BACKGROUND

[0001] In hydrocarbon well development, it is common practice to use electrical submersible pumping systems (ESPs) as a primary form of artificial lift. A challenge with ESP operations is dielectric oil circulation for cooling and lubrication in an ESP motor. In order to extend ESP run life and reduce the need to replace the ESP equipment, an oil slinger is installed in the motor to deflect oil from one end of a rotor assembly and into a stator/rotor cavity where it makes its way back to the other end of the rotor assembly before re-entering the inside of a shaft.

[0002] A typical industry oil slinger found in ESP motors is a simple disc with holes drilled diametrically into a center clearance annulus. The oil slinger is positioned on the shaft to align with the matching holes on the shaft. The drilled holes in the oil slinger can diminish dielectric oil circulation. 3D printing the oil slinger allows a variety of complex geometric shapes to be produced simply and quickly. A 3D printed oil slinger allows the design to be retrofitted to any ESP motor. The design may include an impeller imprint to replace the drilled holes, offering improved dielectric oil circulation at oil cost. The impeller design allows for oil deflection to be directed at any angle within a 180-degree arc.

[0003] In addition, the 3D printed oil slinger may offer higher quality, smoother surface finish, lower drag for more elaborate designs, and lower cost. The 3D printed oil slinger may improve dielectric oil circulation around the rotor cavity of the motor, motor cooling and bearing lubrication, and the total cost of ownership. The typical oil slinger known in the industry does not allow the full benefit of radial and tangential forces. The radial and tangential forces accelerate the dielectric oil into the stator/rotor cavity, which means bearing lubrication and motor cooling are at low efficiency. Accordingly, there exists a need for a way to match with a particular ESP manufacturer’s shaft designs and direct oil deflection. SUMMARY

[0004] This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

[0005] In general, in one aspect, one or more embodiments disclosed herein relate to an oil slinger apparatus comprising: a metal disc comprising a center annulus and an outer annulus configured to be disposed on a motor, wherein the center annulus comprises a space between an inner diameter and an outer diameter and at least one feed hole in the space; an impeller imprint on the outer annulus comprising a vane around each of the at least one feed hole; and a keyway disposed on the metal disc configured to fit a key for aligning the oil slinger to the motor.

[0006] In general, in one aspect, one or more embodiments disclosed herein relate to a method for lubrication and cooling a rotor assembly of a motor, the method comprising: designing an oil slinger to fit in a motor; 3D printing the oil slinger with at least one feed hole and a vane for each of the at least one feed hole; aligning the oil slinger with a shaft in the motor, via a keyway; installing the oil slinger; running the motor on a pump; flowing oil from the shaft into the oil slinger; deflecting and slinging oil, via the oil slinger, in any direction via the vane to an end of a rotor assembly; lubricating a plurality of bearings and cooling a plurality of rotors in the rotor assembly; and flowing oil back into the motor and the shaft.

[0007] Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims.

BRIEF DESCRIPTION OF DRAWINGS

[0008] Specific embodiments of the disclosed technology will now be described in detail with reference to the accompanying figures. Like elements in the various figures are denoted by like reference numerals for consistency.

[0009] FIG. 1 shows an exemplary well with an Electrical Submersible Pump (ESP) completion design in accordance with one or more embodiments. [0010] FIG. 2 is a schematic illustration of an embodiment of an ESP motor useful in conjunction with the well depicted in FIG. 1.

[0011] FIG. 3 is a schematic illustration of an embodiment of a 3D printed oil slinger useful in conjunction with the well depicted in FIG. 1.

[0012] FIG. 4A - 4C show schematic illustrations of multiple embodiments of an oil slinger useful in conjunction with the well depicted in FIG.1.

[0013] FIG. 5 is a flowchart in accordance with one or more embodiments.

DETAILED DESCRIPTION

[0014] Specific embodiments of the disclosed technology will now be described in detail with reference to the accompanying figures. Like elements in the various figures are denoted by like reference numerals for consistency. The sizes and relative positions of elements in the drawings are not necessarily drawn to scale. For example, the shapes of various elements and angles are not necessarily drawn to scale, and some of these elements may be arbitrarily enlarged and positioned to improve drawing legibility. Further, the particular shapes of the elements as drawn are not necessarily intended to convey any information regarding the actual shape of the particular elements and have been solely selected for ease of recognition in the drawing.

[0015] In the following detailed description of embodiments of the disclosure, numerous specific details are set forth in order to provide a more thorough understanding of the disclosure. However, it will be apparent to one of ordinary skill in the art that the disclosure may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.

