PUMP STATOR BINDING LAYER

Description

BACKGROUND

[0001] In many well applications, electric submersible pumps (ESPs) are deployed downhole to provide artificial lift for lifting oil to a collection location. An ESP has a series of centrifugal pump stages contained within a protective housing and mated to a submersible electric motor. The ESP may be installed at the end of a production string and is powered and controlled via an armor protected cable. Electric submersible pumps may be used in a variety of moderate-to-high-production rate wells, however each ESP is designed for a specific well and for a relatively tight range of pumping rates.

[0002] As the well pressure and volume taper off, the ESP can begin to operate outside of the specified range. This results in substantial reductions in system efficiencies and can lead to major mechanical problems, excessive energy costs, and premature pumping system failure. When the efficiency of the pump has been reduced, an operator may transition to a low flow solution such as a sucker rod pump or similar system which can accommodate the lower production volumes. However, such low flow systems have relatively limited applications and often cannot be deployed in unconventional deviated wells, e.g. horizontal wells.

[0003] WO 2022 / 040522 A1 describes a composite structure pump stator having an outer housing and a thermoset resin layer located within the outer housing and secured to the outer housing. The thermoset resin layer is constructed with an internal surface having a thread design. An elastomeric layer is located within the thermoset resin layer and has an interior surface matching the shape of the internal thread of the thermoset resin layer. An elastomer bonding layer is located between the elastomer and the thermoset resin.SUMMARY

[0004] The present invention resides in a fluid displacement pump as defined in claim 1, an electric submersible progressive cavity pump system as defined in claim 10 and a method of fabricating a stator as defined in claim 11. Preferred embodiments are defined in the dependent claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Certain embodiments of the disclosure will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements. It should be understood, however, that the accompanying figures illustrate the various implementations described herein and are not meant to limit the scope of various technologies described herein, and: Figure 1 is a schematic illustration of an example of an electric submersible progressive cavity pumping system having a progressive cavity pump and being deployed downhole in a borehole, e.g. a wellbore, according to an embodiment of the disclosure; Figure 2 is a cross-sectional view of an example of a progressive cavity pump, according to an embodiment of the disclosure; Figure 3 is an orthogonal view of an example of a progressive cavity pump composite stator for use with an electric submersible progressive cavity pump, the composite stator illustration being partially broken away to show examples of composite layers, according to an embodiment of the disclosure; Figure 4 is an end view of an example of a composite stator, according to an embodiment of the disclosure; Figure 5 is an orthogonal view, partially broken away, of an example of a progressive cavity pump composite stator combined with a rotor to form an electric submersible progressive cavity pump, according to an embodiment of the disclosure; Figure 6 is a series of diagrams of examples of pumps; Figure 7 is an example of a plot; Figure 8 is a photograph of an example of a failed stator; Figure 9 is a series of diagrams of examples of pump components; Figure 10 is a series of diagrams of examples of pump operations; Figure 11 is a series of diagrams of examples of pump components; Figure 12 is a diagram of an example of pump components; Figure 13 is a diagram of an example of a chemical formula; Figure 14 is a diagram of an example of a method and an example of a system; and Figure 15 is a diagram of computing devices. DETAILED DESCRIPTION

[0006] In the following description, numerous details are set forth to provide an understanding of some embodiments of the present disclosure. However, it will be understood by those of ordinary skill in the art that the system and / or methodology may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible.

[0007] The disclosure herein generally involves a system and methodology for facilitating efficient well production in relatively low volume applications, e.g. applications after well pressure and volume taper off for a given well. According to an embodiment, use of an electric submersible progressive cavity pump is enabled in harsh, high temperature downhole environments. In some applications, an ESP system may initially be used to pump fluid, e.g. oil, from the well while the volume of flow is moderate to high. However, after the volume of flow tapers off and the ESP efficiency drops a sufficient degree, the ESP system is then removed and replaced by the electric submersible progressive cavity pump. Substitution of the electric submersible progressive cavity pump provides a seamless way for continuing efficient production. As explained in greater detail below, the electric submersible progressive cavity pump is constructed for long-term use even in the high temperature, harsh downhole environment.

[0008] Long-term, efficient use of the progressive cavity pump in harsh downhole environments is facilitated with a composite pump stator. The composite stator can include an outer housing and a thermoset resin layer located within the outer housing and secured to the outer housing. The thermoset resin layer is constructed with an internal surface having an internal thread design, e.g. a helical thread design. Additionally, an elastomeric layer is located within (e.g., radially within and / or on or adjacent an inner surface of) the thermoset resin layer and has a shape which follows the internal thread. In this manner, the elastomeric layer is able to provide an interior surface generally matching the shape of the internal thread of the thermoset resin layer. The arrangement of the layers and the materials selected for the layers provide a composite stator structure which has great longevity in harsh, high temperature downhole environments while providing an appropriate surface for creating pumping cavities along which fluid is pumped when an internal rotor is rotated relative to the composite pump stator. The inner elastomer layer may be initially formed as an extruded tube which is then inserted into an interior of the intermediate thermoset layer. The extruded tube conforms to the thread pattern and provides an enhanced surface interface with the rotor.

[0009] According to an embodiment, the electric submersible progressive cavity pump system combines a progressive cavity pump with a motor and a gearbox which are all submersible and may be fully submersed downhole. This allows the electric submersible progressive cavity pump system to be constructed as a drop-in replacement for an ESP and to utilize the same surface equipment. As a result, continued production can be maintained on a cost effective basis. Additionally, use of a progressive cavity pump enables use of the overall electric submersible progressive cavity pump system in a wide variety of wells including unconventional deviated wells, e.g. horizontal wells.

[0010] Referring generally to Figure 1, an example of an electric submersible progressive cavity pump system 20 is illustrated as deployed in a borehole 22, e.g. a wellbore. In this embodiment, the wellbore 22 is drilled into a subterranean formation 24 and, in some applications, may be lined with casing 26. Perforations are formed through the casing 26 and out into the surrounding formation 24 to enable the inflow of oil 28 and / or other fluids which may then be pumped to a collection location via the electric submersible progressive cavity pump system 20.

[0011] According to the example illustrated, the electric submersible progressive cavity pump system 20 may comprise a submersible motor 30, e.g. an induction motor or a PMM (permanent magnet motor), a submersible gearbox 32 driven by the motor 30, and a progressive cavity pump 34 driven via the gearbox 32. The progressive cavity pump 34 may comprise a rotor 36 rotatably positioned within a surrounding composite stator 38. The motor 30 and gearbox 32 may be used to drive / rotate the rotor 36 within the composite stator 38 to pump fluid, e.g. oil 28. For example, the oil 28 entering wellbore 22 may be drawn in through a pump intake 40 and pumped via progressive cavity pump 34 up through a tubing 42, e.g. a production tubing. From tubing 42, the pumped fluid may be directed through a wellhead 44 to an appropriate surface collection location.

