U.S. patent number 3,800,869 [Application Number 05/103,839] was granted by the patent office on 1974-04-02 for underwater well completion method and apparatus.
This patent grant is currently assigned to Rockwell International Corporation. Invention is credited to Robert E. Bush, Andre H. Drouin, John H. Fowler, David P. Herd.
United States Patent |
3,800,869 |
Herd , et al. |
April 2, 1974 |
**Please see images for:
( Certificate of Correction ) ** |
UNDERWATER WELL COMPLETION METHOD AND APPARATUS
Abstract
Extended casing method and apparatus for completing an
underwater well whereby complete and continuous pressure control is
maintained at the surface drilling platform. A conductor casing is
installed in the floor of a body of water with a casing head and
riser attached near the floor. Other casing is installed and
supported at the water floor by hanger heads and having other
risers extending upwardly therefrom. Pressure control equipment is
installed at the upper end of one of the risers. An innermost
casing having a tubing hanger-head attached is lowered through the
pressure control equipment and installed. An orientation sleeve is
aligned with the tubing hanger-head by properly orient the tubing
hanger. The tubing hanger and tubing is then passed through the
pressure control equipment and the innermost riser, to which the
pressure control equipment is attached and is lowered to engage the
orientation sleeve for proper alignment with the innermost
hanger-head and remotely latched thereto. All seals are then
pressure tested. The tubing is plugged, the riser and control
equipment removed and a Christmas tree adapter connected to the
tubing hanger head. A Christmas tree assembly is then attached to
the adapter in fluidtight flow communication with the tubing
string.
Inventors: |
Herd; David P. (Houston,
TX), Fowler; John H. (Houston, TX), Drouin; Andre H.
(Houston, TX), Bush; Robert E. (Houston, TX) |
Assignee: |
Rockwell International
Corporation (Houston, TX)
|
Family
ID: |
22297285 |
Appl.
No.: |
05/103,839 |
Filed: |
January 4, 1971 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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792912 |
Jan 22, 1969 |
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Current U.S.
Class: |
166/337; 166/368;
166/382; 175/7 |
Current CPC
Class: |
E21B
33/035 (20130101); E21B 33/047 (20130101); E21B
33/043 (20130101) |
Current International
Class: |
E21B
33/035 (20060101); E21B 33/047 (20060101); E21B
33/03 (20060101); E21b 033/35 (); E21b
007/12 () |
Field of
Search: |
;166/.5,.6,313,315,89
;175/7 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Leppink; James A.
Parent Case Text
This application is a continuation of Application Serial No.
792,912, filed January 22, 1969, and now abandoned.
Claims
We claim:
1. A method of completing an underwater well comprising the steps
of:
locating drilling means at an underwater well site;
installing conductor casing in the floor of a body of water with a
casing head and riser attached thereto at a point near said floor,
said riser extending upwardly to said drilling means;
drilling holes for, suspending within said conductor casing and
cementing in place other casing, each of said other casing being
suspended near said floor by hanger means above which other risers,
extending upwardly to said drilling means, are connected;
attaching blowout pressure control equipment to the top of at least
one of said other risers at said drilling means prior to removal of
any of said other risers;
removing through said pressure control equipment any of said other
risers which are surrounded by the riser to which said pressure
control equipment is attached;
running a tubing hanger at at least one tubing string, through said
control equipment and the riser to which it is attached, into the
innermost casing;
suspending and latching said tubing hanger and tubing string in the
innermost hanger means; and
removing said pressure control equipment and the remainder of said
other risers.
2. A method of completing an underwater well as set forth in claim
1, characterized in that prior to running said tubing string first
orientation means is attached to the innermost hanger means and
said tubing hanger is provided with second orientation means
cooperating with said first orientation means to automatically
align said tubing hanger and tubing in a predetermined orientation
as they are run into said innermost casing.
3. A method of completing an underwater well as set forth in claim
1 characterized by the further steps of:
running a Christmas tree adapter means through said conductor riser
and attaching it to one of said hanger means, said adapter means
being provided with a packoff assembly for sealing around the
interior of said one of said hanger means and preventing passage of
fluid therethrough.
4. A method of completing an underwater well as set forth in claim
3 characterized by the further steps of:
running a closure cap means through said conductor riser:
connecting said cap means to said adapter means, closing the upper
end of said adapter means, said innermost casing and said
tubing;
removing said conductor riser; and
temporarily abandoning said well.
5. A method of completing an underwater well as set forth in claim
4 characterized by the further steps of:
removing said closure cap means;
attaching an underwater Christmas tree assembly to said adapter
means; and
preparing said well for production.
6. A method of completing an underwater well as set forth in claim
3 characterized by the further steps of:
removing said conductor riser;
guiding an underwater Christmas tree assembly into place on said
adapter means; and
connecting said Christmas tree assembly to said adapter means.
7. A method of completing an underwater well as set forth in claim
1 characterized in that said tubing hanger is provided with latch
means for said attachment to said innermost hanger means, said
tubing string being longitudinally displaced from its final support
position on said tubing hanger as they are run into said riser,
said tubing string being lowered to its final support position on
said tubing hanger after said tubing hanger reaches its final
support position in said innermost hanger means and thereby
activating said tubing hanger latch means for said attachment to
said innermost hanger means.
8. A method of completing an underwater well as set forth in claim
1 characterized in that after said tubing hanger and tubing string
are latched in said innermost hanger means and before removal of
said pressure control equipment, the seals of said tubing hanger
and tubing string are pressure tested.
9. A method of completing an underwater well as set forth in claim
8 characterized in that after said testing of said seals and before
removal of said pressure control equipment a downhole packer
attached to said tubing string is set and pressure tested.
10. A method of completing an underwater well as defined in claim 9
wherein the method of pressure testing the downhole packer
comprises:
installing a back pressure valve in all tubing strings except one
remaining tubing string which extends below the downhole
packer;
applying a fluid pressure through said remaining tubing string
causing pressure to be applied beneath the packer; and
detecting any pressure leak in the packer by providing an access
port through the tubing hanger which communicates with a handling
string extending to the surface and by monitoring the handling
string for the passage of fluids.
