Note: Descriptions are shown in the official language in which they were submitted.
CA 02590542 2007-06-11
AN APPARATUS FOR CONNECTING TUBULARS
USING A TOP DRIVE
This is a divisional application of Canadian Patent Application Serial Number
2,340,995 filed on August 16, 1999.
This invention relates to an apparatus for facilitating the connection of
tubulars
using a top drive and is more particularly, but not exclusively, intended for
facilitating the
connection of a section or stand of casing to a string of casing. It should be
understood
that the expression "the invention" and the like encompasses the subject
matter of both
the parent and the divisional applications.
In the construction of oil or gas wells it is usually necessary to line the
borehole
with a string of tubulars known as a casing. Because of the length of the
casing required,
sections or stands of say two sections of casing are progressively added to
the string as it
is lowered into the well from a drilling platform. In particular, when it is
desired to add a
section or stand of casing the string is usually restrained from falling into
the well by
applying the slips of a spider located in the floor of the drilling platform.
The new
section or stand of casing is then moved from a rack to the well centre above
the spider.
The threaded pin of the section or stand of casing to be connected is then
located over the
threaded box of the casing in the well and the connection is made up by
rotation there
between. An elevator is then connected to the top of the new section or stand
and the
whole casing string lifted slightly to enable the slips of the spider to be
released. The
whole casing string is then lowered until the top of the section is adjacent
the spider
whereupon the slips of the spider are re-applied, the elevator disconnected
and the
process repeated.
It is common practice to use a power tong to torque the connection up to a
predetermined torque in order to make the connection. The power tong is
located on a
platform, either on rails, or hung from a derrick on a chain. However, it has
recently been
proposed to use a top drive for making such connection. The normal use of such
a top
drive may be the driving of a drill string.
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A problem associated with using a top drive for rotating tubulars in order to
obtain a connection between tubulars is that some top drives are not
specifically designed
for rotating tubulars are not able to rotate at the correct speed or have non
standard rotors.
According to the present invention there is provided an apparatus for
facilitating
the connection of tubulars using a top drive, said apparatus comprising a
motor for
rotating a tool for drivingly engaging a tubular, and means for connecting
said motor to
said top drive, the apparatus being such that, in use, said motor can rotate
one tubular
with respect to another to connect said tubulars. _
The motor can be hydraulically operable, and the suspension unit can, in use,
move the motor relative to the axis of the top drive to facilitate aligning
the tubulars. In
one embodiment, the suspension unit is provided with at least one piston and
cylinder in
order to raise and lower the motor. The at least one piston and cylinder can
be
pneumatically actuated to compensate for. the weight of the tubular.
Furthermore,
suspension unit can comprise spherical bearings to allow movement of the motor
in two
planes, and the suspension unit can comprise adjustable pistons and cylinders
to position
the motor.
In one embodiment, the apparatus can further comprise a mud pipe for
delivering
mud to said tubular. The mud pipe can be provided with a ball joint at both
ends thereof.
In one embodiment, the apparatus can be supported by a top drive.
The present invention also provides a method of connecting first and second
tubulars for use in lining a borehole, the method comprising: coupling said
first tubular
to a top drive using a suspension unit, wherein the tubular engages the rotor
of a motor
supported by the suspension unit; engaging a lower end of said first tubular
with an upper
end of said second tubular; rotating said first tubular using the motor so as
to screw the
tubulars together; and tightening the connection between the tubulars by
rotating the first
tubular using the top drive.
In one embodiment, the method can comprise adjusting the suspension unit prior
to tightening the connection using the top drive so as to bring the first
tubular into
alignment with the top drive.
For a better understanding of the present invention and in order to show how
the
same may be carried into effect reference will now be made, by way of example,
to the
accompanying drawings, in which:
CA 02590542 2007-06-11
2a
Figure 1 is a front perspective view of an apparatus in accordance with the
present
invention; and
Figure 2 is a rear perspective view of the apparatus of Figure 1 in use.
Referring to Figure 1 there is shown an apparatus which is generally
identified by
reference numeral 1.
The apparatus 1 comprises a connecting tubular 2, a suspension unit 3 and a
hydraulic motor 4 and 4'. The hydraulic motor 4,4' has a stator 5 and a rotor
6 and is
driven by a supply of pressurised hydraulic fluid (the fluid supply lines are
not illustrated
in the Figures). The suspension unit 3 suspends the hydraulic motor 4,4' from
the
connecting tubular 2.
The present invention also provides a method of facilitating making of a
connection between an upper tubular and a lower tubular, comprising:
engaging the upper tubular with a tubular engagement tool of a top drive
having a
suspension unit;
engaging a lower end of the upper tubular with an upper end of the lower
tubular;
rotating the upper tubular via the tubular engagement tool, thereby threading
the
tubulars to form the connection;
torquing the connection via the tubular engagement tool; and
compensating for movement of the upper tubular with the suspension unit during
the
threading.
The present invention also provides a method of facilitating making of a
connection between an upper tubular and a lower tubular, comprising:
engaging the upper tubular with a gripping assembly having at least one
radially
displaceable element for gripping the upper tubular, wherein the gripping
assembly is
connected to a top drive having a suspension unit;
compensating for weight of the upper tubular to accommodate movement of the
upper'
tubular while engaged by the gripping assembly;
engaging a lower end of the upper tubular with an upper end of the lower
tubular to
form the connection therebetween; and
delivering torque to the upper tubular via the gripping assembly.