[0016] Throughout the application, ordinal numbers (e.g., first, second, third, etc.) may be used as an adjective for an element (i.e., any noun in the application). The use of ordinal numbers is not to imply or create any particular ordering of the elements nor to limit any element to being only a single element unless expressly disclosed, such as using the terms "before", "after", "single", and other such terminology. Rather, the use of ordinal numbers is to distinguish between the elements. By way of an example, a first element is distinct from a second element, and the first element may encompass more than one element and succeed or precede the second element in an ordering of elements.

[0017] FIG. 1 shows an exemplary Electrical Submersible Pump (ESP) system 100. The ESP system 100 is one example of an artificial lift system that is used to help produce fluids 102 from a formation 104. Perforations 106 in the well’s 116 casing string 108 provide a conduit for the produced fluids 102 to enter the well 116 from the formation 104. An ESP system 100 is an example of the artificial lift system, ESP system and artificial lift system may be used interchangeably within this disclosure. The ESP system 100 includes surface equipment 110 and an ESP string 112. The ESP string 112 is deployed in a well 16 and the surface equipment 110 is located on the surface 114. The surface 114 is any location outside of the well 116, such as the Earth’s surface.

[0018] The ESP string 112 may include a motor 118, motor protectors 120, a gas separator 122, a multi-stage centrifugal pump 124 herein called a “pump” 124, and an electrical cable 126. The ESP string 112 may also include various pipe segments of different lengths to connect the components of the ESP string 112. The motor 118 is a downhole submersible motor 118 that provides power to the pump 124. The motor 118 may be a two-pole, three-phase, squirrel-cage induction electric motor 118. The motor’ s 118 operating voltages, currents, and horsepower ratings may change depending on the requirements of the operation.

[0019] The size of the motor 118 is dictated by the amount of power that the pump 124 requires to lift an estimated volume of produced fluids 102 from the bottom of the well 116 to the surface 114. The motor 118 is cooled by the produced fluids 102 passing over the motor housing. The motor 118 is powered by the electrical cable 126. The electrical cable 126 may also provide power to downhole pressure sensors or onboard electronics that may be used for communication. The electrical cable 126 is an electrically conductive cable that is capable of transferring information. The electrical cable 126 transfers energy from the surface equipment 110 to the motor 118. The electrical cable 126 may be a three-phase electric cable that is specially designed for downhole environments. The electrical cable 126 may be clamped to the ESP string 112 in order to limit electrical cable 126 movement in the well 116. In further embodiments, the ESP string 112 may have a hydraulic line that is a conduit for hydraulic fluid. The hydraulic line may act as a sensor to measure downhole parameters such as discharge pressure from the outlet of the pump 124.

[0020] Motor protectors 120 are located above (i.e., closer to the surface 114) the motor 118 in the ESP string 112. The motor protectors 120 are a seal section that houses a thrust bearing. The thrust bearing accommodates axial thrust from the pump 124 such that the motor 118 is protected from axial thrust. The seals isolate the motor 118 from produced fluids 102. The seals further equalize the pressure in the annulus 128 with the pressure in the motor 118. The annulus 128 is the space in the well 116 between the casing string 108 and the ESP string 112. The pump intake 130 is the section of the ESP string 112 where the produced fluids 102 enter the ESP string 112 from the annulus 128.

[0021] The pump intake 130 is located above the motor protectors 120 and below the pump 124. The depth of the pump intake 130 is designed based on the formation 104 pressure, estimated height of produced fluids 102 in the annulus 128, and optimization of pump 124 performance. If the produced fluids 102 have associated gas, then a gas separator 122 may be installed in the ESP string 112 above the pump intake 130 but below the pump 124. The gas separator 122 removes the gas from the produced fluids 102 and injects the gas (depicted as separated gas 132 in FIG. 1) into the annulus 128. If the volume of gas exceeds a designated limit, a gas handling device may be installed below the gas separator 122 and above the pump intake 130.

[0022] The pump 124 is located above the gas separator 122 and lifts the produced fluids 102 to the surface 114. The pump 124 has a plurality of stages that are stacked upon one another. Each stage contains a rotating impeller and stationary diffuser. As the produced fluids 102 enter each stage, the produced fluids 102 pass through the rotating impeller to be centrifuged radially outward gaining energy in the form of velocity. The produced fluids 102 enter the diffuser, and the velocity is converted into pressure. As the produced fluids 102 pass through each stage, the pressure continually increases until the produced fluids 102 obtain the designated discharge pressure and has sufficient energy to flow to the surface 114.