11. A method of completing an underwater well as defined by claim 8
wherein the method of pressure testing the seals of said tubing
hanger and tubing string comprises:
plugging an access nipple of the tubing hanger with a well
tool;
applying a fluid pressure through said tubing string causing
pressure to be applied beneath the seals; and
detecting any pressure leak in the seals by monitoring the pressure
in the riser to which the pressure control equipment is
attached.
12. A method of completing an underwater well as defined by claim
11 wherein the method of pressure testing the seals further
comprises releasing the pressure through an access port in the well
tool which communicates with a handling string.
13. A method of completing an underwater well as set forth in claim
1 characterized in that after said pressure control equipment and
said other risers are removed, Christmas tree adapter means is
connected to one of said hanger means, said Christmas tree adapter
means being provided with annular seal means for sealing an annular
space between said innermost hanger means and an adjacent hanger
means.
14. A method of completing an underwater well as set forth in claim
13 characterized by the further steps of:
removing said conductor riser; and
attaching a Christmas tree assembly to said adapter means, said
Christmas tree assembly being provided with nipple means
communicating with said tubing string through said tubing
hanger.
15. A method of completing an underwater well as set forth in claim
13 further comprising testing the annular seal means for leaks.
16. A method of completing an underwater well as set forth in claim
15 wherein the method of testing the annular seal means
comprises:
attaching a running tool, having an internal access port in
communication with a handling string, to the Christmas tree
adapter;
sealing the running tool to the Christmas tree adapter above the
annular seal means forming a closed space;
placing a fluid pressure through the internal access port and into
said closed space and
detecting any pressure leak in the seals by monitoring the pressure
in the handling string.
17. A method of completing an underwater well as set forth in claim
1 characterized in that said pressure control equipment is
connected to the innermost of said other risers, said innermost
casing hanger means and riser assembly being provided with first
orientation means placed in a predetermined position before running
of said tubing string, said tubing hanger being provided with
second orientation means cooperating with said first orientation
means to automatically align said tubing hanger and tubing string
in a predetermined position as they are run in said well.
18. A method of completing an underwater well as set forth in claim
14 characterized in that said tubing string is held in an upwardly
displaced position, relative to said tubing hanger by shear means
prior to said latching of said tubing hanger in said innermost
hanger means, said shear means being sheared after said tubing
hanger is latched in allowing said tubing string to be run to
bottom and supported in that position by tubing landing nipples
supported on said hanger means.
19. A method of completing an underwater well as set forth in claim
18 characterized in that said tubing string is cemented in said
well in said bottom supported position prior to removing said
pressure control equipment.
20. An emergency method of completing an underwater well as set
forth in claim 17 characterized in that after said latching of said
tubing hanger in place and lowering of said tubing string as far as
possible and before removal of said pressure control equipment said
tubing string is cemented in said well, slip means are lowered
around the upper part of said tubing string onto said tubing
hanger, said slip means are set on said tubing string and said
tubing string is cut off above said tubing hanger.
21. A method of completing an underwater well as set forth in claim
1 and the further steps of:
lowering Christmas tree adapter means through said conductor
riser;
connecting said adapter means to said innermost hanger means, said
adapter means being provided with packoff means sealingly engaging
the interior of said innermost hanger means and the exterior of an
extension of said tubing string above said tubing hanger preventing
fluid flow through said innermost casing and hanger means.
22. A method of completing an underwater well as set forth in claim
21 characterized by the further steps of:
removing said conductor riser,
attaching a Christmas tree assembly to said adapter means, said
Christmas tree assembly being provided with nipple means engaging
said tubing string extension for fluidtight flow communication
therebetween.
23. Underwater well completion apparatus comprising:
a casing string penetrating the floor of a body of water;
hanger-head means connected to the upper end of said casing string
near the floor of said body of water;
riser means connected to said hanger-head means extending upwardly
through said body of water to the surface of said body of
water;
pressure control means connected to the upper end of said riser
means;
tubing hanger means lowerable through said pressure control means
and said riser means to a position within said hanger-head means to
be supported thereby;
at least one tubing string supported by said tubing hanger means
and lowerable through said pressure control means and said riser
means; and
characterized in that first orientation means are provided near the
base of said riser means cooperable with second orientation means
on said tubing hanger means to automatically position said tubing
hanger within said hanger-head means in a predetermined angular
orientation relative thereto.
24. Underwater well completion apparatus as set forth in claim 23
characterized in that said first orientation means comprises a
helically generated upwardly facing surface.
25. Underwater well completion apparatus as set forth in claim 23
characterized in that said riser means and said first orientation
means are removable and reengageable with said hanger-head means to
permit subsequent removal and replacement of said tubing hanger
means in the same said predetermined angular orientation.
26. Underwater well completion apparatus as set forth in claim 23
characterized in that said tubing hanger means is provided with
remotely actuatable latch means to lock said tubing hanger means to
said hanger-head means.
27. Underwater well completion apparatus as set forth in claim 23
characterized in that said tubing string is cemented in said casing
string.
28. Underwater well completion apparatus comprising:
conductor casing means penetrating the floor of a body of
water;
casing head means attached to said conductor casing means near said
floor;
other casing means concentrically disposed within said conductor
casing means;
hanger-head means connected to said other casing means, said
hanger-head means being provided with support means engageable with
other support means surrounding said hanger-head means to limit
longitudinal movement of said other casing means and said
hanger-head means;
riser means connected to at least one of said hanger-head means
extending upwardly therefrom to drilling means above the surface of
said body of water;
pressure control means connected to the upper end of at least one
of said riser means;
tubing hanger means lowerable through said pressure control means
and said riser means to a supported position on the innermost of
said hanger-head means;
at least one tubing string connected to said tubing hanger means
and lowerable therewith through said pressure control means and
said riser means to said supported position; and
characterized in that said tubing hanger means is provided with
latch means engageable with said innermost hanger-head means on
longitudinal movement of said tubing string relative to said tubing
hanger means to lock said tubing hanger means to said innermost
hanger-head means.
