Note: Descriptions are shown in the official language in which they were submitted.
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TITLE OF THE INVENTION:
Fluid Driven Mud Pump
FIELD OF THE INVENTION
The present invention relates to a fluid driven mud pump
used to pump drilling fluids when earth drilling
BACKGROUND OF THE INVENTION
Fluid driven mud pumps presently in use in the oil and gas
drilling industry consist crankshaft driven pistons which
reciprocate in cylinders. The mud pumps come in duplex and
triplex versions.
Triplex mud pumps have three cylinders which alternatively
discharge drilling fluids into a flow line. Each cylinder
discharges on the forward stroke, and does not create fluid
movement on the backward stroke.
Duplex mud pumps have two cylinders which alternatively
discharge drilling fluids into a flow line. Each cylinder
discharges on both the forward stroke and on the backward
stroke. A greater quantity of fluid is pumped on the forward
stroke as compared to the back stroke. On the forward stroke
the full face of the piston acts against fluid within the
cylinder, whereas on the backward stroke the face area of the
piston acting upon the fluid within the cylinder is reduced by
the diameter of the piston rod. This creates a pressure pulse
as the piston shifts between the forward stroke and the
backward stroke.
SiTHIIKARY OF THE INVENTION
The present invention is an alternative configuration of
fluid driven mud pumps.
According to the present invention there is provided a
fluid driven mud pump; the pump body including a fluid drive
cylinder axially aligned with a first mud cylinder and a second
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mud cylinder. The first mud cylinder has a first end, a second
end, a first inlet and a first outlet. The first inlet and the
first outlet are both positioned toward the first end. The
second mud cylinder has a first end, a second end, a second
inlet and a second outlet. The second inlet and the second
outlet are both positioned toward the second end. The fluid
drive cylinder has a first end, a second end, and a double
acting reciprocating piston. The fluid drive cylinder is
coupled with the second end of the first mud cylinder and the
first end of the second mud cylinder. The first end of the
piston is positioned in the first mud cylinder. The second end
of the piston is positioned in the second mud cylinder. As
the first end of the piston forces liquid from the first outlet
of the first mud cylinder, liquid is concurrently being drawn
through the second inlet into the second mud cylinder. As the
second end of the piston forces liquid from the second outlet
of the second mud cylinder, liquid is concurrently being drawn
through the first inlet into the first mud cylinder.
With the fluid driven mud pump, as described above, the
fluid discharged by the forward stroke is substantially the
same as the fluid discharged by the backward stroke. There is
not a cessation of pumping nor a reduction in output on the
backstroke, as with the prior art mud pumps.
Although beneficial results may be obtained through the
use of the fluid driven mud pump, as described above, it is
desirable to minimize pressure fluctuations. There are a
number of reasons for this. Pressure fluctuations tend to
cause a pulsing of the drilling fluid which causes the drill
bit to "bounce". A bouncing of the drill bit can cause a
fracturing of the formation and can cause the drill bit to
wander adversely affecting directional control. Pressure is
monitored by the drillers to ascertain what is occurring
downhole. As pressure changes the drillers must react to
anticipate problems. For example, the drillers might respond
to a minor change in pressure by altering the viscosity of the
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drilling fluid. The drillers might respond to a major decrease
in pressure by putting additives in the drilling fluid to seal
the formation on the assumption that drilling fluid is being
lost to the formation. The drillers might interpret a major
increase in pressure as an indication that there has been a
loss of circulation of cuttings and take measures to prevent
the drill bit from becoming stuck in the hole. The prior art
fluid driven mud pumps used two hydraulic cylinders so that one
was always discharging while the other was one the backstroke.
