Note: Descriptions are shown in the official language in which they were submitted.
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PATENT APPLICATION
TITLE OF INVENTION:
HYDRAULIC POWERED DOWNHOLE PUMP
INVENTOR: CHARLES 0. STOKLEY
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to United States Patent
Application Serial
Number 13/357,730 filed on January 25, 2012, entitled "Hydraulic Powered
Downhole Pump".
BACKGROUND OF INVENTION
1. Field of the Invention
[0002] This invention relates to a hydraulically powered jet pump for
placement
downhole in a well for the purpose of producing fluids (oil, gas, and/or
water) from a formation
which has special features that provide flexibility and ease of operations in
various types of well
applications. The operation of a jet pump is well known in the art and as such
utilizes high
pressure fluid pumped from the surface to a small interior diameter nozzle
where the flow is
converted to high velocity and lower pressure. As the fluid flow departs the
nozzle, pressure at
the exit point is greatly reduced thus drawing in fluids from an exterior
source such as an oil and
gas producing formation. The mixture is then flowed through a mixing tube
which has a
sequentially increasing interior diameter thus reducing velocity and
increasing pressure. As the
fluid mixture departs the pump into the well annulus, a sufficient pressure is
available to cause
the fluid mixture to return to the surface.
2. Description of Related Art
[0003] The patent to Coleman number 5,372,190 discloses a jet pump that
includes a jet
orifice and diffuser portion not numbered in FIG. 9 and a second diffuser
member 148 that is
attached to a tubular member 164 that includes an alignment edge 166 that
cooperates with pin
170. In order to remove the assembly, the jet orifice and diffuser portion
must first be removed
and then the second member 148 is retrieved using a tool that is lowered by a
wire line or coiled
tubing and that engages profile 204. The patent to Batho et al number
7,114,572 discloses a jet
pump 50 and a subsurface safety valve 52. The patent to Kelly et al 7,219,737
discloses
generally a jet pump 44 that can be moved upwardly in tubing into a
retrievable position by fluid
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injected into the casing of a well. Finally, Jackson patent number 7,909,089
discloses a jet pump
110 that can be configured to pump well fluid up through a tubing string.
BRIEF SUMMARY OF THE INVENTION
[0004] According to one aspect of an embodiment of the invention, a jet
pump includes a
housing and a carrier. The housing interior is of a constant diameter so that
the carrier can easily
be inverted and thus provide a means to use the pump as described above but
with high pressure
power fluid being conveyed down the annulus between the outer diameter of the
inner tubular
member and the well casing interior with the power fluid and formation
production returning to
the surface through the interior of the inner tubular. This flow method is
preferred in wells where
the produced fluid is corrosive and therefore not desirable to contact the
well casing interior or in
wells where a failsafe safety shut-in valve is desired or required. This
configuration is typically
called a "reverse flow- pump and requires wirclinc operations to run and
retrieve.
[0005] The novel design of the reverse flow pump and latching device
allows for
placement of the pump into the well by simply dropping or pumping the assembly
down to seat
in the proper position and to latch into position to prevent the pump from
being displaced upward
when power fluid pressure is applied to the annulus. The novel design of the
latching device is
critical to the assembly and is activated to the locked position by means of
pressure applied to
the interior tubing and thus temporarily plugged assembly. In addition to
placement and locking
of the pump into the proper position, a novel mechanism is also provided that
allows for retrieval
of the pump without the use of a wireline conveyed pulling tool thus greatly
reducing the
operating cost normally associated with retrieval of a reverse flow pump.
[0006] The retrieval mechanism consists of a pulling tool with a seal cup
positioned
above. The mechanism is then pumped down the interior tube until it encounters
and latches onto
the fishing neck of the pump lock. Pressure is then applied to the annulus and
causes an upward
force via the seal cups to move the release sleeve upward and release the
latching dogs and thus
allowing the pump and latch assembly to be forced back to the surface thru
continued circulation
where the assembly can be captured at the surface and removed for design
changes or repairs.
[0007] By developing a carrier which contains the nozzle and mixing tube
in a single
component, the housing can then be of simple design with enlarged interior
diameter versus
exterior diameter as compared to other tools on the market. The larger
exterior diameter of the
carrier therefore allows the use of larger nozzle and mixing tube diameters
and thus increased
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production rates from a formation. For example, existing tools of a 3" to 3.5"
outside diameter
are limited to production rates in the maximum range of 100 gallons per minute
whereas this
novel design can easily achieve rates in excess of 200 gallons per minute.
