Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
This invention relates to well pumps and more particularly
to well pumps in which fluid from the surface is delivered to
the pump to act as a dilutant and/or sand barrier to reduce the
viscosity of the fluid being produced and/or provide a barrier
to prevent or reduce entry of sand into the annulus between the
pump barrel and pump plunger.
It is known in a deep well pump to introduce fluid from
the surface to reduce the viscosity of the fluid being pumped
and to provide a barrier or reduce sand entrained with the
fluid being produced from flowing behind the pump plunger which
sometimes results in sanding up of the pump. It is known to
divert a portion of the dilutant fluid to the intake of the
well pump to further reduce sanding problems. See ~. S. Patent
No. 1,597,161 issued to L. M. Rellogg August 24, 1926. See
also the following ~. S. Patents which relate to well pumps and
to dilutant systems: 2,567,513 issued to M. W. Haines Sept-
ember 11, 1951; 2,596,146 issued to M. W. Haines May 13, 1952;
4,056,335 issued to Walter S. Secrist November 1, 1977;
3,220,354 issued to W. N. Sutliff November 30, 1965; 2,764,940
issued to J. A. Long October 2, 1956; 1,437,939 issued to H. M.
Green December 5, 1922; 1,013,579 issued to B. Andrews January
2, 1912; and 2,530,673 issued to R. H. Zinszer November 21,
1950.
While the two Haines patents teach the use of a back
pressure valve to support the hydrostatic head of fluid in the
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fluid injection column, none of these patents teach the use of
a back pressure valve to control the fluid in the pump barrel.
It is an object of this invention to provide a well pump
in which dilutant or sand barrier fluid, hereinafter referred
to as dilutant fluid, is delivered to the pump and a back
pressure valve controls the condition of the dilutant fluid in
the pump barrel.
Another object is to provide a well pump as in the pre-
ceding object in which the back pressure valve maintains a
selected back pressure on the dilutant fluid which may be
selected to be higher than pressure exerted by the fluid beingpumped so that the dilutant fluid will wash the pump barrel to
reduce sanding problems and in which varying amounts of dilu-
tant fluid may be delivered to the well pump and will pass
through the back pressure valve.
Another object is to provide a well pump with dilutant
fluid in which a back pressure may be maintained on the dilu-
tant fluid at a value selected to be greater than the pressure
of the fluid being pumped to wash the pump plunger and varying
amounts of dilutant fluid may be introduced into the well while
maintaining the selected back pressure.
Another object is to provide a well pump with dilutant
fluid for washing the pump plunger in which a selected differ-
ential p~essure is maintained at the well pump between the
dilutant fluid and the fluid being pumped to provide a positive
wash of the pump plunger with dilutant fluids while permitting
varying amounts of dilutant fluid to be introduced into the
fluid being pumped.
Another object is to provide a well pump with dilutant
fluid for washing the plunger in which the volume of dilutant
fluid being delivered to the well fluids being pumped may be
regulated by a valve at the pump.
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Before provlding a detailed description of the inven-
tion, it seems appropriate to define the invention. The present
invention, in its broadest aspects, may be defined as a well pump
comprising a pump body having pump barrel means including spaced
pump barrels joined by an intermediate connector, standing valve
means in the pump body, pump plungers joined by a connecting
plunger reciprocal in said spaced pump barrels, traveling valve
means carried by said pump plunger means. Said intermediate con-
nector and said connecting plunger are dimensioned to provide a
sealed annulus therebetween. Means are provided for introducing
a dilutant fluid into said annulus to lubricate said pump barrels
and pump plungers. Back pressure valve means are carried by the
pump body to solely and controllably release the flow of said
dilutant fluid from said annulus and to prevent the flow of well
fluid into said annulus, said valve being positioned to release
said dilutant fluid into said well fluid at the entry point of
said standing valve whereby said dilutant fluid mixes with said
well fluid to maintain the quality of said well fluid automat-
ically as said well fluid enters said pump.
In one preferred arrangement the back pressure valve
means relieves fluid from the annulus when the pressure in the
latter exceeds a certain volume.
In another preferred arrangement the back pressure
valve means maintains a selected volume of flow therethrough.
It is also preferred to have the back pressure valve
means maintain a selected differential between the pressure in
the annulus and the hydrostatic pressure of the column of the
fluid being pumped.
In another preferred arrangement, the outlet of the
back pressure valve means is connected to the pump body above the
standing valve means and maintains a selected differential
between said annulus and the pump body at said connection.
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1170905
Other objects, features and advantages of this invention
will be apparent from the drawings, the specification and the
Claims.
In the drawings wherein like reference numPrals indicate
like parts,
Figure 1 is a schematic illustration of a well pump con-
structed in accordance with this invention positioned in the
lower portion of a petroleum well;
Figures 2A, 2B and 2C are continuation views in section
illustrating the preferred form of pump.
The lower section of a petroleum well having a casing 10
is shown in Figure 1. A tubing 11 extends upwardly to the
surface and has on its lower end the well pump indicated gener~
ally at 12. In the conventional manner a sucker rod 13 in
tubular form extends to the surface and in the conventional
manner will extend through the conventional surface packing to
a walking beam for reciprocating the sucker rod. The surface
installation will also include a source of diluent fluid and a
pump for introducing the fluid through the sucker tube 13 to
the pump under pressure.
