MULTI-PISTON PUMP HAVING MULTIPLE INLET CONDUITS

Abstract

A pump includes multiple piston chambers each including a piston, an inlet valve and an outlet valve. The pump further includes a first input conduit coupled to the inlet valve of each of a first subset of the piston chambers, a second input conduit coupled to the inlet valve of each of a second subset of the piston chambers, and one or more output conduit coupled to the outlet valve of each of the piston chambers. A mixed fluid stream may be formed by supplying a first fluid to the first subset of piston chambers, supplying a second fluid to a second subset of piston chambers, operating the pump to discharge the first fluid through the first subset of piston chambers and discharge the second fluid through the second subset of piston chambers, and combining the first fluid discharge and the second fluid discharge to form the mixed fluid stream.

Description

BACKGROUND

The present disclosure relates to a piston pump having multiple pistons.

BACKGROUND OF THE RELATED ART

A piston pump is a type of positive displacement pump where a high-pressure seal reciprocates with movement of the piston. Piston pumps may be used to move liquids or compress gases. These pumps can operate over a wide range of pressures and high-pressure operation can be achieved without a strong effect on flow rate. Piston pumps can also deal with viscous media and media containing solid particles.

Reciprocating piston pumps move the fluid using one or more oscillating pistons, plungers, or membranes (diaphragms), while inlet (i.e., input or intake) and outlet (i.e., output or discharge) valves restrict fluid motion to the desired direction. In order for suction to take place, the pump must first pull the piston in an outward motion or stroke to decrease pressure in a piston chamber. The low pressure in the piston chamber will cause the outlet valve to close and the input valve to open, such that a fluid provided at the input is drawn into the piston chamber. When the piston subsequently pushes in an inward motion or stroke, the piston will increase the pressure within the piston chamber. The high pressure in the piston chamber will cause the inlet valve to close and the outlet valve to open, such that the fluid within the piston chamber is expelled out of the piston chamber.

Multi-piston pumps are one of the most common types of pumps utilized in industry. Pistons in these pumps are driven in unison. For example, the pistons may be attached to a common crankshaft and energized by a motor (diesel, electric or hydraulic). Multi-piston pumps may be delineated by the number of piston chambers/pistons included in the pump. A duplex pump has two piston chambers (cylinders) and a triplex pump has three piston chambers (cylinders). Quadruplex and quintuplex pumps have 4 and 5 piston chambers/pistons, respectively, and are also common. These pumps can also be “single-acting” with suction during one direction of piston motion and discharge during the other direction of piston motion, or “double-acting” with suction and discharge in both directions. The oil and gas industry commonly utilizes triplex and quadruplex pumps because of their robust construction, long service life and ability to pump large volumes of fluids at high pressures.

FIG. 1A is a cross-sectional diagram of a piston chamber 12 of a piston pump 10, where the piston chamber 12 includes a piston 14 coupled to a crank shaft 16, an input or suction valve 18 for drawing fluid into the piston chamber 12 from an input or supply conduit 20, and an output or discharge valve 22 for driving fluid out of the piston chamber 12 into an output or discharge conduit 24. The input valve 18 is a unidirectional valve (check valve) that separates the piston chamber 12 from an input conduit 20 and is configured and oriented to open when the pressure in the input conduit 20 is greater than the pressure in the piston chamber 12 and close when the pressure in piston chamber 12 is greater than the pressure in the input conduit 20. Similarly, the output valve 22 is a unidirectional valve (check valve) that separates the piston chamber 12 from an output conduit 24 and is configured and oriented to open when the pressure in piston chamber 12 is greater than the pressure in the outlet conduit 24 and close when the pressure in the outlet conduit 24 is greater than the pressure in the piston chamber 12.

As the crankshaft 16 is driven to rotate about its axis 26, a radially offset journal 28 travels in a circular path about the axis 26. A connecting rod 30 has a first end pivotally coupled to the journal 28 and a second end pivotally coupled to a connector 32 on the bottom of the piston 14. Accordingly, as the journal 28 follows the circular path around the axis 26, the piston 14 is caused to move upward and downward within the piston chamber 12. As the piston 14 is moving downward, the volume above the piston 14 increases and the pressure above the piston 14 decreases. The low pressure above the piston 14 allows the output valve 22 to close and causes the input valve 18 to open. Therefore, fluid in the input conduit 20 is drawn into the piston chamber 12. With continued rotation of the crankshaft 16, the piston 14 is then causes to move upward to reduce the volume above the piston 14 and increase the pressure in the piston chamber 12. The high pressure above the piston 14 allows the input valve 18 to close and causes the output valve 22 to open, such that fluid within the piston chamber 12 is forceably discharged into the output conduit 24. Controlling the rate at which the crankshaft 16 is rotated while control the rate at which fluid is moved from the input conduit 20 to the output conduit 24.

