U.S. patent number 3,809,158 [Application Number 05/275,576] was granted by the patent office on 1974-05-07 for well completion apparatus and method.
This patent grant is currently assigned to Rockwell International Corporation. Invention is credited to James Vaull Bonds, John Walton McCaskill.
United States Patent |
3,809,158 |
Bonds , et al. |
May 7, 1974 |
**Please see images for:
( Certificate of Correction ) ** |
WELL COMPLETION APPARATUS AND METHOD
Abstract
Well completion apparatus in which a casing hanger is suspended
from a first member of a well tool and a sealing member is
suspended from a second member of the well tool. The first and
second members are releasably connected whereby upon landing the
casing hanger within the well the first member is disconnected from
the second member and the sealing member is lowered into sealing
position independently of the casing hanger. A portion of the
sealing member is rotated to cause an expansion ring to engage an
annular groove in the casing head thereby actuating the sealing
member and locking the sealing member and casing hanger in
position.
Inventors: |
Bonds; James Vaull (Houston,
TX), McCaskill; John Walton (Houston, TX) |
Assignee: |
Rockwell International
Corporation (Pittsburgh, PA)
|
Family
ID: |
23052916 |
Appl.
No.: |
05/275,576 |
Filed: |
July 27, 1972 |
Current U.S.
Class: |
166/382; 285/18;
166/285; 285/402; 285/123.2 |
Current CPC
Class: |
E21B
33/043 (20130101) |
Current International
Class: |
E21B
33/043 (20060101); E21B 33/03 (20060101); E21b
033/035 (); E21b 023/06 () |
Field of
Search: |
;285/18,24,140,142,401,402,376,39
;166/86,87,88,.5,.6,315,250,285 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Jaudon; Henry S.
Assistant Examiner: Kannan; Philip C.
Claims
1. Apparatus for installing and sealing a casing hanger within a
well comprising:
a sealing member;
a lowering member having a first portion releasably attached to a
second portion;
said first portion having first connection means for suspending
such casing hanger;
said second portion having second connection means for suspending
said sealing member;
means for releasing said first portion from said second portion to
lower said sealing member into sealing position; and
said sealing member being clear of such casing hanger prior to
being
2. Apparatus according to claim 1 further including means for
providing a
3. An apparatus according to claim 1 further including means
for
4. An apparatus according to claim 3 wherein said re-engaging means
includes a latch means frictionally wedging between said first
portion and
5. An apparatus according to claim 1 wherein:
said releasing means connects said first portion to said second
portion upon a rotation of said first portion of less than
360.degree.; and
said second connection means disconnects said second portion from
such
6. An apparatus according to claim 1 wherein said releasing means
disconnects said first portion from said second portion upon a
rotation of
7. An apparatus according to claim 6 wherein said releasing means
includes a breech block connection having tooth segment means in
the upper interior of said first portion and correlative tooth
segment means on the exterior
8. An apparatus according to claim 1 in combination with a casing
head having a stop means wherein said sealing member includes latch
means
9. An apparatus according to claim 8 wherein said sealing member
includes a tubular member rotatably connected to a retainer member
and said latching means includes a latch member supported by an
actuator member; said actuator member being reciprocatably mounted
on said retainer member thereby preventing rotation relative
therebetween and being threadingly engaged to said tubular member
whereby upon the rotation of said tubular member said actuator
member moves axially on said retainer member forcing
10. An apparatus according to claim 9 wherein said retainer member
includes a packing element whereby said element is compressed
against a portion of such casing hanger, thereby sealingly engaging
both said casing head and such casing hanger, because of the force
applied to said retainer member by said tubular member upon the
engagement of said latch member and said
11. An apparatus according to claim 10 wherein said retainer member
further includes an upper annular ring and a lower annular ring;
said packing element being positioned between said rings whereby
upon the compression of said packing element, said packing element
is compressed radially inward sealingly engaging the exterior of
such casing hanger and radially
12. An apparatus according to claim 10 wherein said tubular member
is releasably connected to said first portion by said first
connection means and said sealing member further includes
anti-rotation means for preventing said retainer member from
rotating when said sealing member is in the sealing position
whereby upon the rotation of said first portion, said tubular
member rotates and said retainer member remains stationary.