[0012] Electric power may be provided downhole to the submersible motor 30 via a power cable 46. In the example illustrated, the power cable 46 is routed along the tubing 42 and connected with a power source 48, e.g. a variable speed drive or switchboard, via a cable junction box 50. However, appropriate electrical power may be provided to the downhole motor 30 via various types of power supply systems. The power cable 46 is connected to the motor 30 by a sealed motor electrical connector 52.

[0013] Depending on the parameters of a given application, the electric submersible progressive cavity pump system 20 may comprise a variety of other components and / or may be coupled with a variety of other components and systems. By way of example, various shaft seals, motor protectors, and other components may be connected with, or integrated into, the motor 30 and / or gearbox 32. In the illustrated example, a lower component 54 is coupled with motor 30 on a downhole side of the motor 30. By way of example, the lower component 54 may be an oil compensator or a base gauge. However, many other types of components and systems may be connected with or used in combination with the electric submersible progressive cavity pump system 20.

[0014] With additional reference to Figure 2, an embodiment of the composite stator 38 of progressive cavity pump 34 comprises an outer housing 56, e.g. a metal outer housing, and a first layer 58 located within (e.g., radially within) the outer housing 56. The first layer 58 may be formed from a thermoset resin and may be secured to the outer housing 56 along an interior surface of the outer housing 56. The first layer 58 is molded or otherwise constructed to have an interior surface 60 formed as an internal thread 62. For example, the internal thread 62 may be formed as a helical thread (see also Figures 3 and 4).

[0015] The illustrated composite stator 38 further comprises a second layer 64 located within (e.g., radially within and / or on or adjacent an inner surface of) first layer 58. The second layer 64 can be secured to the first layer 58 along the internal thread 62. The second layer 64 may be formed from an elastomer in a shape which follows the internal thread 62 such that a second layer interior surface 66 generally matches the shape of the first layer interior surface 60. In other words, the interior surface 66 of second layer 64 also presents an internal thread construction, e.g. a helical internal thread, which provides an operational interface with rotor 36. The thread configuration of interior surface 66 and a corresponding thread shaped exterior 68 of rotor 36 (see also Figure 5) are constructed to create progressing cavities 70 along composite stator 38 as rotor 36 is rotated relative to composite stator 38. As with conventional progressive cavity pumps, rotation of rotor 36 causes these progressing stator cavities 70 to move fluid, e.g. oil 28, along the composite stator 38 until discharged, e.g. discharged into tubing 42. Thus, the elastomer layer 64 is the primary stator elastomer against which the rotor 36 rotates.

[0016] Referring again to Figures 3 and 4, the various layers of composite stator 38 may be constructed from various types of materials, as described in greater detail below. However, the layer materials as well as the materials / mechanisms for securing the multiple layers together are selected to enable operation at high temperatures and in aggressive fluid environments for long durations. As a result, the composite stator 38 enables long-term operation of the electric submersible progressive cavity pump system 20 in downhole environments.

[0017] In the example illustrated in Figures 3 and 4, the outer housing / layer 56 may be constructed from metal or other suitable material able to withstand downhole conditions. By way of example, the outer housing 56 may be constructed from various carbon steels or stainless steels. However, the outer housing 56 also may be constructed from materials such as ni-resist, nickel alloys, or other suitable materials.

[0018] With respect to the first layer 58, this layer may be constructed from a thermoset resin which may be formulated in various thermoset composites. For example, the first layer 58 may be a structural thermoset resin having a glass transition temperature greater than a desired final application temperature. Additionally, the structural thermoset resin should be capable of bonding completely with a bonding layer as discussed in greater detail below. The thermoset resin layer 58 may be constructed, e.g. molded, from a thermosetting epoxy base system having a high glass transition temperature (Tg) and good resistance to downhole conditions. One example is a thermosetting epoxy comprising CoolTherm EL-636 resin available from Parker LORD.

[0019] However, various types of epoxies may be formed from a variety of thermoset resins for use in constructing the first layer 58 and the internal thread shape. Examples of such thermoset resins and suitable materials for first layer 58 include bismaleimide, cyanate esters, preceramic thermosets, phenolics, novalacs, dicyclopentadiene-type systems, or other thermoset materials with sufficient Tg and bonding capability.

[0020] To further improve performance of the first layer 58 in various harsh operating conditions, various additives may be combined into the thermoset resin. For example, fillers may be incorporated into the thermoset resin to improve heat dissipation and to reduce the coefficient of thermal expansion (CTE). Examples of suitable fillers include mineral particles, metal powder, ceramic or organic particles, silica, alumina fillers, aluminum metal particles, or other suitable metal particles. Additionally, adhesion promoting additives may be combined into the thermoset resin layer 58 to enhance bonding to adjacent layers. In some embodiments, rubberized additives may be added to the thermoset resin layer 58 to increase toughness / fracture resistance. This could involve blending a certain amount of elastomer into the thermoset material. Various other additives may be combined to, for example, promote compatibility with the adjacent elastomer layer 64.

[0021] In the example illustrated in Figures 3 and 4, the second layer 64 is an elastomer layer formed as an extruded tube 72. The extruded tube 72 is inserted or positioned along the interior of the first layer 58 and is sufficiently pliable to conform to the shape of internal thread 62 so as to present its interior surface 66 in a corresponding thread pattern, e.g. a helical thread pattern. By way of example, the second layer 64 may be formed with a generally constant wall thickness.

[0028] The extruded tube 72 or other types of second layer 64 may be formed from a variety of elastomers, e.g. rubbers, able to provide the desired contact and interaction with the rotor 36. The materials selected to form elastomer layer 64 also are resistant to downhole conditions, e.g. resistant to well fluids and downhole temperatures. Specific compounds may be optimized for good dynamic properties, low hysteresis, and high tensile and tear strength.

[0022] By forming the second layer 64 as an extruded tube 72, much higher viscosities can be tolerated. As a result, elastomer materials having much higher strength may be selected so as to provide a substantially greater resistance to damage. Examples of suitable elastomer materials for construction of second layer 64 / extruded tube 72 include nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), and FKM fluoroelastomer, e.g. VITON ™< available from The Chemours Company or Fluorel ™< available from Dyneon LLC. For very high heat applications, e.g. greater than 180°C, the second layer 64 / extruded tube 72 may be constructed from materials such as tetrafluoroethylene propylene (e.g. FEPM) or VITON ™< Extreme ™< fluoroelastomer products available from The Chemours Company.

[0023] For example as shown in the example illustrated in Figures 3 and 4, the composite stator 38 may further comprise a bonding layer 74 located between the outer housing 56 and the first layer 58 and / or a middle bonding layer 76 located between the first layer 58 and the second layer 64. The bonding layer 74 may comprise a variety of materials and / or structures which are able to secure the thermoset resin of first layer 58 to the surrounding housing 56, e.g. metal housing. By way of example, the bonding layer 74 may comprise various adhesives which remain functional in the hot, harsh downhole environment. However, the bonding layer 74 also may comprise physical elements and may be formed with a molded fit, a press fit, or another type of friction fit between the first layer 58 and the surrounding outer housing 56.

