FIELD AND BACKGROUND OF THE INVENTION
[0001] The present invention relates to a method for enabling removal of tubing from a hydrocarbon
well, which tubing is at its upper end provided with a tubing hanger mounted in a
central passage of the wellhead.
[0002] Removing tubing from hydrocarbon well, in particular from subsea hydrocarbon wells
is often necessary in plug and abandonment procedures, i.e. when sealing off a well
at the end of its economic lifetime. To seal off the well, permanent plugs need to
be provided in the wellbore, which requires tubing mounted in the wellbore to be removed
first. This because the tubing is often provided with wires and control lines, extending
along the outside of the tubing, which wires and lines may damage the integrity of
the plugs over time. Thus, to enable reliable and permanent seals to be mounted in
the wellbore, the tubing needs to be removed first.
[0003] It is noted that tubing differs from well casing in that the latter is often cemented
in place during the drilling of the bore hole. This casing can often remain in the
borehole and may serve as a support for plugs mounted in the borehole.
[0004] The tubing can be, for example, a production tubing for the production of hydrocarbon
fluid from a subterranean formation. Such production tubing is near its lower end
generally sealed to the wellbore casing by a production packer.
[0005] Typically, hydrocarbon wells are provided with a wellhead, which wellhead has a central
passage. The tubing is provided with a hanger at its upper end, which tubing hanger
rests on a shoulder in the wellhead. The tubing hanger thus flares out in the radially
outward direction to engage the shoulder provided in the well head. Thus, the outer
diameter of the tubing hanger is a larger than the outer diameter of the tubing itself.
[0006] When the hydrocarbon well is in operation, the wellhead is at its upper end provided
with a X-mas tree from which the produced fluids are transported to a storage device.
Also, when the hydrocarbon well is a subsea hydrocarbon well, the wellhead may be
provided with a BOP to enable a riser, supported from a vessel or jack up rig, to
be connected to the wellhead.
[0007] Retrieval of the tubular element together with the hanger requires the X-mas tree
and/or BOP to have a bore or passage with a diameter large enough for passing the
tubing hanger.
[0008] Furthermore, if the tubular element has to be retrieved from a subsea well, often
a riser is used, which extends from the wellhead up to a vessel or jack up ridge.
Typically the riser, and at least part of the wellbore, are filled with wellbore fluid
to provide counter pressure to prevent the hydrocarbon from escaping the well. Retrieval
of the tubing with the tubing hanger through the riser requires the internal passage
of the riser to be of relatively large diameter, which as a consequence holds a relatively
large volume of drilling fluid. Consequently the riser is heavy. The vessel or platform
supporting the riser has to be suited to support the heavy riser and the drilling
fluid held therein.
[0009] It is an object of the invention to provide an improved method for enabling removal
of tubing from a hydrocarbon well, which method overcomes one or more of the aforementioned
problems, and which preferably obviate the need for a relatively heavy riser and large
vessel.
SUMMARY OF THE INVENTION
[0010] In accordance with the invention there is provided a method according to claim 1,
for enabling removal of tubing from a hydrocarbon well, which tubing is at its upper
end provided with a tubing hanger mounted in a central passage of the wellhead..
[0011] According to the invention, a machining device is lowered into a central passage
of the tubing hanger and machines away at least part of the tubing hanger, thus disconnecting
the tubing from the tubing hanger and enlarging the central passage of the tubing
hanger to a diameter wide enough for lifting the tubing out of the hydrocarbon well.
Thus, the tubing hanger no longer forms an obstacle when removing the tubing from
the hydrocarbon well. Thus the tubing can be removed through an opening or passage
having a diameter larger than the outer diameter of the tubing, but smaller than the
outer diameter of the tubing hanger.
[0012] Furthermore, once the tubing has been disconnected from the tubing hanger and a passage
is provided that has a diameter wide enough for lifting the tubing, including the
control wires and control lines provided on the outside thereof, out of the hydrocarbon
well, there is no need to remove and/or replace equipment, such as a BOP, X-mas tree
or riser, mounted on the wellhead having an internal passage with a diameter smaller
than the outer diameter of the tubing hanger but larger than the outer diameter in
of the tubing. In other words: there is no need to provide equipment, such as a BOP,
X-mas tree or riser, having a passage with an inside diameter large enough for passing
through the tubing hanger when removing tubing form the well bore. Equipment with
a smaller diameter passage, i.e. just large enough for passing through the tubing
including the control wires and control lines provided on the outside thereof, will
suffice.
[0013] Thus the invention facilitates removal of tubing from a hydrocarbon well and reduces
the time needed to plug and abandon a hydrocarbon well.
[0014] According to the invention, a method for enabling removal of tubing from a hydrocarbon
well, which tubing is at its upper end provided with a tubing hanger mounted in a
central passage of the wellhead, comprises the steps:
- lowering a machining device into a central passage of the tubing hanger and machining
away at least part of the tubing hanger, thus disconnecting the tubing from the tubing
hanger and enlarging the central passage of the tubing hanger to a diameter wide enough
for lifting the tubing out of the hydrocarbon well; and
- lifting the disconnected tubing out of the hydrocarbon well.
[0015] Thus, according to the invention the tubing hanger is at least partially removed
and disconnected form the tubing. Thus, the tubing hanger does no longer need to be
removed with the tubing and no longer forms a hindrance.
[0016] Furthermore, the tubing can be lifted out of the well via equipment, such as a BOP,
riser or X-mas tree, having an internal passage larger than the outer diameter of
the tubing but smaller than the outer diameter of the tubing hanger that supported
the tubing.
[0017] It is noted that in particular with BOP's and risers a smaller internal passage comes
with a large saving in weight and volume of the particular equipment. Because the
tubing is removed without the tubing hanger, BOP's and risers having a large sized
passage are no longer required, and a riser and/or BOP having a smaller sized passage
can be used. Thus a significant saving in costs can be achieved.
[0018] It is furthermore noted with respect to X-mas trees that they often have a passage
that is unfit for removing tubing, even without the tubing hanger. This because their
internal passage has a diameter that is too small and/or is provided with valves that
block passage of the tubing. Furthermore, X-mas trees are often too small to allow
for their passage to be enlarged to a passage having a diameter wide enough for passing
a tubing hanger. However, since the invention allows the tubing to be removed via
a relatively small passage, it is now in many cases possible to mill the passage in
an X-mas tree up to the required size and/or remove the valves provided in the passage
using a milling device, to provide the X-mas tree with a passage fit for removing
the tubing. Thus, in such cases the X-mas tree does no longer need to be removed from
the wellhead to allow for the tubing to be removed from the hydrocarbon well.
[0019] The method according to the invention further comprises the steps:
- engaging a top portion of the tubing at its inside and below the tubing hanger using
a clamping device; and
- holding, optionally supporting, the tubing while the machining device is machining
away at least part of the tubing hanger. In a method, a radially expandable clamping
unit is provided for engaging the inside surfaces of the tubing to be lifted from
the well. Such clamping devices are known form the prior art for clamping casing sections,
for example to rotatably fix a Bottom Hole Assembly or for removing a packer from
a well. A clamping device according to the invention differs from the known clamping
devices in that it should be dimensioned to engage the tubing, and to enable lifting
the tubing from the well.
In an alternative embodiment, not according to the invention, the tubing is engaged
by drilling and/or cutting holes in the tubing and providing hooks for engaging the
holes. In an embodiment, for example three radial extending drills are used to drill
through tubing and subsequently function as hooks for engaging the tubing, more in
particular to enable lifting the tubing from the well.