FIG. 1B is a schematic diagram of the piston pump 10 having three piston chambers 12 and three corresponding pistons 14 consistent with FIG. 1A. The piston chamber 12 of FIG. 1A may be considered to be one of the three piston chambers 12 of FIG. 1B. It should be understood that the illustration of the piston pump 10 in FIG. 1B is turned 90 degrees from the illustration in FIG. 1A, such that the axis 26 of the crankshaft 16 extends left-to-right rather than in-and-out of the page.

Each piston chamber 12 illustrates the input valve 18 that separates the piston chamber 12 from an input conduit on one side of the piston pump 10. The output valves 22 (not shown) are located on the opposite side of the piston chamber 12 from the input valves 18. The operation of each piston 14 is the same as described in reference to FIG. 1A. However, the illustration in FIG. 1B shows how the operation of three pistons 14 are coordinated. Each of the piston chambers 12 may be formed identically and each of the pistons 14 may be operated identically, except for the connection of the respective connecting rods 30 to the crankshaft 16. Specifically, the connecting rod 30 of the left-most piston 14 is connected to a first journal 34, the connecting rod 30 of the center piston 14 is connected to a second journal 36, and the connecting rod 30 of the right-most piston 14 is connected to a third journal 38. The journals 34, 36, 38 are each radially offset from the axis 26 and will rotate with the crankshaft 16, but the journals 34, 36, 38 are angularly spaced about the axis 26. For example, with three pistons 14, the journals 34, 36, 38 may be angularly spaced part by about a 120-degree angle relative to the axis 26. As illustrated, the left-most journal may be directed out of the page such that the corresponding piston 14 is in the middle of its stroke, the center journal may be directed up and back of the page such that the corresponding piston 14 is near (but perhaps not quite at) the top dead center of its stroke, and the right-most journal may be directed down and back of the page such that the corresponding piston 14 is near (but perhaps not quite at) the bottom dead center of its stroke. Although the stroke of each piston 14 may have a unique timing, the motor 40 may rotate the crankshaft 16 and cause all three pistons 14 to pump fluid from the inlet valve to the outlet valve of the piston chamber 12 in which the individual piston 14 operates.

FIG. 1C is a schematic diagram of the triplex piston pump 10 of FIG. 1B illustrating the flow of fluid from an input manifold 20 to an output manifold 24. Driving the three pistons (not shown) back and forth in the three piston chambers 12 will take fluid from the input manifold 20 and displace it into the output manifold 24 under pressure. By having three piston chamber 12, each of the pistons (not shown) may be coupled to a crankshaft and timed to offset the strokes of the three pistons. For example, each piston may perform a fluid compression stroke at a different time, such as evenly spaced intervals before repeating the strokes. This reduces the peak load on the motor and produces a more even distribution of fluid flow into and out of the pump.

BRIEF SUMMARY

Some embodiments provide a pump comprising a pump body including multiple piston chambers, each piston chamber including a piston, an inlet valve and an outlet valve. The pump further comprises a first input conduit in fluid communication with the inlet valve of each of a first subset of the piston chambers, a second input conduit in fluid communication with the inlet valve of each of a second subset of the piston chambers, and one or more output conduit in fluid communication with the outlet valve of each of the piston chambers.

Some embodiments provide a method of forming a mixed fluid stream. The method comprises supplying a first fluid to a first subset of piston chambers in a pump having multiple piston chambers, supplying a second fluid to a second subset of piston chambers in the pump having multiple piston chambers, operating the pump to discharge the first fluid through the first subset of piston chambers and discharge the second fluid through the second subset of piston chambers, and combining the first fluid discharged from the first subset of piston chambers with the second fluid discharged from the second subset of piston chambers to form the mixed fluid stream.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIGS. 1A-B are diagrams of a prior art triplex piston pump having three piston chambers and three corresponding pistons for moving fluid from a common input manifold to a common output manifold.

FIG. 1C is a schematic diagram of a prior art triplex piston pump having three piston chambers and three corresponding pistons for moving fluid from a common input manifold to a common output manifold.

FIG. 2 is a schematic diagram of a triplex piston pump having three piston chambers and three corresponding pistons, wherein two of the piston chambers have their input valve directed to a first fluid input conduit or manifold, one of the piston chambers has its input valve directed to a second fluid input conduit, and all three piston chambers have their output valve directed to a common output conduit or manifold.

