Note: Descriptions are shown in the official language in which they were submitted.
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TEM File No. 180.2
TITLE: HYDRAULIC SUBMERSIBLE BOTTOM PUMP ACTUATOR
The present invention relates to a submersible pump arrangement which
hydraulically actuates a conventional oil field bottom hole pump, and in
particular to a
cylinder, concentric gland port and gland packing design which allows separate
and
independent hydraulic application to each port.
The advent of directional and horizontal drilling technology has allowed
greater
production volumes and drainage to be attained from single well bores. A
conventional oil
field bottom hole pump presently operates with a rod string from the pump rod
to surface
and is reciprocated mechanically, usually with a pump jack. Deviated wells
create a variety
of problems for conventionally pumped wells, such as rod drag, tubular and rod
wear.
Because of these problems, conventional pumping can become very costly, and is
generally
not used in well bore deviations exceeding 30 degrees from vertical.
Another problem with conventional pumping systems is that the stroke length
and
the rate of reciprocation is limited by the pump jack, thereby limiting the
production
capacity unless larger equipment is moved in.
US Patent no. 4,925,374 (Carrens), titled "Down Hole Hydraulically Actuated
Pump", offers an alternative to the above conventional pumping systems, but
suffers from
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several disadvantages. First, the Carrens actuator is restricted to only a
single hydraulic
power supply. Second, the actuator exhausts power fluid into the production
fluid stream
for operation, thus needlessly commingling the power fluid with the production
fluid.
Third, Carrens uses a very complex switching valve with small flow channels
that may be
prone to plugging. Fourth, the actuator and pump appear to be integral and
thus not
adapted for use with conventional pumps.
What is therefore desired is a novel submersible hydraulic actuator
arrangement
which overcomes the disadvantages and limitations of conventional
arrangements.
Preferably it should be adapted for use with conventional bottom hole pumps,
it should
operate at any angular deviation, including horizontal, and avoid mechanical
failures
associated with rod strings. The actuator arrangement should further
accommodate any
pump stroke length and provide greater reciprocation rates than are attainable
with
mechanical methods. In particular, the actuator arrangement should use two
distinct and
separate power supply lines to provide power fluid to both ports of a
hydraulic cylinder,
thus creating a true double acting hydraulic actuator, and should use a closed
hydraulic
system to avoid the commingling of power fluid with the produced fluid.
In one aspect the invention provides a double acting hydraulic cylinder
actuator
assembly for submersible actuation of a conventional bottom hole oil field
pump
comprising:
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an actuator adapter for attaching the assembly to the bottom hole pump, and
having a rod wiper and gland packing incorporated to prevent produced fluid
from
entering the actuator assembly;
a gland end port sub for mounting of the pump's outer barrel to the actuator's
hydraulic cylinder, wherein the gland end port sub includes gland end fluid
ports and a
gland packing below the fluid ports to contain hydraulic fluid from escaping
the gland port
supply;
a concentric gland port barrel to contain the gland port supply about the
cylinder
and deliver it to the gland ports; and,
a cylinder end port with integral gland port by-pass channels:
Embodiments of the invention will now be described, by way of example only,
with
reference to the accompanying drawing, wherein:
Figure 1 is a schematic view partially in vertical cross-section showing an
above-
ground wellhead, surface hydraulic power unit with automatic controls and
hydraulic lines,
a production tubing string extending from the wellhead down an oil well to a
horizontal
portion thereof complete with an API pump seating nipple, a hydraulic
submersible bottom
hole pump actuator assembly seated into the API pump seating nipple at the
pump seating
cups, and concentric endless tubing hydraulic lines from the top of the
actuator assembly
internally up the length of the production tubing to the wellhead;
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Figure 2 is a cross-sectional side view of a preferred embodiment of the
hydraulic
submersible bottom hole pump actuator assembly of figure 1 showing a modified
conventional bottom hole pump attached thereto; and,
Figure 2A is a close-up view of the hydraulic actuator assembly from a pump
adapter sub to an endless tubing adapter connection.
T.TST OF EFERENCE NUMERALS IN DRAWINCrS
hydraulic submersible bottom hole pump actuator arrangement
11 production tubing
12 connections of 11
13 API pump seating nipple of 11
14 wellhead
hydraulic tubing supply, end port
16 hydraulic tubing supply, gland port
17 surface hydraulic power supply with automatic flow reversal controls
conventional bottom hole reciprocating pump
21 suction screen of 20
22 standing valve of 20
23 traveling valve of 20
24 plunger of 20
barrel of 20
26 seating assembly of 20
hydraulic submersible pump actuator
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31 actuator - bottom hole pump adapter of 30
31a bottom hole pump discharge ports of 31
31b plunger rod wiper & primary gland packing to seal out produced fluid of 31
31 c secondary gland packing to seal out produced fluid of 31
32 gland packing saver sub of 30
32a lubricant chamber of 32
32b barner seal of 32
32c secondary gland packing to seal hydraulic fluid of 32
33 plunger rod of 30
34 gland end port sub of 30
34a primary gland seal for hydraulic fluid of 34
34b gland ports of 34
34c gland port barrel mount of 34
34d gland port hydraulic cylinder mount of 34
35 gland port barrel of 30
36 actuator hydraulic cylinder of 30
37 hydraulic double acting plunger head with V block seals of 30
38 hydraulic cylinder port end with concentric gland port channels of 30
38a concentric gland port channels
40 concentric endless tubing gland port hydraulic supply of 16
41 concentric endless tubing end port hydraulic supply of 15
42 gland port adapter of 40
43 end port adapter of 41
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DESCRTP ION OF P FFER_RRD EMBODIIVVIENT
Figures 1, 2, and 2A show a hydraulic submersible bottom hole pump actuator
and
conventional oil field bottom hole pump (generally designated by reference
numeral 10)
within a production tubing string 11 which is itself within the production
casing 17 of a
well bore. The pump and attached actuator are typically seated within the
production
tubing using a standard API pump seating nipple 13. The pump and actuator are
run into
the production tubing and seated into the pump seating nipple with attached
endless tubing
hydraulic line 16 running to surface. Once landed in the seating nipple a
second smaller
endless tubing hydraulic line 1 S is run inside of line 16 down to and coupled
with the end
port adapter 43 of the hydraulic actuator.