[0024] With respect to bonding layer 76, this bonding layer may similarly use a variety of materials. According to an embodiment, the bonding layer 76 comprises an elastomer compound which may use the same base polymer as the elastomer of second layer 64 or other suitable variants. For example, if the elastomer layer 64 is formed from nitrile rubber with 40% acrylonitrile (ACN), the bonding layer 76 may use a similar material but with 30% ACN. However, the bonding layer 76 also can be formulated with a different type of elastomer that is at least partially compatible, e.g. forming bonding layer 76 with ethylene propylene diene monomer (EPDM) while the primary elastomer of second layer 64 is formed with hydrogenated nitrile rubber (HNBR).

[0025] In a variety of applications, the bonding layer 76 is formulated with an elastomer material capable of coextrusion and co-crosslinking with the elastomer of elastomer layer 64. Accordingly, both the bonding layer 76 and the elastomer layer 64 may be capable of using the same type of cross-linking system, although the bulk of each elastomer may use different curing systems. To facilitate longevity downhole in certain applications, the formulation of bonding layer 76 may be optimized for bonding instead of, for example, dynamic loading and high tensile strength.

[0026] Accordingly, embodiments of bonding layer 76 may utilize components and techniques known to facilitate bonding between the thermoset resin layer 58 and the elastomer layer 64. Examples of such components / techniques include using hot polymerized nitrile rubber and / or use of fillers that promote bonding, e.g. fumed and precipitated silica, diatomaceous earth, or other mineral fillers. Additional examples include the use of metal oxides that promote bonding. Such metal oxides tend to be elastomer dependent but may include zinc oxide, aluminum oxide, lead oxides, calcium oxides, magnesium oxides, iron oxides, and other suitable metal oxides.

[0027] Additional components and techniques which facilitate bonding include the use of a base polymer in bonding layer 76 with increased unsaturation (higher residual double bond content). Adhesion promoting additive polymers with high unsaturation, e.g. RICON ™< 154 90% vinyl polybutadiene, also may be used in formulating bonding layer 76. There also are many multifunctional additives which promote adhesion and include, for example, maleated polybutadiene, methacrylated polybutadiene, epoxidized polybutadiene, acrylated bonding coagents, and various monomer oligomers or polymers having functionality allowing the bonding layer 76 to interact with two different systems presented by the elastomer of layer 64 and the thermoset material of layer 58.

[0028] Furthermore, the bonding layer 76 may utilize catalysts, curative agents, or reactive agents which enhance reactivity and bonding with the thermoset composite layer. The bonding layer 76 also may be formulated with various additives or according to manufacturing processes which create increased surface area to further enhance bonding with the adjacent layers, e.g. thermoset layer 58. An example of a manufacturing process which facilitates bonding is extruding the bonding layer 76 with a rough or porous surface. Depending on the material composition of both the elastomer layer 64 and the thermoset layer 58, the material of bonding layer 76 may be selected according to its ability to chemically bond with both layers 58, 64.

[0029] By using a thermoset material to form the first layer 58 with internal thread 62 / stator cavities 70 and then inserting a second elastomer layer 64, the composite stator 38 is relatively inexpensive to construct. As described above, the construction of elastomer layer 64, e.g. extrusion of elastomer layer 64 as tube 72, in combination with selecting suitable layer materials described herein and bonding elastomer layer 64 to the first layer 58 via bonding layer 76 provides a composite stator 38 which has a high resistance to temperature and well fluid. This allows use of the composite stator 38 over long periods of time in a variety of downhole applications.

[0030] The securely bonded elastomer layer 64 also presents a rugged, longlasting interior surface 66 for long-term interaction with rotor 36, as illustrated in Figure 5. Once the rotor 36 is inserted into the composite stator 38 and the overall electric submersible progressive cavity pump system 20 is assembled, the pump system 20 may be deployed downhole into a variety of wellbores 22, including many types of deviated, e.g. horizontal, wellbores for production of oil 28 or other downhole fluids. The electric submersible progressive cavity pumping system 20 may initially be employed as the primary artificial lift system. In a variety of applications, however, a conventional ESP system may initially be employed to pump oil and / or other downhole fluids until well pressure and production rate taper off sufficiently to render the conventional ESP system undesirably inefficient. At that time, the conventional ESP system may be removed and replaced with the electric submersible progressive cavity pump system 20 for efficient well production at a lower flowrate.

[0031] The composite structure of stator 38 may be adjusted according to parameters of a given downhole environment and / or pumping application. Additionally, the progressive cavity pump 34 may be constructed in a variety of sizes and configurations. Many types of additional or other components may be incorporated into the overall electric submersible progressive cavity pump system 20 for use in various types and sizes of boreholes, e.g. wellbores.

[0032] Figure 6 shows an example of a drilling assembly 600 in a geologic environment 601 that includes a borehole 603 where the drilling assembly 600 (e.g., a drillstring) includes a bit 604 and a motor section 610 where the motor section 610 can drive the bit 604 (e.g., cause the bit 604 to rotate and deepen the borehole 603).

[0033] As shown, the motor section 600 includes a dump valve 612, a power section 614, a surface-adjustable bent housing 616, a transmission assembly 618, a bearing section 620 and a drive shaft 622, which can be operatively coupled to a bit such as the bit 604.

[0034] As to the power section 614, two examples are illustrated as a power section 614-1 and a power section 614-2 each of which includes a housing 642, a rotor 644 and a stator 646. The rotor 644 and the stator 646 can be characterized by a ratio. For example, the power section 614-1 can be a 5:6 ratio and the power section 614-2 can be a 1:2 ratio, which, as seen in cross-sectional views, can involve lobes (e.g., a rotor / stator lobe configuration). The motor section 610 of Figure 6 may be a POWERPAK family motor section (Schlumberger Limited, Houston, Texas) or another type of motor section. The POWERPAK family of motor sections can include ratios of 1:2, 2:3, 3:4, 4:5, 5:6 and 7:8 with corresponding lobe configurations.

[0035] A power section can convert hydraulic energy from drilling fluid into mechanical power to turn a bit. For example, consider the reverse application of the Moineau pump principle. During operation, drilling fluid can be pumped into a power section at a pressure that causes the rotor to rotate within the stator where the rotational force is transmitted through a transmission shaft and drive shaft to a bit.