[0008] Another objection for using existing jet pumps is the inability or
difficult
operations required to obtain access to the producing formation for purposes
of evaluation of
formation data or modification of the well completion. This novel design
allows easy removal of
the carrier, standing valve and safety valve from the interior of the inner
tubing thus allowing full
access through the remaining pump housing and to the wellbore below. Pending
well conditions,
the carrier, standing valve and safety valve can be removed from the well by
reversing the power
fluid circulation direction and capturing the tools as they reach the surface.
In wells where the
formation pressure is low and thereby will not allow reverse circulation, the
tools (carrier,
standing valve and safety valve) can be removed using a wire and special
retrieving tool to
provide full access to the wellbore below the pump housing assembly.
[0009] In wells located in hostile or sensitive environments such as the
Arctic areas,
wildlife refuges and offshore, rules and regulations often require that each
well be equipped with
a failsafe downhole valve to prevent the flow of oil and gas to the surface in
case of a failure of
the surface valving or integrity of the well. This tool configuration can
include such a device
when required or desired and operates by being open only when power fluid
pressure is applied
and automatically closes anytime power fluid pressure is reduced. Another
advantage of the
safety device is that there are no depth limits at which the valve can be
placed as is the case in
safety valves that are operated by a special tubular line run from the surface
to the valve and the
valve operated by applying pressure to the line and thus to the valve.
[0010] Another feature of this novel design overcomes the typical problem
associated
with damaging or washing seals such as "0" Rings out of their grooves. In
standard seal design,
there is a requirement to provide some amount of "squeeze" as a seal enters
into a bore such that
the interference creates the initial seal between the part containing the seal
and the receiving
device bore. Most seals are activated to an improved "squeeze" when pressure
is applied. When
passing in and out of seal bores, each entry and exit of a seal from the bore
has potential to
damage the seal and eliminate or drastically reduce the interference and the
efficiency of the
initial seal. The initial seal is critical in order for applied differential
pressure to further activate
the seal. In the novel design, standard type seal which require some
interference fit (squeeze) are
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replaced with a seal made of a swellable elastomer that does not require an
initial squeeze.
Swellable elastomers can be provided that increase in size (swell) in the
presence of fresh water,
salt water, oil or gas. All of these fluids are typically contained in oil or
gas wells. By utilizing a
swellable clastomer as the seal, there is no need for the seal to be installed
at a larger outside
diameter than the outside metal diameter of the tool and therefore the seal is
not exposed to
damage that may result from contact with the well tubing or from flow washing
while running
the tool into the well. Once the tool is positioned into the bores, swelling
of the elastomer
automatically creates the squeeze and establishes the initial seal between the
inner tool and bore
and may be further activated for controlling high pressure thru the
application of pressure after
some amount of swelling has occurred.
[0011] Another feature of the disclosed invention is to use shape memory
materials, such
as metals, for seal construction. Shape memory material can be manufactured in
a specific shape
at a base temperature and then formed into a different shape at a different
temperature. It is
therefore feasible to manufacture a shape memory material with a size that
would create
interference between the carrier and housing bore at a temperature such as 150
degree F, typical
of even shallow oil and gas wells, but would not have interference at a lower
temperature. Once
the tool is placed into the housing bore without interference and the well
temperature increases to
above 150 degrees F, the material returns to the original manufactured shape
which does provide
interference and thus sealing capability. Using a corrosion resistant metal
could greatly enhance
the life of the seals in wells where corrosive fluids are produced.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)
[0012] FIG. 1 is a cross sectional view of the housing according to an
embodiment of the
invention.
[0013] FIG. la is a view along line A-A of F1G. I.
[0014] FIG. 2 is a cross sectional view of the carrier assembly according
to an
embodiment of the invention.
[0015] FIG. 3 is a cross sectional view of an embodiment of the jet pump
assembly.
[0016] FIG. 4 is cross sectional view of a second embodiment of the jet
pump assembly.
[0017] FIG. 4a is a cross sectional view of the locking mechanism in a
locked position.
[0018] FIG. 4b is a cross sectional view of a fishing tool engaging the
upper portion of
the jet pump assembly.
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[0019] FIG. 4c is a view of the upper portion of the jet pump assembly as
pressure is
applied from above to pump out the assembly.
