Note: Descriptions are shown in the official language in which they were submitted.
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TITLE OF THE INVENTION
01 Well String Injection System and Method
BACKGROUND OF THE INVENTION
02 This invention relates to devices used to manipulate continuous well
strings for
wellsite operations. Continuous well strings include rod, used for example to
operate
downhole pumps, and continuous tubing, used for example in a variety of
downhole
applications such as drilling and clean out operations. Continuous well
strings are
manipulated downhole typically with continuous chain injection units that
include gripper
pads for gripping the well strings. One early such design is shown in U.S.
Pat. No.
3,559,905 of Palynchuk, issued Feb. 1, 1971, in which a continuous chain with
gripping
blocks carried by the chain is used to inject the well string into the well.
More recently,
such continuous chain gripper systems have been described in U.S. Pat. No.
5,553,668 of
Council, eta!, issued Sep. 10, 1996,
03 The continuous chain injection units when used at a rig conventionally
are
provided with their own hydraulic power supply, separate from the rig power
supply. In
addition, these conventional power supplies provide complicated ways of
changing the
speed of the motors. This invention provides an improvement on such power
supplies.
SUMMARY OF THE INVENTION
04 According to first aspect of the invention, there is provided a
continuous feed
injection unit that operates in a dual speed configuration. The unit comprises
a first
hydraulic motor, a second hydraulic motor, cooperating continuous well string
gripping
chains connected to be driven by the first and second hydraulic motors, a
hydraulic power
supply connected to provide pressurized fluid to the first and second
hydraulic motors and
a control system for the hydraulic power supply.
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05 According to a second aspect of the invention, the power tong supply of
a service
rig is used as the hydraulic power supply for the injection unit The service
rig comprises
a mast, a hydraulic power supply for the power tongs provided adjacent the
mast, a first
hydraulic motor and preferably a second hydraulic motor mounted on the mast, a
return
for hydraulic fluid used by the first hydraulic motor and second hydraulic
motor,
cooperating continuous well string gripping chains connected to be driven by
the first
hydraulic motor and second hydraulic motor, the hydraulic power supply for the
power
tongs being connected to provide pressurized fluid to the first hydraulic
motor and second
hydraulic motor and a control system for the hydraulic power supply.
06 To provide for dual speed operation, the control system for the
hydraulic power
supply has a motor speed control valve with at least a first and second
operating
configuration, the first operating configuration providing power fluid to the
first and
second hydraulic motors in parallel and the second operating configuration
providing
power fluid to the first and second hydraulic motors in series.
07 According to a further aspect of the invention, for use in association
with either
the first or second aspects of the invention, the control system for the
hydraulic power
supply incorporates a motor direction control valve through which the power
fluid flows,
the motor direction control valve being configured to reverse flow of power
fluid through
the first and second hydraulic motors.
08 According to a further aspect of the invention, the continuous chains
comprise a
first continuous chain and a second continuous chain, the first continuous
chain being
driven by the first hydraulic motor and the second continuous chain being
driven by the
second hydraulic motor.
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09 According to a further aspect of the invention, the control system for
the hydraulic
power supply having a motor direction control valve with at least a first,
second and third
operating configuration, the first operating configuration providing power
fluid to the first
hydraulic motor to lift well string from the well, the second operating
configuration
providing power fluid to the first hydraulic motor to inject well string into
the well and
the third operating configuration allowing power fluid to flow from the
hydraulic power
supply directly to the return.
The dual speed configuration allows the drill string to be pulled up slowly
through
viscous fluid, then when the drill string is free of viscous fluid, pulled
rapidly to surface.
The device has particular utility in heavy oil reservoirs. By using the power
tong
hydraulic fluid supply, expensive additional power supplies are not required
and the
injection unit is easily set up and removed with minimal inconvenience to the
rig
operator. These and other aspects of the invention are described in the
detailed
description of the invention and claimed in the claims that follow.
10A According to a still further aspect of the invention, there is provided
a service rig,
comprising a mast having a travelling block, a continuous well string
injection unit
suspended from the travelling block; and a hydraulic power supply for the
continuous
well string injection unit provided adjacent the mast.
10B According to a still further aspect of the invention, there is provided
a continuous
feed injection unit, comprising a first hydraulic motor, a second hydraulic
motor,
cooperating continuous well string gripping chains connected to be driven by
the first and
second hydraulic motors, a hydraulic power supply connected to provide
pressurized fluid
to the first and second hydraulic motors; and a control system for the
hydraulic power
supply.