[0036] A motor section may be manufactured in part of corrosion-resistant stainless steel where a thin layer of chrome plating may be present to reduce friction and abrasion. As an example, tungsten carbide may be utilized to coat a rotor, for example, to reduce abrasion wear and corrosion damage. As to a stator, it can be formed of a steel tube, which may be a housing (see, e.g., the housing 642) with an elastomeric material that lines the bore of the steel tube to define a stator. An elastomeric material may be referred to as a liner or, when assembled with the tube or housing, may be referred to as a stator. As an example, an elastomeric material may be molded into the bore of a tube. An elastomeric material can be formulated to resist abrasion and hydrocarbon induced deterioration. Various types of elastomeric materials may be utilized in a power section and some may be proprietary. Properties of an elastomeric material can be tailored for particular types of operations, which may consider factors such as temperature, speed, rotor type, type of drilling fluid, etc. Rotors and stators can be characterized by helical profiles, for example, by spirals and / or lobes. A rotor can have one less fewer spiral or lobe than a stator (see, e.g., the cross-sectional views in Figure 6).

[0037] During operation, the rotor and stator can form a continuous seal at their contact points along a straight line, which produces a number of independent cavities. As fluid is forced through these progressive cavities, it causes the rotor to rotate inside the stator. The movement of the rotor inside the stator is referred to as nutation. For each nutation cycle, the rotor rotates by a distance of one lobe width. The rotor nutates each lobe in the stator to complete one revolution of the bit box. For example, a motor section with a 7:8 rotor / stator lobe configuration and a speed of 100 RPM at the bit box will have a nutation speed of 700 cycles per minute. Generally, torque output increases with the number of lobes, which corresponds to a slower speed. Torque also depends on the number of stages where a stage is a complete spiral of a stator helix. Power is defined as speed times torque; however, a greater number of lobes in a motor does not necessarily mean that the motor produces more power. Motors with more lobes tend to be less efficient because the seal area between the rotor and the stator increases with the number of lobes.

[0038] The difference between the size of a rotor mean diameter (e.g., valley to lobe peak measurement) and the stator minor diameter (lobe peak to lobe peak) is defined as the rotor / stator interference fit. Various motors are assembled with a rotor sized to be larger than a stator internal bore under planned downhole conditions, which can produce a strong positive interference seal that is referred to as a positive fit. Where higher downhole temperatures are expected, a positive fit can be reduced during motor assembly to allow for swelling of an elastomeric material that forms the stator (e.g., stator liner). Mud weight and vertical depth can be considered as they can influence the hydrostatic pressure on the stator liner. A computational framework such as, for example, the POWERFIT framework (Schlumberger Limited, Houston, Texas), may be utilized to calculate a desired interference fit.

[0039] As to some examples of elastomeric materials, consider nitrile rubber, which tends to be rated to approximately 138 C (280 F), and highly saturated nitrile, which may be formulated to resist chemical attack and be rated to approximately 177 C (350 F).

[0040] The spiral stage length of a stator is defined as the axial length for one lobe in the stator to rotate 360 degrees along its helical path around the body of the stator. The stage length of a rotor differs from that of a stator as a rotor has a shorter stage length than its corresponding stator. More stages can increase the number of fluid cavities in a power section, which can result in a greater total pressure drop. Under the same differential pressure conditions, the power section with more stages tends to maintain speed better as there tends to be less pressure drop per stage and hence less leakage.

[0041] Drilling fluid temperature, which may be referred to as mud temperature or mud fluid temperature, can be a factor in determining an amount of interference in assembling a stator and a rotor of a power section. As to interference, greater interference can result in a stator experiencing higher shearing stresses, which can cause fatigue damage. Fatigue can lead to premature chunking failure of a stator liner. As an example, chlorides or other such halides may cause damage to a power section. For example, such halides may damage a rotor through corrosion where a rough edged rotor can cut into a stator liner (e.g., cutting the top off an elastomeric liner). Such cuts can reduce effectiveness of a rotor / stator seal and may cause a motor to stall (e.g., chunking the stator) at a low differential pressure. For oil-based mud (OBM) with supersaturated water phases and for salt muds, a coated rotor can be beneficial.

[0042] As to differential pressure, it is defined as the difference between the onbottom and off-bottom drilling pressure, which is generated by the rotor / stator section (power section) of a motor. As mentioned, for a larger pressure difference, there tends to be higher torque output and lower shaft speed. A motor that is run with differential pressures greater than recommended can be more prone to premature chunking. Such chunking may follow a spiral path or be uniform through the stator liner. A life of a power section can depend on factors that can lead to chunking (e.g., damage to a stator), which may depend on characteristics of a rotor (e.g., surface characteristics, etc.).

[0043] As to trajectory of a wellbore to be drilled, it can be defined in part by one or more dogleg severities (DLSs). Rotating a motor in high DLS interval of a well can increase risk of damage to a stator. For example, the geometry of a wellbore can cause a motor section to bend and flex. A power section stator can be relatively more flexible that other parts of a motor. Where the stator housing bends, the elastomeric liner can be biased or pushed upon by the housing, which can result in force being applied by the elastomeric liner to the rotor. Such force can lead to excessive compression on the stator lobes and cause chunking.

[0044] A motor can have a power curve. A test can be performed using a dynamo meter in a laboratory, for example, using water at room temperature to determine a relationship between input, which is flow rate and differential pressure, to power output, in the form of RPM and torque. Such information can be available in a motor handbook. However, what is actually happening downhole can be differ due to various factors. For example, due to effect of downhole pressure and temperature, output can be reduced (e.g., the motor power output). Such a reduction may lead one to conclude that a motor is not performing. In response, a driller may keep pushing such that the pressure becomes too high, which can damage elastomeric material due to stalling (e.g., damage a stator).

[0045] Figure 7 shows an example of a plot 700 of power versus differential pressure for surface and downhole conditions. As shown, power can be reduced downhole due to effects of temperature and pressure and / or one or more other factors. The plot 700 shows power versus differential pressure where differences between surface and downhole may increase with higher differential pressures.

[0046] Figure 8 shows an example of a photograph 800 that illustrates fatigue failure as to an elastomeric material of a stator of a motor. Arrows indicate where separation from a tube or housing has occurred and where chunking has occurred.

[0047] Figure 9 shows examples of PCP components, including synthetic and / or natural materials, which can include polymeric materials, metals, composite materials, etc.

[0048] As an example, in various pumps, construction may use one or more compatabilizing layers, which may provide for enhanced adhesion and / or one or more other benefits.

[0049] As explained, ESPs are versatile and adaptable for use in various applications (e.g., artificial lift, injection, etc.). As explained, an ESP can include a series of centrifugal pump stages contained within a protective housing mated to a submersible electric motor. It is installed at the end of the production tubing; an armorprotected cable connects the pump to electric power and surface controls.

[0050] By controlling motor speed from surface, operators can vary production flow rate, for example, from 16 to 4,770 m3 / d [100 to 30,000 bbl / d]. An ESP tends to be appropriate for moderate-to-high-production rate wells, including highly deviated wells and remote, subsea deep-water wells. As production rates fall, the pump motor can be slowed to accommodate, without an expensive well intervention.