The present invention also provides a method of facilitating making of a
connection between an upper tubular and a lower tubular, comprising:
CA 02590542 2009-09-25
2b
providing a make-up unit having a top drive, a suspension unit and a tubular
engagement tool;
engaging the upper tubular with the tubular engagement tool;
engaging a lower end of the upper tubular with an upper end of the lower
tubular;
rotating the upper tubular with the top drive via the tubular engagement tool,
thereby
threading the tubulars to form the connection;
torquing the connection with the top drive via the tubular engagement tool;
and
compensating for movement-of the upper tubular with the suspension unit during
the
threading.
The present invention also provides a method of facilitating making of a
connection between an upper tubular and a lower tubular, comprising:
engaging the upper tubular with a tubular engagement tool attached to a
suspension
unit;
engaging a lower end of the upper tubular with an upper end of the lower
tubular;
rotating the upper tubular via the tubular engagement tool, thereby threading
the
tubulars to form the connection;
torquing the connection via the tubular engagement tool; and
compensating for movement of the upper tubular with the suspension unit during
the
threading.
The present invention also provides a method of facilitating making of a
connection between an upper tubular and a lower tubular, comprising:
engaging the upper tubular with a gripping assembly having at least one
radially
displaceable element for gripping the upper tubular, wherein the gripping
assembly is
connected to a suspension unit;
compensating for weight of the upper tubular to accommodate movement of the
upper
tubular while engaged by the gripping assembly;
engaging a lower end of the upper tubular with an upper end of the lower
tubular to
form the connection therebetween; and
delivering torque to the upper tubular via the gripping assembly.
The present invention also provides an apparatus for making a connection
between an upper tubular and a lower tubular, comprising:
CA 02590542 2009-09-25
2c
a tubular engagement tool for gripping the upper tubular, wherein the tubular
engagement tool includes at least one gripping element displaceable in a
radial direction
for engagement with a wall of the upper tubular in an engaged position; and
a suspension unit connected to the tubular engagement tool, the suspension
unit having
a motor for rotating the tubular engagement tool and a compensation portion,
wherein,
with the tubular engagement tool in the engaged position, the upper tubular is
rotatable
by the motor and is, relative to the lower tubular, movable along with the
tubular
engagement tool by operation of the compensation portion to compensate for
movement
of the upper tubular during making of the connection to the lower tubular.
CA 02590542 2007-06-11
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3
The suspension unit 3 comprises a plate 7 which is fixed to the connecting
tubular 2 by a collar 8. The plate 7 has two projections 9 and 10 which have
holes 11
and 12 for accommodating axles 13 and 14, which are rotationally disposed
therein.
The axles 13 and 14 are integral with a rigid body 15. A slider 16 is arranged
on
runners 17 and (not shown) on the rigid body 15. Arms 18 and 19 are connected
at one
end to the slider 16 via spherical bearings 20 and at the other end to each
side of the
stator 5 via spherical bearings 21 and 21'. The arms 18 and 19 are provided
with lugs
22 and 22' to which one end of a piston and cylinder 23, 24 is attached and
are movable
thereabout. The other end of each piston and cylinder 23, 24 is attached to
lugs 25, 26
respectively and is movable thereabout. A mud pipe 27 is provided between the
plate 7
and the stator 5 for carrying mud to the inside of a tubular therebelow. The
mud pipe 27
comprises curved outer surfaces at both ends (not shown) which are located in
corresponding recesses in cylindrical sections 28, 29, thus allowing a ball
and socket
type movement between the plate 7 and the stator 5.
Referring to Figure 2, the apparatus 1 is suspended from a top drive (not
shown)
via connecting shaft 2. A too] 30 for engaging with a tubular is suspended
from beneath
the rotor 6 of the hydraulic motor 4. Such a tool may be arranged to be
inserted into the
upper end of the tubular, with gripping elements of the tool being radially
displaceable
for engagement with the inner wall of the tubular so as to secure the tubular
to the tool.
In use, a tubular (not shown) to be connected to a tubular string held in a
spider
(not shown) is located over the tool 30. The tool 30 grips the tubular. The
apparatus I
and the tubular are lowered by moving the top drive so that the tubular is in
close
proximity with the tubular string held in the spider. However, due to amongst
other
things manufacturing tolerances in the tubulars, the tubular often does not
align
CA 02590542 2007-06-11
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4
perfectly with the tubular held in the spider. The suspension unit 3 allows
minor
vertical and horizontal movements to be made by using alignment pistons 31 and
32 for
horizontal movements, and piston and cylinders 23 and 24 for vertical
movements. The
alignment piston 31 acts between the rigid body 15 and the plate 7. The
alignment
piston 32 acts between the slider 16 and the arm 19. The alignment pistons 31
and 32
and pistons and cylinders 23, 25 are actuated by hydraulic or pneumatic means
and
controlled from a remote control device.
The piston and cylinders 23, 24 are hydraulically operable. It is envisaged
however, that the piston and- cylinders 23, 24 may be of the pneumatic
compensating
type, i.e. their internal pressure may be adjusted to compensate for the
weight of the
tubular so that movement of the tubular may be conducted with minimal force.
This
can conveniently be achieved by introducing pneumatic fluid into the piston
and
cylinder 23, 24 and adjusting the pressure therein.
Once the tubulars are aligned, the hydraulic motor 4 and 4' rotate the tubular
via
gearing in the stator 5 thereby making up the severed connection. During
connection
the compensating piston and cylinders 23, 24 expand to accommodate the
movement of
the upper tubular. The alignment pistons 31 and 32 can then be used to move
the top of
the tubular into alignment with the top drive. If necessary, final torquing
can be
conducted by ' the top drive at this stage, via rotation of the pipe 27, and
the main
elevator can also be swung onto and connected to the tubular prior to
releasing the slips
in the spider and lowering the casing string. It will be appreciated that the
suspension
unit 3 effectively provides an adapter for connecting a top drive to the
tubular engaging
tool 30.
