U.S. patent application number 11/103067 was filed with the patent office on 2006-08-03 for hydraulic pump jack sytem for reciprocating oil well sucker rods.
Invention is credited to T. Leon Brown.
Application Number | 20060171821 11/103067 |
Document ID | / |
Family ID | 35253754 |
Filed Date | 2006-08-03 |
United States Patent
Application |
20060171821 |
Kind Code |
A1 |
Brown; T. Leon |
August 3, 2006 |
Hydraulic pump jack sytem for reciprocating oil well sucker
rods
Abstract
A pumping system for vertical reciprocation of a string of
sucker rods within oil well tubing having a positive displacement
pump at the bottom thereof, includes a vertically positioned
elongated hydraulic cylinder supported above the tubing and in
alignment therewith, the cylinder having a vertically displaceable
piston therein. A pump rod is affixed to the piston and extends
beyond the bottom end of the cylinder. A seal member affixed to the
lower end of the cylinder sealably and reciprocally receives the
piston rod. A Tee fitting is secured between the tubing and the
cylinder bottom end and reciprocally receives the piston rod. A
controlled hydraulic power system provides fluid pressure to the
cylinder to vertically reciprocate the piston and thereby the
piston rod and tubing string to pump crude oil upwardly in the
tubing, the crude oil flowing under pressure into the Tee fitting
and out through a side opening.
Inventors: |
Brown; T. Leon; (Amarillo,
TX) |
Correspondence
Address: |
GABLE & GOTWALS
100 WEST FIFTH STREET, 10TH FLOOR
TULSA
OK
74103
US
|
Family ID: |
35253754 |
Appl. No.: |
11/103067 |
Filed: |
April 11, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60562207 |
Apr 13, 2004 |
|
|
|
Current U.S.
Class: |
417/390 ;
417/398 |
Current CPC
Class: |
F04B 47/02 20130101;
F04B 47/08 20130101; E21B 43/126 20130101 |
Class at
Publication: |
417/390 ;
417/398 |
International
Class: |
F04B 17/00 20060101
F04B017/00 |
Claims
1. A pumping system for vertical reciprocation of a string of
sucker rods in oil well tubing having a positive displacement pump
at the bottom thereof, comprising: a vertically positioned
elongated hydraulic cylinder having a top and bottom end and
supported above said tubing and in alignment therewith; a
vertically displaceable piston within said cylinder; a pump rod
affixed to said piston and extending beyond said cylinder bottom
end; a seal member affixed to said lower end of said cylinder for
sealably and reciprocally receiving said piston rod; a Tee fitting
having a vertical passageway therethrough, having a lower open end
secured to said tubing, an upper open end secured to said cylinder
bottom end and a side opening communicating with said passageway
that reciprocally receives said piston rod; and a controlled
hydraulic power system providing fluid pressure to said cylinder to
vertically reciprocate said piston and thereby said piston rod and
rod string to pump crude oil upwardly in the tubing, the crude oil
flowing under pressure into said Tee fitting passageway and out
through said side opening.
2. A pumping system according to claim 1 wherein said cylinder top
end is vented to the atmosphere.
3. A pumping system according to claim 1 including: a top seal
affixed to said upper end of said cylinder; an upper piston rod
affixed to said piston and extending beyond said cylinder top end
and sealably and reciprocally received by said top seal; and
wherein said hydraulic power system provides controlled fluid flow
to said cylinder above and below said piston.
4. A pumping system according to claim 1 wherein said hydraulic
power system is programmable permitting separate selectable upward
and downward sucker rod acceleration rates.
5. A pumping system according to claim 4 wherein said hydraulic
power system includes a program providing selectable delays at the
top and/or bottom of sucker rod reciprocations.
6. A pumping system according to claim 1 including a sucker rod
length adjustment mechanism between said pump rod and said sucker
rod string.