FIG. 3 is a schematic diagram of a triplex piston pump having three piston chambers and three corresponding pistons, wherein two of the piston chambers have their input valve directed to a first fluid input conduit or manifold and their output valve directed to a first output conduit or manifold, and wherein one of the piston chambers has its input valve directed to a second fluid input conduit and its output valve direct to a second fluid output conduit.

FIG. 4 is a schematic diagram of a system in which the first and second output conduits from the triplex piston pump are coupled to separate concentric channels in a coiled tubing that is controllably positioned in a desired location within a well.

DETAILED DESCRIPTION

Some embodiments provide a pump comprising a pump body including multiple piston chambers, each piston chamber including a piston, an inlet valve and an outlet valve. The pump further comprises a first input conduit in fluid communication with the inlet valve of each of a first subset of the piston chambers, a second input conduit in fluid communication with the inlet valve of each of a second subset of the piston chambers, and one or more output conduit in fluid communication with the outlet valve of each of the piston chambers.

In some embodiments, the multiple piston chambers may have any number of piston chambers, such as range from 2 to 5 piston chambers, without limitation. Each piston chamber will have a piston that is mechanically driven to reciprocate within the piston chamber. For example, each piston may have a connector that is pivotally connected to a first end of a connecting rod. The second end of the connecting rod may be pivotally connected to an offset journal of a crank shaft. A motor may be turned as a controlled speed (i.e., rotations per minute, RPMs) to cause the piston to reciprocate back and forth within the piston chamber at a rate proportional to the speed of the motor. Each piston then goes through a suction or intake stroke moving away from the valves and then a compression or discharge stroke moving toward the valves. The flow of fluid into and out of the piston chamber above the piston is controlled by the valves, which serve as check valves. Accordingly, the inlet valve only allows fluid into the piston chamber during a suction or intake stroke and the outlet valve only allows fluid out of the piston chamber during a compression or discharge stroke. A separate connecting rod to each piston may be pivotally coupled to the same crank shaft, but the point of connection the crank shaft is typically offset by an angle of rotation so that the compression or discharge strokes of each piston do not occur at the same time and are preferably equally angularly offset about an axis of the crank shaft.

In some embodiments, the pump may be characterized in that a ratio of an amount of fluid pumped from the first input conduit to an amount of fluid pumped from the second input conduit is a function of a first number of the piston chambers in the first subset (which are in fluid communication with the first input conduit) and a second number of piston chambers in the second subset (which are in fluid communication with the second input conduit). However, the ratio of fluid amounts pumped from the first and second conduits may be a function of, or affected by, the pressure in the first and second inlet conduits and the pressure in the one or more outlet conduit. Furthermore, where the first input conduit is coupled for a first fluid source and the second input conduit is coupled to a second fluid source, the ratio of the amount of the first fluid pumped from the first conduit to the amount of the second fluid pump from the second conduit may also be a function of, or affected by, the viscosities of the first and second fluids. The exact ratio of first and second fluids passing through the pump may be empirically determined. In applications where the exact ratio is critical, it is an option to modify the composition and/or viscosity of the first fluid source and/or the second fluid source.

In some embodiments, the one or more output conduit is a single output manifold that is in fluid communication with the outlet valve of each of the piston chambers in the pump body. Accordingly, fluid output from the multiple piston chambers into the single output manifold may include a mixture of a first fluid from the first input conduit and a second fluid from the second input conduit. For example, the mixture may be characterized by a predetermined ratio of an amount of the first fluid to an amount of the second fluid that a function of, or affected by, a ratio of a first number of the piston chambers in the first subset and a second number of piston chambers in the second subset. For example, the mixture may be characterized by a predetermined ratio of an amount of the first fluid to an amount of the second fluid that is equal to, or substantially equal to, a ratio of a first number of the piston chambers in the first subset and a second number of piston chambers in the second subset. The first and second fluids may the same fluid or different fluids.

Many processes require that a two or more fluids be mixed at precise ratios to ensure a particular designed effect. Common mix ratios of two separate fluids include mix ratios of 1:1, 2:1 or 3:1 ratio or other fixed mixing ratio. Depending upon the purpose of the mixing, such as a combination of reactants to cause a chemical reaction, accurately achieving a prespecified mix ratio may range from important to critical. In fact, achieving a desired mix of two or more fluids is performed as a preliminary step before introducing the mixed fluids into a process or location where the mixed fluid will be utilized. For example, a two-part epoxy formulation would typically be mixed in a tank until the quantity of each part was verified and the mixing was determined to be thorough. Then, the mixed epoxy composition may be pumped out of the tank to a desired location, such as into an oil well or gas well.