29. Underwater completion apparatus as set forth in claim 28
characterized by first orientation means on said innermost
hanger-head means and second orientation means on said tubing
hanger means cooperable with each other to automatically orient
said tubing hanger means in a predetermined angular position
relative to said innermost hanger-head means.
30. Underwater well completion apparatus as set forth in claim 29
characterized in that said first orientation means comprises an
upwardly facing helical surface terminating at a longitudinal slot
means and said second orientation means comprises key means
engageable with said helical surface and slidable thereon to rotate
said tubing hanger means to allow said key means to engage said
slot means.
31. Underwater well completion apparatus as set forth in claim 28
characterized in that said riser means to which said pressure
control means is attached is removable from said hanger-head means
by rotation of less than 360.degree..
32. Underwater well completion apparatus comprising:
outer casing means penetrating the floor of a body of water;
casing head means attached to said outer casing means near said
floor;
riser means attached to said casing head means extending upwardly
through said body of water to the surface of said body of
water;
pressure control means connected to the upper end of said riser
means;
inner casing means lowerable through said pressure control means
and riser means and concentrically disposed within said outer
casing means;
hanger-head means lowerable through said pressure control means and
riser means and connected to said inner casing means, said
hanger-head means being provided with support means engageable with
other support means surrounding said hanger-head means to limit
longitudinal movement of said inner casing and said hanger-head
means; and
tubing hanger means lowerable through said pressure control means
and riser means and supported on the innermost of said hanger-head
means, said tubing hanger means having a generally cylindrical
exterior of a diameter less than the major internal diameter of
said innermost hanger-head means.
33. Underwater well completion apparatus as set forth in claim 32
characterized by tubular Christmas tree adapter means lowerable to
and engageable with one of said hanger-head means in fluidtight
connection therewith.
34. Underwater well completion apparatus as set forth in claim 33
characterized in that said adapter means is provided with packoff
means engageable with a cylindrical wall of the hanger-head means
to which said adapter means is attached and engageable with at
least one other radially displaced cylindrical wall to prevent
fluid passage through said hanger-head means to which said adapter
is attached.
35. Underwater well completion apparatus as set forth in claim 34
characterized in that said one other radially displaced cylindrical
wall comprises a portion of tubing string nipple means extending
upwardly from said tubing hanger means, and the base of said
packoff means is provided with a frusto-conical guide surface
surrounding a passage through said packoff means, the axis of said
passage and said frusto-conical guide surface being coincident.
36. Underwater well completion apparatus as set forth in claim 33
characterized in that said adapter means and the said hanger-head
means with which it is engageable are provided with connection
means fully engageable on less than 360.degree. rotation of said
adapter means relative to said hanger-head means, said connection
means being provided with locking means engageable with said
adapter means and said hanger-head means to prevent disengagement
of said connection means.
37. Underwater well completion apparatus comprising:
conductor casing means penetrating the floor of a body of
water;
casing head means attached to said conductor casing means near said
floor;
other casing means concentrically disposed with said conductor
casing means;
hanger-head means connected to said other casing means, said
hanger-head means being provided with support means engageable with
other support means surrounding said hanger-head means to limit
longitudinal movement of said other casing means and said
hanger-head means;
tubing hanger means supported on the innermost of said hanger-head
means the maximum diameter of said tubing hanger means being less
than the internal diameter of at least one of said other casing
means;
at least one tubing string supported by said tubing hanger
means;
tubular Christmas tree adapter means connected to one of said
hanger-head means above and independently of said tubing hanger
means;
a Christmas tree assembly connected above said adapter means, said
Christmas tree assembly being provided with at least one flow bore;
and
nipple means being said tubing hanger means and said Christmas tree
assembly providing fluidtight flow communication between said
tubing string and said Christmas tree assembly flow bore.
38. Underwater well completion apparatus as set forth in claim 37
characterized in that the maximum external diameter of said adapter
means is less than the internal diameter of said conductor
casing.
39. Underwater well completion apparatus as set forth in claim 37
characterized in that the said hanger-head means to which said
adapter means is connected is one which surrounds said innermost
hanger-head means leaving an annular space therebetween, packoff
means being installed in said annular space to prevent fluid
passage therethrough.
40. Underwater well completion apparatus as set forth in claim 39
characterized in that said hanger-head means to which said adapter
means is connected and said innermost hanger-head are provided with
orientation means for positioning said innermost hanger-head means
in a predetermined position within said surrounding hanger-head
means relative thereto.
41. Underwater wellhead completion apparatus as set forth in claim
37 characterized in that said adapter means is connected to said
innermost hanger-head means and in that packoff means is installed
within said innermost hanger-head means sealing against the
interior of said innermost hanger-head means and the exterior of
said nipple means to prevent fluid flow through said innermost
hanger-head means.
42. Underwater well completion apparatus as set forth in claim 41
characterized in that said packoff means is rotatingly attached to
said adapter means and provided with a downwardly facing
frusto-conical guide surface, the axis of which is coincident with
the axis of said nipple means.
43. Underwater well completion apparatus as set forth in claim 41
characterized in that said innermost hanger-head means and said
tubing hanger means are provided with orientation means for
positioning said tubing hanger means within said innermost
hanger-head means in a predetermined angular orientation relative
thereto.
44. Underwater well completion apparatus as set forth in claim 41
characterized in that said tubing string is supported on said
tubing hanger means by slip means, said nipple means comprising a
portion of said tubing string extending upwardly from said tubing
hanger means.
45. A method of completing an underwater well comprising the steps
of:
locating drilling means at an underwater well site;
installing conductor casing in the floor of a body of water with a
casing head and riser attached thereto at a point near said floor,
said riser extending upwardly to said drilling means;
drilling holes for, suspending within said conductor casing and
cementing in place other casing, each of said other casing being
suspended by hanger means above which other risers, extending
upwardly to said drilling means, are connected;
attaching blowout pressure control equipment to the top of at least
one of said other risers at said drilling means;
drilling a hole for, suspending within said other casing and
cementing in place an innermost casing having tubing support
means;
running a tubing hanger and at least one tubing string, through
said control equipment and the riser to which it is attached, into
said innermost casing;
suspending said tubing hanger and tubing string in said innermost
casing;
latching said tubing hanger with said tubing support means; and
removing said pressure control equipment and said other risers.