7. A pumping system according to claim 6 including: a vertical
tubular adjustment member affixed at an upper end to said plumb rod
and having a reduced internal diameter open lower end; an
externally threaded adjustment rod having an upper end portion
received within said tubular adjustment member and a lower end
affixed to the sucker rod string; and an internally threaded
adjustment nut threadably received on said adjustment rod within
said adjustment tubular member, the length of the sucker rod string
be adjustable by the rotational position of said adjustment bolt.
Description
REFERENCE TO PENDING APPLICATIONS
[0001] This application is based on Provisional Patent Application
60/562,207 filed April 13, 2004 entitled PUMP APPARATUS AND METHOD
FOR OIL WELL PRODUCTION.
REFERENCE TO MICROFICHE APPENDIX
[0002] This application is not referenced in any microfiche
appendix.
FIELD OF THE INVENTION
[0003] This invention relates to a system for reciprocating an oil
well pump located in the bottom portion of a string of tubing in
which the pump is reciprocated by sucker rods extending from the
pump to the earth's surface.
BACKGROUND OF THE INVENTION
[0004] Oil wells typically vary in depth from a few hundred feet to
several thousand feet. In many wells there is insufficient
subterranean pressure to force the oil to the earth's surface. For
this reason some system must be devised for pumping the crude oil
from the producing formation to the earth's surface. The most
common system for pumping an oil well is by the installation of a
pumping unit at the earth's surface that vertically reciprocates a
string of sucker rods extending within tubing to a subsurface
pump.
[0005] Traditionally sucker rod strings have been reciprocated by a
device known as a pump jack which operates by the rotation of an
eccentric crank driven by a prime mover which may be an engine or
an electric motor. Such mechanical drive mechanism has been
utilized extensively in oil production industry for decades and
continues to be a primary method for extracting oil from a well.
However, such mechanical systems suffer from a number of inherent
disadvantages or inefficiencies that include their substantial size
and weight that makes them expensive to produce, difficult to
transport and expensive to install. The mass of such units also
requires significant structural support elements at the wellhead
which adds to the complexity and expense of the overall drive
mechanism. Furthermore, mechanical drive systems have components
that are physically linked or connected in some form by way of
connecting rods, cams and gear boxes. For a variety of different
reasons it often becomes necessary to adjust the travel of the pump
rod. Mechanical linkages, as have been previously used, present
difficulties in adjusting the travel or displacement of the pumping
rods. With most mechanical pumping systems in present use adjusting
the rod displacement or pumping speed requires the drive system to
be shut down, wasting valuable production time and increasing labor
costs. Mechanical drive pump jacks are also limited in their
ability to control acceleration and deceleration of the pump rod
during its reciprocation.
[0006] To combat these limitations in mechanical pump jack drive
systems, others have provided a variety of different pneumatic and
hydraulic drive mechanisms that have met varying degrees of
success. Most hydraulic drive systems in use today are mounted
above a stuffing box through which a polished rod extends. Below
the stuffing box is a T-fitting so that produced oil is diverted
from upward flow within the well tubing to a gathering line that
connects to the stuffing box. Stuffing boxes require frequent
lubrication. If not constantly lubricated, the packing in stuffing
boxes soon wear out resulting in leakage that can spread crude oil
to the environment. The invention herein provides an improved
hydraulic operated pumping unit that, among other advantages,
eliminates the need for a stuffing box.
[0007] For additional information relating to pumping units
employed in the oil industry for reciprocating sucker rod strings,
reference may be had to the following previously issued U.S.