[0051] While ESPs can be used for a wide range of flow rates, each specific system may be designed for a specific well; namely a tight range of pumping rates. As the well pressure and volume taper off, the pump begins to operate outside the specified range for the ESP originally installed. This can result in reductions in system efficiencies which can lead to mechanical problems, excessive energy costs, and premature system failure. When the efficiency of the pump has been reduced, inevitably, the operator will transition to a low flow solution such as a sucker rod pump or similar system which can accommodate the lower production volumes. However, these are often limited in effectiveness now that many ESPs are deployed in unconventional deviated wells many of which are even horizontal wells. Consequently, operators are often left without effective means of production alternatives and rely on cost intensive solutions which accelerate the aging of the equipment such as cycling the ESP on and off.

[0052] A complementary option to the ESP is an electrical submersible progressive cavity pump (ESPCP). When ESP efficiency drops off, migrating to an ESPCP may be a relatively seamless way to continue efficient production. An ESPCP may be a fully submersible pumping system. While various types of PCP may utilize a motor and gearbox to remain at the surface and the rotor to be driven from the surface by attaching to a long shaft, the ESPCP has a motor and gearbox attached to the pump fully submersed in the well and driven by an electrical power cord. As such, an ESPCP can be a drop-in replacement for the ESP and may utilize the same surface equipment. This reduces the work over cost as well as providing an effective alternative for unconventional deviated and horizontal wells.

[0053] As explained, in various types of pumps, one or more stator components may be sources of issues. As an example, a stator may be an injectable elastomer that the rotor moves against. Over time, the elastomer may degrade and / or swell from exposure to the downhole environment. In some instances, for PCP applications, stator deterioration is managed by swapping rotors at the surface. However, with an ESPCP fully submerged, the stator must survive the harsh conditions for generally a longer time than PCP stators can manage in order to make a system a more viable alternative for the low flow unconventional applications.

[0054] In various examples of system, such as one or more of those mentioned above, a technique and materials can be employed for bonding of elastomer to a rigid support structure which in the case of the composite PCP may be a thermoset material. Various PCPs utilize one or more of various types of solvent based adhesives such as Megum, Chemlok, or Thixon to bond the elastomer to the housing. These types of adhesives use highly reactive functional groups to promote interaction between the desired layers to be bonded. However, the reactive functionality that gives theses adhesives strong initial bonding also may predispose them to degradation in a hot / wet downhole environment. The reactive chemistries frequently utilized in solvent based adhesives include isocyanates, phenol / formaldehyde systems, cyanoacrylates, acrylated molecules, chlorinated polymers, and other reactive, typically polar materials that may generate strong adhesive bonds but are subject to hydrolytic degradation and thermal breakdown over time in the downhole environment. When compared to the fluid resistance and thermal stability of typical stator elastomer and structural thermoset elements, the adhesive material very quickly and obviously becomes the limiting factor. By utilizing an compatabilizing elastomer based tie layer, a more robust bonding of the elastomer and thermoset can be generated through covalent bonding of each material; chemically crosslinking the elastomer to a thermoset. As such the limiting factor to the bond may be transferred to mechanical and chemical stability of the elastomer or thermoset and no longer a third material susceptible to adhesive failure from aging.

[0055] As mentioned, a method can use of a compatabilizing elastomer based adhesion promotor that facilitates covalent bonding of a primary stator elastomer to a rigid support structure which in the case of a composite PCP tends to be a thermoset material. Such an approach can generate a more fully bonded stator elastomer to structural thermoset system by incorporating a compatabilizing tie layer that, for example, incorporates elements of both an elastomer and a thermoset material, enabling it to complete covalent bonding reactions with both. By avoiding the use of a solvent based adhesive system and utilizing a compatabilizing hybrid material, also known as a tie layer, a more robust bonding of the elastomer and thermoset can be generated through covalent bonding of each material; chemically crosslinking the elastomer to the thermoset. As such a limiting factor to the bond can now be transferred to mechanical and chemical stability of the elastomer or thermoset and no longer a third material susceptible to adhesive failure from aging. In one or more embodiments, the tie layer may be made up of several layers. In such an embodiment, the tie layers may be made of the same material, such as, but not limited to, a compatabilizing elastomer based adhesion promotor, or one or more of the tie layers may be made of a different material than other layers.

[0056] As explained, geometry of a standard PCP stator can makes it inherently a source of elastomer inconsistencies. The shape profile can describe an eccentric displacement that results in uneven sections of elastomeric material. A thick uneven elastomer wall can exhibit several drawbacks that can result in it being a primary source for failure down hole.

[0057] Figure 10 shows an example of a PCP 1000 with various types and ranges of motions that can impact various components, particularly when exposed to downhole conditions. Specifically, there can be swell of elastomer where, because the wall is uneven, when exposed to downhole fluid and gas, the stator elastomer can swell unevenly, resulting in stator fit mismatch that can result in reduced pumping efficiency and damage to the elastomer. Further, as to heat dissipation, elastomeric materials tend to be inherently good thermal insulators. As a result, heat generated from the dynamic oscillation of the elastomer wall can buildup in the thick elastomer portions and eventually lead to thermal degradation of the elastomer.

[0058] Figure 11 shows examples of two PCPs 1110 and 1150. A composite PCP stator in the PCP 1150, compared to the PCP 1110, can reduces the primary degradation mechanisms in the elastomer by a construction designed to mitigate several failure modes. The composite design separates structural and dynamic pumping functions of the stator and selects materials that are optimized to perform each function. The shape of the lobed stator may be defined by a rigid, thermally conductive structural composite material. This material can be less susceptible to swell, but also may optionally provide improved heat dissipation away from the inner layer. The inner layer of the composite PCP stator design 1150 includes an elastomer material that may be applied with a desired wall thickness (e.g., an even-wall thickness or other desirable wall thickness) over one or more surfaces of a structural composite.

[0059] As an example, a composite PCP stator construction may be designed with a compilation of layers including but not limited to a thermoset region and an elastomer layer advantageous to the application. For a stator application, an elastomer can be designed for dynamic operation, mechanical robustness, resistance to well fluid resistance, and excellent thermal stability while the thermoset is designed for heat dissipation, structural rigidity, and dimensional stability.

[0060] As explained, one or more compatabilizing layers may be utilized to allow for more complete and permanent bonding of these dissimilar materials (e.g., dynamic elastomer to structural thermoset).

[0061] A compatabilizing layer can facilitate bonding of an elastomer to a rigid support structure which in the case of the composite PCP can be a thermoset material. A tie layer can be a compatabilizing tie layer that is designed with several potential advantages, which can include one or more of permanent bonding, improved aging and bond facilitation.

[0062] Figure 12 shows an example of a PCP with a tie layer adjacent to a thermoset resin and a rubber lining where the PCP includes a metallic tube for a housing (e.g., exterior shell).