[0020] FIG. 5 is a schematic view of a typical well installation.
DETAILED DESCRIPTION OF THE INVENTION
[0021] FIG. 5 shows a typical well construction utilizing a hydraulic jet
pump and
associated completion equipment. A well normally has a casing string 11
extending from surface
to or below the producing formation 12 and is cemented in place as shown at
13. Slots or
perforations 14 in the casing allow flow of production fluids from the
formation into the inside of
the casing 11. An additional tubular member, called tubing 15, extends from
surface to a packer
16 which seals the annulus 17 between the tubing 15 and casing 11. A jet pump
housing 18 is run
as an integral part of the tubing 15 and is positioned above the packer. The
housing accepts the
pump carrier 19 with nozzle and mixing tube components and thereby provides
the means to
artificially lift produced fluids from the lower part 20 of the well to the
surface.
[0022] FIG. 1 is a cross section of a housing 18 which is included by
threaded means to
the tubing 15 and positioned above the packer 16. A top sub 21 connects the
tubing to the
housing by various types of threads common for use in oil and gas wells. The
top sub is
connected by threads to a sleeve 22 used for correct spacing of the various
seal bores of the
housing. The lower end of the sleeve is connected to the exit port sub 23. The
exist port sub is
connected to a lower sub 24 which in turn is connected by threads to the well
tubing 15.
[0023] Included in FIG. 1 is a restricted or smaller inside diameter
shoulder 29 for
insertion and restriction of a standing valve (not shown). A guide pin 28
extends into the interior
of the seal bore of the exit port sub for contact with a helical surface 40 of
the lower end of the
carrier and thus assuring proper orientation of the carrier when positioned
inside the housing.
[0024] As shown more fully in FIG. 3, an eccentric flow path 25 extends
partially around
the inside diameter of the exit port sub and provides a means for produced
fluids to flow from the
formation, thru the interior of the tubing and alongside the carrier to the
inlet ports 33 of the
carrier when the carrier is in its proper position inside the housing. A port
26 in the exit port sub
23 provides a communication means from the exit flow path 49 of the carrier,
thru the exit port
sub wall and into the annulus 19 of the well.
[0025] As shown in the cross section of the carrier assembly 10 in FIG. 2,
a fishing neck
31 is provided on the top of the carrier assembly for convenience of retrieval
from the well using
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well known wireline conveyed fishing tools which are designed to latch onto
the shoulder 37 and
retrieve the carrier assembly from the well. A shoulder 31a at the lower end
of the fishing neck is
slightly larger than the outside diameter of the carrier body 32 and provides
a stopping means to
properly position the carrier assembly inside the housing as it cannot pass
the shoulder 27 of
FIG. L
[0026] The body 32 of the carrier is connected by threads 36 to the fishing
neck 31 on the
upper end and the lower carrier sub 39 on the lower end. Internal to the body
are the critical
components of the pump, nozzle 34 and mixing tube 35 which are each positioned
properly by
an interference fit shoulder 34a and 35a respectively. A series of ports 33 in
the wall of the body
allow produced fluids to enter into the interior of the body at the outlet end
of the nozzle where a
low pressure area has been created as a result of the extremely high velocity
exiting from the tip
of the nozzle. Fluid pumped down the interior of the tubing and into the
interior of the carrier 46
passes into the tapered flow path 45 of the nozzle where pressure is decreased
and velocity
increased as well known in the art. As the fluid exits the tip of the nozzle
at high velocity, a
responding reduction in pressure occurs thereby pulling produced fluids into
the area
immediately below the tip of the nozzle. The mixture of fluids enters the
mixing tube and flows
down a sequentially larger diameter flow path 44 in the mixing tube. With the
increasing interior
flow area, velocity is reduced and subsequently pressure increased. The flow
continues
downward inside the lower carrier body with increasing diameter and turns to
exit from the
carrier 45 and through the ports of the exit port sub 23 of the housing as
shown in FIG. 3 where a
sufficient increase in pressure at the exit point can overcome the hydrostatic
pressure of the
fluids from the depth of the pump to the surface and thereby pump the mixture
back to the
surface for separation and further processing as may be required to allow sale
of the oil and gas
and reuse or disposal of the produced water. A tapered lower end of the lower
carrier body 40
engages the guide pin 28 extending into the interior of the housing and
automatically follows the
taper and into the guide slot 41 to properly orient the carrier such that the
exit ports of the lower
carrier body and exit port sub are aligned.