Embodiments of the multi-piston pump disclosed herein provide the ability to accurately pump different fluids at exact ratios without pre-mixing those fluids. Rather, two or more fluids may be accurately mixed in real-time during pumps of the fluids. This provides a technical benefit in that the fluids are not mixed until they are being pumped into a process or location. Another technical benefit is that the piston chambers may, in some embodiments, never contain the mixture of fluids. This may mean that the physical properties of the separate fluids being pumped are more stable and easier to handle than the physical properties of the mixed fluids. Furthermore, the expense, process time and cleanup of dedicated mixing equipment is avoided. Still further, some embodiments of the multi-piston pumps disclosed herein are able to pump multi-component fluids at high volumes, such as from 10 to 500 or more gallons per minute (gpm), and high pressure, such as from 100 to 10,000 or more pounds per square inch (psi), in reliable fixed quantities.

The configuration of multiple input conduits or manifolds, and perhaps also multiple output conduits or manifolds, for the multi-piston pumps allows for the pumps to provide fixed metering of multi-component fluids at high flows and pressures. Each piston chamber (cylinder) in a multi-piston pump may have the same dimension and configuration. Accordingly, as each piston completes a stroke, a consistent and identical volume of fluid is taken in, compressed and expelled. If a multi-component fluid mixture requires a 2:1 ratio, then the input manifold of a triplex (three-piston chamber) pump would be replaced with a first input conduit or manifold configured to supply component A into two piston chambers (i.e., a first piston chamber and a second piston chamber) and a second input conduit configured to supply component B into one piston chamber (i.e., a third piston chamber). Each complete rotation of the pump crankshaft would produce a volume of 2 parts A to 1 part B.

Some embodiments may provide pumps over a range of numbers of piston chambers and a range of numbers of input and output conduits or manifolds. In a first example, the first and second piston chambers of a duplex pump may each be directed to one of two input conduits to form a mixture of first and second fluids at a ratio of 1:1. In a second example, the three piston chambers of a triplex pump may be directed to 2-3 input conduits or manifolds to form a mixture of two fluids at a ratio of 2:1 or to form a mixture of three fluids at a ratio of 1:1:1. In a third example, the four piston chambers of a quadruplex pump may be directed to 2-4 input conduits or manifolds to form a mixture of two fluids at a ratio of 1:1 (i.e., 2 fluids to each of two inlet manifolds) or 3:1 or to form a mixture of four fluids at a ratio of 1:1:1:1. In a fourth example, the five piston chambers of a quintuplex pump may be directed to 2-5 input conduits or manifolds to form a mixture of two fluids at a ratio of 4:1 or 3:2, to form a mixture of three fluids at a ratio of 2:2:1 or 3:1:1, to form a mixture of four fluids at a ratio of 2:1:1:1, or to form a mixture of five fluids at a ratio of 1:1:1:1:1.

In some embodiments, the one or more output conduit includes a first output conduit and a second output conduit, wherein the first output conduit is in fluid communication with the outlet valve of each of the first subset of the piston chambers, and wherein the second output conduit is in fluid communication with the outlet valve of each of the second subset of the piston chambers. The operation of the pump may be characterized in that a ratio of a first amount of fluid pumped from the first input conduit into the first output conduit to a second amount of fluid pumped from the second input conduit into the second output conduit is a function of, or affected by, a ratio of a first number of the piston chambers in the first subset to a second number of piston chambers in the second subset. The first and second fluids may be the same fluid or different fluids, but the first and second fluids are kept separate from each other as they pass through the respective input conduits, piston chambers and output conduits. Having separate flow paths into, through, and out of the pump prevents mixing of the first and second fluids.

In some embodiments, the system may further include a mixing chamber or device, such as an inline mixer, in fluid communication with the first output conduit and the second output conduit for receiving and mixing a first fluid from the first output conduit and a second fluid from the second output conduit. An inline mixer may be either active or passive, where the later is sometimes referred to as a static mixer. An advantage of using a mixing chamber or device coupled to first and second output conduits rather than having a single output conduit or manifold is that the mixing of the first and second fluids may occur at a selected location that is some distance from the pump. A fluid that is pumped through a conduit at a given flow rate over a particular distance will have a determinable residence time within the conduit. Depending upon the dynamics of a particular application for pumping the first and second fluids, a particular residence time may be beneficial while other residences times may be detrimental. For example, in applications where the first fluid includes a first reactant, the second fluid includes a second reactant that is reactive with the first reactant, and the reactions between the first and second reactants forms a solid material, then it may be beneficial to transport the first and second fluids in separate first and second conduits until any remaining residence time in the conduit(s) is less than the amount of time for the first and second reactants to form a solid.