[0063] As to permanent bonding, often elastomers are bonded using an adhesive material, which "glues" the two layers together, typically resulting in mechanical bond combined with van der Waals forces. In the case of highly reactive adhesives, it is possible to form chemical covalent bonds to a surface. However, the reactive chemistries frequently used for these adhesives typically can be susceptible to chemical and thermal degradation at downhole conditions. Typically, for those materials to contain sufficient reactivity to act as an adhesive (e.g., low viscosity, high surface energy), the material is less robust to chemical attack and aging. As explained, a compatabilizing tie layer can include thermoset reactive functionality along with elastomer reactive functionality. Such an approach allows a tie layer to co-cure with both an elastomer layer and a thermoset later, resulting in a covalently bonded system. By providing a custom formulated layer that integrates into both the structural thermoset and the elastomer, robust bonding can occur using the same high-performance materials each individual layer is utilizing.

[0064] As to aging, a tie layer system may employ a common base chemistry and a common cure system as stator and thermoset regions to achieve desired bonding. Desirable properties for mechanical stability, chemical resistance, swell, embrittlement, softening, etc., can be imparted through use of a tie layer system where they may no longer be weak points in the bonding of the layers.

[0065] As to bond facilitation, a tie layer may be an additional layer that is a layer to facilitate bonding. For maximum resistance to the downhole fluids and gases that a pump may encounter, a primary rubber lining of an elastomer stator may be formulated using one or more elastomer materials with inherently low reactivity and high degree of saturation in the polymer backbone. As a result of this high saturation and low reactivity, elastomers based on these systems tend to be inherently difficult to bond. As an example, a tie layer may be an elastomer with properties that may be selected or otherwise tailored to be similar to a stator elastomer and, for example, with greater unsaturation in a polymer backbone. In such an approach, greater unsaturation enables bonding to be much easier and more complete with adhesives. As such an approach still utilizes an elastomer that can have similar properties to a primary stator elastomer, a method can include co-vulcanizing with a primary elastomer liner.

[0066] As to an example of a tie layer, considering a composite PCP construction where the primary stator liner is HNBR and the structural thermoset composite is an epoxy resin system, an example tie layer system may include an elastomer compound that contains (e.g., or is wholly comprised of) a co-functional system.

[0067] Figure 13 shows an example of a co-functional system 1300 that includes polybutadiene with grafted epoxide functionality. As shown in the example of Figure 13, a polymeric molecule can include one functionality that is an epoxide reactive group while another functionality is a pendant vinyl group able to vulcanize with an elastomer material. Such materials can find use as epoxy toughening agents (e.g., consider resins from Cray Valley, Nagase, Nisso). A tie layer system may also incorporate fillers (e.g., carbon black, clay, silica, etc.) antioxidants, process aids and / or oils, curative systems, etc. A tie layer may also utilize increased unsaturation to provide more sites for co-vulcanization with a primary elastomer material.

[0068] According to the invention, stator elastomers includes one of NBRs, HNBR aFKM and FEPM. The material of the tie layer is modified based on a stator elastomer in order to match a vulcanization system used in the elastomer and to match a base resin and cure system of a structural thermoset.

[0069] As to some examples of thermosetting chemistries for high temperature bonding applications, these may be based on cyanoacrylate, acrylate, polyester, epoxy, benzoxazine, polyimide, bismaleimide, and / or cyanate ester chemistry. While robust in many uphole applications, these thermosets may be limited in chemical compatibility and high-temperature capability. For example, with high-temperature exposure with small amounts of water, these polymers may be susceptible to hydrolytic attack, which results in a depolymerization reaction of the material and subsequent loss of adhesion.

[0070] However, a range of resin chemistries for encapsulation are available. Such resin chemistries can offer low viscosity processing, high glass transition temperatures, excellent electrical / mechanical / thermal properties, and hydrolysis resistant chemistries. These materials can be formulated for the material to be used at temperatures up to 300 C (572 F).

[0071] As an example, a polymer may be a thermosetting polymer. As an example, a polymer may be a non-thermosetting polymer. As an example, a polymeric material may include a mixture of one or more thermosetting polymers and one or more non-thermosetting polymers. A US Patent Application Publication having Pub. No. US20210288541A1, published 16 September 2021, describes various types of polymers, pumps, etc.

[0072] As an example, a polymeric material may be or include an ethylene propylene diene monomer (M-class) rubber (EPDM), which is a type of synthetic rubber that is an elastomer. As an example, a polymeric material may be or include a nitrile butadiene rubber (NBR), which is a family of unsaturated copolymers of 2-propenenitrile and various butadiene monomers (1,2-butadiene and 1,3-butadiene). As an example, a polymeric material may be or include polyether ether ketone (PEEK), which is an organic thermoplastic polymer in the polyaryletherketone (PAEK) family. As an example, a polymeric material may be or include polyvinylidene fluoride, or polyvinylidene difluoride (PVDF), which is a thermoplastic fluoropolymer produced by the polymerization of vinylidene difluoride. The aforementioned EPDM, NBR (e.g., also consider HNBR), PEEK, PAEK and PVDF materials are given as some examples of types of polymers that may be in a polymeric material.

[0073] Epoxy resins, also known as polyepoxides are a class of reactive prepolymers and polymers which contain epoxide groups.

[0074] Maleimide and its derivatives can be prepared from maleic anhydride, for example, by treatment with amines followed by dehydration. A feature of the reactivity of maleimides is their susceptibility to additions across the double bond either by Michael additions or via Diels-Alder reactions. Bismaleimides are a class of compounds with two maleimide groups connected by the nitrogen atoms via a linker. Bismaleimides can be used as crosslinking reagents (e.g., in polymer chemistry).

[0075] Polybutadiene is a synthetic rubber that is a polymer that can be formed from the polymerization process of the monomer 1,3-butadiene.

[0076] Oxazines are heterocyclic compounds that include one oxygen atom and one nitrogen atom. Isomers exist depending on the relative position of the heteroatoms and relative position of the double bonds. Derivatives may also referred to as oxazines; examples include ifosfamide and morpholine (tetrahydro-1,4-oxazine).

[0077] Cyanate esters include an -OCN group. Cyanate esters can be cured and / or postcured by heating. As an example, curing may be alone at elevated temperatures or, for example, at lower temperatures in presence of a suitable catalyst. As an example, a catalyst may be a transition metal complex such as, for example, one that includes cobalt, copper, manganese and / or zinc. As an example, cyanate esters can be used to produce a thermoset material with a relatively high glass-transition temperature (Tg), for example, up to about 400 degrees C with a relatively low dielectric constant. A cyanate ester material may exhibit relatively low moisture uptake and a higher toughness compared to epoxies.

[0078] Silicones are polymers that include repeating units of siloxane. Silicones can be relatively heat-resistant and / or rubber-like, for example, consider examples such as silicone oil, silicone grease, silicone rubber, silicone resin, and silicone caulk.