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BRIEF DESCRIPTION OF THE DRAWINGS
11 There will now be described preferred embodiments of the invention, with
reference to the drawings, by way of illustration only and not with the
intention of
limiting the scope of the invention, in which like numerals denote like
elements and in
which:
Fig. 1 shows a side view of a service rig with a continuous feed injection
unit
according to the invention;
Fig. 1A shows a section through a continuous chain drive unit for use with the
invention; and
Fig. 2 is a schematic of a power supply for use with the continuous feed
injection
unit of Fig. 1.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
12 In this patent document, "comprising" means "including". In addition, a
reference
to an element by the indefinite article "a" does not exclude the possibility
that more than
one of the element is present. A valve as referred to herein need not be a
single unit, but
may be composed of several valve pieces. For example, the valves 36, 80 and 82
together
constitute a single valve.
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13 Referring to Fig. 1, there is shown a service rig 10 with a conventional
mast 12
from which is suspended a continuous feed injection unit 14 using the
conventional
travelling block shown. A hydraulic power supply 16 for conventional power
tongs (not
shown) are provided adjacent the mast 12. Tong hoses 18 lead out from the
power supply
16 to the rig 10. The continuous feed injection unit 14, see particularly Fig.
1A, includes a
pair of hydraulic motors 20, 21 (Fig. 2) and cooperating continuous chains 22,
23
connected to be driven by the hydraulic motors 20, 21 through shafts 15 of
conventional
gear reducers (not shown) and sprockets 17. The continuous chains 22, 23
include
conventional gripper pads 19 for gripping continuous well string. The
hydraulic power
supply 16 for the power tongs is connected to provide pressurized fluid to the
hydraulic
motors 20, 21. A guide 24 provides continuous well string (not shown) from a
conventional carousel (not shown) to the continuous chains 22, 23. Squeeze
cylinders 86
squeeze the continuous chains 22, 23 between two free wheeling chain blocks
25, 26, by
moving the chain block 25 laterally towards the fixed chain block 26. The
chain block 25
is mounted on the cylinders 86. The squeeze cylinders preferably excerpt a
high pressure
in the order of 120,000 psi to grip and hold continuous rod. A lower pressure
is used for
coiled tubing. Chain tension cylinders 100, 101 are connected to sprockets
103, 102
respectively to maintain tension in the chain. The gripper blocks 23 and
chains 22, 23 are
conventional chains.
14 Referring to Fig. 2, there is shown a control system 13 for the
hydraulic power
supply 16. Pressurized power fluid at for example 40 gpm and 2500 psi is
supplied
through line 30 and filter 33 to flow divider 32. A fraction for example 20%
of the flow is
C1. 02351648 2001-06-25
diverted to auxiliary safety system 34. The remainder of the flow is direction
to a
directional control valve 36 which provides either straight through flow to
lines 38, 39 or
cross-over flow to reverse direction of fluid flow. Flow returns through check
valve 40 to
return 42. A pressure relief valve 31 is provided directly between the line 30
and return
42 to relieve excess pressure in the line 30.
In the case where fluid flow is straight through valve 36, which corresponds
to the
chains 22, 23 being operated to pull or lift well string from a well, the flow
bypasses
counterbalance valve 44 through check valve 46 and is provided directly to
hydraulic
motor 20. fhe power fluid is also provided to four way directional control
valve 48,
which controls flow to the hydraulic motors 20, 21 to govern the speed at
which the
motors 20, 21 operate. The control valve 48 functions as a motor speed control
valve. In a
first operating configuration, control valve 48 supplies fluid from line 50 to
line 52 and
then through valve 54 to motor 21, so that the motors 20, 21 operated in
parallel. In a
second operating configuration, directional valve 48 supplies power fluid that
has passed
through motor 20 along line 56 along line 52 through valve 54 to motor 21 so
that the
motors 20, 21 operate in series. In eithcr case, the power fluid is returned
through line 58
and check valve 40 to the return 42. Direction of movement of the motors 20,
21 is
controlled by manually operated valve 80 and directional control valve 82,
which control
the control ports of directional valve 36, to set the directional valve 36 to
the cross-over
position, neutral position or straight through position. The valves 36, 80 and
82 function
as a motor direction control valve.