[0020] A further method according to the invention comprises the step:
- cutting the tubing downhole prior to engaging the top portion of the tubular string.
For example, in a method the tubing is cut near or at its bottom end, i.e. near or
at the production packer, so that after removal of the tubing hanger, substantially
the entire production tubing can be lifted from the well. In an alternative method,
the tubing is not cut near or at its bottom end, but is cut somewhere between its
bottom end, and its top end, i.e. the end at the tubing hanger. This may be the case
when the tubing has been fixed in the well at intermediate locations between the top
of the well and the bottom well. In such a method the tubing is not lifted form the
well in its entirety, but may be removed out of the well section by section. Also,
a bottom section may remain in the well if this does not interfere with reliable sealing
the well. In an alternative embodiment, the tubing does not need to be cut, for example
because it is not fixed to the well or because it has already been cut free in a previous
step.
[0021] In a further method according to the invention the hydrocarbon well is a subsea well,
and the method further comprises the steps:
- providing a riser between the well head and a surface vessel or jack up rig, the riser
having a central passage with a diameter larger than the external diameter of the
tubing but smaller than the diameter of the central passage of the wellhead above
the tubing hanger;
- optionally: lowering the machining device into the wellhead via the central passage
of the riser; and
- lifting the disconnected tubing through the central passage of the riser to the vessel
or jack up rig.
[0022] In a further method according to the invention, the diameter of the central passage
of the riser is smaller than an external diameter of the tubing hanger.
[0023] A further method according to the invention comprises the step:
- mounting a BOP on the wellhead, the BOP having a bore connecting the well head to
the riser string. Thus, in such an embodiment, the tubing is lifted from the well
via the central passage of the well head, via the bore of the BOP and via the central
passage of the riser. In a further method according to the invention, the bore has
a diameter which is larger than the diameter of the central passage the riser string,
preferably is substantially similar to the diameter central passage of the wellhead
above the tubing hanger, the method further comprising the step:
- providing an adapter between the BOP and the riser string, the adapter having a conduit
that connects the bore of the BOP with the central passage of the riser.
In such an method, the riser can be provided with an internal diameter large enough
for removing the tubing, including the control wires and control lines provided on
the outside thereof, but smaller than the external diameter of the tubing hanger,
since the tubing hanger, or at least what remains of the tubing hanger, does not need
to be removed from the well head. Thus, compared with current techniques, in which
the tubing hanger is removed with the tubing, a comparatively small diameter riser
can be used, even when the BOP does have a large diameter bore, i.e. a bore having
a diameter large enough for removing the tubing hanger.
[0024] In a further method according to the invention, the bore of the BOP has a diameter
which is smaller than the diameter of central passage of the wellhead above the tubing
hanger, preferably is substantially similar to the diameter of the central passage
of the riser string, the method further comprises the step:
- providing an adapter between the wellhead and the BOP, the adapter having a conduit
that connects the bore of the BOP with the central passage of the wellhead.
In such an embodiment, the riser and BOP can be provided with an internal diameter
large enough for removing the tubing, including the control wires and control lines
provided on the outside thereof, but smaller than the external diameter of the tubing
hanger, since the tubing hanger, or at least what remains of the tubing hanger, does
not need to be removed from the well head. Thus, compared with current techniques,
in which the tubing hanger is removed with the tubing, a comparatively small diameter
BOP and riser can be used, even when the well head does have a large diameter central
passage, i.e. a central passage having a diameter large enough for removing the tubing
hanger.
[0025] A further method according to the invention comprises the step:
- shredding swarf generated by machining away the tubing hanger, or at least a part
thereof, for example using a shredding device such as a plasma cutter provided in
an adapter, and/or collecting swarf generated by machining away the tubing hanger,
for example using a collecting device such as a magnet provided in the adapter.
[0026] A further method according to the invention comprises the step:
- supporting the machining device using a tubular, for example a drilling string or
coiled tubing, the tubular extending through the riser. In such an embodiment, preferably
the tubing is used to lower the machining device through the riser, and preferably
for lifting the machining device and the tubing after the tubing hanger has been partially
removed by the machining tool.
[0027] A further method according to the invention comprises the step:
- rotating the tubular and using this rotational movement for driving the machining
device, for example driving the machining device by rotating a drill string supporting
the machining device. Thus, the machining device does not need to comprise a drive,
such as an electric drive, which allows for a compact configuration of the machining
device.
[0028] A further method according to the invention comprises the step:
- circulating drilling mud through the wellhead to drive the machining device and/or
to remove swarf (cuttings) generated by the machining of the tubing hanger, the drilling
mud flowing downward via an annulus between the tubular and the riser string and flowing
upward through the tubular or vice versa. Preferably, the swarf is removed from the
well head during the milling away of the tubing hanger, such that the cutting do not
interfere with the milling process. Furthermore, the swarf is preferably removed from
the well head prior to lifting the tubing form the well, thus reducing the chance
that swarf may hamper the lifting process, for example gets stuck between the tubing
and/or milling device on the one hand and the well head, BOP or riser on the other
hand.
[0029] A further method according to the invention comprises the step:
- enlarging the diameter of a bore in a X-mas tree mounted on the wellhead to a diameter
larger than the outer diameter of the tubing. In such an embodiment a machining tool,
preferably the machining tool for machining at least part of the tubing hanger, is
used for enlarging the diameter of the bore in the X-mas tree mounted on the wellhead.
When the bore of the X-mas tree is in line with the well, the machining device can
for example be lowered from the riser, through the bore in the X-mas tree and into
the tubing hanger. In a method, the machining device is configured for machining away
part of the X-mas tree and at least part of the tubing hanger separate, subsequent
steps. In a method, the machining device is first lowered onto or into the bore of
the x mas tree, is secured relative to the X-mas tree and subsequently is used to
machine part of the X-mas tree to enlarge the bore.
In an embodiment, the machining device is configured to machine the bore of the X-mas
tree in an axial direction thereof, preferably in a single machining step.
In an alternative embodiment, the machining device is configured to machine the bore
of the X-mas tree in a substantially radial direction, preferably in a single step.
In an alternative embodiment, the machining of the X-mas tree is done in several subsequent
steps, comprising machining a section of the bore in a radial direction, lowering
the machining device further down the bore and again machining a section of the bore.
[0030] A further method according to the invention comprises the step:
- positioning a tubing hanger removal tool, the tool comprising the machining device
adapted to machine away at least part of the tubing hanger, below the BOP, or at least
below the shear rams of the BOP, prior to the machining away of the tubing hanger,
and keeping the tool below the BOP, or at least below the shear rams of the BOP, during
the machining away of the tubing hanger. In such an embodiment, the tool does not
obstruct the working of the shear rams of the BOP. It is noted that BOP's are typically
configured for shearing tubulars. Therefore, other bodies, such as a milling device,
may prevent the BOP from functioning correctly, i.e. prevent the BOP from blocking
the riser, in case of a blow out.
[0031] A further method according to the invention comprises the step:
- after removal of the tubing, providing temporary abandonment caps in the wellhead
and/or providing one or more plugs in the bore hole, preferably permanent plugs. Thus
the well is plugged, preferably permanently plugged. The plugs may be provided by
pouring concrete into the well and/or by mechanical devices being secured in the well
or well head. Other techniques for providing a plug, known from the prior art, may
also be used.