patents. TABLE-US-00001 Pat. No. Inventor Title 2,645,900
Hutchinson Hydraulic Type Fluid Transmission 2,651,914 Joy Pumping
Head and Operating Mechanism For Wells 2,699,154 Smith Oil Well
Pumping Apparatus 2,729,942 Billings et al. Manually Controllable
Pumping Jack 2,838,910 Bacchi Hydraulic Pumping Jack 2,982,100
Sinclair Pumping Unit 4,320,799 Gilbertson Oil Well Pump Driving
Unit 4,448,110 Polak et al. Hydraulic Pump 4,480,685 Gilbertson Oil
Well Pump Driving Unit 4,490,097 Gilbertson Hydraulic Pump Driving
Unit For Oil Wells 4,637,459 Roussel Anti Rotational Device For
Down Hole Hydraulic Pumping Unit 4,646,517 Wright Hydraulic Well
Pumping Apparatus 5,996,688 Schultz et al. Hydraulic Pump Jack
Drive System For Reciprocating An Oil Well Pump Rod
BRIEF SUMMARY OF THE INVENTION
[0008] The hydraulic pump jack drive system for reciprocating a
down hole oil well pump by means of a sucker rod string, that is
the subject of this invention, includes a vertically positioned
hydraulic cylinder having a reciprocated piston therein. A
cylindrical, polished, piston rod extends from a lower end of the
piston and through a bottom seal that closes the lower end of the
hydraulic cylinder. The hydraulic cylinder preferably sits above a
wellhead that has the lower end thereof connected to a tubing
string that extends from the earth's surface downward to a
subterranean oil producing formation. The wellhead has an upper end
that is connected to the lower end of the hydraulic cylinder.
Further the wellhead includes at least one side orifice that is
adapted to be connected to a collection line by which crude oil
produced by the well can be conveyed to a collection system. This
arrangement eliminates the expense of providing a stuffing box that
is typically employed with the systems currently used by the oil
industry for pumping reciprocated bottom hole pumps. Not only does
the system herein eliminate the stuffing box but eliminates the
time and expense encountered in keeping a stuffing box properly
lubricated and the packing replaced.
[0009] The invention herein provides a hydraulic system in which
the stroke action can be significantly varied. By controlling the
application of hydraulic fluid pressure the sucker rod strings can
be raised at a selected rate from a lower to an upper position. At
the upper positions the sucker rod strings may be held briefly in a
steady state so that if the bottom hole pump is of the type
designed to release gas trapped within the pump, ample opportunity
is given for the gas release. Thereafter, the hydraulic system may
be controlled so that sucker rod string is dropped rapidly to
recharge the bottom hole pump and to restart the pumping cycle.
[0010] The present invention addresses and solves many of the
problems involved in fluid extraction from oil and gas wells with
current art pumping systems. The loss of pump capacity due to rod
stretch is eliminated. Full stroke of the pump plunger on each
stroke prevents debris accumulating in the normally unused upper
section of the pump barrel and therefore allows the pump to be
unseated without sticking the plunger in the pump barrel. The
repair of pumps is reduced when the plunger and barrel can be
reused. Well pulling costs are reduced when the pump can be
unseated and the tubing flushed without sticking the plunger in the
pump barrel. Well pulling rig costs are reduced due to the ability
of the invention to long stroke the pump. When needed the rods can
be dropped at a velocity equal to a method only possible in current
art pumping systems when a pulling rig is used. The present
invention makes possible full control of the reciprocating action
of the pump including the ability to stop at the peak of the
upstroke or any position in the cycle. The present invention can
prevent pipeline damage by adjusting or stopping the rate of the
sucker rod fall on the down stroke cycle.
[0011] In many wells, and stripper wells in particular, the walking
beam pumping system cannot run at a slow enough rate. Well pulling
and well tubing, rod and pump repair expense is reduced by slowing
the rate to four strokes per minute or less in most wells.
Electrical power use and maintenance is reduced. Horse power demand
is less and power is only needed on the upstroke of the pump.
Elimination of the cyclic load created by a walking beam pumping
unit on the electric motor results in reduced power factor
penalties from electrical utility companies. In stripper wells in
particular which produce ten barrels or less per day, the cost of
daily operations are reduced. Reduced risk of pipe line leaks, the
elimination of stuffing box leaks and no mechanical maintenance
reduces the cost of field equipment and employees required to
operate wells.
