DUAL STRING TUBING ROTATOR

ROTATEUR DE TRAINS DE TIGES DOUBLES

English Abstract

A producing oil well has two strings, a production tubing string containing a rod-driven pump and a secondary tubing string extending along the well for the supply of flushing or injection fluid to the well bore. Rod wear on the production tubing string is distributed by rotating the production tubing using a tubing rotator mounted on the wellhead. The rotator includes a mandrel and gear drive for rotating the tubing string and an offset for the secondary string that may be connected to a coiled tubing hanger.

French Abstract

Un puits de pétrole en production a deux trains, un train de tubage de production comportant une pompe entraînée par tige et un train de tubage secondaire s'étendant le long du puits pour l'alimentation en fluide de rinçage ou d'injection du puits de forage. L'usure de tige sur le train de tubage de production est répartie par rotation du tubage de production à l'aide d'un rotateur de tubage monté sur la tête de puits. Le rotateur comprend un mandrin et un engrenage d'entraînement destinés à faire tourner le train de tubage et un déport pour le train secondaire qui peut être connecté à un dispositif de suspension de tube enroulé.

Claims

Claims
1. A method of operating a producing oil well having a well bore, a
production tubing string extending along the well bore, a rod-driven pump in
the
production tubing string and a secondary tubing string extending along the
well
beside the production tubing string, said method comprising:
driving the pump to deliver fluid to the production tubing string; and
distributing rod wear on the production tubing string by rotating the
production tubing string.
2. A method according to Claim 1 comprising introducing fluid into the bore
through the secondary tubing string.
3. A method according to Claim 2 comprising flushing the bore with the fluid
introduced through the secondary tubing string.
4. A method according to Claim 2 comprising injecting fluid into the well bore
with the secondary tubing string.
5. In an oil well having a well bore:
production tubing extending along the well bore;
a pump coupled to the production tubing for pumping oil along the
production tubing;
rod means extending along the production tubing for driving the pump;
stationary tubing extending along the well bore beside the production
tubing; and
means for rotating the production tubing in the bore.

6. An oil well according to Claim 5 wherein the stationary tubing includes a
guide tube string and coiled tubing extending along the guide tube string.
7. An oil well according to Claim 5 wherein the pump is a rotary pump.
8. A dual string tubing rotator for a wellhead, comprising:
a hanger for mounting on the wellhead, the hanger having first and second
tubing bores therethrough;
a rotatable mandrel extending into the first hanger bore, the mandrel
having an inlet end engageable with a production tubing string and a
delivery end;
mandrel drive means for rotating the mandrel;
means for delivering oil from the delivery end of the mandrel to a
stationary delivery line; and
stationary string coupling means for coupling a stationary tubing string to
the second tubing bore of the hanger.
9. A rotator according to Claim 8 including a bonnet over the hanger, the
bonnet comprising an offset bore communicating with the second of the hanger
bores and diverging from the mandrel in a direction away from the hanger.
10. A rotator according to Claim 9 wherein the mandrel drive means comprise
a gear drive on the bonnet.
11. A rotator according to Claim 8, 9 or 10 including a coiled tubing hanger
mounted on the stationary string coupling means.

Description

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DUAL STRING TUBING ROTATOR
FIELD OF THE INVENTION
The present invention relates to dual string oil wells and to
methods and apparatus useful in such wells.
BACKGROUND
In a dual string oil well, a production tubing string delivers oil
from the well to the surface, while a second tubing string may be used for
various purposes, including delivering fluid to the well for flushing or
injection purposes, hanging down hole recorders or wireline logging tools.
When a rod-driven pump, for example a progressive cavity pump is used in
such a well, the rod operating in the production tubing can rub on the
tubing, causing rapid wear. This rubbing may be caused, for example, by
rod whipping or by the bending of the rod into contact with the production
tubing in a deviated well.
While in single string wells, it has been possible to distribute
rod wear on the tubing by rotating the production tubing, it has not been
possible to use this technique in a dual tubing string installation. The
present invention addresses this problem.
SUMMARY
According to one aspect of the present invention there is
provided a dual string tubing rotator for a wellhead, comprising:
a dual hanger for mounting on the wellhead, the hanger having
first and second tubing bores therethrough;
a rotatable mandrel extending into the first dual hanger bore,
the mandrel having an inlet end engageable with a production tubing string
and a delivery end;
mandrel drive means for rotating the mandrel;
rotary coupling means for delivering oil from the delivery end of