13. An apparatus according to claim 12 in combination with such
casing hanger wherein said anti-rotation means includes a clutch
connection
14. An apparatus according to claim 13 wherein said clutch
connection includes biased lugs reciprocatably mounted on said
retainer member for insertion into correlating recesses in said
portion of said casing hanger in said sealing position thereby
preventing rotation of said retainer
15. Apparatus comprising
a casing hanger having means thereon for supporting a casing
therebelow, and means for engaging a surrounding well head for
support of the casing hanger on the well head,
a running tool extending upwardly from said casing hanger,
means on said running tool and said casing hanger for releasably
supporting said casing hanger on said running tool,
a compressible packoff surrounding a portion of said running tool,
and
means on said running tool and said packoff for releasably
supporting said packoff on said running tool,
the latter means comprising a J-slot connection, whereby said
running tool and said packoff may be disengaged and re-engaged for
support of said packoff by said running tool upon rotation of said
running tool less than one turn,
said running tool including a releasable connection intermediate
the casing hanger support means and the packoff support means which
allows movement of said packoff longitudinally relative to said
casing hanger when said
16. A method of installing a casing hanger comprising the steps
of:
suspending a sealing member from a first portion of a well tool and
a casing hanger from a second portion of the well tool;
lowering the sealing member and casing hanger into the well on the
well tool;
landing the casing hanger on the previously installed casing
head;
rotating the first portion to disconnect the first portion from the
second portion of the well tool;
lowering the first portion and sealing member further into the
well;
rotating the first portion to set the sealing member within the
well;
raising the first portion to disconnect the first portion from the
sealing member; and
rotating the first portion to engage the second portion of the well
tool
17. A method as defined in claim 16 wherein the first portion is
always
18. A method of installing and sealing a casing hanger affixed to
and supporting a string of casing in a remote previously installed
casing head in a well comprising
lowering the casing hanger and a sealing member therefor into the
well on a running tool until the casing hanger lands on the casing
head,
cementing the casing in the well,
setting the sealing member,
pressure testing the sealing member without removing the running
tool,
unsetting the sealing member and raising it from the well on said
running tool, without removing said casing hanger, and
19. A method of installing a casing hanger in a casing head
comprising the steps of
suspending a sealing member from a first portion of a well tool and
a casing hanger from a second portion of the well tool,
lowering the sealing member and casing hanger into the well on the
well tool,
landing the casing hanger on the previously installed casing
head,
disconnecting the first portion from the second portion of the well
tool,
lowering the first portion and sealing member further into the
well,
setting the sealing member within the well,
disconnecting the first portion from the sealing member,
moving the first portion to engage the second portion of the well
tool,
disconnecting the second portion from the casing hanger, and
raising the first portion and the second portion of the well tool
from the
20. Apparatus comprising
a casing hanger having means thereon for supporting a casing
therebelow, and means for engaging a surrounding well head for
support of the casing hanger on the well head,
a running tool extending upwardly from said casing hanger,
said running tool comprising a first portion and a second portion
releasable from each other on manipulation of said running
tool,
means on the second portion of said running tool and said casing
hanger for releasably supporting said casing hanger on said second
portion of said running tool,
a compressible packoff adapted to provide a seal between said
casing hanger and said well head, and
means on the first portion of said running tool and said packoff
for releasably supporting said packoff on said first portion of
said running
21. Apparatus as defined by claim 20 wherein said second portion of
said running tool is telescopically retained within said first
portion of said
22. Apparatus as defined by claim 21 wherein said second portion of
said running tool is connected to said casing hanger by means of a
left-hand
23. Apparatus for setting a casing hanger connected to a casing in
a well head located at a remote location below the surface, and
setting a packoff to seal between said casing hanger and said well
head, comprising
an elongate rotatable and reciprocable running tool having a length
sufficient to extend from the surface to the well head,
said running tool having a first portion connected to its lower end
and a second portion carried by said first portion,
a casing hanger having means thereon for supporting a casing
therebelow and means for engaging the well head to support the
casing hanger and the casing on the well head,
means on the second portion of the running tool and on the casing
hanger for releasably supporting the casing hanger,
a packoff adapted to provide a seal between said casing hanger and
said well head,
means on the first portion of the running tool and on the packoff
for releasably supporting the packoff on the first portion of the
running tool, and
a releasable connection between said first portion and said second
portion operable upon manipulation of said running tool to permit
said first portion to move downwardly relative to said second
portion and to be
24. Apparatus as defined by claim 23 wherein said second portion is
telescoped within said first portion and carried on a shoulder
therein.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention pertains to the drilling and completion of oil and
gas wells and more particularly to the installation and sealing of
a pipe hanger within such a well.