[0023] In other embodiments, sensors may be installed in various locations along the ESP string 112 to gather downhole data such as pump intake volumes, discharge pressures, shaft speeds and positions, and temperatures. The number of stages is determined prior to installation based of the estimated required discharge pressure. Over time, the formation 104 pressure may decrease and the height of the produced fluids 102 in the annulus 128 may decrease. In these cases, the ESP string 112 may be removed and resized. Once the produced fluids 102 reach the surface 114, the produced fluids 102 flow through the wellhead 134 into production equipment 136. The production equipment 136 may be any equipment that can gather or transport the produced fluids 102 such as a pipeline or a tank.

[0024] The remainder of the ESP system 100 includes various surface equipment 110 such as electric drives 137, production controller 138, the control module, and an electric power supply 140. The electric power supply 140 provides energy to the motor 118 through the electrical cable 126. The electric power supply 140 may be a commercial power distribution system or a portable power source such as a generator. The production controller 138 is made up of an assortment of intelligent unit- programmable controllers and drives which maintain the proper flow of electricity to the motor 118 such as fixed-frequency switchboards, soft-start controllers, and variable speed controllers. The production controller 138 may be a variable speed drive (VSD), well choke, inflow control valve, and/or sliding sleeves. The production controller 138 is configured to perform automatic well operation adjustments. The electric drives 137 may be variable speed drives which read the downhole data, recorded by the sensors, and may scale back or ramp up the motor 118 speed to optimize the pump 124 efficiency and production rate. The electric drives 137 allow the pump 124 to operate continuously and intermittently or be shut-off in the event of an operational problem.

[0025] FIG. 2 is a schematic illustration of an embodiment of the motor 118 useful in conjunction with the well 116 depicted in FIG. 1. The motor 118 rotates and may contain multiple grades of dielectric oil. Dielectric oil is commonly known for lubrication, insulation, and for homogeneous distribution of heat. The motor 118 may include one or more components including but not limited to a stator 202, rotor 210, shaft 216, and bearing 218. The stator 202 may be a core or electrical field of the motor 118. The stator 202 may be composed of a stator core 204, stator windings 206, and housing material for the desired diameter. Housing material may form the cover for the motor 118 and may be chosen dependent upon environment. The stator core 204 may include stator laminations 208 stacked under pressure. Stator laminations 208 may be thin sheets of a material such as die-punched steel or bronze. The stator laminations 208 are commonly used around the stator core 204 for insulation. The stator windings 206 may provide magnetizing winding wound through the slots in the stator core 204. The stator windings 206 may be made of a Polyimide material.

[0026] The rotor 210 may be a device that rotates inside of the stator core 204. The rotor may include rotor bars 212 and rotor lamination 214. Rotor bars 212 may be of bar shape, round shape, or tombstone shape. The rotor bar 212 shape and placement may be critical in producing horsepower. Rotor bars 212 may provide current path to build an induced magnetic field. The rotor bars 212 may be of copper material to provide field strength. The rotor lamination 214 may be of smaller size than the stator laminations 208. The rotor lamination 214 may create an iron core. The shaft 216 may be a central component of the motor 118. The shaft 216 may be of cylindrical shape. The shaft 216 may be hollow. The shaft 216 may be a rotor shaft or a stator shaft. One or more rotors 210 and a shaft 216 may make up a rotor assembly in the motor 118.

[0027] The bearing 218 may centralize the rotor 210 within the cavity of the stator 202. The bearing 218 may create friction and generate heat. The bearing 218 may contain fluid holes to insure oil circulation and wide-angle oil grooves on the outer diameter. The fluid holes and grooves may provide evenly distributed lubrication over the bearing 218. The motor 118 may include a variety of bearing types including but not limited to rotor bearings 218 and motor thrust bearings. Those skilled in the art might appreciate that the bearing 218 may have insulation. The insulation may prevent circulating rotor 210 currents which may damage the bearing 218.

[0028] FIG. 3 is a schematic illustration of an embodiment of a 3D printed oil slinger useful in conjunction with the well 116 depicted in FIG. 1. In one or more embodiments, the ESP system 100 includes an oil slinger 300 in the motor 118. The motor 118 may have a different shape and require the oil slinger 300 to be retrofitted. The oil slinger 300 is a metal disc configured to be disposed on the motor 118. The oil slinger 300 may have a center annulus 302 and an outer annulus 304. The center annulus 302 includes a space between the inner diameter and the outer diameter of the center annulus 302. The center annulus 302 is aligned and locked in position on the shaft 216 with a key within the motor 118. The key may be an industry standard key for ESP motors 118. The key is used in a keyway 306 disposed on the oil slinger 300 and outside diameter of the shaft 216. The center annulus 302 has at least one feed hole 308 in the space utilized for communication between the inside of the hollow section of the shaft 216 to the outer portion of the shaft 216.