The pump includes a pump barrel which preferably has
spaced seal sections 14 and 15. While the pump barrel could be
of constant diameter, it is preferred to have two seal sections
with an intermediate enlarged section 16 as shown.
The pump has a pump plunger which preferably has a pair of
spaced pump plunger sections 17 and 18 connected by a reduced
diameter plunger section 19. Again, the section 19 could be of
the same diameter as the pump plunger sections 17 and 18.
- The pump barrels 14 and ~ together with the intercon-
necting barrel section 16 and the foot section 20 make up the
body of the pump. The body o~ the pump is also provided with a
standing valve indicated generally at 21.
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The pump plunger carries the traveling valve indicated
generally at 22.
The pump plunger has a flow conduit 23 therethrough which
terminates in an outlet 24 in the reduced diameter section 1
of the pump plunger. Thus, diluent fluid pumped from the
surface through the sucker tube is delivered to the annulus
between the plunger and pump barrel through the outlet 24.
It will be appreciated that the diluent fluid could be
delivered in any desired manner, as for instance a suitable
crossover could be provided and the fluid might be delivered
through the tubing instead of through the sucker tube. Also,
a separate tube might be employed and diluent fluid delivered
through tne wall of the pump barrel.
If production is carried out through the sucker tube
diluent fluid might be delivered to the pump plunger directly
from the tubing annulus in the manner taught in the Kellogg
1,597,161 patent. As pointed out in this patent, in such an
arrangement the upper seal might be dispensed with.
In any event, the diluent fluid is delivered in any desired
manner from the surface to the pump plunger under a sufficient
pressure that leakage of fluid is from the diluent fluid source
such as outlet 24 toward the fluid being pumped. In the pump
illustrated leakage would be upwardly past the pump plunger
j section and downwardly past the pump plunger section 18 to
wash these surfaces. This would wash sand away from the pump
plunger and where highly viscous fluids are being pumped would
limit entry of the viscous fluids to reduce drag on the pump
plunger.
Where highly viscous fluids are present or where sand is
present, it is also desirable to deliver diluent fluid in
addition to that used as a wash fluid to the bottom of the pump
to dilute the incoming fluid and reduce its viscosity to make
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1 1701~05
it e~sier to pump and where sand is present to reduce the sand
density. In order to provide for this additional fluid while
maintaining a differential in pressure across the pump plunger
in a direction from the diluent fluid toward the fluid being
pumped a back pressure valve indicated generally at 25 is
provided. This back pressure valve may be of any desired type
which will maintain the desired back pressure on the diluent
fluid so that the diluent fluid will be under a greater pres-
sure than the fluid being pumped. For instance, a simple
spring-loaded valve may be employed in which the valve member
is opened by exerting a selected pressure on the valve member.
This pressure would be such that pressure at the plunger
exerted by the diluent fluid would be greater than pressure
exerted by the fluid being pumped. For instance, the diluent
fluid might have a pressure at valve 25 maintained at 50 to 100
pounds greater than the pressure of the fluid being pumped.
With the valve in full open position it is preferred that the
flowway through the valve 25 would not provide a material
restriction to flow through the valve and thus the volume of
diluent fluid pumped through the valve could be controlled from
the surface and a desired volume of fluid pumped into the
casing while maintaining the valve in open position with, of
course, the desired back pressure being maintained on the fluid
between the pump barrel and pump plunger.
In one common installation for well pumps, the casing-
tubing annulus is open to the surface and the only fluid in the
annulus would be the diluent fluid pumped into the annulus and
fluid rising from the well formation. Such fluids would
normally not exert a substantial back pressure on the valve 25
as the hydrostatic head of fluid would be relatively low and
the valve may be considered to function substantially in
response to pressure of the diluent fluid and the force exerted
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117090S
by the spring 26 in the valve. Thus, the spring 26 may be
preset before the pump is run to provide the selected back
pressure.
If desired, the outlet from valve 25 may be connected to
the pump barrel at a point where it is exposed to the hydro-
static head of the fluid being pumped. In this instance the
back pressure exerted by the hydrostatic head of fluid being
pumped would then be effective on the valve and a selected
differential would be maintained between the diluent fluid and
the fluid being pumped. While it is preferred that the outlet
of the valve 25 be connected to the pump body just above the
standing valve, where a differential pressure is desired, it
may, of course, be connected to any point along the pump body.
It is preferred that the outlet be connected closely adjacent
the standing valve to dilute the the incoming well fluids at
the bottom of the pump.
As another alternative the back pressure valve 25 could be
of the regulator type which maintains a back pressure at the
inlet to the valve while regulating the flow through the
valve. Thus, the valve could be set to provide a selected
continuous flow while maintaining a back pressure on the valve
inlet which could be controlled from the surface by controlling
the pressure under which the diluent fluid is pumped into the
well.