The fluid driven mud pump, as described above, provides
equivalent output to the two hydraulic cylinders of the prior
art. However, even more beneficial results may be obtained
when two or more pump bodies form one pumping unit, with the
positioning of the piston of the fluid drive cylinder of each
pump body being out of phase to provide a constant sequential
discharge. This enables, two, three, four or more pump bodies
to pump as a unit. The configuration which will hereinafter
be further described uses three pump bodies. In doing so, the
present invention is able to maintain a much more constant
pressure than was possible with prior art fluid driven mud
pumps.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features of the invention will become more
apparent from the following description in which reference is
made to the appended drawings, the drawings are for the purpose
of illustration only and are not intended to in any way limit
the scope of the invention to the particular embodiment or
embodiments shown, wherein:
FIGURE 1 is a side elevation view, in section, of a first
embodiment of fluid driven mud pump constructed in accordance
with the teachings of the present invention, using a single
pump body.
FIGURE 2 is a top plan view, in section, of a second
embodiment of fluid driven mud pump constructed in accordance
with the teachings of the present invention, using three pump
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bodies at the initiation of a pumping cycle.
FIGURE 3 is simplified top plan view of the fluid driven
mud pump illustrated in FIGURE 2, showing a first of six piston
positions with the three pump bodies operating 1/3 out of
phase.
FIGURE 4 is simplified top plan view of the fluid driven
mud pump illustrated in FIGURE 2, showing a second of six
piston positions with the three pump bodies operating 1/3 out
of phase.
FIGURE 5 is simplified top plan view of the fluid driven
mud pump illustrated in FIGURE 2, showing a third of six piston
positions with the three pump bodies operating 1/3 out of
phase.
FIGURE 6 is simplified top plan view of the fluid driven
mud pump illustrated in FIGURE 2, showing a fourth of six
piston positions with the three pump bodies operating 1/3 out
of phase.
FIGURE 7 is simplified top plan view of the fluid driven
mud pump illustrated in FIGURE 2, showing a fifth of six piston
positions with the three pump bodies operating 1/3 out of
phase.
FIGURE 8 is simplified top plan view of the fluid driven
mud pump illustrated in FIGURE 2, showing a sixth of six piston
positions with the three pump bodies operating 1/3 out of
phase.
FIGURE 9 is simplified top plan view of the fluid driven
mud pump illustrated in FIGURE 2, showing a commencement of a
second pumping cycle with the three pump bodies operating 1/3
out of phase.
FIGURE 10 is a side elevation view, in section, of the
second embodiment of fluid driven mud pump illustrated in
FIGURE 2.
FIGURE 11 is a block diagram of the position sensors,
computer and logic controller for the second embodiment of
fluid driven mud pump illustrated in FIGURE 2.
FIGURE 12 is a detailed side elevation view, in section,
of the valving for the second embodiment of fluid driven mud
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pump illustrated in FIGURE 2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The preferred embodiment, a fluid driven mud pump
5 generally identified by reference numeral 10, will now be
described with reference to FIGURE 1. A second embodiment of
fluid driven mud pump generally identified by reference numeral
100 will be described with reference to FIGURES 2 through 12.
Structure and Relationship of Parts for Fluid Driven Mud
Pump 10:
Referring to FIGURE 1, there is provided a first
embodiment of a fluid driven mud pump 10, which includes a
pump body 12 with a fluid drive cylinder 14 that is axially
aligned with a first mud cylinder 16 and a second mud cylinder
18. Support legs 20 are provided on pump body 12 for supporting
mud driven pump 10.
First mud cylinder 16 has a first end 22, a second end 24,
a first inlet 26 and a first outlet 28. First inlet 26 and
first outlet 28 are both positioned toward first end 22 of
first mud cylinder 16. A one way valve 30 and a one way valve
31 are provided in first inlet 26 and first outlet 28,
respectively. One way valve 30 allows fluids to enter first
mud cylinder 16 through first inlet 26, but does not permit
fluids to exit first mud cylinder 16 via first inlet 26.
Conversely, one way valve 31 allows fluids to exit first mud
cylinder 16 through first outlet 28, but does not permit fluids
to enter first mud cylinder 16 via first outlet 28. A first
piston 32 is positioned in first mud cylinder 16.