46. Underwater completion apparatus comprising:
a casing string penetrating the floor of a body of water;
hanger-head means connected to the upper end of said casing string
near the floor of said body of water;
riser means connected to said hanger-head means extending upwardly
through said body of water to the surface of said body of
water;
a blowout preventer connected to the upper end of said riser
means;
an inner casing string lowerable through said blowout preventer and
said riser means;
tubing hanger means lowerable through said blowout preventer and
said riser means to a position within said inner casing;
tubing head means lowerable through said blowout preventer and said
riser means for suspension of said inner casing and for the support
of said tubing hanger means; and
at least one tubing string supported by said tubing hanger means
and lowerable through said blowout preventer and said riser
means.
47. Underwater well completion apparatus comprising:
conductor casing means penetrating the floor of a body of
water;
casing head means attached to said conductor casing means near said
floor;
other casing means concentrically disposed within said conductor
casing means;
hanger-head means connected to said other casing means, said
hanger-head means being provided with support means engageable with
other support means surrounding said hanger-head means to limit
longitudinal movement of said other casing means and said
hanger-head means;
riser means connected to at least one of said hanger-head means
extending upwardly therefrom to drilling means above the surface of
said body of water;
pressure control means connected to the upper end of at least one
of said riser means;
tubing hanger means lowerable through said pressure control means
and said riser means to a supported position within the innermost
of said hanger-head means;
means secured to said tubing hanger means for aligning said tubing
hanger means within said innermost hanger-head means; and
means secured to said tubing hanger means for locking down said
tubing hanger means within said innermost hanger-head means.
48. Underwater well completion apparatus comprising:
conductor casing means penetrating the floor of a body of
water;
casing head means attached to said conductor casing means near said
floor;
other casing means concentrically disposed within said conductor
casing means;
hanger-head means connected to said other casing means, said
hanger-head means being provided with support means engageable with
other support means surrounding said hanger-head means to limit
longitudinal movement of said other casing and said hanger-head
means;
conductor riser means attached to said casing head means extending
upwardly through said body of water to the surface of said body of
water;
tubing hanger means supported on the innermost of said hanger-head
means;
sealing means for sealing between said innermost hanger-head means
and said tubing hanger means; and
means secured to and engageable with said tubing hanger means for
testing the integrity of said sealing means.
49. Underwater well completion apparatus comprising:
conductor casing means penetrating the floor of a body of
water;
casing head means attached to said conductor casing means near said
floor;
other casing means concentrically disposed with said conductor
casing means;
hanger-head means connected to said other casing means, said
hanger-head means being provided with support means engageable with
other support means surrounding said hanger-head means to limit
longitudinal movement of said other casing means and said
hanger-head means;
tubing hanger means supported on the innermost of said hanger-head
means;
at least one tubing string supported by said tubing hanger
means;
tubular Christmas tree adapter means connected to one of said
hanger-head means other than said innermost hanger-head means and
independently of said tubing hanger means; and
sealing means for sealing between said innermost hanger-head means
and said one of said hanger-head means; and
means engageable with said Christmas tree adapter means for testing
the integrity of said sealing means.
50. An underwater well completion apparatus comprising:
casing head means;
hanger-head means;
a tubing hanger for supporting at least one string of tubing; said
casing head means having hanger suspension means to support said
hanger-head means; said hanger-head means including casing
suspension means for supporting a string of casing and tubing
support means for supporting said tubing; said tubing hanger being
supported by said tubing support means; said hanger-head means
being adapted to be received within said casing head means;
flow control means surmounting said hanger-head means and connected
in fluid flow relationship with said tubing hanger;
adapter means sealingly connecting said flow control means to said
hanger-head means;
seal means; said adapter means sealingly engaging said hanger-head
means by packing said seal means between said hanger-head means and
said casing head means; said seal means being connected to said
adapter means by a retainer means; and
said adapter means being attached to said retainer means by bearing
means permitting said adapter means to rotate with said seal means
remaining stationary.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention concerns underwater drilling of oil and gas wells.
Specifically, it pertains to methods and apparatus used in
underwater extended casing operations.
2. Description of the Prior Art
Increased activity in offshore drilling has resulted in a
continuous search for better methods and apparatus in this area. To
cope with the unique problems associated with underwater drilling
various extended casing methods have been developed. Basically,
extended casing methods have a well conductor anchored to the sea
floor which provides support for a special underwater wellhead. The
wellhead, in turn, supports a multiple number of casing strings and
their respective casing hangers. The drilling platform is thus
relieved of much of the structural support responsibilities of
other methods. After drilling is completed, the well may be
permanently abandoned, temporarily abandoned or immediately
completed. For any of these options, the completion equipment may
be installed at the sea floor, leaving the drilling platform free
for relocation and freeing the underwater wellhead from the hazards
of ocean going traffic and structural support problems. One such
extended casing method is fully described in copending U.S. Pat.
Application Ser. No. 572,599 now U.S. Pat. No. 3,421,580.
In the extended casing methods of the prior art, one or more
intermediate casing strings, in addition to the conductor casing
and the innermost production casing string, are usually supported
in the wellhead. Casing extensions or risers are attached to these
strings as they are lowered into place and landed. The extensions
are connected at the surface to a blowout preventer for pressure
control and also serve as a return for cement circulation. In the
past it has been necessary to remove all casing extensions, except
possibly the outer conductor riser, for installation of the tubing
head with the collet connector flange for making connection with
the underwater tree, the tubing hanger, and tubing strings. This
requires removal of the surface blowout prevention equipment. In
some cases, for safety precautions, a bridge plug is set in the
production casing prior to removal of the production casing riser.
The tubing head is attached to the production casing hanger head
and a high pressure riser extended back to the surface for
reattachment of the preventer equipment. The bridge plug is then
drilled out or otherwise and the well is then ready to receive
tubing. These operations require additional equipment time, and
consequently expenses.