In operation the plunger of the pump is reciprocated in
the conventional manner. Well fluids flow into the pump barrel
through the standing valve 21. Diluent fluid is pnmped down
through the sucker tube 13 and delivered to an intermediate
portion of the pump plunger. During reciprocation the standing
valve opens and closes in the conventional manner to raise
fluid in the tubing. During reciprocation the back pressure
valve 25 in whatever form will always maintain a pressure at
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the inlet of the back pressure valve which is a selected value
greater than the pressure o~ the fluids being pumped so that
flow across the pump plunger will always be from the diluent
fluid source toward the fluid being pumped to lubricate and
wash the pump barrel and plunger while at the same time de-
livering diluent fluid for mixing with the fluid being pumped.
This diluent fluid together with fluid passing through the back
pressure valve 25 will dilute the well fluids making them less
viscous and easy to pump and reducing the denæity of sand to
thus reduce the problems of the pump sanding up. Using a
simple back pressure valve, such as a spring-loaded valve or a
dome charged valve member such as is conventional with gas lift
valves, the system will maintain the desired back pressure
while permitting flow of varying volumes of fluid through the
back pressure valve depending upon the volume of fluid pumped
from the surface. Where the outlet from the valve 25 is con-
nected to the pump above the standing valve, a differential in
pressure between the pressure of fluid being lifted and the
diluent pressure will be maintained. Where a regulator valve
is employed, a fixed volume of fluid will be delivered through
the regulator valve and the pressure upstream of the regulator
valve will be maintained by providing an adequate pressure from
the surface. In all cases, no matter what type of valve is
employed, a back pressure is maintained at the inlet to the
valve 25 so that flow of diluent fluid past the pump plunger is
always from the source of diluent fluid toward the fluid being
pumped.
In Figures 2A through 2C a pref~rred form of valve is
shown. The pump body includes the upper pump barrel 31 and
lower pump barrel 32 suitably spaced by connector 33. The pump
barrel is suspended from the tubing ~by coupling 30. The
bottom of the pump body includes the standing valve housing 34
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connected to pump barrel 32 by coupling 35. The barrel may
terminate at its lower end in a coupling 36 to which may be
secured any desired equipment, such as a screen.
Within the standing valve housing 34 are a suitable seat
37 and a standing valve 38 which are conventional in form.
The pump plunger means includes spaced upper and lower
pump plungers 39 and 41 joined by a connec~ing plunger 42. The
connecting plunger 42 and the body connector 33 are preferably
dimensioned to provide an annulus 43 therebetween. This
annulus may be provided by enlarging the bore through the
connector 33 relative to the diameter of the pump barrels 31
and 32 and reducing the diameter of the connecting plunger 42
relative to the pump plungers 39 and 41 as shown. Depending
upon the service to which the pump is to be put, an annulus may
be provided in this manner or one or both of the connector and
pump barrels, and the pump plungers and connector plungers may
be of substantially the same diameter so long as there is
provided space for adequate flow of fluid to the back pressure
valve.
Suspended from the lower end of lower plunger 41 is a
traveling valve cage 44 having therein a seat 45 and a valve
member 46. These parts are in conventional form and any desired
traveling valve may be utilized.
A means for introducing fluid into the annulus 43 is pro-
vided by a connecting conduit 47 which interconnects the sucker
tubing 13 with the outer periphery of the special coupling 43
which interconnects the upper pump plunger 39 with the con-
necting plunger 42. This fluid will wash the upper and lower
pump barrels 31 and 32 and will be maintained under a suitable
back pressure in the annulus 43 by the bac~ pressure valve
indicated generally at 25.
The back pressure valve 25 is carried in a suitable boss
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33a of the connector 33. The back pressure valve includes
valve seat 49 with which the ball valve member 51 cooperates.
Spring 52 is held in compression and urges the ball carrier 53
downwardly under a suitable force determined by the compression
within spring 52. This compression may be varied by varying
the position of adjusting plug 54 and lock plug 55.
In the operation of the valve, flow from the annulus 43
reaches the valve member through port 33b in the boss 33a and
passes upwardly through the bore in connector 56 to the valve
seat 49. The pressure within the annulus 43 lifts valve
member 51 from its seat and the fluid passes through the valve
outlet 57 into the casing annulus. If it is desired to main-
tain a differential back pressure with the valve 25, the outlet
57 of the valve is connected by a flow conduit 58 to a port 59
which is preferably positioned closely adjacent to the standing
valve. Thus, the outlet of the valve 25 will be subject to the
hydrostatic head of fluid in the tubing above the standing
valve. The port 59 could be positioned at any point along the
body of the pump, but it is preferred to position it closely
adjacent the standing valve so that maximum dilutant effect
will be obtained. Where the conduit 58 is not utilized the
dilutant fluid passing into the tubing casing annulus will mix
with fluid flowing into the well from the formation and reduce
the viscosity of this fluid and/or reduce the density of sand
entrained therewith to facilitate pumping of the well fluids
and to protect the well pump.
The foregoing disclosure and description of the invention
are illustrative and explanatory thereof and various changes in
the size, shape and materials, as well as in the details of the
illustrated construction, may be made within the scope of the
appended claims without departing from the spirit of the inven-
tion.