[0032] In a preferred embodiment according to the invention for removal of tubing from a
subsea hydrocarbon well, which tubing is at its upper end provided with a tubing hanger,
which tubing hanger is mounted in a central passage of a wellhead, comprises the steps:
- providing a riser between the well head and a surface vessel or jack up rig, the riser
having a central passage;
- providing a tubing hanger removal tool, the tubing hanger removal tool comprising
a machining device and a clamping device;
- lowering the tubing hanger removal tool into the wellhead via the central passage
of the riser, and thus lowering the machining device into a central passage of the
tubing hanger and the clamping device into the tubing below the tubing hanger;
- engaging a top portion of the tubing at its inside and below the tubing hanger using
the clamping device; and
- machining away at least part of the tubing hanger, thus disconnecting the tubing from
the tubing hanger and enlarging the central passage of the tubing hanger to a diameter
wide enough for lifting the tubing out of the hydrocarbon well; and
- lifting the disconnected tubing out of the hydrocarbon well, through the central passage
of the tubing hanger and through the central passage of the riser, to the vessel or
jack up rig, wherein the central passage of the riser has a diameter larger than the
external diameter of the tubing but smaller than the diameter of the central passage
of the wellhead above the tubing hanger and smaller than an external diameter of the
tubing hanger.
Thus, a method according to the invention allows for using a compact riser, i.e. a
riser having an internal diameter smaller than an external diameter of the tubing
hanger, when removing the tubing from a well. Also, the method according to the invention
allows for using a BOP with an internal bore having a diameter smaller than an external
diameter of the tubing hanger, when removing the tubing from a well.
[0033] The disclosure furthermore provides a tubing hanger removal tool for enabling removal
of tubing from a hydrocarbon well, which tubing is at its upper end provided with
a tubing hanger mounted in a central passage of a wellhead. According to the disclosure,
the tubing hanger removal tool comprises a machining device adapted to be lowered
into a central passage of the tubing hanger and to machine away at least part of the
tubing hanger, thus disconnecting the tubing from the tubing hanger and enlarging
the central passage of the tubing hanger to a diameter wide enough for lifting the
tubing out of the hydrocarbon well, and to thus enable lifting the disconnected tubing
out of the hydrocarbon well.
[0034] In an embodiment, the tubing hanger removal tool further comprises a clamping device,
for engaging the inside of the tubing at a top portion thereof, and for holding, optionally
supporting, the tubing while the machining device is machining at least part of the
tubing hanger.
[0035] In an embodiment, the tubing hanger removal tool is adapted to be fully lowered into
tubing, and the machining device is adapted to cut the tubing downhole and/or the
tool comprises a cutting device adapted to cut the tubing downhole. Thus, if a lower
section of the tubing is secured to the well, for example to the production packer
and/or to the casing located in the well, the secured tubing section can be severed
from the tubing section to be removed from the well. The tubing section that remains
in the well later, or can be left in the well permanently.
[0036] In an embodiment, the tubing hanger removal tool is adapted to operate in a subsea
hydrocarbon well, preferably is provided with a communication device that allows the
tool to be operated from a vessel or a jack up. Preferably, the communication device
provides information on the position of the machining device relative to the tubing
hanger, to thus facilitate correctly positioning the machining device in the well
head. In an alternative method, wherein the position of the well head is known. The
machining device is lowered through a riser using a tubular string, and the length
of the tubular string is registered and used to determine the position of the machining
device relative to the well head, more in particular to the tubing hanger in the well
head.
[0037] In an embodiment, the tubing hanger removal tool is adapted to be lowered into the
wellhead via a central passage of a riser extending between the wellhead and a vessel
or a jack up and/or via a bore of a BOP mounted on the well head, wherein preferably
the central passage of the riser and/or the bore of the BOP have a diameter larger
than the external diameter of the tubing but smaller than the diameter of the central
passage of the wellhead. Thus, in such an embodiment, the riser can be provided with
an internal diameter large enough for removing the tubing, including the control wires
and control lines provided on the outside thereof, but smaller than the diameter of
the central passage of the wellhead. In this context it is noted that typically the
central passage of the well head is configured for passing the tubing hanger, to thus
enable installing the tubing and the tubing hanger. However, the invention allows
for the tubing hanger, or what remains of the tubing hanger after the severing the
tubing in the well head form the tubing hanger, to remain in the well head. Therefore,
the BOP and riser do not need to be dimensioned for removing the tubing hanger with
the tubing. Thus, compared with current techniques, in which the tubing hanger is
removed with the tubing, a comparatively small diameter BOP and/or small diameter
riser can be used when removing the tubing from a well.
[0038] In an embodiment, the tubing hanger removal tool further comprises a coupling device,
which coupling device is adapted to couple the tubing hanger removal tool to a tubing
hanger removal tool support, preferably a tubular, for example a drilling string or
coiled tubing, the tubular extending through the riser. In such an embodiment, the
tubing can be used to lower the tubing hanger removal tool is supported by the tubing,
and can be lowered through the riser, and can be lifted through the riser, using the
tubing supporting the removal tool. This is in particular beneficial when for example
a drilling rig is used for providing the tubing hanger removal tool, since a drilling
rig is typically configured for lowering a string of tubulars into, and lifting a
string of tubulars out of, a riser. Furthermore, in such a configuration, the tubulars
for supporting the tubing hanger removal tool can also be sued for lifting the tubing
from the well, after the tubing in the well has been disconnected from the tubing
hanger.
In a preferred embodiment, the tubing hanger removal tool is lifted together with
the disconnected tubing form the well.
[0039] In an embodiment, the tubing hanger removal tool is configured to couple the disconnected
tubing, i.e. the tubing in the well that has been disconnected from the tubing hanger,
with the tool support, for example a string of drilling tubulars extending through
a riser, said riser connecting the well with a surface vessel such as a jack up or
drilling vessel, such that the disconnected tubing can be lifted through the riser
to the vessel or jack up rig using tool support. Thus, in such an embodiment the tubing
hanger removal tool is not only configured for machining away at least part of the
tubing hanger, but also forms a coupling device for connecting the severed tubing
with the tubing hanger removal tool support. In an embodiment, the tubing hanger removal
tool is provided with a clamping device configured for engaging the inside surface
of the tubing located in the well, preferably prior to the tubing being severed from
the tubing hanger, with a force sufficient to enable lifting the tubing from the well
after at least part of the tubing hanger has been removed.
[0040] In an embodiment of the tubing hanger removal tool, preferably the machining device
of the tubing hanger removal tool, is adapted to be coupled with a tubular tool support,
and preferably to be driven via that tubular tool support by a drive located above
the connecting tool, preferably located on a vessel or jack up.
[0041] In an embodiment, the tubing hanger removal tool is adapted to be rotatably supported
by the tool support and/or the tubing hanger removal tool further comprises a clamping
device for engaging the inside of the tubing supported by the tubing hanger at a top
portion thereof, and for holding, optionally supporting, the tubing while the machining
device is machining at least part of the tubing hanger, wherein the clamping device
is rotatably connected to the tool.
[0042] In an embodiment, the tubing hanger removal tool is provided with a drive, for example
an electric drive or a mud motor, for driving the machining device.
[0043] In an embodiment of the tubing hanger removal tool, the tubing hanger removal tool
further comprises a clamping device for engaging the inside of the tubing supported
by the tubing hanger at a top portion thereof, and for holding, optionally supporting,
the tubing while the machining device is machining at least part of the tubing hanger,
and the machining device has a cutting face that is rotatably mounted such that it
can rotate relative to the clamping device and about the longitudinal axis of the
tubing removal tool.
[0044] In an embodiment of the tubing hanger removal tool the machining device has a cutting
face that is adapted for cutting in a direction parallel to a longitudinal axis of
the tubing hanger removal tool, preferably in a downward direction.