[0029] The feed hole 308 may allow for dielectric oil to be centrifuged. The dielectric oil may be centrifuged from inside the hollow section of the shaft 216 and into an annular groove 314 via the at least two feed holes 308. The dielectric oil may then be centrifuged into the cavity of the stator 202 and rotor 210 via the oil slinger 300, whereupon dielectric oil may migrate along the length of the cavity lubricating bearings 218 and cooling rotors 210. The dielectric oil may follow the full length of the cavity before it re-enters another end of the rotor shaft 216 to travel back towards any oil slinger 300 cross-drilled hole. The cross-drilled hole may be a feed hole 308. The oil slinger 300 may include an impeller imprint 310. The impeller imprint 310 may be a vane 312 set around and open to the annular groove 314 with access to holes such as the feed holes 308. Specific to this embodiment, four vanes 312 are designed on the oil slinger 300. The impeller imprint 310 may be an impeller design indented on the oil slinger 300.

[0030] The annular groove 314 may be a rounded channel. The annular groove 314 may be around the center annulus 302. The vanes 312 may be equally spaced to each other. The vanes 312 may be adjusted or designed to provide the most efficient profile to maximize the outlet flow for a given shaft 216 design. The vanes 312 may have a variety of thickness. The impeller imprint 310 of the vanes 312 may allow a fluid outlet to be directed left, right, or any angle within a 180-degree arc. As labeled in FIG. 3, those skilled in the art might appreciate reference to the result of flow exiting the oil slinger 300 may follow centrifugal impeller rules, where radial and tangential components of flow will combine to form the actual directions into the stator 202 and rotor 210 cavity. An example of rotation direction is shown in FIG. 3 illustrating the flow direction with radial and tangential components.

[0031] FIG. 4 shows a schematic illustration of multiple embodiments of an oil slinger useful in conjunction with the well depicted in FIG. l. FIG. 4A - 4C illustrates three options for an oil slinger 300 design. FIG. 4 A shows a traditional/current oil slinger design. FIG. 4 A illustrates one or more feed holes 308 inside the center annulus 302 from inside to outside of the hollow portion of the shaft 216 leading into the annular groove 314 on the oil slinger 300. Further, FIG. 4A illustrates four discharge holes 400 in the outer annulus 304 of the oil slinger 300. The discharge holes 400 may be industry standard of the traditional oil slinger design. FIG. 4B illustrates an embodiment of the 3D printed oil slinger 300 with four vanes 312 equally spaced around four feed holes 308 from the shaft 216. FIG. 4C illustrates an embodiment of the 3D printed oil slinger 300 with nine equally spaced vanes 312 around the annular groove 314 fed by the four feed holes 308 from the shaft 216.

[0032] FIG. 5 shows a flowchart in accordance with one or more embodiments. Specifically, FIG. 5 shows a method and apparatus for the 3D printed oil slinger 300. One or more blocks in FIG. 5 may be performed using one or more components as described in FIGs. 1 through 4. While the various blocks in FIG. 5 are presented and described sequentially, one of ordinary skill in the art will appreciate that some or all of the blocks may be executed in parallel and/or iteratively. Furthermore, the blocks may be performed actively or passively.

[0033] In Block 500, an oil slinger 300 is designed to fit in the motor 118. The motor 118 may be an ESP motor. In Block 502, the oil slinger 300 is 3D printed with at least one feed hole 308 and a vane 312 for each feed hole 308. The feed hole 308 may be into an annular groove 314 around the outer annulus 302 of the oil slinger 300. The annular groove 314 may feed into the vanes 312. The feed holes 308 may feed into the vanes 312 when there is no annular groove 314. The vanes 312 may be equally spaced to each other. The vane 312 for each feed hole 308 may be around an annular groove 314. In Block 504, the oil slinger 300 is aligned with a shaft 216 in the motor 118. The feed holes 308 may fit onto the shaft 216 and be driven rotationally via a key on the shaft 216 through the keyway 306. The key may align the feed hole 308 into the vane 312 for designs without an annular groove 314. In Block 506, the oil slinger 300 is installed in the motor 118. In Block 508, the motor 118 is run on the pump 124. In Block 510, oil is flowed, deflected, and slung in the vane’s 312 direction into the oil slinger 300 and rotor assembly to lubricate bearings 218 and cool rotors 210. Deflecting and slinging oil via the oil slinger 300 to an end of the rotor assembly may be directed via the vane 312. The vane’s 312 direction may be any direction within a 180-degree arc. In Block 512, the oil flows back into the motor 118 and shaft 216. The oil slinger 300 may be designed to fit a new motor 118 or to be fitted for existing designs of any ESP motor 118.

[0034] Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from this invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures.