Note: Descriptions are shown in the official language in which they were submitted.
DOWNHOLE WE:LI, PUM:P POWE 1~ ME'I!,NS
The presen-t invention relates -to a system for pumpiny
fluid from a well, in particular an oil well.
It is common in oil wells of the low pressure type that
the oil must be removed by pumping the same out of the well
through suitable tubing.
In general the present invention provides a sy.stem whereby
a pump in a well may be operated by the rotation of a tubular
string or pipe through which the fluid is to be transported to
the surface; i.e. a long, hollow drive shaft serves both to
provide the pump with the necessary power and to deliver the
pumped fluid to the surface. The system can be used with deep
wells.
In particular, the present invention provides a rotary
type fluid pump for fluids containing sand comprising a sleeve,
means non-rotatably mounting said sleeve in a well, a pump in
said sleeve including a rotor and a stator, a tubing rising
from the pump, said tubing forming a portion of said rotor and
receiving pumped fluid therethrough~ means releasably coupling
the tubing and the sleeve, said pump having a sump therein, and
a check valve in said sump.
The Moineau pump is preferable because it can be
ope~ated at low speed and yet still produce fluid at sufficierlt
pressure to pump the fluid -to the surface of the well.
According to the system of t:he presen-t invention a maxi-
mum amount of equipment may be located at the surface, e.g. the
power source can be at the surface where speed and torque can be
more conveniently controlled. Therefore, the presen-t system
q"?~
provides suf~:icient f1exlbl:Lity to ~eter the pump from belng
damaged by running dry.
With the power source at the surEace less equipment is
necessary in the well. For example, the system of the present
invention will eliminate a number o~ pieces of equipmen-t that are
now used in pumping deep wells. Present systems usually consist
of a pump jack reciprocating a string of pu~p rods whlch are
connected to a reciprocating pump at the bottom of the production
tubing; the present invention can eliminate the sucker rod string,
pump-jack and reciprocating bottom hole pump.
The hollow tubing string used to deliver power to the
pump can transmit more torque per weight than a solid shaft and
will facilitate the pumping of viscous fluids. q'he removal of the
power source from the well will result in a space saviny and will
allow the drilling of smaller (and cheaper) well bores than are
required fox pumps powered by downhole motors.
As indicated above, the system of the present invention
can advantageously be used in conjunction with pumps o~ the
Moineau-type. Essentially the Moineau type pump comprises inner
and outer gea~ elements. Usual practice requires that the outer
pumping element be a fixed elongated female member having internal
helical threads forming a helically threaded passage; i.e. the
outer pumping element according to usual practice constitutes a
stator. The inner pumping element according to usual practice
comprises a xotatable helically threaded male member located
within the passage, the inner pumping element according to
usual practice constitutes a rotorO The outer and inner pumping
elements are arranged and shaped such that a plurallty of cavities
g~
or poc]~ets are deEirle~ hetweerl the t~o elements. When the inner
pumping e]ement is rotated relative to the outer pumpirly element
the cavitles are displaced in a given direc-tion with the result
that a fluid material can be transported between the two elemen-tc
to obtain a desired pumping action. Reference can be made to
United 5tates Patent Nos. 1,892,217 René Joseph Louis Moineau,
December 27, 1932 and 2,028,407 William F. Parker, Januar~ 21r
1936 for a detailed consideration of the theory and operation of
these types of pumps.
The outer pumping element may be made of a resilient
material such as natural or synthetic rubber or may be made of
tool steel or stainless steel. The inner pumping element may be
made of metal such as tool steel or stainless steel and may be
chrome plated.
According to usual practice the inner pumping element is
rotated and its axis defines a gyratory path about the central
axis of the outer pumping element which makes it necessary to
transmit power to the inner pumping element through a suitable
c oupling device; such a suitable flexible element is referred to
in Canadian Patent No. 458,797, ~ohn B. Wade, August 8, 1948.
According to the present invention, -the necessary -torque
is obtained by rotating the tubing which is also the pipe string
through which the ~luid is to be brought to the surface. The
power unit is at the surface and may consis-t, for example, o~ a
five horsepower electric motor with a rotary speed, for example,
of about 100 to 20Q RPM's with a simple belt and pulley arrangement
(or a worm gear and crown gear). The emerging Eluid can flow
through a sui-table swivel head.
~ ~D~
In drawings which i:LLu~tratc an embod:Lrrl~n-t Oe the preserlt
invention,
Figure 1 is a cross-sectional view of a well incorporating
a system of the present invention,
Figure 2 is a cross-sectional view illustrating an anchor
suitable for use with a Moineau pump, and
Figure 3 is a cross-sectional view of a swivel head.
Figure 1 illustrates a well bore 10 with casing 11
cemented in the well. The well bore 10 need not be vertical,
although it is so illustrated in the Figure 1.