[0045] In an embodiment of the tubing hanger removal tool the machining device, in particular
the cutting face of the machining device, has a fixed outer diameter which is larger
than the outer diameter of the tubing but is smaller than the inner diameter of the
bore of the BOP and/or the central passage of the riser. In such an embodiment, cutting
face of the machining device can pass through the bore of the BOP and/or through the
central passage of the riser, and is large enough for machining the tubing hanger
such that the tubing, when cut from the tubing hanger, can be lifted through what
remains of the tubing hanger and the BOP and/or the central passage of the riser.
In an alternative embodiment, the machining device, in particular the cutting face
of the machining device, has a compact transport configuration and an extend machining
configuration. In such an embodiment, the machining device for example has a cutting
face composed out of multiple cutting face sections, which cutting face sections can
be moved and/or hinged between an extended cutting position and a retracted transport
position. It is submitted that other techniques, known from the prior art and suitable
for transporting cutting faces through risers, can also be used for providing such
a cutting face.
In an embodiment of the tubing hanger removal tool the machining device comprises
two or more counter rotating cutting faces to at least partially cancel out the torque
generated by the machining of the tubing hanging.
[0046] In an embodiment of the tubing hanger removal tool the tubing hanger removal tool
is provided with one or more inner channels for guiding drilling mud from one end
to an opposite end of the tubing hanger removal tool, which channels preferably have
at one end openings adapted to be connected with a tubular supporting the tool. Thus,
the drilling mud can be guide from the supporting tubulars towards and optionally
through the machining device, for example to drive the machining device and/or for
removing swarf during the cutting process.
[0047] In an embodiment, the tubing hanger removal tool comprises a clamping device for
engaging the inside of the tubing supported by the tubing hanger at a top portion
thereof, which clamping device is configured to be manipulated, i.e. to be switched
between an active position in which it engages the inside surface of the tubing and
an inactive positon in which it does not engage the inside surface of the tubing,
by the drilling mud, for example by pressure difference in the flow of drilling mud
passing the tubing hanger removal tool.
[0048] In an embodiment, the tubing hanger removal tool comprises a clamping device, and
the tool provides channels between a tubing section above the clamping device and
a tubing section below the clamping device that allows drilling mud to flow between
those sections. In such an embodiment a flow of drilling mud can pass the clamping
device while the clamping device engages the inside surface of the tubing, i.e. the
tubing to be removed from the well. Thus the clamping device can engage the inside
of the tubing without obstructing the flow of drilling mud.
[0049] It is noted that when the tubing hanger removal tool is used, drilling mud is not
circulated in the riser and/or well for driving a drill bit. The drilling mud can
be provided to a certain pressure in the well and thus prevent gasses or liquids to
escape from the well. The drilling mud can be circulated through the riser and/or
well for example to drive the machining device and/or to remove swarf during the machining
process.
[0050] In an embodiment, the tubing hanger removal tool further comprises a shredder device
for shredding cuttings generated by the machining device. The shredder device can
be a mechanical shredder, preferably drive by the drive that also drives the machining
device. In an alternative embodiment, the shredder can be a mechanical shredder.
[0051] In an embodiment, the tubing hanger removal tool is at its front end provided with
a reaming device for enlarging the diameter of a bore in a X-mas tree mounted on the
wellhead to a diameter larger than the outer diameter of the tubing.
In such an embodiment the reaming device is used to enlarge the diameter of the bore
in the X-mas tree mounted on the wellhead. When the bore of the X-mas tree is in line
with the well, the machining device can for example be lowered from the riser, through
the bore in the X-mas tree and into the tubing hanger. In such an embodiment, the
tubing hanger removal tool is configured to first machine away part of the X-mas tree,
for example for machining away valves provided in the bore of the X-mas tree, and
subsequently machine the tubing hanger, or at least a part thereof to an extend sufficient
to sever the tubing hanging in the well from the tubing hanger. Thus, when the well
head is provided with an X-mas tree having a bore too narrow for passing through the
tubing to be removed from the well, it is not required to remove the X-mas tree. By
reaming the bore and/or removing vlaves provided in the bore of the X-ams tree, the
X-mas tree is adapted to allow for the tubing to be lifted form the well.
In an embodiment, the tubing hanger removal tool is at its front end provided with
a reaming device for enlarging the diameter of the central passage of the tubing.
Thus, the inside surface of the tubing can be provided with a clean and/or flat gripping
surface for engagement by a clamping device, preferably for engagement by a clamping
device of the tubing hanger removal tool.
[0052] In an embodiment, the tubing hanger removal tool is dimensioned such that, at least
during the machining of the tubing hanger, the tool is located below the BOP, or at
least below the shear rams of the BOP. In such an embodiment, the tubing hanger removal
tool does not obstruct the working of the shear rams of the BOP while machining the
tubing hanger. It is noted that BOP's are typically configured for shearing tubulars.
Therefore, other bodies, such as a machining device, may prevent the BOP from functioning
correctly, i.e. prevent the BOP from blocking the riser, in case of a blow out.
[0053] In an embodiment, the tubing hanger removal tool is adapted to be mounted on a well
head, or on an adapter mounted on a well head.
[0054] The disclosure furthermore provides a tubing removal assembly comprising a tubing
hanger removal tool according to the disclosure, and an adapter, wherein the adapter
is adapted to be mounted between a BOP and the wellhead, the bore of the BOP having
a diameter smaller than the diameter of the central passage of the wellhead, or is
adapted to be mounted between a riser and a BOP, the central passage of the riser
having a diameter smaller than the diameter of the bore of the BOP.
Providing an assembly comprising such an adapter, allows for using a riser and optionally
for using a BOP having a comparatively small central passage and bore.
This is beneficial because a riser with a reduced central passage has a reduced internal
volume and thus holds a smaller volume of drilling mud. Therefore, during use, i.e.
when filled with drilling mud, a riser having a smaller central passage is easier
to support.
Also, a BOP having a large bore typically has a larger weight and is more voluminous
as a BOP having a smaller bore, This is even more the case since BOP's, for safety
reasons, are over dimensioned. Also, the diameter of the central passage of a riser
typically matches the bore of the BOP, and the bore of the BOP often matches the central
passage of the well head. Since a heavier, more voluminous BOP is difficult to move,
especially at great depths, it is beneficial when it is not required to replace a
BOP already present on a wellhead with a smaller BOP to allow for a riser with a smaller
central passage.
Also, when no BOP is provided on the well head, and presence of a BOP is required
for safety reasons during the removal of the tubing form the well, it is beneficial
when a more compact BOP can be used, and consequently a compact riser, by providing
an adapter between the well head and the BOP.
[0055] Thus, providing an assembly comprising an adapter, or adapters, as set out above,
allows for using a riser and optionally a BOP that match the outer diameter of the
tubing to be lifted form the well. The riser no longer needs to match a wider diameter
of a BOP already present on the well head, and when a BOP needs to be provided, the
BOP does no longer need to match the wide passage of the well head.
When completing a well, the tubing is preferably lifted from the well to the surface
via a riser, to thus prevent the tubing contaminating the seawater. Thus, the riser
and optionally the BOP are provided by the vessel or jack up providing the tubing
hanger removal tool. Any reduction in weight of the riser and/or BOP facilitates installation
and support of the riser and/or BOP, and thus facilitates the over al process of removing
the tubing from the well.
[0056] Preferably, the adapter is a separate component, to be mounted between the BOP and
riser or between the BOP and wellhead prior to the tubing hanger removal tool to be
lowered into the wellhead.