Second mud cylinder 18 has a first end 34, a second end
36, a second inlet 38 and a second outlet 40. Second inlet 38
and second outlet 40 are both positioned toward second end 36
of second mud cylinder 18. A one way valve 42 and a one way
valve 43 are provided in a second inlet 38 and a second outlet
40, respectively. One way valve 42 allows fluids to enter
second mud cylinder 18 through second inlet 38, but does not
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permit fluids to exit second mud cylinder 18 via second inlet
38. Conversely, one way valve 43 allows fluids to exit second
mud cylinder 18 through second outlet 40, but does not permit
fluids to enter second mud cylinder 18 via second outlet 40.
One way valves 30, 31, 42 and 43 are the same in structure and
operation as one way valves which will hereinafter be described
in greater detail with reference to the second embodiment 100.
A second piston 44 is positioned in second mud cylinder 18.
Fluid drive cylinder 14 has a first end 46, a second end
48, and a double acting reciprocating piston 50. Fluid drive
cylinder 14 is coupled with second end 24 of first mud cylinder
16 and first end 34 of second mud cylinder 18. A first end 52
of reciprocating piston 50 is positioned in first mud cylinder
16 and secured by a rod clamp 54 to first piston 32. A second
end 56 of reciprocating piston 50 is positioned in second mud
cylinder 18 and secured by rod clamp 54 to second piston 44
such that as first end 52 of reciprocating piston 50 forces
liquid from first outlet 28 of first mud cylinder 16, liquid is
concurrently being drawn through second inlet 38 into second
mud cylinder 18, and as second end 56 of reciprocating piston
50 forces liquid from second outlet 40 of second mud cylinder
18, liquid is concurrently being drawn through first inlet 26
into first mud cylinder 16.
A sensor 58 is provided on reciprocating piston 50 to
sense the position of reciprocating piston 50 during a
compression stroke.
Operation of Fluid Driven Mud Pump 10:
The use and operation of fluid driven mud pump 10 will
now be described with reference to FIGVRE 1. The unique aspect
of fluid driven mud pump 10 is the action of reciprocating
piston 50. Referring to FIGURE 1, when fluid driven mud pump
10 is activated, first end 52 of reciprocating piston 50 forces
liquid from first outlet 28 of first mud cylinder 16 while
liquid is concurrently being drawn through second inlet 38 into
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second mud cylinder 18. As second end 56 of reciprocating
piston 50 forces liquid from second outlet 40 of second mud
cylinder 18, liquid is concurrently being drawn through first
inlet 26 into first mud cylinder 16.
Although beneficial results can be obtained through the
use of fluid driven mud pump 10, even greater benefits are
obtained when two or more fluid driven mud pumps 10 are
combined to form a pumping unit as will hereinafter be further
described in relation to fluid driven mud pump 100.
Structure and Relationship of Parts for Fluid Driven Mud
Pump 100:
Fluid driven mud pump 10 will now be described with
reference to FIGURES 2 through 12. Referring to FIGURE 2,
there is provided a second embodiment of a fluid driven mud
pump, which is generally referenced by numeral 100. Second
embodiment of fluid driven mud pump 100 differs from first
embodiment 10, in that first embodiment 10 has only one pump
body, whereas second embodiment 100 includes a group of three
identical pump bodies, similar to fluid driven mud pump 10,
which form one pumping unit. For the purpose of identification
these pump bodies will hereinafter be identified as 112a, 112b,
and 112c. Each of pump bodies 112a, 112b, and 112c include
fluid drive cylinder 114 that is axially aligned with a first
mud cylinder 116 and a second mud cylinder 118.
Referring to FIGURE 10, pump bodies 112a, 112b, and 112c
are supported by legs 120. First mud cylinder 116 has a first
end 122, a second end 124, a first inlet 126 and a first outlet
128. First inlet 126 and first outlet 128 are both positioned
toward first end 122. A first piston 132 is positioned in
first mud cylinder 116. Second mud cylinder 118 has a first
end 134, a second end 136, a second inlet 138 and a second
outlet 140. Second inlet 138 and second outlet 140 are both
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positioned toward second end 136.