Some methods have utilized underwater blowout preventers installed
near the underwater wellhead. However, such preventers are very
expensive and more complex to operate than the conventional above
water type.
SUMMARY OF THE INVENTION
The present invention concerns a method of completing an underwater
well comprising the steps of: locating drilling means at an
underwater well site; installing conducting casing in the floor of
a body of water with a casing head and riser attached thereto at a
point near the floor, the conductor riser extending upwardly to the
drilling means; drilling holes for, suspending within the conductor
casing and cementing in place other casing, each of the other
casing being suspended near the floor by hanger means above which
other risers, extending upwardly to the drilling means, are
connected; attaching blowout pressure control equipment to the top
of at least one of the other risers prior to removal of any of the
other risers; removing through the pressure control equipment any
of the other risers which are surrounded by the riser to which the
pressure control equipment is attached; running a tubing hanger and
at least one tubing string, through the control equipment and the
riser to which it is attached, into the innermost casing;
suspending and latching the tubing hanger and tubing string in the
innermost hanger means; and removing the pressure control equipment
and the remainder of the other risers.
This method provides complete and continuous pressure control
throughout completion by providing apparatus whereby the tubing
hanger and tubing string may be lowered through blowout preventers
and a riser to their support positions. After latching the tubing
hanger and tubing string in place the tubing is plugged and the
riser and pressure control equipment are removed for installation
of the Christmas tree assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and advantages of the invention will become apparent
from the description which follows when taken in conjunction with
the drawing in which:
FIGS. 1 through 6 are step by step sectional elevation views of an
underwater well showing a method and apparatus for completing a
dual tubing string well according to a preferred embodiment of the
invention, and
FIGS. 7 through 10 are step by step sectional elevation views of an
underwater well showing a method and apparatus for tubingless
completion of a well according to a preferred embodiment of the
invention.
FIGS. 11 and 12 illustrate an exemplary environment in which the
present invention may operate.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is an extended casing completion system for
use when drilling from a bottom supported rig with blowout
prevention control equipment at the surface. Several options on the
method of completion are available, including:
1. Easy permanent abandonment,
2. Temporary abandonment,
3. Completion by extension of casing, risers to a platform,
4. Casing-tubing sub-surface completion with optional diver support
or fully remote operation, and
5. Tubingless sub-surface completion with optional diver support or
fully remote operation.
The apparatus of the present invention permits installation of one
or more tubing strings through blowout prevention control equipment
and extended risers, eliminating the necessity of removing the
risers and blowout preventers when preparing the well for
completion. Because all operations are conducted through the risers
and blowout preventers, well pressure control is continuous and
remote guidance systems are not necessary when temporarily
abandoning the well or preparing it for completion. A guide base is
not installed until a decision is made to complete the well. This
allows a selection at that time of either fully remote Christmas
tree installation or diver support Christmas tree installation.
Referring now to FIGS. 11 and 12, there is illustrated a bottom
supported well drilling and completion apparatus which is entirely
conventional except for the tubing hanger-head which is shown in
more detail in the other figures. FIG. 11 shows the upper portion
of a bottom supported rig 1 with blowout prevention control
equipment 2 above the water surface 4 and surmounting the upper end
of risers 12, 43, 53 and 63 extending from the rig 1 to the well
head 5 at the mudline 3.
FIG. 12, in larger scale, shows a downward extension of risers 12,
43, 53, 63 from the rig 1 to the mudline 3 beneath the water
surface 4, and also shows the well head 5 supporting progressively
smaller concentric casing strings 10, 40, 50 and 60 in the well
bore. Each string of casing is cemented in the well bore from the
lower ends of the casing strings to a level thereabove as indicated
at 6, 7, 8, and 9. Production casing 60 extends from the rig 1
through the ocean floor 3 and water 4 to the production zone
14.
Referring first to FIGS. 1 through 6, a step by step description of
casing-tubing sub-surface completion, according to a preferred
embodiment of the invention, will be given. The system described
will be a 30 inch .times. 16 inch .times. 103/4inch .times. 7 inch
casing program with two 23/8 inch tubing strings. However, it is to
be understood that the size and number of casing and tubing may
vary without departing from the principles of the invention.
First, a 30 inch conductor casing 10, casing head 11, and conductor
riser 12 are lowered from the drilling platform 1 and driven or
jetted into the sea floor 1 until casing head 11 rests near the
floor. If bottom conditions require it, a hole may be drilled for
conductor casing 10. Casing head 11 is provided with an upwardly
facing stop shoulder 13 for locating the surface casing.
Riser 12 is connected to casing head 11 by an easily disengageable
connection 14. One type of easily disengageable joint is shown in
FIG. 1A. This type of joint, which we refer to as a breech block
joint, reduces drilling costs by eliminating on-site welding,
permitting easy recovery of casing risers and reducing rig time
during making, running and recovering casing risers. The joint
comprises a female member 20 and a male member 30. Segmented
threads 21 of a square non-lead profile spaced 30.degree. apart are
milled in the female member for engagement with corresponding
segmented threads 31 on the male member. Smooth milled out areas
22, 32 are provided between the thread segments 21, 31. For
descriptive purposes the thread segments 21, 31 are referred to as
lands and milled out areas 22, 32 as grooves. Engagement is
accomplished by inserting the lands of the male member 30 in the
grooves of the female member 20, then rotating the male member 30
thirty degrees in either direction until the lands of each member
are in full engagement. A positional stop 33 on the male member
cooperates with lugs 35 around the female member to limit rotation
to 30.degree.. A pivotable anti-rotation latch 34 may be provided
to engage the opposite side of lugs 35 preventing disengagement of
the joint.
After the 30 inch conductor casing is set, a hole is drilled for 16
inch surface casing 40, which is lowered into place with surface
casing head 41, back-off joint 42 and surface casing riser 43
attached thereto. Back-off joint 42 and head 41 may be connected by
a breech block joint 46 similar to that shown in FIG. 1A. Landing
lugs 44 are provided on surface casing head 41 cooperating with
stop shoulder 13 to locate surface casing 40. The surface casing 40
is then cemented in place. The remaining strings will be supported
by the cement around surface casing 40. Casing head 41 is provided
with internal annular recesses to receive hanging latches for the
next string.