[0057] In a further embodiment, the adapter of the tubing removal assembly according to
the disclosure comprises one or more of the following:
a sealing device, for example comprising a hatch or valve, for temporarily sealing
off the central passage of the wellhead, and thus sealing off the hydrocarbon well;
a sealing device, for example comprising a hatch or valve, for temporarily sealing
off the bore of the BOP mounted on the well head and thus sealing off the hydrocarbon
well;
a positioning device, for example a mount, movable grips or a robot arm, for positioning
the machining device relative to the tubing hanger;
a positioning device, for example a mount, movable grips or a robot arm, for stabilising
the machining device while it is machining the tubing hanger;
a storage space for holding a temporary abandonment cap, and preferably mounting device
for mounting the temporary abandonment cap in the well head;
a communication device for communicating with the machining device; and
a swarf collecting device for collecting swarf generated by machining away the tubing
hanger, or at least a part thereof.
[0058] Advantageous embodiments of the method according to the invention are disclosed in
the subclaims and in the description, in which the invention is further illustrated
and elucidated on the basis of a number of exemplary embodiments, of which some are
shown in the schematic drawing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0059] In the drawings:
Fig. 1 shows a side view in cross section of the top of a subsea hydro carbon well
with tubing supported via tubing hanger in a well head mounted in a conductor wellhead;
Fig. 2 shows the removing of the tubing with the tubing hanger through a schematically
indicated BOP having a wide bore;
Fig. 3 shows schematically a tubing hanger removal tool inserted in the wellhead and
the tubing hanger via an BOP having a small sized bore, which BOP is mounted on the
well head using an adapter, and which tubing hanger removal tool is supported by a
tubular string;
Fig. 4 shows a machining device of the tool machining away part of the tubing hanger,
while a clamping device of the tool engages an upper section of the tubing, thus supporting
the tubing;
Fig. 5 shows the machining device in a retracted position, and the enlarged central
passage of the tubing hanger;
Fig. 6 shows the lifting of the tubing out of the hydrocarbon well into the BOP and
riser, using the tubing hanger removal tool.
DETAILED DESCRIPTION
[0060] Fig. 1 shows a side view in cross section of the top of a hydro carbon well 1 with
tubing 2 supported via tubing hanger 3 in a well head 4.
In the particular configuration shown, the wellhead 4 is mounted in a conductor wellhead
5 and is provided with a temporary abandonment cap 17.
[0061] The hydrocarbon well 1 depicted is a subsea hydrocarbon well, the well head 4 extending
above the seafloor 6.
[0062] In the configuration shown, the wellhead 4 further supports intermediate casing strings
7, 7', which casings strings are supported by casing hangers 8 in the wellhead. It
is submitted herewith that a method according to the invention and a tool according
to the disclosure may also be used in removing intermediate casing strings supported
via casing hangers in a well head, in particular in a wellhead of a subsea hydrocarbon
well. It is however noted that casing often remains in the well, as it can be used
as a basis for securing the concrete plugs to seal off the well. Furthermore, a casing
hanger removal tool would differ in dimensions from a tubing hanger removal tool according
to the disclosure since the tubing is provided inside the casing, the casing and corresponding
casing hangers thus having a central passage with an inside diameter larger than the
outside diameter, and consequently than the inside diameter, of the tubing.
[0063] Fig. 2 depicts the removing of the tubing 2 with the tubing hanger 3 through a schematically
indicated BOP 9 having a wide bore 10. Above the BOP there is provided a riser 11,
having a central passage 12, which riser connects the hydrocarbon well 1 with a surface
vessel or platform, for example a jack up.
[0064] It is noted that it will often be necessary to provide a BOP on the wellhead during
the main part of plug and abandonment activities, in particular when removing the
tubing. This, because during this stage of the plug and abandonment process, the well
has not yet been plugged, and therefore there is the potential risk of a blow-out.
[0065] To enable the tubing to be removed, currently BOP's are used with a large sized bore,
i.e. a bore wired enough to allow the tubing with the tubing hanger to be lifted out
of the well, through the BOP and through the riser provided above the BOP to a vessel
or platform, such as a jack up rig, supporting the riser.
[0066] Fig. 3 shows the hydrocarbon well 1, well head and tubing of fig. 1, but now in combination
with a, schematically depicted, tubing hanger removal tool 15 according to the disclosure
shown. The tubing hanger removal tool 15 has been lowered into the wellhead 4 and
into the tubing hanger 3 via a BOP 13 and a riser 111.
[0067] The schematically depicted BOP 13 is a BOP with a small size bore 14, i.e. a bore
having a diameter larger than the outer diameter of the tubing 2, but smaller than
the outside diameter of the tubing hanger 3.
[0068] Furthermore, the riser 111 is a riser having a small sized central passage 112, i.e.
a central passage having a diameter larger than the outer diameter of the tubing 2,
but smaller than the outside diameter of the tubing hanger 3. In the particular embodiment
shown, the central passage 112 of the riser 111 fits the bore 14 of the small sized
BOP 13.
[0069] In the particular embodiment shown, the tubing removal tool 15 is part of a tubing
removal assembly, the assembly comprising the tubing hanger removal tool 15, and an
adapter 16. In the particular embodiment shown, the adapter 16 is mounted between
the BOP and the wellhead, such that a BOP having a diameter smaller than the diameter
of the central passage of the wellhead can be used in removing the tubing from the
well.
[0070] Thus, a BOP that has been designed to be mounted on a wellhead having a smaller central
passage can be used.
[0071] In an alternative embodiment, in addition to or instead of an adapter mounted between
wellhead and BOP, an adapter can be provided between BOP and riser as well. The adapters
enable to use a riser and BOP having a central passage and bore large enough for lifting
the tubing out of the well, but not larger than that.
[0072] It is noted that in the embodiment shown, a simple adapter is provided, i.e. an adapter
that is mainly configured for mounting a BOP on a wellhead and which does not comprise
additional devices and or features. In a further embodiment, the adapter cnabe provided
with for example monitoring equipment, for monitoring conditions inside the well head
during the plug and abandonment procedure. Also, the adapter can for example be provided
with excess ports, for example an excess port that allows for a small sized remotely
operated vehicle (ROV) to enter the well head.
[0073] The exemplary embodiment of the tubing hanger removal tool 15 is configured for enabling
removal of tubing, which tubing is at its upper end provided with a tubing hanger
mounted in a wellhead, from a hydrocarbon well. The tubing hanger removal tool comprises
a coupling device 19, a clamping device 20 and a tubing hanger machining device 21.
[0074] The coupling device 19 of the tubing hanger removal tool 15 is located at a first
end of the tubing hanger removal tool. The coupling device 19 is adapted to couple
the tubing hanger removal tool to a tubing hanger removal tool support 22, in the
particular embodiment shown a drilling string, i.e. a string of drilling tubulars.
[0075] The clamping device 20 is located at a second end of the tubing removal tool 15.
The clamping device 20 is adapted for engaging the inside of the tubing 2 at a top
portion thereof and for holding the tubing. It is noted that the clamping device 20
is located for engaging the tubing 2 at a section located below the tubing hanger
3. Thus it does not block obstruct removal of the tubing hanger.
[0076] In the particular embodiment shown, the tubing hanger removal tool is configured
to connect the tubing 2 with the tool support 22. Furthermore, since the clamping
device 20 is configured for supporting the tubing 2. the tubing hanger removal tool
15 thus enables the tool support 22 to be used for lifting the tubing 2 out of the
well.