In some embodiments, the system may include a source of a first fluid connected to the first input conduit to supply the first fluid to the inlet valve of each of the first subset of the piston chambers, and a source of a second fluid connected to the second input conduit to supply the second fluid to the inlet valve of each of the second subset of the piston chambers. Optionally, the first fluid may include an epoxy resin and the second fluid may include a hardener that reacts with the epoxy resin to form a solid. Some embodiments may provide the technical benefit of enabling the compositions of the first and second fluids to be optimized for forming a solid with the desired physical properties, rather than having the compositions of the first and second fluid be dictated by reaction dynamics that must be slowed or retarded so that the mixed reactants will not solidify while they are still in the conduit (i.e., during the residence time). A further technical benefit of some embodiments is that any interruption in the pumping process, such as a loss of electrical power to the pump, simply delays the mixing of the first and second fluids, rather than leaving the mixed reactants to solidify within the conduit.

In some embodiments, the system may also include a coiled tubing injector for controllably extending concentric tubing into a well, wherein the first output conduit is coupled to a first channel within the concentric tubing and the second output conduit is coupled to a second channel within the concentric tubing. An inline mixer may be coupled to a distal portion of the concentric tubing such that a first fluid passing through the first channel and a second fluid passing through the second channel are both input into one end of the inline mixer for mixing. Optionally, the inline mixer may be connected to a distal end of the coiled tubing. The well may include a wellbore formed to reach a subterranean formation containing valuable hydrocarbons, such as oil and/or gas. However, depending upon the presence of various zones producing oil, gas, water and combinations of these fluids, it can be important isolate one or more zones containing an undesired fluid from one or more other zones containing a desired fluid. For example, a first zone that contains mostly water or brine may be isolated from a second zone that contains a high concentration of oil, so that the oil can be produced from the well while minimizing the amount of water or bring that must also be produced and processed. Embodiments of the pumps and tubing described herein provide the technical benefit of enabling a two-part reactive composition to be introduced at a desired location within a well to form a plug isolating one zone from another zone with greater control over the delivery of the proper ratio of reactants into the desired location of the well while also reducing or eliminating the need for equipment cleanup and/or the potential for equipment damage due to solidification in mixing containers, pumps, tubing and the like.

Some embodiments provide a method of forming a mixed fluid stream. The method comprises supplying a first fluid to a first subset of piston chambers in a pump having multiple piston chambers, supplying a second fluid to a second subset of piston chambers in the pump having multiple piston chambers, operating the pump to discharge the first fluid through the first subset of piston chambers and discharge the second fluid through the second subset of piston chambers, and combining the first fluid discharged from the first subset of piston chambers with the second fluid discharged from the second subset of piston chambers to form the mixed fluid stream. In one option, the first fluid is discharged from the first subset of piston chambers into a discharge conduit or manifold, the second fluid is discharged from the second subset of piston chambers into the discharge conduit or manifold, and the first and second fluids are combined within the discharge conduit or manifold. In another option, the first fluid is discharged from the first subset of piston chambers into a first discharge conduit or manifold, the second fluid is discharged from the second subset of piston chambers into a second discharge conduit or manifold, and the first and second discharge conduits or manifolds are connected at a point some distance downstream to cause mixing of the first and second fluids. According to the latter option, the first and second fluids may be pumped through separate conduits any desired distance before combining the first and second fluids. Optionally, separate first and second discharge conduits may be connected to an inline mixer that mixes the first and second fluids before releasing the mixed fluids in a desired location, such as a location within a well between two formations or zones in order to form a plug that isolates the two formations or zones. It is a technical benefit of some embodiments that no single piston chamber of the pump will contain both the first and second fluids.

In some embodiments, the first subset of piston chambers includes a first number of piston chambers, the second subset of piston chambers includes a second number of piston chambers, and a ratio of the first number of piston chambers and the second number of piston chambers affects relative amounts of the first fluid and the second fluid in the mixed fluid stream. In some instances, a ratio of a first number of piston chambers in the first subset to a second number of piston chambers in the second subset may establish a volumetric ratio of the first fluid and the second fluid in the mixed fluid stream. For example, the ratio of the first number of piston chambers in the first subset to the second number of piston chambers in the second subset may be, without limitation, selected from 1:1, 2:1, 3:1, 4:1, 3:2. Other configurations for pumping two or more fluids may be built to combine fluid in other ratios as described according to the specific examples herein and/or the principles discloses herein.

In some embodiments, the first fluid includes a first reactant and the second fluid includes a second reactant that is reactive with the first reactant. For example, the first and second reactants may be the components of a two-part epoxy formulation, such as where the first reactant is an epoxy resin and the second reactant is a hardener. Non-limiting examples of the hardener may include an amine, imidazole, and/or anhydride.