2. Description of the Prior Art
In recent years the drilling of sub-sea and other underwater wells
for the production of oil and gas has increased greatly requiring
special equipment. In an underwater well initially a conductor
casing is jetted or driven into the ocean floor. A riser or casing
is then extended from the conductor casing to the drilling platform
at the surface. From the drilling means on the surface a hole is
drilled in the ocean floor for the suspension of a casing string
within the conductor casing. This casing string is suspended from
the conductor casing by means of a casing hanger which is supported
by the conductor casing. An inner riser extends from the casing
hanger to the drilling surface.
To hold the casing string in place within the newly drilled bore,
it is cemented. Cement is passed through the inner riser and down
through the casing string. The cement is forced around the lower
end of the casing string and into the annulus formed by the earth
bore and casing string. By computing the volume of the annulus, it
may be determined approximately how much cement is required to
reach a certain level in the annulus. After the cement has reached
the desired level, the annulus is sealed off above the cement level
by means of a sealing element. This sealing element is generally
located near the casing hanger.
Most sub-sea hanger systems require that the hanger and sealing
element be run separately into the well. To first install the
casing hanger, then cement, and then run in the sealing element
requires great expense and time. Therefore, it is desirable to run
the casing hanger and sealing element into the well in a single
trip.
Single trip running tools for running the hanger and sealing
element into the well together are shown in U.S. Pat. Nos.
3,638,725; 3,492,026; 3,489,436; 3,468,559; 3,460,615; 3,382,921;
3,335,799; and 3,279,539.
U.S. Pat. Nos. 3,460,615, 3,382,921; 3,279,539; and the Ahlstone
U.S. Pat. Nos. 3,638,725; 3,492,026; 3,489,436; and 3,468,559 show
a running tool permitting the axial movement of one portion of the
running tool with respect to another portion. The Ahlstone U.S.
Pat. and U.S. Pat. Nos. 3,382,921 and 3,279,539 show an assembly
where the outer portion of the running tool drives the sealing
element into sealing engagement with the casing hanger. In the
Ahlstone patents and U.S. Pat. No. 3,279,539 the sealing element is
connected to the outer portion of the running tool.
The Ahlstone patents show a sealing element having two portions
connected by ball bearing means. U.S. Pat. Nos. 3,492,026;
3,489,436; 3,468,559; and 3,460,615 show the assembly having a bowl
protector. U.S. Pat. Nos. 3,638,725; 3,492,026; 3,489,436;
3,460,615; 3,382,921; 3,335,799; 3,279,539; and 3,273,646 show the
sealing element actuated upon righthand rotation of the driving
member. U.S. Pat. Nos. 3,638,725 and 3,279,539 show the
disconnection of the running tool from the casing hanger by
rotation to set the seal and then a lifting of the running
tool.
The prior art assemblies have proven to be inadequate since they
require a direct connection between the seal and the casing hanger.
Generally, this connection is a threaded engagement between the
sealing element and the casing hanger. Such a connection creates
difficulties where the seal fails to become established on the
first attempt thereby requiring that the seal be removed from the
well and reinserted. Upon running the seal in the second time, the
prior art connections require the running tool to pick up the lead
thread on the casing hanger to threadingly engage the sealing
elements onto the casing hanger to set the seal. Where the lead
thread has been damaged, the sealing element can never be
re-engaged.
A connection between the sealing element and casing hanger requires
a special casing hanger since some kind of connection means must be
formed on the hanger to connect with the sealing element.
A combined means for compressing the sealing element and for
securing the casing hanger in the well is shown in U.S. Pat. No.
3,540,533.
SUMMARY OF THE INVENTION
The present invention is an apparatus for installing and sealing a
casing hanger within a casing head. It includes a running tool
having an outer portion releasably connected to an inner portion.
The outer portion is releasably connected to a sealing member and
the inner portion is releasably connected to the casing hanger.
Upon landing the casing hanger within the well, the outer portion
is disconnected from the inner portion and the sealing member is
lowered into position between the casing hanger and casing head.
There is no connection between the sealing member and casing
hanger, thereby permitting a standard casing hanger to be used.
The outer portion of the running tool is rotated to the right
causing a latch to expand thereby actuating a compression seal
attached to the sealing member which then seals the annulus
surrounding the casing hanger. The expanded latch holds the sealing
member into position and locks the casing hanger in place within
the well.
The invention has the further advantage that if the seal fails to
sealingly engage in the first attempt, the seal can be removed from
the well and upon rerunning the seal back into the well, no lead
thread need be picked up to re-engage the sealing member and to
actuate the seals within the well.
Other objects and advantages of the invention will appear from the
following discription.
BRIEF DESCRIPTION OF THE DRAWINGS
For a detailed description of a preferred embodiment of the
invention, reference will now be made to the accompanying drawings
wherein:
FIG. 1 is a cross-sectional view of the environment in which the
present invention operates;
FIG. 2 is a cross-section of a portion of embodiment I after
landing the casing hanger;
FIG. 2A is an isometric view of a J-slot connection for a bowl
protector;
FIG. 3 is a cross-section of a portion of embodiment I after
lowering the sealing element into position;
FIG. 4 is a cross-section of a portion of embodiment I after
expanding the hold down latch;
FIG. 5 is a cross-section of a portion of embodiment I after
releasing the sealing element and re-engaging the running tool;
FIG. 6 is a partial cross-sectional view and perspective view of
the breech block connection;
FIG. 7 is a cross-section of a portion of embodiment I after
releasing the running tool from the casing hanger;
FIG. 8 is a cross-section of a portion of embodiment II after
landing the casing hanger;
FIG. 9 is a cross-section of a portion of embodiment II after
lowering the sealing element and expanding the hold down latch;
FIG. 10 is a cross-section of a portion of embodiment II after
releasing the sealing element and reengaging the running tool;
FIG. 11 is a cross-section of a portion of embodiment II after
releasing the running tool from the casing hanger; and
FIG. 12 is a cross-section of a multiple installation of the
present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is a method and apparatus for running a
casing hanger and a sealing member into an oil or gas well on a
single trip of the running tool. Although the present invention may
be used in a variety of environments, FIG. 1 illustrates the
installation of the present invention in the ocean floor of an
off-shore well.
Referring to FIG. 1, a guide base 10, conductor casing 12, a well
head 14, and a conductor riser 16 are lowered from a drilling means
(not shown) such as barge or a bottom supported platform and
installed into the sea floor 18. The conductor casing 12 may be
driven or jetted into the sea floor 18 until well head 14 rests
near the floor, or if the bottom conditions so require, a hole may
be drilled for the insertion of conductor casing 12. The riser 16
extends from the well head 14 to the drilling means (not
shown).
Drilling apparatus is lowered through riser 16 and casing 12 to
drill a bore 20 in the earth for surface casing 22. A surface
casing hanger head 24, suspending surface casing 22, is lowered
through conductor casing 16 until hanger head 24 lands and is
connected to well head 14. A riser 26 is connected to hanger head
24 and extends to the drilling means (not shown).
The drilling apparatus is then lowered through riser 26 to drill a
bore 28 for casing string 30.
EMBODIMENT I
Embodiment I is illustrated in FIGS. 2-7. In FIG. 1 there is shown
generally a casing hanger 32 suspending casing string 30 with a
riser or handling string 34 extending to the drilling means. In
FIG. 2 there is shown in detail the combination of handling string
34 suspending a well or running tool 36 which in turn suspends a
sealing member or packoff 38 and casing hanger 32 in the bore 28 of
the well.
The running tool 36 is connected to handling string 34 by means of
coupling 42. The upper portion of coupling 42 is a box 44 with
interior threads 46 engaging the exterior threads 48 on the pin 50
of the lowermost section of handling string 34. The lower portion
of coupling 42 is a pin 52 with exterior threads 54 engaging the
interior threads 56 disposed on the upper end of running tool 36.
The threads 46, 48, 54 and 56 are shown as right hand engageable
threads since such is generally the case in oil and gas wells. The
connections between the sections of handling string 34 are also
right hand engageable connections. This causes the connections to
tighten upon the right hand rotation of handling string 34. The
advantage of coupling 42 is that it permits the handling string 34
to be of varied diameters. A different sized handling string 34 may
be used by merely changing the coupling 42.