Next a hole is drilled for the 103/4 inch intermediate casing
string 50 which is lowered into the hole attached to hanger-head
51, back-off joint 52, and riser 53 and cemented in place.
Hanger-head 51 and back-off joint 52 are connected with another
breech block connection 54. Hanger-head 51 is provided with spring
biased latches 55 which support the casing string 50 within the
well. As the latches 55 engage recesses 45, a locking rib 56 on the
hanger-head body locks them into positive engagement. Hanger-head
51 may be provided with internal circulation ducts 57 or the
latches 55 may be fluted for cement circulation. Internal latch
recess 58 and circulation ducts 59 may be provided for ducting
around the next hanger-head. Blowout prevention control equipment
is attached to the top of riser 53 at the drilling platform 1.
Next the hole for production casing string 60 is drilled and the
production string is landed and cemented in place attached to
hanger-head 61, back-off joint 62 and riser 63. Production string
hanger-head 61 is similar to hanger-head 51 having spring latches
65 a locking rib 66 and if necessary flow ducts 67. However, it has
no internal latch recesses and it is connected to back-off joint 62
by a left hand thread connection 64 rather than a breech block
joint. Immediately above the connection 64 two internal tubing
hanger hold down recesses 68 are cut. An external key 69 provides
orientation for a subsequently installed tubing hanger. Therefore,
the production string 60 must be properly oriented while running in
place.
The aforementioned drilling is done through the blowout prevention
equipment at the drilling platform. At this stage of the drilling,
the wellhead equipment would be as shown in FIG. 1. At this time
the production string riser 63 is removed by rotating the riser 63
and back-off joint 62 to the right.
Referring specifically now to FIG. 2, an orientation sleeve 70
connected by a "J" slot arrangement 76 to running tool 71 and
running string 72 is run through 103/4 inch riser 53. A
longitudinal slot at the base of sleeve 70 engages hanger-head key
69 and the sleeve comes to rest against hanger-head shoulder 73. An
orientation bushing 74 is affixed to the interior of sleeve 70 for
automatic guidance of a tubing hanger which is to be installed. It
has a dual 180.degree. ramp 75 and a vertical slot 76 communicating
with the ramp at its lowermost intersection. Tool 71 is then
disconnected from orientation sleeve 70 and removed.
Referring now to FIG. 3, a tubing hanger 80, tubing 90, 91 and
annulus access nipple 92 are installed along with test tool 93.
Tubing hanger 80 is provided with three vertical bores 81, 82 (one
not shown) communicating with annulus access nipple 92 and tubing
strings 90, 91. Long tubing handling string 94 is connected to
hanger 80 by a handling nipple (not shown) similar to handling
nipple 95 connected to short string handling string 79. Both
nipples pass through test tool 93. However, nipple 95 is screwed
into a landing nipple 96 whereas the long string handling nipple is
screwed directly in hanger 80. Both tubing strings 90, 91 are
lowered together. However, short string 91 is displaced upwardly a
slight amount from the position shown in FIG. 3.
Hanger 80 is provided with a longitudinal key 83 which rides on
orientation bushing ramp 75 until it engages orientation slot 76
orienting the tubing hanger 80. The tubing hanger comes to rest on
the upper shoulder 85 hanger-head 61. A hold down latch 86 and
locking sleeve 87 are mounted in the skirt portion of hanger 80
near its base. In the running position the latch 86 is retracted
and locking sleeve 87 is held up against the body of hanger 80 by
engagement with landing nipple 96. When the hanger 80 is landed,
short tubing string 91 and landing nipple 96 are allowed to move
downwardly to the position shown in FIG. 3, where it is supported
by shoulder 88, causing locking sleeve 87 to force hold down latch
86 into engagement with hanger-head hold down recesses 68. Up to
this point handling nipple 95 and landing nipple 96 are fully made
up so that the upper edge of landing nipple 96 is abutting
downwardly facing shoulder 97 on handling nipple 95. By rotating
handling nipple 95 to the right these shoulders are separated
allowing a snap ring 89 in hanger 80 to spring out engaging the
upper edge of landing nipple 96 and holding the short tubing string
91 down. At this point all wellhead components appear as shown in
FIG. 3.
Next the tubing hanger seals would be tested by pressurizing
through short tubing string 91. Pressure would then be applied
below the tubing hanger 80 and through annulus access nipple 92 and
tubing 90. Testing tool 93 is provided with a vertical port 98 and
a horizontal port 99 which communicates with long tubing string 90
through a port in the handling nipple (not shown) attached to
handling string 94. Should any of the seals around hanger 80 and
landing nipple 96 leak it will be detected in riser 53.
Next, the downhole tubing packer is set, usually by hydraulic
means, a back pressure valve is installed in long string 90 and the
packer pressure tested. Pressure is applied through short string
91. If the packer leaks the test fluid passes through annular
access nipple 92 and through test tool ports 98, 99 into handling
string 94 for detection.
If all tests are positive, the tubing handling strings 94, 79,
their respective handling nipples, and test tool 93 are removed
from the hole by rotating the handling strings to the right. The
orientation sleeve 70 and orientation bushing 74 are removed using
the running tool 71. The tubing strings 90, 91 and annulus access
nipple 92 are plugged. It will be noticed that throughout running
and setting of the tubing hanger and tubing strings complete
pressure control is maintained at the surface by blow-out
prevention equipment connected to 103/4 inch riser 53.
Next, the pressure control equipment, 103/4 inch riser 53 and 16
inch riser 43 are removed by 30.degree. rotation to the right for
disengagement of breech block connections 54 and 46. At this stage,
the wellhead will appear as shown in FIG. 4 with conductor
extension 12 being the only remaining riser.
Referring now to FIG. 5, a tubular Christmas tree adapter 100 is
run on drill pipe 120 using a combination running testing tool 130.