[0027] In addition to the interference seal achieved at the larger diameter
of the fishing
neck 31a against the top sub restriction 27 an additional seal such as an "0"
Ring 34a may be
provided as a backup sealing mechanism. Additional seals 48a are required to
seal above and
below the exit port of the carrier and the exit ports of the exit port sub 23.
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[0028] Under certain well conditions, a check valve 79 as shown
in FIG. 3, often called a
standing valve, is required to prevent produced and power fluids from flowing
back into the
formation when pumping has ceased. In this configuration, a fish neck 72 is
provided to allow
retrieval of the standing valve in such cases as access to the formation is
desired. A shoulder 73
is provided on the standing valve to prevent the valve from passing through
the housing seat 29
and provides a metal to metal seal between the standing valve and the housing.
As certain well
conditions could exist where formation pressure is lower than the hydrostatic
pressure above the
standing valve, an equalizing mechanism is provided such as a sealed piston 74
which is held in
place by shear pins 75. When retrieving the standing valve, it is necessary to
add an equalizing
prong to the fishing tool and mechanically contact the piston to forcefully
expel the piston and
allow the well pressures to equalize before attempting to retrieve the
standing valve.
[0029] FIGs 4, 4a, 4b, and 4c depict the sequential operation of
an embodiment of the
novel reverse flow pump. Once the carrier assembly is positioned against the
restricted shoulder
31a, a temporary device such as a dissolvable ball 51, rupture disk or
lightweight ball is provided
to seal the interior diameter of a sliding sleeve 81 with Seal 81a which
includes a fishing neck 31
and thereby provides a piston area to generate a force when pressure is
applied to shear the
retaining pin 53 and move the sleeve and fishing neck downward, forcing the
larger diameter
shoulder 54 under the dogs 56 whereby the dogs are moved into the groove 21a
of the top sub 21
of the pump housing, as shown in FIG. 4a.
[0030] In this series of depictions, the carrier body 36
containing the nozzle 34 and
mixing tube 35 is inverted thereby providing a pumping means wherein the power
fluid is
pumped down the annulus between the tubing 15 and the casing 11 and produced
fluid mixture
returns to surface up the tubing.
[0031] FIG. 4a shows the assembly locked in position after
applying pressure above the
pump and forcing the shoulder 54 under the dogs 56 and forcing the dogs
outward and into the
groove 2Ia of the top sub 21. A variety of means can be added to the end area
of the smaller
outside diameter section 55 of the fishing neck 31 to provide some resistance
to inadvertent
upward movement of the fishing neck during operations of the pump.
[0032] FIG. 4b depicts the initial step of retrieval of the pump
carrier wherein a standard
type fishing tool 62 which is modified to contain a seal cup 61 or other
sealing mechanism to at
least partially seal between the fishing tool and tubing interior wall. The
fishing tool and seal cup
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are then dropped into the tubing and allowed to fall to the top of the pump or
the assembly can be
pumped into position. The end of the fishing tool contains dog latching arms
and a shoulder 63
that is allowed to expand over the pump fishing neck 31 and latch underneath
the fishing neck
shoulder 37. The fishing tool is also provided with a secondary fishing neck
62a in case
operational problems require that conventional wireline operations are used to
retrieve the
fishing tool or pump.
[0033] FIG. 4c depicts the released position of the pump wherein pressure
is applied to
the annulus in the same manner as when the pumping operations were active. The
applied
pressure acting against the seal cup creates an upward force that move the
fishing neck 31 and
the large diameter section 54 upward and out from under the dogs 55, allowing
the dogs to
retract from the groove 21a and releasing the locking mechanism to allow
upward movement of
the entire assembly. Continued circulation of fluids down the annulus and up
the tubing causes
the tool to be pumped to the surface where a variety of prior art and known
methods allows the
tool to be captured and removed from the well for repairs, redesign or other
modifications.
[0034] Seals 48a may be made from a swellable elastomer material or from a
shape
memory material. As discussed above, the seals may be initially sized so that
the seals are not
deformed as the carrier assembly is positioned within the housing. Rather,
upon exposure to well
fluids or elevated temperatures, the seal increases in size to form a seal
between the housing and
the carrier assembly.
[0035] Although the present invention has been described with respect to
specific details,
it is not intended that such details should be regarded as limitations on the
scope of the invention,
except to the extent that they are included in the accompanying claims.
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