The running tool 36 has two principle members, an outer cylindrical
portion or nipple 60 and an inner cylindrical portion or mandrel
70.
Nipple 60 has interior threads 56 disposed on its upper end for
connection with pin 52 of coupling 42 and suspends packoff 38 at
the lower end by means of the connection at 62.
Mandrel 70 is suspended by and connected to nipple 60 by means of a
breech block type threaded connection 66 illustrated in detail in
FIG. 6 and described in U.S. Pat. Nos. 3,442,536 and 3,421,580. A
plurality of longitudinally extending tooth segments 68 are
machined on alternate 30.degree. segments of the exterior of
mandrel 70, the arcuate length of the teeth being slightly less
than 30.degree.. Matching tooth segments 74 are machined in the
upper interior of nipple 60. These teeth also have a length
slightly less than 30.degree.. The teeth shown are generally in the
form of a buttress thread, but it will be appreciated that other
forms can be used.
The teeth are engaged with each other by lowering the mandrel 70
into the nipple 60 with the teeth segments 68 positioned to pass
between the teeth segments 74. The lowest tooth 76 on mandrel 70
has a double width, so that mandrel 70 must be lowered far enough
into nipple 60 to engage the double thickness tooth in the double
width groove 75 of nipple 60. The mandrel 70 may then be rotated 30
degrees to engage the breech block connection 66. A stop means 72
is provided on mandrel 70 to stop the rotation of mandrel 70 within
nipple 60 after the tooth segments 68, 74 have engaged.
The teeth segments 74 of nipple 60 are disposed below threads 56 a
sufficient distance to permit the disconnection of the breech block
connection 66 and to lower packoff 38 into sealing position as
shown in FIG. 3 and yet provide clearance between the upper
terminal end of mandrel 70 and the lower terminal end of coupling
42 in the sealing position. The teeth segments 68 are disposed on
the uppermost exterior of mandrel 70 to permit the shortest
distance between threads 56 and teeth 74 on nipple 60.
An interference seal 78 is provided below teeth segments 68 in
annular groove 80 in the external surface 82 of mandrel 70. Seal 78
may be in the form of an O-ring or a T-ring which sealingly engages
the smooth internal sealing surface 84 of nipple 60. Seal 78 is
disposed a sufficient distance below teeth segments 68 such that
upon disconnecting breech block connetion 66 and lowering packoff
38 into sealing position, as shown in FIG. 3, seal 78 will always
engage some portion of surface 84 and will never contact the
lowermost tooth of teeth segments 74. The primary purpose of seal
78 is to permit the pressure testing of packoff 38 after its
actuation. It also permits a continuous seal throughout the
installation and sealing operation to prevent well fluids and other
material from passing through breech block connection 66.
The lower end of mandrel 70 suspends casing hanger 32 by threaded
connection 84. The external threads 86 disposed on the lower end of
mandrel 70 engage the interior threads 88 disposed in the box 90
forming the upper portion of casing hanger 32. Connection 84 is a
left hand engageable threaded connection permitting the unthreading
of connection 84 upon the right hand rotation of mandrel 70. Shear
means in the form of shear pin 92 passes through box 90 and into
bore 91 in mandrel 70 to prevent the premature loosening of
connection 84 by any right hand torque inadvertently placed on
mandrel 70 during the disconnection of breech block connection 66
hereinafter discussed.
An interference seal 94, in the form of an O-ring or T-ring, is
disposed below bore 91 and above threads 86 in an annular groove 96
in the external surface 98 of mandrel 70. The primary purpose of
seal 94 is to sealingly engage the smooth internal surface 100 of
casing hanger 32 to permit the pressure testing of packoff 38. Seal
94 also prevents any well fluids or other material from passing
through connection 84.
FIG. 2 illustrates the previously described combination landed
within the well. The casing hanger 32 has a radially extending
annular ridge 102 which engages an internal annular restrictive
shoulder 104 on casing hanger head 24. Shoulder 104 provides the
support for casing hanger 32 upon engagement by ridge 102.
The cementing operation for cementing casing string 30 into the
well requires a passageway from the annulus 106, between casing
string 22 and casing string 30, to annulus 108, between riser 26
and riser 34, to flow the returns to the surface. Ridge 102 has
apertures in the form of flutes or circulation ports 110 for fluid
flow around casing hanger 32.