[0012] The present invention provides a pumping system which is
easily installed on existing wells and is cheaper to operate and
maintain. The productive life of all oil and gas wells depend on
the economics involved in extracting and delivering the well bore
fluids. The apparatus of the present invention includes (a) a
hydraulic cylinder connected to the pumping tee; (b) a pump spacing
adaptor attached to the cylinder rod; (c) a sucker rod string
attached to the spacing adaptor; (d) a hydraulic pump of
pre-determined pressure and rate to raise the rod string and load
the down hole pump; (e) a means to control the hydraulic flow at
the top of the upstroke of the down hole pump; (f) a means to hold
the pump at the top of the stroke for a pre-determined time; (g) a
means to release fluid back to the hydraulic reservoir and allow
the gravity fall of the sucker rod string; (h) a means to regulate
the speed of the gravity fall of the sucker rod string on the down
stroke; and (i) a means to restart the pumping cycle at a
pre-determined time.
[0013] The method of the present invention is an improved method
using the above described apparatus for oil and gas well fluid
extraction, which comprises, hydraulic fluid pumped into the
hydraulic drive cylinder at sufficient pressure to raise the
cylinder rod and sucker rod to load the down hole pump. When the
pull rod of the down hole pump reaches the maximum stroke length of
the pump barrel, pressure increases above what is required to lift
the rods. An adjustable pressure switch stops the flow of drive
fluid at a pre-determined pressure above the string weight, but
less than the pressure required to unseat the pump. This insures
full stroke of the pump regardless of the rod stretch. The gas
venting pump is held at the peak of the up stroke for a
pre-determined time to vent gas out of the fluid chamber and
facilitate maximum fluid pump efficiency. After a pre-determined
time an adjustable time delay opens a solenoid valve and fluid is
allowed to flow from the drive cylinder back to the hydraulic
reservoir. Gravity and fluid column pressure in the well tubing
allow the rods and pump to return to the down stroke position. A
variable orifice valve adjusts the speed of the down stroke by
holding back pressure on the drive cylinder. The pressure on the
drive cylinder is adjusted to remain above the well tubing pressure
with an adjustable back pressure valve. This insures that well
fluids cannot dilute hydraulic drive fluid. An adjustable electric
time delay restarts the hydraulic pump for the next cycle at a
pre-determined time.
[0014] Another important advantage of the present invention is the
provision of a unique system for adjusting the length of the sucker
rod string for more efficient actuation of the bottom hole
pump.
[0015] A better understanding of the invention will be obtained
from the following detailed description of the preferred
embodiments taken in conjunction with the drawings and the attached
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is an elevational diagrammatic view of a pumping unit
according to this invention showing a system for producing
hydraulic fluid pressure flow for the actuation of a piston within
a cylinder.
[0017] FIG. 2 is an elevational view of the hydraulic cylinder with
a piston rod extending therefrom.
[0018] FIG. 3 is an elevational view of the components of the
system used to adjust the length of the sucker rod string to more
effectively accommodate a bottom hole pump.
[0019] FIG. 4 is an elevational, partial cross-sectional view
showing diagrammatically the components making up the system of
this invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] It is to be understood that the invention that is now to be
described is not limited in its application to the details of the
construction and arrangement of the parts illustrated in the
accompanying drawings. The invention is capable of other
embodiments and of being practiced or carried out in a variety of
ways. The phraseology and terminology employed herein are for
purposes of description and not limitation.
[0021] Elements shown by the drawings are identified by the
following numbers:
[0022] 10 wellhead
[0023] 12 tubing
[0024] 14 earth's surface
[0025] 16 Tee fitting
[0026] 18 top of 16
[0027] 20 hydraulic cylinder
[0028] 22 top end
[0029] 24 bottom end
[0030] 26 piston
[0031] 28 internal cylinder wall
[0032] 30 downward extending piston rod
[0033] 32 seal member
[0034] 34 closure member
[0035] 36 air vent
[0036] 38 hydraulic fluid pump
[0037] 40 pipe
[0038] 42 inlet opening
[0039] 44 return pipe
[0040] 46 prime mover
[0041] 48 battery
[0042] 50 hydraulic controls
[0043] 52 string of sucker rods
[0044] 54 bottom hole pump
[0045] 56 side opening
[0046] 58 upwardly extending piston rod
[0047] 60 upper seal member
[0048] 62 tubular adjustment member
[0049] 64 reduced diameter lower end
[0050] 66 adjustment rod
[0051] 68 adjustment nut
[0052] 70 coupling
[0053] Referring to the drawings and first to FIG. 1, the basic
elements making up a system that can be used to practice the
invention are illustrated. A wellhead 10 of the type that is
typically secured to the upper end of oil well casings is
illustrated. Extending upwardly from wellhead 10 is the upper end
portion of tubing 12. Tubing 12 is typically supported by slips
within the wellhead 10, the tubing 12 hanging downwardly in the
wellhead and extending down to a producing formation in the earth
which may be from several hundred to several thousand feet below
the earth's surface 14.