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the mandrel to a stationary delivery line; and
stationary string coupling means for coupling a stationary
tubing string to the second tubing bore of the hanger.
The rotator enables the rotation of the production tubing in a
dual string well. The stationary string coupling means preferably include an
offset section sloping outwardly from the mandrel, away from the hanger.
This allows a coiled tubing hanger to be connected to the stationary string
coupling means for running coiled tubing into the well bore.
According to another aspect of the present invention there is
provided, in an oil well having a well bore:
production tubing extending along the well bore;
a pump coupled to the production tubing for pumping oil along
the production tubing;
rod means extending along the production tubing for driving the
pump;
stationary tubing extending along the well bore for introducing
fluid into the bore; and
means for rotating the production tubing in the bore.
According to a further aspect of the present invention there is
provided a method of operating a producing oil well having a well bore, a
production tubing string extending along the well bore, a rod-driven pump in
the production tubing string and a secondary tubing string extending along
the well, said method comprising:
driving the pump to deliver fluid the production tubing; and
distributing rod wear on the production tubing by rotating the
production tubing.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings, which illustrate exemplary

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embodiments of the present invention:
Figure 1 is a schematic view of a dual string deviated well;
Figure 2 is a cross-sectional view of a dual string tubing rotator
according to the present invention;
Figure 3 is a cross-section of an alternative embodiment of the
dual string tubing rotator incorporating a coiled tubing hanger.
DETAILED DESCRIPTION
Referring to the accompanying drawings, and especially to
Figure 1, there is illustrated a an oil well 10 having a well bore 12 lined
with
a well casing 14. The well is a deviated well with a vertical upper section
15, and horizontal lower section 16 and a curved transition section 17
between them. Extending along the casing 14 is a production tubing string
18 connected at its bottom end to a progressive cavity pump 19. The pump
is driven by a rotating rod 20 that will, in normal practice, rub on the
production tubing 18, causing it to wear. The well casing 14 also contains
a guide tube string 22 that contains a string 24 of coiled tubing 25
connected at its end to an injection nozzle 26 for injecting fluid into the
well.
At the end of the casing 14 is a slotted liner 28 for admitting oil into the
bottom end of the casing.
At the top of the well bore is a hanger 30. Mounted on this
wellhead hanger is a tubing rotator 32 that will be described in more detail
in the following. This in turn is connected to an integrated blow-out
preventer and a flow-tee 34 for delivering the oil produced by the well to a
pipeline 35. On top of the blow-out preventer and flow-tee is a rod drive 36
for driving the rod 20.
Shown in broken line in Figure 1 is a coiled tubing hanger 38
connected to the tubing rotator 32 for hanging the coiled tubing 24 from the
wellhead .

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An embodiment of the dual string tubing rotator 32 is illustrated
in Figure 2. This rotator includes a dual hanger 42 that is seated into the
wellhead hanger 30. The dual hanger has two bores 44 and 46 for the two
tubing strings. The bore 46 accommodates a hanger coupling 48 with a
thread 50 for coupling to the top end of the guide string 22 (Figure 1 ).
On top of the wellhead hanger 30, over the hanger 42 is a
bonnet 52. This has a base section 54 with an upwardly facing shoulder 56
near the bottom end. The shoulder engages a mating shoulder on a
surrounding annular flange 58. This allows the flange to be rotated to bring
the bolt holes 59 into line with bolt-holes in the flange on the wellhead
hanger 30 regardless of the orientation of the bonnet.
The bonnet 52 has an offset guide string bore 60. This has a
bottom end that aligns with the hanger coupling 48 and inclines outwardly
from the center of the bonnet. A second bore 62 extends vertically through
the bonnet. It has two sets of lands 64 accommodating appropriate packing
for sealing the bore to a tubular mandrel 68 extending along the inside of
the bore. The mandrel has a tube 70 with a threaded bottom end 72 for
connection to a production tubing string. The tube has an external flange
74 partway along that is connected to a worm gear 76. The worm gear
rides in a gear casing 77 forming the upper end of the tubular rotator. The
worm gear is driven by a worm 78 to rotate the mandrel 68.
The top end of the rotator 32 has a flange 80 and an internal
thread 82 for connection to the blow-out preventer and flow-tee.
An alternative embodiment of the invention is illustrated in
Figure 3, where the top end of the rotator has an externally threaded pin top
connector 84 but is otherwise the same as the previously described rotator.
This rotator is also shown with the guide string of the bore 60 connected to
the coiled tubing hanger 40 so that coiled tubing can be run into the well

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through the guide tubing string.
With the present invention, it is possible for the first time to run
a dual string well with the ability to rotate the production tubing string to
distribute rod wear.
While certain embodiments of the present invention have been
described in the foregoing, it is to be understood that other embodiments
are possible within the scope of the invention. The invention is to be
considered limited solely by the scope of the appended claims.
r

Representative Drawing