Mandrel 70 has a reduced diameter portion 112 generally at its mid
section between annular groove 78 at its upper end and bore 91 at
its lower end which creates annular passageway 118. Reduced
diameter portion 112 is adjacent to packoff 38 so that fluid can
flow between the interior of packoff 38 and the external surface
114 of reduced diameter portion 112.
A plurality of circulation ports 116 shown in FIG. 2 communicate
between annulus 108 and passageway 118. These permit return fluids
to flow up annulus 106, through ports 110, into the passageway 118,
and through ports 116 into annulus 108.
The sealing member or packoff 38, suspended by nipple 60, is to be
used to seal off the passageway 118 to the flow of fluids after the
completion of the cementing operation. Packoff 38 is connected to
the lower end of nipple 60 by the connection at 62. A plurality of
equally spaced lands 124, alternated with grooves 126, are disposed
on the lower end of nipple 60. The upper end of packoff 38 has
lands 128 and grooves 130 correlating with grooves 126 and lands
124 respectively thereby forming a type of clutch. This permits a
torque to be placed on packoff 38 upon the rotation of nipple 60.
Packoff 38 is suspended axially by shear pin 122 passing through
land 126 and into a bore 123 in the lower end of nipple 60.
The sealing member 38 has a connector element 132 forming the
connection at 62 at its upper end, and which is telescopically
received at its lower end by a compression ring 134 which is
rotatably connected to the lower end of connector element 132 by
ball bearing means 136. Ball bearing means 136 has a plurality of
metal balls 138 rotatably mounted in an annular race 140 in the
exterior surface of connector element 132 and in annular race 142
in the interior surface of compression ring 134.
An inner cylindrical-shaped packing element 150 and an outer
cylindrical-shaped packing element 151 are retained against the
lower terminal end of compression ring 134 by a cylindrical packing
gland 152. Packing gland 152 has an annular stem 153 received by a
correlating annular groove 154 in the terminal end of compression
ring 134. Stem 153 is reciprocably retained within groove 154 by
means of a plurality of set screws 155 passing through the exterior
of compression ring 134 and into groove 154 to be received by
correlating vertical slots 156 in the upper portion of stem
153.
Packing gland 152 has an inner and outer annular shoulder 158, 160
respectively supporting packing elements 150, 151 against
compression ring 134. Shoulders 158, 160 and the lower end of
compression ring 134 control the expansion of packing elements 150,
151 during compression hereinafter discussed in more detail.
A hold down and compression means is mounted on sealing member 38
to lock and secure the casing hanger 32 in place and to compress
the packing elements 150, 151 so as to sealingly engage casing head
24 and casing hanger 32. This is achieved by a wholly inwardly
biased expandable latch 162 as for example of the type shown in
U.S. Pat. No. 3,540,533, and actuator nut 164 housed in a reduced
diameter portion 166 in the external surface of connector element
132. The actuator nut 164 has right hand threads 168 on its
internal surface which threadingly engage right hand threads 170 on
the external surface of reduced diameter portion 166. Expandable
latch 162 is mounted above actuator nut 164.
Latch 162 is actuated by the right hand rotation of handling string
34. To prevent actuator nut 164 from rotating with connector
element 132, nut 164 is mounted on the upper end of compression
ring 134 by means of a clutch connection. Finger-like projections
172 extend from the lower end of actuator nut 164 into correlating
recesses 174 in the upper portion of compression ring 134.
Compression ring 134 and Packing gland 152 are prevented from
rotating relative to each other by means of set screws 155 and
slots 156.
Packing gland 152 is held stationary by means of another clutch
type connection formed with casing hanger 32. A plurality of lugs
176, reciprocably mounted in recesses 178 in the lower portion of
retainer ring 152, are biased outwardly by springs 180. Lugs 176
are retained in recesses 178 by means of interlocking ears at 182.
Lugs 176 mate in correlating recesses 183 in annular ridge 102 in
the sealing position illustrated in FIG. 3 thereby preventing the
rotation of Packing gland 152, compression ring 134 or actuator nut
164.
