsaver valve 228 has been inserted into a casing
section, such as the casing section 10, not shown in FIGS. 8 and 9,
the drag members 242 will engage the casing bore wall sufficiently
to allow the closure member 60 be moved to the position shown in
FIG. 9 upon downward movement of the conduit 26, coupling 27 and
mandrel 61. The mudsaver valve 228 may be moved to the closed
position by pulling up on the conduit 26, coupling 27 and mandrel
61 until the closure member 60 has moved to the position shown in
FIG. 8 whereupon the mudsaver valve 228 may be withdrawn from a
casing section. One advantage of the mudsaver valve 228 resides in
the arrangement of the drag assembly 240 with respect to the
coupling 27. As shown in FIG. 9, as the mandrel 61 and coupling 27
move downward relative to the body 230, the coupling 27 may engage
the body 245 to assure that the body and drag assembly 240 are
fully inserted into the upper end of a casing section. Accordingly,
upon withdrawal of the mudsaver valve 228 from a casing section the
closure member 60 will move back into the body 230 before the valve
is removed from the upper end of the casing.
[0044] The construction and operation of the mudsaver valves 28,
128 and 228 is believed to be readily understandable to those of
ordinary skill in the art based on the foregoing description.
Conventional engineering methods and materials for mudsaver valves
may be used in fabricating the valves 28, 128 and 228. Although
preferred embodiments of a mudsaver valve in accordance with the
invention have been described in detail herein, those skilled in
the art will also recognize that various substitutions and
modifications may be made without departing from the scope and
spirit of the invention as recited in the appended claims.
* * * * *