FIG. 2 is a schematic flow diagram of the triplex piston pump 10 having three piston chambers 12, wherein two of the piston chambers have their input valve directed to a first fluid input manifold 50 (i.e., a conduit having multiple inputs and/or multiple outlets), one of the piston chambers has its input valve directed to a second fluid input conduit 52, and all three piston chambers 12 have their output valve directed to a common output manifold 24. Although the corresponding three pistons are not shown, they would be located in each of the piston chambers for reciprocation back and forth with respect to the unidirectional valves consistent with FIGS. 1A-B. For example, each piston chamber 12 may have a piston that would move back and away from the illustrated plane in order to draw fluid into the piston chamber through the input valve from the first fluid input manifold 50 or the second fluid input conduit 52 and would then move forward and toward the illustrated plane in order to push the fluid out of the piston chamber 12 through the output valve into the output manifold 24. Accordingly, the input and output valves may be considered to be located at one end of the piston chamber 12, such as above the top dead center position of the piston. Note that a first fluid source 54 (“Component A”) and a second fluid source 56 (“Component B”) are input to separate subsets of piston chambers 12, but become mixed in the single (common) output manifold 24. Note that since the first fluid input manifold 50 supplies the first fluid (“Component A”) to two piston chambers 12 and the second fluid input conduit 52 supplies the second fluid (“Component B”) to one piston chamber 12, the mixed fluid discharge 58 may include an amount of the first fluid (“Component A”) that is substantially twice the amount of the second fluid (“Component B”) included in the mixed fluid 58 ((i.e., an A:B ratio of about 2:1).

FIG. 3 is a schematic flow diagram of the triplex piston pump 10 having three piston chambers 12 as in FIG. 2. Furthermore, two of the piston chambers 12 have their input valve directed to the first fluid input manifold 50 (i.e., a conduit having multiple inputs and/or multiple outlets) the receives fluid from the first fluid source 54 (“Component A”) and one of the piston chambers has its input valve directed to the second fluid input conduit 52 that receives fluid supplied from the second fluid source 56 (“Component B”).

However, unlike the configuration in FIG. 2, the piston pump 10 has a first fluid output conduit (manifold) 60 and a separate second fluid output conduit 62. Accordingly, the first and second fluids do not become mixed in a single fluid output conduit (manifold) but are kept as separate fluid streams. The first fluid discharge 64 (“Component A”) receiving the output of the first fluid output conduit 60 and the second fluid discharge 66 (“Component B”) receiving the output of the second fluid output conduit 62. Note that since the first fluid output conduit 60 receives the first fluid (“Component A”) from two piston chambers 12 and the second fluid output conduit 62 receives the second fluid (“Component B”) from one piston chamber 12, the relative amount of the first fluid (“Component A”) moved through the piston pump 10 is substantially twice the amount of the second fluid (“Component B”) that is moved through the piston pump 10 (i.e., an A:B ratio of about 2:1). The two fluids (Components A and B) are supplied to the pump by separate input conduits or manifolds, input to separate subsets of piston chambers, and are output to separate output conduit such that the two fluids are kept separate. However, the first and second fluid discharges 64, 66 may be coupled to pipes, tubes or channels that extend to a target location for mixing, such as by directing the two fluids through a static mixer.

FIG. 4 is a schematic diagram of a system 70 in which the first and second output conduits 60, 62 from the triplex piston pump 10 are coupled to separate concentric channels 72, 74 in coiled tubing 76 that is controllably positioned to have a distal end 78 in a desired location within a well 80. For example, the first fluid (“Component A”). Embodiments may also include other bi-channel tubing configurations or the use of two separate tubes. In some embodiments, the objective of the operation may be to form a solid plug 82 within a target region 84 of the well 80, such as to isolate an upper formation from a lower formation. For example, the solid plug 82 may be an epoxy plug formed by delivering a first and second reactive components to the target region 84 of the well 80 where they can react and form the solid plug 82.

A first storage tank 54 may store a first liquid composition (A) containing a first reactive component and a second storage tank 56 may store a second liquid composition (B) containing a second reactive component. Optionally, the first and second liquid compositions may include any number of components, whether reactive or non-reactive, but the components within the first liquid composition should not undergo a reaction independent of the second liquid composition, and the components within the second liquid composition should not undergo a reaction independent of the first liquid composition. As a result, both first and second liquid compositions are stable until mixed together.