Upon the rotation of connector element 132, actuator nut 164 is
therefore held stationary as connector element 132 rotates on
bearings 138. This causes nut 164 to rise due to right hand threads
168, 170. An annular beveled edge 184 is disposed on reduced
diameter portion 166 thereby camming expandable latch 162 outward
as nut 164 forces latch 162 upward. An annular groove 186 is
disposed in the internal surface of casing head 24 to receive latch
162. Groove 186 has upper and lower frusto-conical shoulders 187
which aid in the reception of latch 162. Latch 162 has a leading
beveled edge 163 which engages the interior of groove 186 until
edge 163 rests against the upper frusto-conical shoulder 187
thereby wedging latch 162 into place as shown in FIG. 4. This
causes the nut 164 to halt its upward movement and causes a
downward force to be placed on compression ring 134 as nipple 60
continues rotation. Stem 153 moves deeper into groove 154 as
compression ring 134 compresses packing gland 150 into sealing
engagement with the external surface of casing hanger 32 and with
the internal surface of casing head 24.
Upon completion of the activation of packoff 38, it is seen that
latch 162 also locks and secures casing hanger 32 against shoulder
104 thereby preventing any movement of casing hanger 32 within the
well.
Connector element 132 is provided with means for suspending a
succeeding casing hanger. As shown in FIG. 3 an annular shoulder
188 is disposed on the interior of connector element 132 for
engagement and support of the next casing hanger to be installed
within the well. Annular groove 190 is disposed below shoulder 188
for recovery of the packoff 38 with a secondary recovery tool (not
shown). Upon the installation of the succeeding casing hanger, the
added weight of the casing string suspended from that casing hanger
will add a further load on the packoff 38 and casing hanger 32.
Referring now to FIG. 2 and FIG. 2A, a bowl protector 192 can be
added to protect the interior surface 194 of casing head 24. Often
damage is caused to critical surfaces by the passage of equipment
through the flow bore. The protector 192 is mounted on the upper
end of connector element 132 at 196 by a J-slot connection 197.
Connection 197 includes a series of J-slots 199 in the lower end of
bowl protector 192 which receive correlating pins 201 disposed in
reduced diameter section 203 of connector element 132. A connection
means is provided on the upper portion of protector 192 for
engagement by a fishing tool to remove it prior to the installation
of a succeeding casing hanger. FIG. 2 illustrates the connection
means as an annular groove 198 with vertical slots 199 disposed in
the upper interior surface of protector 192. Stop lugs (not shown)
are affixed within groove 198 to form a plurality of J-slots.
In operating the invention, the assembly, including casing hanger
32, sealing member 38, and well tool 36, is connected to the last
section of casing string 30. The first section of handling string
34 is then attached to well tool 36 and the assembly is lowered
into the well by adding successive sections onto handling string 34
until the ridge 102 of casing hanger 32 lands on shoulder 104 of
casing head 24.
After landing the casing hanger within the well, cement is passed
through handling string or riser 34 and down through casing string
30. After the proper volume of cement has been put in the well, a
wiper plug (not shown) is put in the well and well fluids are run
into the well forcing the cement around the lower end of casing
string 30 and into annulus 106 until the cement rises to the
desired level.
Referring now to FIG. 3, to seal off annulus 106 nipple 60 is
disconnected from mandrel 70 upon a 30.degree. rotation of nipple
60 to disconnect the breech block connection 66. The handling
string 34 is then forced farther into the well to push and force
the sealing member 38 into sealing position if necessary.
Referring now to FIG. 4, connector element 132 is rotated by the
right hand rotation of handling string 34 causing actuator nut 164
to rise. Latch 162 expands into annular groove 186, and further
rotation compresses packing elements 150 and 151. As the packing
elements are compressed, they sealingly engage the exterior surface
of casing hanger 32 and the interior surface of casing head 24.
The packoff 38 is then tested by applying a pressure in the annulus
108. The flow bore of riser 34 and casing string 32 is then
monitored at the surface to detect any leak in the seals 78, 94. If
packoff 38 leaks, a pressure drop will be detected in annulus
108.
If a leak is detected, packoff 38 is removed by the left hand
rotation of connector element 132 causing actuator nut 164 to
descend, releasing latch 162 so that it can retract from annular
groove 186 when riser 34 is lifted, to permit packoff 38 to be
lifted from the sealing position.