[0054] Affixed to the upper end of tubing 12 is a Tee fitting 16
that has a vertical passageway therethrough. Supported on the top
18 of the Tee fitting is a vertically positioned elongated
hydraulic cylinder 20. Cylinder 20 has a top end 22 and a bottom
end 24.
[0055] FIG. 4 shows hydraulic cylinder 20 in cross-sectional view
and shows a piston 26 that is vertically and slidably displaceable
within the internal cylindrical wall 28 of hydraulic cylinder 20.
Affixed to piston 26 is a vertical, downwardly extending piston rod
30. Piston rod 30 is shown in dotted outline in FIG. 1.
[0056] Closing the bottom end 24 of hydraulic cylinder 20 is a seal
member 32 that slidably and sealably receives piston rod 30.
[0057] The top end 22 of hydraulic cylinder 20 receives a closure
member 34 and in the embodiments of FIGS. 1 and 4 closure member 34
has an air vent 36 therein.
[0058] As seen in FIG. 1, a hydraulic fluid pump 38 has a high
pressure fluid outlet that is connected by pipe 40 to an inlet
opening 42 in the cylindrical wall of hydraulic cylinder 20. Also
illustrated in FIG. 1 is an optional return pipe 44 that in the
embodiments of FIGS. 1 and 2 connects to an outlet opening 45 in
the sidewall of cylinder 20. This permits top member 34 to be
closed so that air above piston 26 can be circulated back and forth
by the hydraulic fluid pump system 38. However, return pipe 44 is
optional since it may be eliminated if closure member 34 has an air
vent 36 as illustrated in FIGS. 1 and 2. In an alternate
embodiment, as will be discussed with reference to FIG. 4, return
pipe 44 connects outlet opening 45 in hydraulic cylinder 20 back to
the hydraulic fluid pump 38.
[0059] The hydraulic system of FIG. 1 includes a prime mover 46,
such as an engine or electric motor, by which pump 38 is powered.
If prime mover 46 is a motor, energy may be supplied by way of a
battery 48 that is representative of any other kind of electrical
energy source. In addition, the hydraulic system includes hydraulic
control 50 by which the force of hydraulic fluid applied to move
piston 26 (as seen in FIG. 4) is controlled. The importance of the
hydraulic control 50 will be described subsequently.
[0060] Piston rod 30 extending through seal member 32 is attached
to the upper end of a string of sucker rods, generally represented
by the numeral 52 in FIG. 4. The lower end of the sucker rod string
52 is secured to a bottom hole pump generally indicated by the
numeral 54 in FIG. 4. Sucker rod reciprocated bottom hole pumps are
well known in the industry and are used for lifting fluid from a
subterranean formation upwardly within tubing 12 to the earth's
surface. As the fluid is pumped upwardly from the subterranean
formation within tubing 12, it enters into the internal passageway
within Tee fitting 16. A side opening 56 in the Tee fitting
provides a way of channeling the pumped crude oil to a collection
line (not shown) by which the produced crude oil may be conveyed to
a storage tank or otherwise passed to systems whereby it is
ultimately delivered to a refinery for production of diesel fuel,
gasoline, lubricating oils and other derivatives.
[0061] The seal member 32 at the lower end of hydraulic cylinder 20
confines the produced crude oil to the interior of Tee fitting 16
and thereby eliminates the requirement for a stuffing box. That is,
there is no provision needed to seal around piston rod 30 exterior
of the hydraulic cylinder 20.