Referring to FIGURE 12, a one way valve 130 and a one way
valve 131 are provided in first inlet 126 and first outlet 128,
respectively. One way valve 130 allows fluids to enter first
mud cylinder 116 through first inlet 126, but does not permit
fluids to exit first mud cylinder 116 via first inlet 126.
Conversely, one way valve 131 allows fluids to exit first mud
cylinder 116 through first outlet 128, but does not permit
fluids to enter first mud cylinder 116 via first outlet 128.
Referring to FIGURE 12, one way valve 142 and one way
valve 143 are provided in a second inlet 138 and a second
outlet 140, respectively. One way valve 142 allows fluids to
enter second mud cylinder 118 through second inlet 138, but
does not permit fluids to exit second mud cylinder 118 via
second inlet 138. Conversely, one way valve 143 allows fluids
to exit second mud cylinder 118 through second outlet 140, but
does not permit fluids to enter second mud cylinder 118 via
second outlet 140.
Referring to FIGURE 12, each of valves 130, 131, 142 and
143 consists of a plug-like tapered valve member 145 which is
received in a circular tapered valve seat 147. Each valve
member 145 is biased by a spring 149 into engagement with valve
seat 147. Fluid pressure coming in the direction of arrow 151
overcomes the biasing force of spring 149 and moves valve
member 145 off valve seat 147 to allow fluid to pass. Fluid
pressure coming in the opposite direction presses valve member
145 into engagement with valve seat 147.
Referring to FIGURE 2, fluid drive cylinder 114 has a
first end 146, a second end 148, and a double acting
reciprocating piston 150. Fluid drive cylinder 114 is coupled
with second end 124 of first mud cylinder 116 and first end 134
of second mud cylinder 118. Referring to FIGURE 10, a first
end 152 of piston 150 is positioned in first mud cylinder 116
and connected by a rod clamp 154 to first piston 132. A second
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end 156 of piston 150 is positioned in second mud cylinder 118
and connect by rod clamp 154 to second piston 144. As first end
146 of reciprocating piston 150 forces liquid from first outlet
128 of first mud cylinder 116, liquid is concurrently being
drawn through second inlet 138 into second mud cylinder 118,
and as second end 156 of reciprocating piston 150 forces liquid
from second outlet 140 of second mud cylinder 118, liquid is
concurrently being drawn through first inlet 126 into first mud
cylinder 116.
Referring to FIGURE 11, sensors 158 are provided on
reciprocating pistons 150 for sensing the linear position of
reciprocating piston 150 during a compression stroke. In the
illustrated embodiment sensors 158 are sonic, however other
types of sensors such as laser or radio sensors could also be
used. A computer 160 with programmable logic controller 162 is
provided for controlling the linear positioning of
reciprocating piston 150 during a compression stroke.
The positioning of reciprocating piston 150 of fluid
drive cylinder 114 of each of three pump bodies 112 is out of
phase by approximately 1/3 during the course of operation, as
will hereafter be further described with reference to FIGURES 2
through 9.
Operation of Fluid Driven Mud Pump 100:
The use and operation of fluid driven mud pump 100 will
now be described with reference to FIGURES 2 through 12.
The key aspect of fluid driven mud pump 100 is its ability to
maintain a constant pressure. An operational cycle of fluid
driven mud pump 100 will be followed with reference to FIGURES
2 through 9, to demonstrate how this is accomplished.
Referring to FIGURE 2, upon start up of fluid driven mud pump
100 reciprocating piston 150 of each of pump bodies 112a, 112b,
and 112c is in the same position. Reciprocating piston 150 of
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pump body 112a is set in motion while reciprocating pistons 150
of pump bodies 112b and 112c remain stationary. The direction
of motion is indicated by arrow 202. Referring to FIGURE 3,
when reciprocating piston 150 of pump body 112a reaches 1/3 of
5 its stroke, reciprocating piston 150 of pump body 112b is set
in motion to follow reciprocating piston 150 of pump body 112a.