[0077] The tubing hanger machining device 21 is located between the coupling device 19 and
the clamping device 20. The machining device 21 is adapted to be lowered into a central
passage 23 of the tubing hanger 3 and to machine away at least part of the tubing
hanger, which has been depicted in figs. 4 and 5, thus disconnecting the tubing 2
from the tubing hanger 3 and enlarging the central passage 23 of the tubing hanger
3 to a diameter wide enough for lifting the tubing 2 out of the hydrocarbon well 1,
and to thus enable lifting the disconnected tubing out of the hydrocarbon well. The
latter has been depicted in Fig. 6.
[0078] In the particular embodiment shown, the tubing hanger removal tool 15 is provided
with a machining device 21 for cutting away part of the tubing hanger 3. The machining
device 21 has a cutting face that is rotatably mounted such that it can rotate relative
to the clamping device and about a longitudinal axis of the tubing removal tool 1.
Furthermore, the cutting face of the machining device faces forward, i.e. the machining
device has a cutting face that is adapted for cutting in a direction parallel to the
longitudinal axis of the tool, and thus parallel to the longitudinal axis of the tubing
supported by the tubing hanger. When cutting away part of the tubing hanger, and possibly
some of the tubing, the cutting face engages the tubing hanger from above and cuts
to the bottom end of the tubing hanger in a downward direction.
[0079] In the particular embodiment shown, the cutting face of the machining device, has
a fixed outer diameter which is larger than the outer diameter of the tubing but is
smaller than the outer diameter of the tubing hanger. The outer diameter of the cutting
face furthermore is smaller than the inner diameter of the bore of the BOP and/or
the central passage of the riser, thus enabling the machining device to be transported
via the riser and the BOP.
[0080] In an alternative embodiment, the machining device could be provided with many types
of cutting blades or cutting teeth, for example with retractable cutting blades that
allow for a compact configuration of the machining device when transported through
the riser and are to be extended prior to the cutting of the tubing hanger to form
the cutting face.
[0081] Fig. 4 shows the machining device 21 of the tool 15 machining away part of the tubing
hanger 3, while the clamping device 20 of the tool 15 engages an upper section of
the tubing 2, thus supporting the tubing.
[0082] Fig. 5 shows the machining device 21 in a retracted position, and the enlarged central
passage 23 of the tubing hanger 3.
[0083] Fig. 6 shows the lifting of the tubing 2 out of the hydrocarbon well 1 through the
BOP 13 and riser 111, using the drilling string 22 to lift the tubing hanger removal
tool 15 and thus the tubing.
[0084] Thus, according to the invention the tubing, and the control lines provided on that
tubing, can be removed from a hydro carbon well.
[0085] It is noted that when performing plug and abandonment of wells from a vessel or jack
up it will often be required to pull the tubing from the well. In particular if the
tubing has control lines attached, especially in the deeper regions where one would
want to set isolation plugs. The control lines may otherwise constitute leak paths
when extending through plugs cemented in the wellbore.
[0086] Thus, the disclosure provides a tubing hanger removal tool to enable removal of tubing
from a hydrocarbon well in an efficient way, more in particular a tool that enables
lifting tubing out of a well through opening having an inner diameter smaller than
the outer diameter of the tubing hanger. According to the invention, the tubing hanger
is separated from the tubing hanger. Of the tubing hanger a central part is cut away
to provide a passage for the tubing to be lifted from the well, the passage being
large enough to pass there through the tubing and its control lines.
[0087] Thus, with a method according to the invention, part of the tubing hanger remains
in the well head, and the tubing is lifted through the central, enlarged opening of
the tubing hanger out of the well.
[0088] With a method according to the invention, a riser and BOP having an inner diameter
smaller than the outer diameter of the tubing hanger can be used for lifting the tubing
to a surface vessel or jack up. This allows for a light and compact riser and BOP,
which are more easy to handle and install. Thus the tubing removal can dealt with
in an efficient manner.
[0089] In a further preferred embodiment of the tubing hanger removal tool, the tool is
furthermore configured for engaging and supporting the tubing, such that the tubing
hanger removal tool can also be sued for lifting the tubing. Thus, with lifting the
removal tool from the well, the top end of the tubing is lifted from the well as well.
[0090] The tubing hanger removal tool 15 according to the disclosure comprises a machining
device 21 adapted to be lowered into a central passage 23 of the tubing hanger 3 and
to machine away at least part of the tubing hanger, thus disconnecting the tubing
2 from the tubing hanger 3 and enlarging the central passage 23 of the tubing hanger
3 to a diameter wide enough for lifting the tubing out of the hydrocarbon well, and
to thus enable lifting the disconnected tubing out of the hydrocarbon well.
[0091] The preferred embodiment of a tubing hanger removal tool 15 shown further comprises
a clamping device 20, for engaging the inside of the tubing at a top portion thereof,
and for holding, optionally supporting, the tubing 2 while the machining device is
machining at least part of the tubing hanger. The clamping device thus secures the
tubing hanger removal tool 15 in the tubing hanger 3, which may be beneficial to support
torque forces generated by the milling of the tubing hanger. Thus, the machining device
21 can held in place during the removal of the central part of the tubing hanger 3.
[0092] In the preferred tubing hanger removal tool 15 shown, the clamping device 20 is configured
to support the disconnected tubing 2 such that the disconnected tubing can be lifted
through the tubing hanger 3 to the vessel or jack up rig using the tubing hanger removal
tool support.
[0093] The tubing hanger removal tool 15 is lowered into, and lifted out of, the well head
4 using a tool support 22, in the embodiment shown a drilling string, i.e. a string
of drilling tubulars. The tubing hanger removal tool 15 is connected to the drilling
string 22 with a coupling device 19.
[0094] The tubing hanger removal tool is furthermore dimensioned such that, at least during
the machining away of the tubing hanger, the tool is located below the BOP, or at
least below the shear rams of the BOP. Thus, the in case of a blowout, the shear rams
only need to cut through the drilling string supporting the tubing hanger removal
tool, and not through tool. In this context it is noted that BOP's are typically designed
for cutting tubulars, and may malfunction when trying to cut through other objects,
such as the tubing hanger removal tool.
[0095] In a preferred embodiment according to the invention, the tubing is removed from
the subsea hydrocarbon well 1 using the tubing hanger removal tool 15 shown. The method
comprises the steps:
- providing the riser 11 between the well head 4 of the hydrocarbon well 1 and a surface
vessel or jack up rig, the riser 111 having a central passage 12;
- providing the tubing hanger 15 removal tool, the tubing hanger removal tool 15 comprising
the machining device 21 and the clamping device 20;
- lowering the tubing hanger removal tool 15 into the wellhead 4 via the central passage
12 of the riser 11, and thus lowering the machining device 21 into a central passage
23 of the tubing hanger 3 and the clamping device 20 into the tubing 2 below the tubing
hanger 3;
- engaging a top portion of the tubing 2 at its inside and below the tubing hanger 3
using the clamping device 20;
- machining away at least part of the tubing hanger 3, thus disconnecting the tubing
from the tubing hanger and enlarging the central passage 23 of the tubing hanger 3
to a diameter wide enough for lifting the tubing 2 out of the hydrocarbon well 1;
and
- lifting the disconnected tubing 2 out of the hydrocarbon well 1, through the central
passage 23 of the tubing hanger 3 and through the central passage 12 of the riser
11, to the vessel or jack up rig,
wherein the central passage 12 of the riser 11 has a diameter larger than the external
diameter of the tubing 2 but smaller than an external diameter of the tubing hanger
3.
[0096] In the particular embodiment shown, the tubing hanger removal tool 1, more in particular
its machining device 21, is driven via the tubular removal tool support 22 by a drive
located on the surface vessel or platform, for example a jack up, supporting the riser.