[0062] FIG. 2 shows a different embodiment of the invention in
which the hydraulic cylinder 20 has a piston therein (not seen in
FIG. 2) that has extending downwardly from it piston rod 30 as has
been described with reference to FIGS. 1 and 4 and in addition,
there is an upwardly extending piston rod 58. That is, in FIG. 2
the piston has a double extending piston rod arrangement--one
extending upwardly and one extending downwardly. In this
arrangement, an upper seal member 60 is used at the upper end 22 of
hydraulic cylinder 20. In the embodiment of FIG. 2 member 60 that
closes the upper end 22 of the hydraulic cylinder 20 is a seal
member that slidably and sealably receives an upper extending
piston rod 58. When the embodiment of FIG. 2 is employed, hydraulic
fluid pressure exists within the cylinder above the piston and
therefore a return pipe 44 is required. The double rod piston
arrangement of FIG. 2 that includes, in addition to the downward
extending piston rod 30, the upwardly extending piston rod 58 is
important in a closed hydraulic system since the quantity of
hydraulic fluid remains constant during the up and down strokes of
the piston.
[0063] It is important that the length of the sucker rod string 52
as seen in FIG. 4 be adjustable for the accurate positioning of
bottom hole pump 54. FIG. 3 illustrates a system for adjusting the
length of sucker rod string 52.
[0064] FIG. 3 shows a vertical tubular adjustment member 62 secured
to the lower end of piston rod 30. The tubular adjustment member 62
has a reduced internal diameter open lower end 64 that receives an
externally threaded adjustment rod 66. Within tubular adjustment
member 62 is an internally threaded adjustment nut 68. By the
threadable position of adjustment nut 68 on adjustment rod 66, the
effective length of the sucker rod string 52 can be varied. A
coupling 70 is threadably attached at the lower end of adjustment
rod 62 and to the upper end of sucker rod string 52.
[0065] As previously stated, the pumping system of FIG. 1 includes
a hydraulic control system 50. This enables the pumping unit to be
operated in a manner to make most effective use of the down hole
pump 54 that is being employed. For instance, down hole pump 54 may
be of a gas release type in which case the hydraulic control system
50 will be regulated so that hydraulic fluid is supplied from
hydraulic pump 38 by way of pipe 40 to the lower surface of piston
26 in such a way that the piston is raised at a predetermined rate
of speed which can be relatively constant. The upward movement of
piston 26 lifts piston rod 30 and thereby sucker rod string 52 and
a plunger (not shown) in bottom hole pump 54, all in an upper
direction. When piston 26 reaches the upper end of its stroke as
seen in FIG. 4, the hydraulic control system 52 may be regulated
such that the piston movement pauses before a downward stroke is
commenced. The length of this pause can be adjusted by the system
50. Further, the hydraulic system may be programmed so that the
downward movement of piston 26 occurs at a much faster rate than
the upward movement. The downward movement rate can be as fast as
the fall rate of the sucker rod strings. After the sucker rod
string, piston rod and piston have reached their lower downward
limit then the upward cycle can begin with or without a delay.
Thus, in a preferred way, the pumping cycle applied to bottom hole
pump 54 can be carefully regulated to match the requirements of the
pump.
[0066] Thus, it can be seen that the pumping system herein is more
economical than the typical hydraulic pumping system used for
reciprocating sucker rod strings in that the need for a stuffing
box is eliminated and the need for the constant repair and
lubrication of the typical stuffing box is eliminated. Further, the
pumping system includes provision for regulating the length of the
sucker rod to accurately position the down hole pump in a well and
the pumping cycle of the system can be regulated to match the
characteristics of the particular down hole pump being
employed.
[0067] While the invention has been described with a certain degree
of particularity, it is manifest that many changes may be made in
the details of construction and the arrangement of components
without departing from the spirit and scope of this disclosure. It
is understood that the invention is not limited to the embodiments
set forth herein for purposes of exemplification, but is to be
limited only by the scope of the attached claims, including the
full range of equivalency to which each element thereof is
entitled.
* * * * *