The direction of motion is indicated by arrow 204.
Reciprocating piston 150 of pump body 112c remains stationary.
Referring to FIGURE 4, when reciprocating piston 150 of pump
10 body 112a reaches 2/3 of its stroke, and reciprocating piston
150 of pump body 112b reaches 1/3 of its stroke, reciprocating
piston of pump body 112c is set in motion to follow the
reciprocating pistons of pump bodies 112a and 112b. The
direction of motion is indicated by arrow 206. Referring to
FIGURE 5, as reciprocating piston 150 of pump body 112a
completes its stroke, reciprocating piston 150 of pump body
112b is reaching 2/3 of its stroke, and reciprocating piston
of pump body 112c is reaching 1/3 of its stroke. Referring to
FIGURE 6, reciprocating piston 150 of pump body 112a then
changes direction, the change of direction being indicated by
arrow 208. As reciprocating piston 150 of pump body 112a
reaches 1/3 of its return stroke, reciprocating piston 150 of
pump body 112b is completing its initial stroke, and
reciprocating piston of pump body 112c is reaching 2/3 of its
initial stroke. Referring to FIGURE 7, reciprocating piston
150 of pump body 112b then changes direction, the change of
direction being indicated by arrow 210. As reciprocating
piston 150 of pump body 112a reaches 2/3 of its return stroke,
reciprocating piston 150 of pump body 112b is reaching 1/3 its
return stroke, and reciprocating piston of pump body 112c is
completing its initial stroke. Referring to FIGURE 8,
reciprocating piston 150 of pump body 112c then changes
direction, the change of direction being indicated by arrow
212. As reciprocating piston 150 of pump body 112a completes
its return stroke, reciprocating piston 150 of pump body 112b
is reaching 2/3 its return stroke, and reciprocating piston 150
of pump body 112c is reaching 1/3 its return stroke. Referring
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to FIGURE 9, reciprocating piston 150 of pump body 112a then
changes direction again to repeat the cycle, the change of
direction being indicated by arrow 214. As reciprocating
piston 150 of pump body 112a reaches 1/3 of a new strokes
cycle, reciprocating piston 150 of pump body 112b is completing
its return stroke, and reciprocating piston 150 of pump body
112c is reaching 2/3 its return stroke. It can be, therefore,
be seen how the discharge phase of each of pump bodies 112a,
112b and 112c is 1/3 out of phase, thereby maintaining a
relatively constant pressure. Referring to FIGURE 11, computer
160 with programmable logic controller 162 receives data from
sensors 158 to control and maintain the relating positioning of
reciprocating pistons 150.
The preferred version of fluid driven mud pump with two
or more pump bodies formed as a pumping unit, as described
above, provides a number of advantages. It maintains a
constant sequential discharge pressure that has fewer
pulsations than was possible with prior art mud pumps. It has
less weight and puts out a higher volume over a broader range
of pressure than mechanical systems that operate off a
crankshaft. It is capable of working up to an maintaining a
desired pressure when coupled with feedback sensors and
computer controls. The pumping unit uses a slower stroke rate
to acconplish desired pressure levels. The slower stroke rate
extends the life of parts which are prone to wear, such as
seals. If greater pump capacity is required, more pumping
modules can be added to the described configuration of 3 to
from a configuration with greater capacity having 4, 5, 6, 7,
or more pumping modules.
The embodiments described above may be used in
combination with a drilling rig to supply drilling fluid.
In this patent document, the word "comprising" is used in
its non-limiting sense to mean that items following the word
are included, but items not specifically mentioned are not
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excluded. A reference to an element by the indefinite article
"a" does not exclude the possibility that more than one of the
element is present, unless the context clearly requires that
there be one and only one of the elements.
It will be apparent to one skilled in the art that
modifications may be made to the illustrated embodiment without
departing from the spirit and scope of the invention as
hereinafter defined in the Claims.