In the particular embodiment shown, the clamping device rotation of the tool support
22 rotates the cutting face of the machining device.
In an embodiment, the tubular removal tool support rotates part of the toll comprising
the machining device, and thus rotates the cutting face of the machining device about
a longitudinal axis of the tubing hanger removal tool. In such an embodiment, the
part of the tool comprising the clamping device is rotatable connected with the part
of tool comprising the machining device to thus enable the clamping device to engage
the tubing while the cutting face of the machining device is rotated.
In an alternative embodiment, the tubing removal tool is provided with a drive, for
example an electric drive or a mud motor, for driving the machining device.
[0097] In a further embodiment, the tubing hanger removal tool is adapted to be fully lowered
downhole, i.e. past the tubing hanger and into the tubing towards the bottom of the
well, and the machining device is adapted to cut the tubing downhole prior to removing
part of the tubing hanger. In an alternative embodiment, the tubing hanger removal
tool comprises a further cutting device specifically adapted to cut the tubing downhole.
[0098] In an embodiment, the tubing hanger removal tool is at its front end, i.e. the end
of the tool facing a bottom of the well when the machining device is machining the
tubing hanger, provided with a reaming device for enlarging the diameter of a bore
in a X-mas tree mounted on the wellhead to a diameter larger than the outer diameter
of the tubing, to thus enable the tubing to be lifted out of the well through the
tubing hanger and subsequently through X-mas tree the riser.
1. Verfahren zum Entfernen eines Rohrs (2) aus einem Kohlenwasserstoffbohrloch (1), wobei
das Rohr an seinem oberen Ende mit einer Rohraufhängung (3) versehen ist, wobei die
Rohraufhängung (3) in einem zentralen Durchgang eines Bohrlochkopfs (4) montiert ist,
wobei das Verfahren den Schritt umfasst:
- Absenken einer Bearbeitungsvorrichtung (21) in einen zentralen Durchgang (23) der
Rohraufhängung (3);
dadurch gekennzeichnet, dass das Verfahren ferner die Schritte umfasst:
- Eingreifen eines oberen Abschnitts des Rohrs (2) an seiner Innenseite und unterhalb
der Rohraufhängung (3) unter Verwendung einer Klemmvorrichtung (20);
- Wegbearbeiten eines Teils der Rohraufhängung (3), um so das Rohr (2) von der Rohraufhängung
(3) zu trennen und den zentralen Durchgang der Rohraufhängung (3) auf einen Durchmesser
zu vergrößern, der groß genug ist, um das Rohr (2) durch den zentralen Durchgang der
Rohraufhängung (3) aus dem Kohlenwasserstoffbohrloch (1) heraus zu heben;
- Halten, optional Stützen, des Rohrs (2), während die Bearbeitungsvorrichtung (21)
zumindest einen Teil der Rohraufhängung (3) bearbeitet; und
- Herausheben des abgetrennten Rohrs (2) durch den zentralen Durchgang der Rohraufhängung
(3) aus dem Kohlenwasserstoffbohrloch (1).
2. Verfahren nach Anspruch 1, das ferner den Schritt umfasst:
- Schneiden des Rohrs im Bohrloch vor dem Eingreifen in den oberen Abschnitt des Rohrs.
3. Verfahren nach Anspruch 1 oder Anspruch 2, wobei das Kohlenwasserstoffbohrloch ein
Unterwasserbohrloch ist, wobei das Verfahren ferner die Schritte umfasst:
- Bereitstellen eines Steigrohrs zwischen dem Bohrlochkopf und einem Überwasserschiff
oder einer Hubbohrinsel, wobei das Steigrohr einen zentralen Durchgang mit einem Durchmesser
aufweist, der größer ist als der Außendurchmesser des Rohrs, aber kleiner als der
Durchmesser des zentralen Durchgangs des Bohrlochkopfs über der Rohraufhängung;
- Absenken der Bearbeitungsvorrichtung in den Bohrlochkopf über den zentralen Durchgang
des Steigrohrs; und
- Heben des abgetrennten Rohrs durch den zentralen Durchgang des Steigrohrs zum Schiff
oder zur Hubbohrinsel.
4. Verfahren nach Anspruch 3, das ferner den Schritt umfasst:
- Montieren eines BOP am Bohrlochkopf, wobei der BOP eine Bohrung aufweist, die den
Bohrlochkopf mit dem Steigrohrstrang verbindet.
5. Verfahren nach Anspruch 4, wobei die Bohrung des BOP einen Durchmesser aufweist, der
größer ist als der Durchmesser des zentralen Durchgangs des Steigrohrs, wobei das
Verfahren ferner den Schritt umfasst:
- Bereitstellen eines Adapters zwischen dem BOP und dem Steigrohr, wobei der Adapter
eine Leitung aufweist, die die Bohrung des BOP mit dem zentralen Durchgang des Steigrohrs
verbindet.
6. Verfahren nach Anspruch 4, wobei die Bohrung einen Durchmesser aufweist, der kleiner
ist als der Durchmesser des zentralen Durchgangs des Bohrlochkopfs, wobei das Verfahren
ferner den Schritt umfasst:
- Bereitstellen eines Adapters zwischen dem Bohrlochkopf und dem BOP, wobei der Adapter
eine Leitung aufweist, die die Bohrung des BOP mit dem zentralen Durchgang des Bohrlochkopfs
verbindet.
7. Verfahren nach einem oder mehreren der Ansprüche 3-6, wobei das Verfahren ferner den
Schritt umfasst:
- Schreddern von Spänen, die durch das Wegbearbeiten der Rohraufhängung erzeugt werden,
zum Beispiel unter Verwendung einer Schreddervorrichtung, wie einem Plasmaschneider,
der in einem Adapter bereitgestellt wird.
8. Verfahren nach einem oder mehreren der Ansprüche 3-7, das ferner den Schritt umfasst:
- Sammeln von Spänen, die durch das Wegbearbeiten der Rohraufhängung erzeugt werden,
zum Beispiel unter Verwendung einer Auffangvorrichtung, wie einem Magneten, der in
dem Adapter bereitgestellt wird.
9. Verfahren nach einem oder mehreren der Ansprüche 3-8, das ferner den Schritt umfasst:
- Stützen der Bearbeitungsvorrichtung unter Verwendung einer Röhre, zum Beispiel eines
Bohrstrangs oder eines gewickelten Rohrs, wobei sich die Röhre durch das Steigrohr
erstreckt.
10. Verfahren nach Anspruch 9, das ferner den Schritt umfasst:
- Drehen der Röhre und Verwenden dieser Drehbewegung zum Antreiben der Bearbeitungsvorrichtung.
11. Verfahren nach Anspruch 9, das ferner den Schritt umfasst:
- Zirkulieren von Bohrschlamm durch den Bohrlochkopf zum Antreiben der Bearbeitungsvorrichtung,
wobei der Bohrschlamm über einen Ringraum zwischen der Röhre und dem Steigrohr nach
unten und durch die Röhre nach oben fließt oder umgekehrt.
12. Verfahren nach einem oder mehreren der vorstehenden Ansprüche, wobei das Verfahren
ferner das Verwenden eines Rohraufhängung-Entfernungswerkzeugs umfasst, wobei das
Rohraufhängung-Entfernungswerkzeug umfasst:
die Bearbeitungsvorrichtung und die Klemmvorrichtung.