The external midportion of adapter 100 is provided with the male
part of a breech block connection 101 for engagement with the
female part of the connection 101 in the 103/4 inch head 51.
Rotatably connected by ball bearings 102 to the lower part of
adapter 100 is an annular packoff assembly comprising a resilient
seal member 104 sandwiched between upper and lower retainer members
103, 105. Lower retainer 105 is stopped against hanger-head
shoulder 106 and as the breech block connection 101 is engaged
upper retainer ring 103 presses against seal member 104 causing it
to sealingly engage the walls of hanger-heads 51 and 61. A port 131
connects the bore 132 of tool 130 with the annular space between
adapter 100 and tubing hanger 80. This space is sealed at 133, 134
by O-rings, allowing adapter seals 104, 108, 109 and tubing hanger
seals 110 to be tested.
Christmas tree adapter 100 has an upper flange member 111 and
internal connection threads 112 to which tool 130 is connected.
Christmas tree adapter 100 also has stop lugs 113 which cooperate
with stop lugs 114 on the top of hanger-head 51 when the
breech-block connection is made to stop rotation at full
engagement. To prevent disengagement, a locking ring 115 with
depending lugs 116, is mounted around adapter 100 and held upwardly
thereon as shown by radial pins 117 which ride in an "L" slot 135
in sleeve skirt 136 of tool 130. A shear pin 137 is sheared on
further right hand rotation of tool 130. This allows skirt 136 to
rotate to a position where pins 117 drop out of the "L" slot
allowing the locking ring 115 to drop downwardly so that its lugs
116 fall between the back of adapter lugs 113 and the next closest
hanger-head lug 114. This prevents rotation of adapter 100 in
either direction thus locking it in position. Further rotation of
tool 130, to the right, releases it for removal from the well.
If it is decided to temporarily abandon the well, rather than
immediately complete it, a corrosion cap (not shown) may be run on
drill pipe using a "J" type running tool. It would be connected to
the internal threads 112 of tubing head adapter 100. The corrosion
cap could be provided with a port for spotting oil within the
wellhead to prevent corrosion. This port would, of course, be
plugged after the oil was injected. After installation of the
corrosion cap, conductor riser 12 would be removed by rotating
30.degree. to the right. A corrosion cap top could be installed by
a diver and the well could be temporarily abandoned.
Alternatively, if it is desired to immediately complete the well,
rather than install a corrosion cap, the Christmas tree would be
installed. To do this, conductor riser 12 would be removed. Now
referring also to FIG. 6, a small guide base 140 with two guide
posts 141 would be clamped around the lower part of adapter 100 or
hanger-head 51 by a diver. The guide base would be oriented by a
tool with two pins adapted to engage tubing hanger receiving
pockets 118, 119.
Next, Christmas tree 150 would be lowered to the wellhead. It would
be provided with guide arms 151 and bell bottom sleeves 152 which
would engage guide posts 141 to assist a diver in installing the
tree 150. The base of tree 150 carries three long nipples 153, 154,
the one for tubing 90 not shown, which sealingly engage the
corresponding receiving sockets 118, 119, the one for tubing 90 not
shown, in hanger 80. The base of tree 150 would come to rest
against the upper face of adapter 100. An annular seal ring 155
would be provided at the joint. The tree 150 is then clamped to
Christmas tree adapter 100 by a standard type clamp 160. A remote
hydraulic connector could be used as an option eliminating the need
for a diver to torque up clamp bolts. Thus, as shown in FIG. 6, the
well is ready for production.
Should it be necessary at a future date to perform workover
operations, tubing strings 90, 91 would be plugged and the
Christmas tree 150 removed. Then a workover riser with a built in
orientation sleeve and bushing similar to sleeve 70 and bushing 74
in FIGS. 2 and 3 would be attached to tree adapter 100. The
orientation bushing would have a slot to engage key 83 of tubing
hanger 80. In this manner, after the tubing hanger 80 is
re-installed, following workover operations, it is landed in the
same position as it was before workover operations.
If a tubingless sub-surface completion is desired, instead of a
casing-tubing sub-surface completion, a somewhat different
procedure is followed. However, with reference to FIG. 7, the first
steps are the same as in the casing-tubing sub-surface completion
just described. A 30 inch conductor casing 210, casing head 211,
and conductor riser 212 connected by breech-block joint 214 are
installed. A 16 inch surface casing 240, casing head 241, back-off
joint 242, and riser 243 are installed. Next, the 103/4 inch casing
string 250, hanger-head 251, back-off joint 252, and riser 253 are
installed as in the conventional completion.
There is a slight difference in hanger-head 251 and back-off joint
252. Hanger-head 251 is provided with an internal vertical slot 259
immediately above the hanging recesses 258. Orientation in this
method will be obtained by orienting the 103/4 inch hanger-head 251
rather than the 7 inch hanger-head in the afore-described
casing-tubing sub-surface completion. Backoff joint 252 is provided
with an orientating bushing 260 which has a double ramp orienting
slot 261 cut on a 45.degree. angle. A vertical slot 262 is cut at
the bottom or ramp 261 for alignment with hanger head slot 259. A
hanger-head and back-off joint equipped with the modifications of
hanger-head 251 and back-off joint 252 could be used with the
casing-tubing sub-surface completion previously described,
providing an option, at this point, of either casing-tubing
completion or tubingless completion.
Blowout prevention equipment 2 is attached at the upper end of
riser 253 at the drilling platform. Running of tubing will be
performed through this blowout prevention equipment so that full
pressure control is maintained at all times as in the previously
described method.
In the next step, two strings of tubing 270, 271 are clamped
together and run in the well tied by shear pins 273 to a tubing
hanger assembly 280. Tubing hanger 280 is provided with outwardly
biased hanging latches 281 and inwardly biased tubing latches 282
around openings 284, 285 through which tubing strings 270, 271
pass. An offset opening (not shown) through the hanger 280 provides
access to the annulus between the tubing string 270, 271 and 103/4
inch casing 250. This allows both cementing circulation and limited
gas lift production.
Also provided on hanger 280 is an external spring loaded dog 290.