The triplex piston pump 10 has a first inlet conduit 50 in fluid communication with the first storage tank 54 (“Component A”), a second inlet conduit 52 in fluid communication with the second storage tank 56 (“Component B”), a first output conduit 60 in fluid communication with the first input conduit 50 (“Component A”) and the annular channel 72 of the bifurcated tubing 76, and a second output conduit 62 in fluid communication with the second input conduit 52 (“Component B”) and the central channel 74 of the bifurcated tubing 76. Operation of the motor 40 causes the piston pump 10 to draw the first fluid (“Component A”) from the first storage tank 54 and deliver the first fluid into the annular channel 72 of the bifurcated tubing 76 while simultaneously drawing the second fluid from the second storage tank 56 and delivering the second fluid into the central channel 74 of the bifurcated tubing 76. A tubing reel 90 may be provided and may include fluidic connections between the outlet conduits 60, 62 to the first and second channels 72, 74 of the tubing 76.

In the illustrated embodiment, a coiled tubing injector 94 is suspended above the wellhead 96 to allow the coiled tubing 76 to be raised and lowered in the well 80. The tubing 76 may be inserted into the well 80 until the distal end 78 supporting an inline mixer 98 reaches the target region 84. With the distal end of the tubing in a desired position, the piston pump 10 is operated to deliver the first and second fluids, in the predetermined ratio, into the first and second channels of the bifurcated tubing 76, through the static mixer 98, and into the wellbore below or around the static mixer 98. The first and second reactive components of the first and second fluids 54, 56, respectively, begin to react upon mixing in the static mixer 98 and will continue to react in the wellbore to form the solid plug 82.

After a sufficient total volume of the mixture has been delivered into the wellbore 80 to form the solid plug 82, the tubing 76 may be withdrawn from the well 80. Optionally, any of the first and/or second liquid compositions that were not used or contaminated may be flushed back into the appropriate storage tank to be used later. Only the mixing device 98 should have any of the reaction products, such as catalyzed or hardened polymer, that may require cleanup, greatly reducing handling and cleanup costs.

Non-Limiting Example

An epoxy resin is developed to be pumped into an oil and gas well to produce a gas impermeable plug. The epoxy resin may be formed by the reaction of reactants of two separate fluid compositions (A and B) that must be mixed at a 2:1 ratio, such as two (2) parts A to one (1) part B. For this example, assume that the flow rate at which the epoxy must be pumped and the pressures which are needed to overcome friction and hydrostatic pressure require that the epoxy must be pumped at 5,000 psi.

Current practice in the oil and gas industry would be to pour the required total volume of fluid composition A and fluid composition B of the epoxy into a large mixing vessel. As the reactants in compositions A and B catalyze, an exothermic reaction would occur, and the heat produced would accelerate the reaction. Chemical retarders would therefore be added to the mix to prevent “flash curing”. Once mixed, the fully mixed and reacting epoxy composition would then be pumped with a low-pressure transfer pump to a high-pressure piston pump and displaced into the well. The mixer, low pressure transfer pump, high-pressure pump and the tubing would then have to be flushed to remove the catalyzing epoxy.

A triplex pump may be configured to pump the same epoxy formulation and perform the mixing at a 2:1 ratio of compositions A and B, respectively. Specifically, composition A may be supplied via a first input conduit to two of the piston chambers and composition B may be supplied via a second input conduit to the remaining one piston chamber to achieve the required 2:1 ratio of compositions A and B in a single output conduit or manifold. The triplex pump is capable of producing the required pressures, rates and volumes. With a triplex pump configured in the manner described, an operator may simply run the triplex pump until the desired amount of epoxy resin has been pumped into the well. Optionally, displacement water may then be fed through all piston chambers of the triplex pump as a means of displacing the catalyzing epoxy resin from the tubing into the well and cleaning the pump and associated flow paths of all catalyzing epoxy, thus eliminating any cleanup, reducing environmental impact.

The two compositions A and part B of the epoxy formulation may be discharged from the pump chambers under pressure and may be placed into significant turbulent flow. The turbulent flow conditions cause the two components to become thoroughly mixed. If further blending of the epoxy formulation is needed, then the output manifold from the triplex pump can be fitted with a mixing apparatus, such as a static mixture.

As will be appreciated by one skilled in the art, embodiments may take the form of a system, method or computer program product. Accordingly, embodiments may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, embodiments may take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied thereon.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the claims. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components and/or groups, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The terms “preferably,” “preferred,” “prefer,” “optionally,” “may,” and similar terms are used to indicate that an item, condition or step being referred to is an optional (not required) feature of the embodiment.

The corresponding structures, materials, acts, and equivalents of all means or steps plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. Embodiments have been presented for purposes of illustration and description, but it is not intended to be exhaustive or limited to the embodiments in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art after reading this disclosure. The disclosed embodiments were chosen and described as non-limiting examples to enable others of ordinary skill in the art to understand these embodiments and other embodiments involving modifications suited to a particular implementation.