13. Verfahren nach Anspruch 12, wobei das Rohraufhängung-Entfernungswerkzeug ferner eine
Kopplungsvorrichtung aufweist, wobei die Kopplungsvorrichtung angepasst ist, um das
Rohraufhängung-Entfernungswerkzeug an einen Rohraufhängung-Entfernungswerkzeugträger
zu koppeln, vorzugsweise eine Röhre, zum Beispiel einen Bohrstrang oder ein gewickeltes
Rohr, wobei sich die Röhre durch das Steigrohr erstreckt.
14. Verfahren nach Anspruch 12 oder Anspruch 13, wobei das Rohraufhängung-Entfernungswerkzeug
angepasst ist, um in den Bohrlochkopf über einen zentralen Durchgang eines Steigrohrs
abgesenkt zu werden, das sich zwischen dem Bohrlochkopf und einem Überwasserschiff
oder einem Hebebohrer erstreckt, wobei der zentrale Durchgang des Steigrohrs einen
Durchmesser aufweist, der größer als der Außendurchmesser des Rohrs, aber kleiner
als der Durchmesser des zentralen Durchgangs des Bohrlochkopfs ist.
15. Verfahren nach Anspruch 14, wobei das Verfahren ferner den Schritt umfasst:
- Positionieren eines Rohraufhängung-Entfernungswerkzeugs unter Scherbacken eines
BOP, vor dem Wegbearbeiten der Rohraufhängung, und Halten des Werkzeugs mindestens
unter den Scherbacken des BOP, während des Wegbearbeitens der Rohraufhängung.
1. Procédé pour retirer une colonne de production (2) d'un puits d'hydrocarbures (1),
laquelle colonne de production est, au niveau de son extrémité supérieure, prévue
avec une suspension de colonne de production (3), laquelle suspension de colonne de
production (3) est montée dans un passage central d'une tête de puits (4), le procédé
comprenant l'étape consistant à :
abaisser un dispositif d'usinage (21) dans un passage central (23) de la suspension
de la colonne de production (3) ;
caractérisé en ce que le procédé comprend en outre les étapes consistant à :
mettre en prise une partie supérieure de la colonne de production (2) au niveau de
son intérieur et au-dessous de la suspension de colonne de production (3) à l'aide
d'un dispositif de serrage (20) ;
usiner une partie de la suspension de colonne de production (3), déconnectant ainsi
la colonne de production (2) de la suspension de colonne de production (3) et agrandissant
le passage central de la suspension de colonne de production (3) jusqu'à un diamètre
assez large pour lever la colonne de production (2) à travers le passage central de
la suspension de colonne de production (3) hors du puits d'hydrocarbures (1) ;
maintenir, facultativement supporter, la colonne de production (2) alors que le dispositif
d'usinage (21) usine au moins une partie de la suspension de colonne de production
(3) ; et
lever la colonne de production (2) déconnectée, à travers le passage central de la
suspension de colonne de production (3) hors du puits d'hydrocarbures (1).
2. Procédé selon la revendication 1, comprenant en outre l'étape consistant à :
couper la colonne de production au fond avant de mettre en prise la partie supérieure
de la colonne de production.
3. Procédé selon la revendication 1 ou la revendication 2, dans lequel le puits d'hydrocarbures
est un puits sous-marin, le procédé comprenant en outre les étapes consistant à :
prévoir une colonne montante entre la tête de puits et un navire de surface ou une
plateforme auto-élévatrice, la colonne montante ayant un passage central avec un diamètre
supérieur au diamètre externe de la colonne de production mais inférieur au diamètre
du passage central de la tête de puits au-dessus de la suspension de colonne de production
;
abaisser le dispositif d'usinage dans la tête de puits via le passage central de la
colonne montante ; et
lever la colonne de production déconnectée, à travers le passage central de la colonne
montante jusqu'au navire ou à la plateforme auto-élévatrice.
4. Procédé selon la revendication 3, comprenant en outre l'étape consistant à :
monter un BOP (bloc obturateur de puits) sur la tête de puits, le BOP ayant un alésage
raccordant la tête de puits au train de colonnes montantes.
5. Procédé selon la revendication 4, dans lequel l'alésage du BOP a un diamètre qui est
supérieur au diamètre du passage central de la colonne montante, le procédé comprenant
en outre les étapes consistant à :
prévoir un adaptateur entre le BOP et la colonne montante, l'adaptateur ayant un conduit
qui raccorde l'alésage du BOP avec le passage central de la colonne montante.
6. Procédé selon la revendication 4, dans lequel l'alésage a un diamètre qui est inférieur
au diamètre du passage central de la tête de puits, le procédé comprenant en outre
l'étape consistant à :
prévoir un adaptateur entre la tête de puits et le BOP, l'adaptateur ayant un conduit
qui raccorde l'alésage du BOP avec le passage central de la tête de puits.
7. Procédé selon une ou plusieurs des revendications 3 à 6, comprenant en outre l'étape
consistant à :
broyer les copeaux générés par l'usinage de la suspension de colonne de production
par exemple à l'aide d'un dispositif de broyage tel qu'un dispositif de découpe au
plasma prévu dans un adaptateur.
8. Procédé selon une ou plusieurs des revendications 3 à 7, comprenant en outre l'étape
consistant à :
collecter les copeaux générés par l'usinage de la suspension de colonne de production,
par exemple à l'aide d'un dispositif de collecte tel qu'un aimant prévu dans l'adaptateur.
9. Procédé selon une ou plusieurs des revendications 3 à 8, comprenant en outre l'étape
consistant à :
supporter le dispositif d'usinage à l'aide d'un tubulaire, par exemple un train de
tiges de forage ou une colonne de production hélicoïdale, le tubulaire s'étendant
à travers la colonne montante.
10. Procédé selon la revendication 9, comprenant en outre l'étape consistant à :
faire tourner le tubulaire et utiliser ce mouvement de rotation pour entraîner le
dispositif d'usinage.
11. Procédé selon la revendication 9, comprenant en outre l'étape consistant à :
faire circuler la boue de forage à travers la tête de puits afin d'entraîner le dispositif
d'usinage, la boue de forage s'écoulant vers le bas via un anneau entre le tubulaire
et la colonne montante et s'écoulant vers le haut par le tubulaire ou vice versa.
12. Procédé selon une ou plusieurs des revendications précédentes, le procédé comprenant
en outre l'étape consistant à :
utiliser un outil de retrait de suspension de colonne de production, dans lequel l'outil
de retrait de suspension de colonne de production comprend :
le dispositif d'usinage et le dispositif de serrage.
13. Procédé selon la revendication 12, dans lequel un outil de retrait de suspension de
colonne de production comprend en outre un dispositif de couplage, lequel dispositif
de couplage est adapté pour coupler l'outil de retrait de suspension de colonne de
production à un support d'outil de retrait de suspension de colonne de production,
de préférence un tubulaire, par exemple un train de tiges de forage ou une colonne
de production hélicoïdale, le tubulaire s'étendant à travers la colonne montante.
14. Procédé selon la revendication 12 ou la revendication 13, dans lequel l'outil de retrait
de suspension de colonne de production est adapté pour être abaissé dans la tête de
puits via un passage central d'une colonne montante s'étendant entre la tête de puits
et le navire de surface ou une plateforme, dans lequel le passage central de la colonne
montante a un diamètre supérieur au diamètre externe de la colonne de production mais
inférieur au diamètre du passage central de la tête de puits.
15. Procédé selon la revendication 14, le procédé comprenant en outre l'étape consistant
à :
positionner un outil de retrait de suspension de colonne de production au-dessous
des vérins de cisaillement d'un BOP, avant d'usiner la suspension de colonne de production,
et maintenir l'outil au moins au-dessous des vérins de cisaillement du BOP, pendant
l'usinage de la suspension de colonne de production.