[0079] Ring-opening metathesis polymerization (ROMP) is a type of olefin metathesis chain-growth polymerization. Reactions can be driven by relief of ring strain in cyclic olefins (e.g. norbornene, cyclopentene, etc.). A catalyst that may be used in a ROMP reaction can include a metal, for example, consider a RuCl 3 / alcohol mixture, a catalyst, etc. As an example, a catalyst can be a transition metal carbene complex. For example, consider benzylidene-bis(tricyclohexylphosphine)-dichlororuthenium, [1,3-bis-(2,4,6-trimethylphenyl)-2-imidazolidinylidene]dichloro(phenylmethylene)(tricyclohexylphosphine)ruthenium, Dichloro(o-isopropoxyphenylmethylene)(tricyclohexylphosphine)ruthenium(II), and [1,3-Bis-(2,4,6-trimethylphenyl)-2-imidazolidinylidene]dichloro(o-isopropoxyphenylmethylene)ruthenium.

[0080] As an example, a polymer may be formed at least in part via ROMP. For example, as a prepolymer component amenable to forming a polymer via ROMP, consider a carbon backbone with functional groups that include at least one oxygen that provides an amount of hydrophilicity may be present along with a hydrocarbon chain (e.g., carbon backbone) that provides an amount of hydrophobicity where at least one functional group may be present on the hydrophobic hydrocarbon chain where such a functional group may participate in ROMP (e.g., via relief of ring stress). In such an example, the prepolymer component may be an ester such as a diester, a triester, etc. (e.g., an n-ester). As an example, consider a triester that includes at least one hydrocarbon chain with a functional group that includes a ring that is amenable to ROMP via relief of ring stress.

[0081] As mentioned, a ROMP process can employ a catalyst that can include a metal (e.g., Ru, etc.). As an example, a ROMP process may be utilized to form a copolymer (e.g., via two monomers, three monomers, etc.). For example, consider a scheme for forming a copolymer utilizing a functionalized triester as one of the monomers. As an example, DILULIN material (Cargill Inc., Minneapolis, MN) may be utilized, which is a mixture of norbornyl-functionalized linseed oil and cyclopentadiene (CPD) oligomers (e.g., one fraction consisting of modified linseed oil at about 70 percent by weight and another of cyclopentadiene (CPD) oligomers at about 30 percent by weight). In such an example, the norbornene groups are ROMP-reactive. In such a scheme, one or more additional materials can be included such as, for example, one or more of dicyclopentadiene (DCPD) and ethylidenenorbornene (ENB) (e.g., to form a copolymer, which may be a terpolymer, etc.). At room temperature, DCPD is a white crystalline solid. Norbornene is a bridged cyclic hydrocarbon that can be provided as a white solid. Norbornene includes a cyclohexene ring with a methylene bridge between C-3 and C-6; it carries a double bond which induces ring strain. ENB is a bicyclic monomer and intermediate that includes two double bonds, each with a different reactivity. ENB can be produced from vinyl norbornene, which can be made from butadiene and dicyclopentadiene DCPD.

[0082] As an example, a terpolymer may be a DCPD / ENB / DILULIN terpolymer (DED terpolymer). Synthesis of such a terpolymer may proceed at least in part via ROMP. For example, DED terpolymer can be cured via ROMP using transition metal chlorides (e.g., WCl 6 , hexachloro tungsten) in combination with Lewis-acidic cocatalysts (e.g., EtAlCl 2 , ethylaluminum dichloride). As an example, a DED terpolymer can also be cured with transition metal complexes (e.g. titanium, tungsten, molybdenum, ruthenium, osmium, etc.) with organic ligands. As an example, cationic polymerization can be accomplished using one or more cationic catalysts, such as, for example, one or more of BF 3 ·O(C 2 H 5 ) 2 (boron trifluoride ethyl etherate), B(C 6 F 5 ) 3 (tris (pentafluorophenyl) borane), MAO (methylalumoxane), VCl 4 (tetrachlorovanadium), and AlBr 3 (tribromoalumane).

[0083] While a terpolymer is mentioned as an example of a copolymer, in general, one or more types of copolymers may be synthesized. For example, consider a DCPD / DILULIN copolymer (DD copolymer) or an ENB / DILULIN copolymer (ED copolymer).

[0084] As mentioned, a copolymer thermosets can be synthesized from DCPD and / or ENB as well as a functionalized oil (e.g., as in the DILULIN material, etc.). Such synthesis can include ring opening metathesis polymerization (ROMP), which may employ a catalyst or catalysts (e.g., 2nd generation Grubbs' catalyst, etc.). The DILULIN material includes norbornyl-functionalized linseed oil synthesized by Diels-Alder reaction of linseed oil and DCPD at high temperatures and pressures. The DILULIN oil component, a triester, has an average of less than one bicyclic moiety per triglyceride. The low reactivity of the DILULIN material due to the low number of bicyclic moiety compared to DCPD and ENB can decrease curing kinetics, which can, for example, provide time for one or more filling and / or impregnation process (e.g., before gelation, a transition from liquid to solid). As an example, the relatively low viscosity of DCPD and / or ENB may be controlled by adding different concentrations of the DILULIN material.

[0085] As an example, a terpolymer or other copolymer formed via use of a functionalized n-ester and ROMP, may exhibit toughness and adhesion (e.g., via presence of the n-ester structure).

[0086] As an example, a copolymer formed at least in part from a functionalized n-ester. For example, the aforementioned DED copolymer thermoset may be utilized. Such DED copolymer thermosets have relatively high toughness at relatively high temperature and pressure, which may extend service time. As an example, due to the relatively low viscosity and ability to manipulate processability and thermal conductivity, a copolymer based at least in part on a functionalized n-ester may be useful as, for example, a potting material, an encapsulation material, etc., particularly for relatively extreme environments.

[0087] As an example, a copolymer material formed at least in part from a functionalized n-ester and ROMP can be utilized where high Tg, high toughness thermoset resins with a very low curing temperature are presently used. As an example, such a copolymer material may replace one or more of phenolic and epoxy materials (e.g., while providing improved properties and processability).

[0088] A pre-ceramic polymer can be a polymer that can be heated to elevated temperature or pyrolyzed to form a ceramic material. For example, consider polycarbosilanes, with a carbon-silicon backbone, that produce silicon carbide on pyrolysis and polysiloxanes, with a silicon-oxygen backbone, that produce silicon oxycarbides on pyrolysis.

[0089] As an example, a polymer composite material can include a polymer matrix that is an organic or inorganic polymer matrix (e.g., one or more of epoxy, bismaleimide, polybutadiene, benzoxazine, cyanate ester, silicone, Ring-Opening Metathesis Polymers (ROMP), preceramic polymers) or a mixture thereof.

[0090] As an example, a polymer composite material can be cured by application of heat and can be used as either a solvent free system or dispersed in solvent to aid in viscosity reduction. As an example, a polymer composite can be obtained through use of a polymer matrix filled with particulate filler. As an example, particulate filler can include one or more of aluminum oxide, aluminum nitride, boron nitride, silicon nitride, and beryllium oxide.