Referring also to FIG. 7A dog 290 is beveled at the top 291 and
bottom 292 so that it is cammed inwardly by any horizontal shoulder
it encounters as the hanger is lowered into the well. However,
looking at the face of dog 290, its bottom 292 is "V" shaped
providing 45.degree. angle edges 293, 294. If these angle edges
293, 294 encounter a matching 45.degree. angle shoulder such as
orienting ramp 261, the dog 290 will not be cammed inwardly but
will ride down the ramp causing the tubing hanger 280 to rotate
therewith. Thus, as the tubing strings 270, 271 and hanger 280 are
lowered into the well, dog 290 engages ramp slot 261 rotating the
hanger 280 until dog 290 falls through vertical slot 262 and into
slot 259 as shown. Latches 281 engage hanging recesses 258 in a
proper orientation.
Attached to the upper end of tubing strings 270, 271 are tubing
hanging nipples 275, 276 which are provided with external hanging
grooves 277, 278. One of the nipples, in this case 275, is longer
than the other for reasons to be described subsequently. Running
tools 286, 287 connect the hanging nipples 275, 276 to running
strings 296, 297.
After the tubing hanger 280 is in place as shown in FIG. 7, the
weight of tubing 270, 271 shears pins 273. Both strings 270, 271
are then run to bottom and tubing latches 282 engage the latch
grooves 277, 278 in hanging nipples 275, 276, supporting the tubing
strings as shown in FIG. 8. Both strings can then be cemented and
handling strings 296, 297 and running tools 286, 287 removed by
rotation to the right. At this stage of completion the wellhead
equipment appears as in FIG. 8.
If for any reason tubing strings 270, 271 should become stuck after
tubing hanger 280 is latched in, and cannot be freed, both strings
would be cemented in. Then a standard outside tubing cutter would
be run over one of the tubing strings. The cutter would be modified
slightly to support tubing slips at its bottom. These tubing slips
(not shown) would be lowered to engage tapered receiving bowls 288,
289 in the top of the hanger 280. The slips would be set and then
the tubing string would be cut off at a distance from hanger 280
equal to the height of hanging nipples 275, 276, one longer than
the other. After one tubing is set and cut the same procedure would
be followed for the other tubing string.
Next, tubing strings 270, 271 are plugged and risers 253 and 243
are removed by 30.degree. rotational disengagement of breech-block
connections 246, 254 as in the casing-tubing sub-surface completion
previously discussed. This leaves only the 30 inch riser 212.
As now shown in FIG. 9, a Christmas tree adapter 300, similar to
the adapter 100 (FIGS. 5 and 6), is lowered through riser 212 on
drill pipe 320 and combination running and testing tool 330. The
external midportion of adapter 300 is provided with the male part
of breech-block connection 301 for engagement with head 251.
Rotatably connected by ball bearings 302, at the lower part of
adapter 300, is annular packoff assembly 303. Assembly 303 differs
from the casing-tubing sub-surface completion apparatus in that it
is designed to also packoff around hanging nipples 275, 276 as well
as against head 251. The lower retaining ring 304 of packoff
assembly 303 is provided with an offset frusto-conical surface, the
axis of which coincides with the axis of landing nipple 275. Thus,
if the packoff assembly is not properly oriented as tubing head
adapter 300 is lowered into place, the frusto-conical surface 305
contacts one of the tubing nipples, and is cammed around to the
proper orientation. Nipple 275 is longer than nipple 276 to prevent
the possibility of both nipples contacting surface 305 at the same
time should assembly 300 be exactly 90.degree. out of proper
orientation. Packoff assembly 300 also has an annular access port
306.
Running tool 330 seals on the inside diameter of adapter 300 at 307
and on the outside diameter of hanging nipples 275, 276 at 308,
309. Internal porting 310 within the tool 330 permits pressure
testing of the packoff assembly 303.
Christmas tree adapter 300 has an upper flange member 311 and
internal connection threads 312 to which tool 330 is connected. The
adapter 300 also has stop lugs 313 which cooperate with hanger-head
stop lugs 314 to limit stop rotation at full engagement as
explained with reference to FIG. 5 in the casing-tubing sub-surface
completion method previously described herein. Also provided is a
lock ring 315 held first in an upward position by sleeve skirt 336
of the tool 330. After shearing of pin 337 right hand rotation of
tool 330 allows pins 317 to drop out of "L" slots 335 in sleeve 336
allowing its lugs 316 to drop between the back of adapter lugs 313
and the next closest hanger-head lugs 314, locking the adapter in
its fully engaged position. Further rotation of tool 330 frees it
for retrieval from the well.
The well can then be temporarily abandoned as explained in the
casing-tubing sub-surface method previously described or it can be
completed for production. If it is to be completed for production,
at this point, conductor riser 212 is disconnected from conductor
head 211 by thirty degree rotation and removed.
Now referring to FIG. 10, a spool piece 350, and Christmas tree 360
is guided into place and attached to adapter flange 311 by standard
type diver assist clamp 351. Spool pieces 350 may be lowered by
itself first with Christmas tree 360 being lowered afterward.
Alternatively, Christmas tree 360 may be assembled with spool piece
350 by clamp 361, then lowered together into place for attachment
to adapter 300. Spool piece 350 is provided with nipples 352, 353
which stab and seal over hanging nipples 275, 276. It is also
provided with a side opening outlet 354 and bore 355 communicating
with port 306 and tubing-casing annulus below hanger 280 through a
port (not shown) in hanger 280. A valve removal plug 356 allows for
future installation of a side outlet valve. Christmas tree 360 is
provided with short nipples 362, 363 which sealingly engage pockets
provided for this purpose in spool piece 350. Nipples 362, 363,
352, 353, 275, 276 and spool bores 357, 358 provide unobstructed
full opening into tubing strings 270, 271.
The foregoing methods and apparatus for completing an underwater
well for both the casing-tubing sub-sea completion or tubingless
completion offer definite advantages in both speed and safety.
Complete pressure control at the drilling platform is maintained at
all times and the apparatus used permits fast connection and
disconnection for reduction of expensive rig time.
* * * * *