Upward movement of riser 34 is continued until the lower teeth
segments 76 are engaged by the shoulder 73 in the nipple 60 below
the teeth segments 74. The handling string 34 is then rotated to
the right, the teeth segments 74 and 68 acting as a splined
connection to drive the left hand thread connection 84, until
completely disengaging from casing hanger 32. The well tool 36 may
then be lifted from the well and the problems with the sealing of
the packoff 38 corrected.
The packoff 38 may be again lowered into the well on nipple 60 and
re-engaged in the sealing position as previously described. No lead
thread need be picked up to re-engage the sealing member 38 since
only the smooth neck of the casing hanger 32 and the smooth bore
194 of the well head 24 with the simple interior annular groove 186
will have to be engaged.
If no leaks are detected, nipple 60 is released from connector
element 132 as shown in FIG. 5. Shear pin 122 is broken by applying
an upward force on handling string 34, since sealing member 38 is
secured by the latch 162.
Breech block connection 66 is then re-engaged and connection 84 is
disengaged as previously described to permit well tool 36 to be
removed from the well.
EMBODIMENT II
In embodiment II a threaded connection 200 and friction set latch
connection 202 are utilized to connect nipple 204 with mandrel 206
instead of breech block connection 66 as shown in embodiment I.
Referring now to FIG. 8 the upper portion of mandrel 206 has a
reduced diameter section 208 with threads 210 being disposed on the
exterior surface of mandrel 206 at the end of section 208. A land
212, disposed on the interior of nipple 204 with threads 214
thereon, engages threads 210 of mandrel 206.
Upon the right hand rotation of nipple 204, threads 210, 214
disengage, and land 212 is received by reduced diameter section 208
as sealing member 220 is lowered into sealing position shown in
FIG. 9. Nipple 204 is lowered until frusto-conical shoulder 216
disposed below threads 214 almost engages frusto-conical shoulder
218 disposed on the exterior of mandrel 206 at the lower end of
section 208 as shown in FIG. 9 but no engagement is permitted
because friction would arise upon rotating nipple 204 thereby
inhibiting the seating of sealing member 220. This suspends sealing
member 220 and sealing elements 228 in sealing position without
permitting friction set latch connection 202 to engage.
Referring now to FIG. 9, latch connection 202 comprises an
expandable latch 222 provided within an annular recess 224 disposed
in the external surface of mandrel 206 just below section 208. A
set screw 207 passes through nipple 204 to retract latch 222 to
disassemble well tool 203 after it has been removed from the well.
The lower exterior edge 223 of latch 222 has teeth segments 225 to
provide added friction. The upper interior edge 227 of latch 222 is
beveled to engage the upper cam surface 229 of recess 224.
An annular groove 226 is provided in the interior surface of nipple
204 and is adjacent recess 224 when in the sealing position such
that the latch 222 expands into groove 226. Recess 224 has a
reduced depth portion 231 at its upper end whereby upon setting
sealing member 220 and securing casing hanger 230 by rotating
handling string 221, the shear pin 232 is broken by lifting nipple
204 thereby disconnecting the nipple 204 from the sealing member
220. Self expanding latch 222 then automatically expands into
groove 226. Beveled edge 227 of latch 222 may engage cam surface
229 if necessary to force latch 222 into reduced depth portion 231
as shown in FIG. 10.
The friction between the inner surface of groove 226, the latch
222, and the inner surface of recess 224 permits the translation of
torque from nipple 204 to mandrel 206. Therefore the rotation of
nipple 204 breaks shear pin 234 and mandrel 206 is unthreaded from
casing hanger 230 due to left hand threaded connection 236. This is
shown in FIG. 11.
A threaded connection could be used in place of the friction set
latch connection 202 and the breech block connection 66 as shown in
embodiments I and II, but it would obviously be less
advantageous.
FIG. 12 illustrates a multiple installation of the present
invention with casing head 300 supporting casing hanger 302 which
suspends casing string 304, and which supports sealing member 306.
Latch 308 is shown compressing packing element 310 to sealingly
engage casing head 300 and casing hanger 302.
A second casing string 320 is shown suspended from a second casing
hanger 322 which is supported by the connector element 312 of
packoff 306. Any number of succeeding casing strings can be
installed.
While a preferred embodiment of the invention has been shown and
described, modifications thereof can be made by one skilled in the
art without departing from the spirit of the invention.
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