The tubular strlng 12 is suspended ~rom a rotating swivel
head indicated generally at 13. The swivel head 13 will be
discussed in more detail in relation to Figure 3. The tubular
string 12 may be rotated by means of a crown and pinion or a worm
and pinion as illustrated generally at 14. The system may be
powered by a suitable motor indicated generally at 15.
The produced fluid may be transferred to a production line
(not shown) through a swivel shown generally at 16. Such swivel
devices 16 are common devices and are readily available commer-
cially.
The tubular string 12 in the embodiment illustrated in
Figure 1 is shown stabilized or centralized inside the casing 11
by means of suitable stabilizing devices, one of which is shown
generally at 17. These stabilizing devices act as bearings or
bushings to deter the tubular string 12 from wobbling. The
stabilixing devices may be made of suitable materials, for
example, of nylon or other plastic-like material. Suitable
stabilizer devices are commonly used in the drilling industry.
The tubulax strinrJ l2 is attache~cl hy sJuitclb:le m~3ans at :i-ts
lower end -to -the pump lndlca-ted generally at 18.
The element of the pump 18 acting as stator ls fixed by
means of an anchor indicated generally at 19 suspended below the
pump 18. A suitable anchoring device will be discussed further
on in relation to Figure 2.
As the tubular string 12 rotates under the influence of the
motor 15 fluid entering the casing 11 through perforations 2~ is
picked up by the pump 18 and pushed to the surface through the
tubular string 12.
The pump 13 is a Moineau-type pump as discussed above. The
inner pumping element of the Moineau pump is fixed by anchor 19,
while the outer pumping element is suitably connected to the
tubular string 12, the rotation of the tubular string 12 -thus
causiny the outer purnping element to rotate about the inner
pumping element of the Moineau pump. The fluid is pushed to the
surface through the tubing string 12.
Turning now to E'igure 2, the Figure shows a Moineau-type
pump and anchor in a well bore, the inner pumping element of the
Moineau pump being affixed to the anshor device. In Figure 2 the
well ~ore casing i5 indicated generally at 11. The Moineau--type
pump is indicated generally at 18 and the anchor device is indi-
cated generally at 19.
The inner rnandrel 32 of the anchor device 19 tends to remain
stationary because of the spring-loaded drag blocks 33. Shear pins
34 and 35 are attached to the inner mandrel 32 and are engaged in a
spiral thread on the outer mandrel 36. ~ suitable rotating motion
causes the inner mandrel 32 to be pulled up into the outer mandrel
36 which forces the wedges 37 ancl 3~ to be forced ove:r -the doub:Le
tapered colla.r 39, expanding the wedges out agains-t the wall of
the casing 11 and thus engagi.ng the anchor 19. The wedges 37
and 38 are split longitudinallyO The anchor can be released by
reverse rotation, or by a pull of sufficient force to shear the
pins 3~ and 35. Th.e wedges 37 and 38 are then retracted by the
circumferen~.ial springs designated 40.
As indicated with respect to Figure 1, -the inner pumping
element 51 of ~he Moineau pump 18 is attached to the anchor device
19 by any suitable attachment means indicated generally at 52.
The attachment means 52 is such that the outer pumping element 53
is free to rotate and gyrate about ~he inner pumping elemen-t 51
as the outer pump housing 54, to whlch it is attached, is caused
to rotate by the tubular string. Fluid entry ports are provided
at 55.
In operation the anchor device 19 is run into the well
suspended from the bottom of -the pump 18 which is in turn sus-
pended from the tubular string :by suitable known attachment means.
When the pump is in position, the tubular string is rotated to
2Q begin the pumping action and engage the anchor. As the outer
pumping element 53 is caused to rota.te, at a speed normally in
the range lQ0-200 RPM, about the inn.er pumping element 51, fluid
is pumped up into the tubular string which is in fluid communica
tion with.the ~oineau pump 18.
Figure 3 illustrates a swivel head which allows rotation
of the tubular string. A casing "bowl" 61 is mounted on top of
the well-bore casing 11. The tubular striny 12 is the tubular
string which, when rotated, provides the necessary power to the
--6--
pump in the well and throuyh which the fluld :is :brouyht -to -the
surface. The tubular striny 12 is suspended from a mandrel 62;
the mandrel 62 can also be referred to as a tubing hangar or
"doughnut". The mandrel 62 is free to rotate since it slts on
bearings shown generally at 63 and 6~. Pressure in the annular
space between the casing 11 and the tubular string 12 can be
confined, if necessary, by provision of "O-ring" seals or other
suitable sealing devices, as indicated generally at 65. Luhri-
cation of the bearings referred to above may be provided through
a grease fitt.ing, for example, the :nipple indicated generally at
66. A cap 67 is provided to prevent the rotatable mandrel 62
from being lifted upwards by extreme pressures from below. The
mandrel can be rotated, for example, by means of a worm or pinion
engaging a gear ring system indicated generally at 68.