At surface the hydraulic lines are sealed from each other to provide separate
hydraulic lines to each port of the actuator, line 15 being for the end port
and the annulus
of lines 15 and 16 for the gland port. The separate hydraulic lines are
connected at surface
to a manifold and control system built onto a hydraulic power supply 17. Each
hydraulic
supply line contains a pressure switch and relay connected to an electric
switching valve.
When the actuator plunger reaches the end of its' stroke, the hydraulic
pressure will
increase above the working pressure. This increased pressure will be
identified by the
respective pressure control switch and an electronic signal will be relayed to
the control
valve which will reverse the hydraulic flow down the other hydraulic line. The
actuator
plunger 37 will then travel to the other end of its' stroke where the process
is repeated.
Since the actuator plunger rod 33 is connected to the bottom hole pump plunger
24 and
traveling valve 23, the bottom hole pump 20 reciprocates as the hydraulic
actuator 30
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cycles back and forth. A typical hydraulic supply 17 may range from 10-20 gpm,
at 1500-
3000 PSI.
The hydraulic submersible actuator 30, which is connected to a slightly
modified
standard oil-field bottom hole pump 20, is an arrangement of the following
general
components:
a pump adapter 31 for connecting the actuator to the pump and preventing
produced fluid
from entering the actuator via a built in rod wiper and gland packing 31b, and
secondary
gland packing 31 c to prevent produced fluid entry;
a gland packing saver sub 32 having a lubricant chamber 32a, a barner seal
32b, and
secondary gland packing 32c to facilitate greater gland packing seal life;
a gland end, port sub 34 which connects the gland end port hydraulic supply to
the
cylinder via gland ports 34b, which contains the primary gland packing 34a to
prevent the
hydraulic supply from escaping the hydraulic cylinder gland end, and which
provides a
hydraulic cylinder mount 34d for centering the hydraulic cylinder 36 within
the gland port
barrel and a gland port barrel mount 34c to connect the gland port supply to
the gland
ports;
a gland port barrel 3 5 which provides a concentric hydraulic channel to the
gland ports 34b
outside of the cylinder 36;
a hydraulic cylinder 36 which provides the plunger head stroke area;
a plunger rod 33 which contains a hydraulic plunger head in the actuator end
and is
attached to plunger 24 and a traveling valve 23 of the bottom hole pump 20 at
the other
end;
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a hydraulic plunger head 37 containing hydraulic V cup seals to facilitate the
containment
of hydraulic fluid from either side;
a cylinder end port 38 with concentric gland port by-pass channels 38a which
allows gland
port hydraulic flow to enter and exit the gland port barrel, the cylinder end
port engaging
the threaded top of the gland port barrel which centers and supports the
cylinder end port;
an external concentric tubing adapter 42 which engages the same threaded
connection on
top of the gland port barrel, and screws down to and tightens against the top
of the
hydraulic cylinder end port 38 to connect the external concentric hydraulic
tubing line 16
with the gland port barrel 35 and lock down the cylinder end port; and,
an internal concentric tubing adapter 43 to couple the inside hydraulic tubing
line 1 S to the
hydraulic cylinder end port 38, for allowing end port hydraulic fluid to enter
and exit the
cylinder end port.
The operation of the present hydraulic actuator, and thus the reciprocation of
the
attached bottom hole pump, is accomplished by providing power fluid to either
port supply
line. If fluid power is supplied to the end port line, the power fluid pushes
the plunger rod
head 37 down the hydraulic cylinder 36 to the gland port sub 34. The plunger
rod 33,
attached to the plunger rod head 37 in the hydraulic actuator 30, is attached
to the bottom
hole pump plunger 24 and to the bottom hole pump traveling valve 23 in the
bottom hole
pump 20.
As a result, powering the end port of the actuator pushes the plunger rod and
the
pump plunger with the traveling valve to the bottom of the pump stroke. At the
bottom of
the stroke the plunger stalls, forcing the power fluid pressure to increase
above normal
operating pressure. This increase is detected at the power fluid supply 17,
and an
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electronic signal is relayed to a valve manifold which switches the power
fluid to the gland
port line. With power fluid now being applied to the gland port 34, the
plunger head,
plunger rod, bottom hole pump plunger and traveling valve are forced to travel
in the
opposite direction until the plunger head reaches the end port and the BHP
plunger
reaches the top stroke position of the pump. At the top stroke position the
plunger again
stalls, forcing the power fluid pressure to increase above the normal working
pressure. A
pressure sensor then electronically signals the valve manifold which switches
the power
supply to the other port which repeats the cycle.
The present hydraulic system does not circulate nor does it allow commingling
of
power fluid with produced fluid. The separate hydraulic lines alternately
function as
"supply", when power fluid is applied, and as "return" when power fluid is
being applied to
the other line. The BHP plunger and traveling valve are thus reciprocated by
the actuator,
and the fluid produced by this pumping action is discharged from the bottom
hole pump
discharge ports 31a of the actuator-bottom hole pump adapter sub 31. The
discharged
production fluid is then carned to surface in the annular area between the
production
tubing 11 and the gland port hydraulic supply line 16.
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