16 Flow from flow divider 32 is directed along line 60 through check valves
62 to
accumulators 64 and 66 in thc auxiliary safety system 34. An unloading valve
61 is
provided on the auxiliary line 60 to direct flow to the return 42 when high
pressure is
sensed on line 63. Line 68 provides control fluid through lines 70 and 72 to
the control
port 76 on directional control valve 48. Flow to the directional control valve
48 is
controlled by manual operation of valve 74 on line 72. Fluid along line 70 is
also
provided under control of manual directional control valve 84 to squeeze
cylinders 86,
- _________________
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which provide the gripping force for the grippers on the chains 22, 23. To
prevent
damage from running oversized rod through the grippers, extra relief is
provided on line
88 by relief valve 90.
17 Each of the motors 20, 21 is provided with a spring actuated brake 90,
91
respectively, which are held open by pressure in fluid line 92. Fluid line 92
also provides
pressure to pilots 94, 96, which, when pressured, open the check valves 54 and
55 to
allow power fluid from line 50 to power the motors.
18 Line 92 also supplies fluid through check valve 97 and line 98 to chain
tension
cylinders 100, 101. The chain tension cylinders 100, 101 engage sprockets 102,
103
respectively, which support the continuous chains 22, 23. A pressure relieving
valve 104
is provided on line 98 to relieve excess fluid pressure sensed by pilot line
105, for
example when the rod or tubing being moved snags on an obstacle. Excess
pressure is
relieved through line 107 connected to the fluid return 42 through lines 110
and 112. The
pressure for the chain tension cylinders 100, 101 is preferably maintained at
a relatively
low level, for example 500 psi.
19 Fluid in line 92 is supplied via four way directional valve 106 from
line 108,
which is supplied fluid from the accumulators 64. 66, through line 70. The
directional
valve 106 is also connected through drain line 110 to drain fluid to the
return 42.
Directional control valve 106 is controlled by a pilot 114 that connects
through two safety
control valves 116 and 118 to the accumulators 64, 66. The control valve 116
functions as
a parking brake.
20 Pressure to the motors is regulated by pilot operated pressure relief
valves 122 and
132 connected respectively to the lines 39, 38. The relief pressure is set by
remote
pressure controls 124, 134. When pressure in lines 39, 38 exceeds a pressure
set by
controls 124, 134 respectively, lines 126, 136 sense the pressure and open
valves 122,
132 respectively to drain fluid through lines 128. 138, check valve 139 and
line 140 to the
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return 42. When the parking brake is on, pressure in line 131 opens the check
valves 127,
137, and vents the pilots on the valves 122, 124, 132 and 134 to drain, thus
setting the
valves 122, 132 to drain at zero pressure and disabling the motors 20, 21.
Valve 118 is a
main safety valve. When valve 118 is manually operated to the cross-over
position, safety
brake cylinder 120 is actuated by fluid through line 130 to stop the chains
22, 23. The
safety brake cylinder 120 remains activated until released by 100 psi pressure
from source
121 through hose 133.
21 The manner in which the hydraulic control system works will now be
described.
When the system is hooked up to the tong power lines 30, the valve 36 is set
at neutral
and fluid runs back through line 140 to the return 42. Valve 82 is also in the
neutral
position initially.
22 To grip rod with the gripping blocks 23. valve 84 is set to the cross-
over position.
which forces the movable chain block 25 laterally towards chain block 26 and
grip rod or
tubing between the chains 22. 23.
23 To power the motors, the parking brake 116 is released and the main
safety valve
118 is placed in the cross-over position to allow pilot line 114 to activate
valve 106.
Valve 106 moves into the cross-over position and power fluid supplied though
lines 70
and 108 is provided to lines 92 and 142. Fluid in line 92 releases the brakes
90, 91 on the
motors 20,21, opens the check valves 54, 55 to allow power fluid to allow
power fluid in
line 50 to activate the motors 20, 21 and powers the chain tensioners 100, 101
through
line 98. Fluid in line 142 activates valve 82 into the straight through
position.
24 The speed setting of the tool is selected by valve 74 as follows. The
straight
through position provides power fluid in line 70 through line 72 to actuate
valve 76 to the
cross-over position, which forces the motors 20, 21 to operate in parallel,
thus providing
low speed, high pressure. The cross-over position of valve 74 allows fluid in
line 72 to
drain to the return 42 through line 112, and the valve 76 resets to the
neutral position
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which forces the motors 20, 21 to operate in series, thus providing a high
speed, low
pressure operation of the motors 20, 21.