[0091] Figure 14 shows an example of a method 1400 that includes providing materials 1410; bonding two of the materials using another one of the materials as a tie layer to form a stator material 1420; forming a stator for a pump using the stator material 1430; and operating the pump 1440.

[0092] A fluid displacement pump can include a rotor; and a stator, where the stator includes two materials bonded by a tie layer. In such an example, the two materials can include a thermoset and an elastomer.

[0093] As an example, a fluid displacement pump can include a motor operatively coupled to a rotor. As an example, a fluid displacement pump can include a fluid inlet and a fluid outlet. In such an example, a rotor may be driven by fluid flowing from the fluid inlet to the fluid outlet.

[0094] As an example, a fluid displacement pump can include a housing where, for example, a stator is disposed at least in part in a bore of the housing.

[0095] As an example, a method can include providing materials; bonding two of the materials using another one of the materials as a tie layer to form a stator material; forming a stator of a pump using the stator material. In such an example, one of the two materials can include an elastomer and another one of the two materials can include a thermoset.

[0096] As an example, bonding can include chemical bonding and / or one or more other types of bonding.

[0097] As an example, a stator can be disposed at least in part in a bore of a housing where, for example, the housing can be a metallic housing.

[0098] As an example, a tie layer may be shaped and / or sized for one or more purposes. As an example, a number of tie layers may be utilized for a number of interfaces. As an example, a tie layer may be uniform or may be non-uniform. As an example, a non-uniform tie layer may be shaped and / or sized and / or formulated to handle one or more types of stresses (e.g., due to operational conditions, etc.).

[0099] In some embodiments, the methods of the present disclosure may be executed by a computing system. Figure 15 illustrates an example of such a computing system 1500, in accordance with some embodiments. The computing system 1500 may include a computer or computer system 1501-1, which may be an individual computer system 1501-1 or an arrangement of distributed computer systems such as systems 1501-2, 1501-3 and 1501-4. The computer system 1501-1 includes instructions 1502 that are configured to perform various tasks according to some embodiments, such as one or more methods disclosed herein. To perform these various tasks, the instructions 1502 can execute independently, or in coordination with, one or more processors 1504, which is (or are) connected to one or more storage media 1506. The processor(s) 1504 is (or are) also connected to a network interface 1507 to allow the computer system 1501-1 to communicate over a data network 1509 with one or more additional computer systems and / or computing systems, such as 1501-2, 1501-3, and / or 1501-4 (note that computer systems 1501-2, 1501-3 and / or 1501-4 may or may not share the same architecture as computer system 1501-1, and may be located in different physical locations, e.g., computer systems 1501-1 and 1501-2 may be located in a processing facility, while in communication with one or more computer systems such as 1501-3 and / or 1501-4 that are located in one or more data centers, and / or located in varying countries on different continents).

[0100] A processor may include a microprocessor, microcontroller, processor module or subsystem, programmable integrated circuit, programmable gate array, or another control or computing device.

[0101] The storage media 1506 may be implemented as one or more computerreadable or machine-readable storage media. Note that while in the example embodiment of Figure 15 storage media 1506 is depicted as within computer system 1501-1, in some embodiments, storage media 1506 may be distributed within and / or across multiple internal and / or external enclosures of computing system 1501-1 and / or additional computing systems. Storage media 1506 may include one or more different forms of memory including semiconductor memory devices such as dynamic or static random access memories (DRAMs or SRAMs), erasable and programmable read-only memories (EPROMs), electrically erasable and programmable read-only memories (EEPROMs) and flash memories, etc.

[0102] Although a few embodiments of the disclosure have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without departing from the scope of the invention as defined in the appended claims.

Claims

1. A fluid displacement pump comprising: a rotor (36); and a composite stator (38) comprising a thermoset material (58) and an elastomer material (64) bonded by a tie layer (76), wherein the tie layer (76) comprises a compatabilizing elastomer-based material that contains both thermoset reactive functionality and elastomer reactive functionality to facilitate co-curing of the tie layer (76) with both the elastomer layer (64) and the thermoset layer (58) resulting in a covalently bonded system and wherein the elastomer material (64) comprises one of nitrile rubber, hydrogenated nitrile rubber, fluoroelastomer and tetrafluoroethylene propylene and the thermoset material (58) is an epoxy resin system, wherein the material of the tie layer (76) is modified based on the elastomer material (64) to match the vulcanization system used in the elastomer material (64) and to match the base resin and cure system of the thermoset material.

2. The fluid displacement pump of claim 1, wherein the elastomer material (64) is hydrogenated nitrile rubber and the thermoset material (58) is an epoxy resin system and the tie layer (76) comprises an elastomer compound including the polymeric molecule 3. The fluid displacement pump of claim 2, wherein the tie layer (76) further incorporates one or more of fillers, antioxidants, process aids or oils and curative systems.

4. The fluid displacement pump of claim 2, wherein the tie layer (76) further utilizes increased unsaturation to provide sites for co-vulcanization with the elastomer material.

5. The fluid displacement pump of any preceding claim, comprising a motor (30) operatively coupled to the rotor (36).

6. The fluid displacement pump of claim 1, comprising a fluid inlet and a fluid outlet.

7. The fluid displacement pump of claim 6, wherein the rotor (36) is driven by fluid flowing from the fluid inlet to the fluid outlet.

8. The fluid displacement pump of claim 1, comprising a housing (56).

9. The fluid displacement pump of claim 8, wherein the stator (38) is disposed at least in part in a bore of the housing (56).

10. An electric submersible progressive cavity pump (ESPCP) system for use within a well, the ESPCP system (20) comprising: a motor (30); and a fluid displacement pump (34) coupled to the motor (30), the fluid displacement pump as defined in any preceding claim.

11. A method for fabricating a stator (38), the method comprising: providing a thermoset material (58), an elastomer material (64) and a compatabilizing elastomer-based material that contains both thermoset reactive functionality and elastomer reactive functionality, wherein the elastomer material (64) comprises one of nitrile rubber, hydrogenated nitrile rubber, fluoroelastomer and tetrafluoroethylene propylene and the thermoset material (58) is an epoxy resin system; modifying the compatabilizing elastomer-based material based on the elastomer material (64) to match the vulcanization system used in the elastomer material (64) and to match the base resin and cure system of the thermoset material (58); bonding the thermoset material (58) and the elastomer material (64) using the compatabilizing elastomer-based material as a tie layer (76) resulting in a covalently bonded system that forms a composite stator material; forming the stator (38) of a pump (34) using the composite stator material.

12. The method of claim 11, wherein the elastomer material (64) is hydrogenated nitrile rubber and the thermoset material (58) is an epoxy resin system and the tie layer comprises an elastomer compound including the polymeric molecule