Claims

1. A system, comprising: a pump including multiple piston chambers, each piston chamber including a piston, an inlet valve and an outlet valve;a first input conduit in fluid communication with the inlet valve of each of a first subset of the piston chambers;a second input conduit in fluid communication with the inlet valve of each of a second subset of the piston chambers; andone or more output conduit in fluid communication with the outlet valve of each of the piston chambers.

2. The system of claim 1, wherein the multiple piston chambers range from 2 to 5 piston chambers.

3. The system of claim 1, characterized in that a ratio of an amount of fluid pumped from the first input conduit to an amount of fluid pumped from the second input conduit is predetermined by a first number of the piston chambers in the first subset and a second number of piston chambers in the second subset.

4. The system of claim 1, wherein the one or more output conduit is a single output manifold that is in fluid communication with the outlet valve of each of the piston chambers in the pump body.

5. The system of claim 4, wherein a fluid output from the multiple piston chambers into the single output manifold includes a mixture of a first fluid from the first input conduit and a second fluid from the second input conduit, wherein the mixture is characterized by a predetermined ratio of an amount of the first fluid to an amount of the second fluid that is established by a ratio of a first number of the piston chambers in the first subset and a second number of piston chambers in the second subset.

6. The system of claim 1, wherein the one or more output conduit includes a first output conduit and a second output conduit, wherein the first output conduit is in fluid communication with the outlet valve of each of the first subset of the piston chambers, and wherein the second output conduit is in fluid communication with the outlet valve of each of the second subset of the piston chambers.

7. The system of claim 6, further comprising: an inline mixer in fluid communication with the first output conduit and the second output conduit for receiving and mixing a first fluid from the first output conduit and a second fluid from the second output conduit.

8. The system of claim 7, further comprising: a source of a first fluid connected to the first input conduit to supply the first fluid to the inlet valve of each of the first subset of the piston chambers; anda source of a second fluid connected to the second input conduit to supply the second fluid to the inlet valve of each of the second subset of the piston chambers, wherein the first fluid includes an epoxy resin and the second fluid includes a hardener.

9. The system of claim 8, further comprising: a coiled tubing injector for controllably extending concentric tubing into a well, wherein the first output conduit is coupled to a first channel within the concentric tubing and the second output conduit is coupled to a second channel within the concentric tubing, and wherein the inline mixer is coupled to a distal portion of the concentric tubing.

10. A method of forming a mixed fluid stream, comprising: supplying a first fluid to a first subset of piston chambers in a pump having multiple piston chambers;supplying a second fluid to a second subset of piston chambers in the pump having multiple piston chambers;operating the pump to discharge the first fluid through the first subset of piston chambers and discharge the second fluid through the second subset of piston chambers; andcombining the first fluid discharged from the first subset of piston chambers with the second fluid discharged from the second subset of piston chambers to form the mixed fluid stream.

11. The method of claim 10, wherein the first fluid is discharged from the first subset of piston chambers into a discharge manifold, the second fluid is discharge from the second subset of piston chambers into the discharge manifold, and the first and second fluids are combined within the discharge manifold.

12. The method of claim 10, wherein the first fluid is discharged from the first subset of piston chambers into a first discharge conduit, the second fluid is discharged from the second subset of piston chambers into a second discharge conduit, and the first and second discharge conduits are connected downstream to cause mixing of the first and second fluids.

13. The method of claim 12, wherein the first and second discharge conduits are connected to a static mixer that mixes the first and second fluids.

14. The method of claim 10, wherein the first subset of piston chambers includes a first number of piston chambers, the second subset of piston chambers includes a second number of piston chambers, and a ratio of the first number of piston chambers and the second number of piston chambers affects relative amounts of the first fluid and the second fluid in the mixed fluid stream.

15. The method of claim 10, wherein a ratio of a first number of piston chambers in the first subset to a second number of piston chambers in the second subset establishes a volumetric ratio of the first fluid and the second fluid in the mixed fluid stream.

16. The method of claim 15, wherein the ratio of the first number of piston chambers in the first subset to the second number of piston chambers in the second subset is selected from 1:1, 2:1 and 3:1.

17. The method of claim 10, wherein the first fluid includes a first reactant and the second fluid includes a second reactant that is reactive with the first reactant.

18. The method of claim 17, wherein the first and second reactants are the components of a two-part epoxy formulation.

19. The method of claim 18, wherein the first reactant is an epoxy resin and the second reactant is a hardener selected from an amine, imidazole, and/or anhydride.

20. The method of claim 18, wherein none of the piston chambers in the pump ever contain both the first and second fluids.