25 When the operator is surc the rod or tubing is gripped, and the brakes
are off,
valve 80 is manually operated to select up or down motion for the motors. In
the cross-
over position, fluid in line 70 forces valve 36 into the straight through
position. Power
fluid then flows through line 38 and line 50 to the motors 20, 21, which will
be operating
in high speed or low speed depending on the selection of valve 74. The motors
20, 21 will
be operating in the upward, pulling direction. When it is desired to lower rod
into the
well, valve 80 is set to the straight through position, which sets valve 36
into the cross-
over position. Power fluid then is supplied through line 39 to counterbalance
valve 39,
and opens it to allow fluid to drain through lines 38 and 142 to the return.
At the same
time, fluid from line 39 is provided along line 58 to power the motors 20, 21
in either
high speed or low speed operation depending on the position of valve 74.
Counterbalance
valve 44 places a drag on the motors 20, 21 to prevent them from overrunning
due to the
weight of the rod or tubing.
26 Operation of the valve 80 is used to shut off the motors if desired. The
main safety
valve 118 may also be operated to engage the stop cylinder 120 (which squeezes
the rod
to stop it), engage the brakes 90, 91 on the motors 20, 21, and activate the
check valves
54, 55 to prevent the motors 20, 21 from operating.
27 The continuous gripper chain unit as well as the motors 20, 21, and
cylinders 86,
100, 101 are mounted on the well, while the controls (right side of Fig. 2)
are mounted in
a separate unit about 30 ft away. Conventional hoses 150, 152 and 154, with
quick
couplings 151, 153 and 155 may be used to connect the units.
28 In this way, the continuous feed injection unit of the present invention
may be
operated using the power tong hydraulic power supply of a conventional rig,
and may be
readily operated in a high speed, low pressure configuration when the well
string is held
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by viscous fluid and a low speed, high pressure configuration when well string
is free of
viscous fluid.
29 Parts for the control system may be obtained as follows:
Item Description Source Part No.
36, 48 4-way directional control valve Rexroth 4WH22G7X
106 4-way directional valve Rexroth 4WH6D5X
74, 116, 84 4-way directional control valve Rexroth 4WMM6D5X/F
118 4-way directional control valve Rexroth 4WMM1003XJF
54, 55 Pilot check valve Sun CKGB-XCN-HCM
127, 137 Pilot check valve Sun CKCB-XCN-ECJ
62, 139 Check Valve (T-5A CAVITY) Sun CXFA-XAN-DAK
40 50 PSI Check Valve(T-16A CAVITY) Sun CXHA-XDN-IAN
122, 132 Pressure Relief Valvc(T-17A CAVITY) Sun RVGA-LAN-HCM
124 Remote Pressure Control Sun RBAC-KBN-FAJ
134 Remote Pressure Control Sun RBAC-KAN-FAJ
44 Counterbalance Valve Sun CBOO-LJN-HCM
31 Pressure Relief Valve Sun RDFA-LAN-CAL
61 Unloading Valve Denison R4L106-503-12*1
104 Pressure Reducing/Relieving Valve Sun PPFB-LAN-BAL
64,66 2.5gallon Accumulator Accumulators Inc. A-2.5-3100L
26, 21 Hydraulic Motor Pen-nco M7500A767ADNE20-6
90, 91 Brake Eskridge 75C-4-C-4-B068-D
- Gear Reducer (not shown) Heco 20DGF-11-6-31-1
97 lnline Check Valve Parker C820-S
90 Pressure Relief Valve Sun RPEC-KAN-FAJ
86 Squeeze Cylinders C-TECH MK1 G625D109
100, 101 Chain Tensioner Cylinders C-TECH MK1 G625D117
120 6" Safety Cylinder Yates H6M-N6.0P-3.00N2.50TXS11
32 20/80 Gear Type Flow Divider Control Flow
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FD5088YAD25-1GED07-1BY
80 4-way directional control valve Rexroth 4WMM6J5XJF
150 3/8" HOSE-30 FT-06NPTM/08JICF Greenline G122R-06M68FJ30
151 Quick Coupling Greenline C701H/702H-06
152 'A" HOSE-30 FT-08NPTM/12JICF Greenline G122R-08M812FJ30
153 Quick Coupling Greenline C701H/702H-08
154 3/4"HOSE-30 FT-12NPTM/16JICT Greenline 0122R-12M1216FJ30
155 Quick Coupling Greenline C701H/70211-12
82 4-way directional control valve Rexroth 4WH6G5X/S0135
33 High Pressure Filter Stauff SF0456208-TIJ/BAT
133 1/4" 250 PSI Pneumatic Hose ¨30 FT. Greenline G222-025M66M30
Immaterial modifications may be made to the invention described here without
departing from the essence of the invention. For example, one or more
additional motors
may be used in parallel and in series.
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