Patent Publication Number: US-2020284263-A1

Title: Low profile pump motor lead protector

Description:
PRIORITY CLAIM AND INCORPORATION BY REFERENCE 
     This application is a continuation of U.S. Non-Provisional patent application Ser. No. 16/416,578 filed May 20, 2019 which is a continuation of U.S. Non-Provisional patent application Ser. No. 15/651,704 filed Jul. 17, 2017 now U.S. Pat. No. 10,323,643 which is a continuation of U.S. Non-Provisional patent application Ser. No. 15/165,078 filed May 26, 2016 now U.S. Pat. No. 9,742,241 which is a continuation of U.S. Non-Provisional patent application Ser. No. 14/266,994 filed May 1, 2014 titled LOW PROFILE PUMP MOTOR LEAD PROTECTOR now U.S. Pat. No. 9,356,484 and claims priority to U.S. Provisional Patent Application No. 61/883,347 filed Sep. 27, 2013 titled PUMP MOTOR LEAD PROTECTOR which is incorporated herein, by reference, in its entirety and for all purposes. U.S. Pat. No. 6,863,124 B2 filed Dec. 17, 2002 is incorporated herein, by reference, in its entirety and for all purposes. 
    
    
     BACKGROUND OF THE INVENTION 
     Field Of The Invention 
     The present invention relates to the mechanical arts. In particular, the invention relates to a manufacture incorporating structural parts for covering and protecting electrical leads connected to a pump motor in a downhole pumping apparatus. 
     Discussion Of The Related Art 
     Electric motor driven pumps may be used in severe service locations such as those at depth in downhole oilfield applications. For example, such an apparatus may be used to return oil to the surface. Electrical and other leads that attach to the pump and its motor typically follow a string of pipe from the downhole location to a “topside” location at or near the earth&#39;s surface. Means to protect these leads from damage during installation, use and recovery of the pump have advanced little during recent years, perhaps due to the industry&#39;s reluctance to rely on new and arguably unproven equipment. 
     SUMMARY OF THE INVENTION 
     The present invention discloses a low profile pump motor lead protector. In various embodiments, the protector covers leads from a pump motor such as leads for one or more of electric power, electric telemetry, optical telemetry, fluid, pressurized fluid, and other similarly useful leads. 
     In an embodiment, a lead protector is for use with a downhole pump and motor in an oil production string comprising: a head guard and a trailing guard; the head guard covering a head end of a lead; the trailing guard covering a portion of the lead trailing from the lead head end; and, the head guard and the trailing guard configured to substantially cover the lead as it passes through a space between a production string casing and the pump and motor. 
     In various embodiments, the protector includes a head portion and a trailing portion either or both of which may be made of one or several parts. For example, some embodiments utilize one part head portion and a multipart trailing portion. 
     In various embodiments, a head guard and a trailing guard provide a means for continuously protecting a lead such as an electric power, electric signal, or other lead from the pump and motor. In an embodiment, the protector is configured to guard at least an electric power lead from a pump motor used downhole in an oil production string. 
     In various embodiments, the lead protector is mounted to a pump and motor apparatus. The head guard covers a penetration/terminal of the pump and motor apparatus where electric and/or other leads to be protected exit the pump and motor apparatus. In various embodiments, the head guard is made from metal such as stainless steel and has a clam-shell like construction providing a void on its bottom side to receive the abovementioned lead(s). And, in various embodiments, the head guard is configured to mate with the trailing guard to provide protection of a continuous or substantially continuous length of the lead(s). 
     And, in various embodiments, the trailing guard has a channel like shape with opposed sides and a web therebetween. And, in various embodiments, the trailing guard is made from a metal such as stainless steel. Some embodiments of the protector utilize several mated trailing guards such as overlapping trailing guards. 
     In an example, the pump and motor apparatus is surrounded by a casing such that a small annular like clearance is formed between the pump and motor apparatus and the surrounding casing. Here, the protector shields the lead(s) against physical damage that might result from the lead(s) touching the casing or other objects within the annulus. 
     With various embodiments of the pump and motor apparatus and insertion of the pump and motor apparatus in particular wells or well casings, there are particular dimensions such that different production strings have different dimensions which call for appropriate pump and motor apparatus to accommodate physical dimensions and quantities of product/oil to be produced. 
     In an exemplary operation, the lead protector provides a lead cover affixed to a pump and motor apparatus via a band like clamping system. During insertion of the pump and motor apparatus in a surrounding such as a casing, during operation of the pump and motor apparatus, and during extraction of the pump and motor apparatus from a surrounding such as a casing, the lead protector shields the covered lead(s) from damage such as damage caused by rubbing, pulling, scraping, and the like. Embodiments of the invention provide a lead protector of a length that protects from damage occurring in the annulus between a casing and the pump and motor apparatus. 
     In an embodiment, a method of using a low profile lead protector to prevent damage to an electrical lead of a pump motor during insertion, operation, and removal of an electric submersible pump assembly in an oil well casing comprising: providing a head guard including a front section with a front end and a rear section with a rear end, the head guard front section tapering toward the head guard front end and defining a ventral curved surface for mating with a pump motor exterior and defining a dorsal surface in the shape of a truncated triangle, and including bolt holes in opposite corners of and passing through the ventral curved surface; providing a head guard rear section that is depressed with respect to the front guard section, the head guard rear section defining a ventral curved surface for mating with a pump motor exterior and including a socket flanked by flanges with bolt holes; providing a trailing guard having an “n” shaped cross-section with six sides, two of the six sides being opposed and having aligned slots, the trailing guard secured at one end by the head guard rear section; on a production string, placing the trailing guard over a section of the pump motor lead and placing the head guard over the pump motor lead where it joins the motor and over an end portion of the trailing guard; on the production string, bolting the head guard to the pump motor; on the production string, banding the trailing guard to the pump and motor assembly; during insertion of the production string, the lead protector moving relative to the casing and the lead protector and fending off stationery obstructions to protect the pump motor lead; during operation of the production string, the lead protector shielding the pump motor lead from contact with the casing and objects in an annulus between the casing and the pump motor to protect the pump motor lead; and, during extraction of the production string, the lead protector moving relative to the casing and the lead protector and fending off stationery obstructions to protect the pump motor lead. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is described with reference to the accompanying figures. In the figures, like reference numbers indicate identical or functionally similar elements. The accompanying figures, which are incorporated herein and form part of the specification, illustrate the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the relevant art to make and use the invention. 
         FIGS. 1-3  show a motor lead protector in accordance with the present invention. 
         FIG. 4  shows an embodiment of a head guard that is a part of the motor lead protector of  FIG. 1 . 
         FIGS. 5-7  show an embodiment of a trailing guard that is a part of the motor lead protector of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The disclosure provided in the following pages describes examples of some embodiments of the invention. The designs, figures, and description are non-limiting examples of embodiments they disclose. For example, other embodiments of the disclosed device and/or method may or may not include the features described herein. Moreover, disclosed advantages and benefits may apply to only certain embodiments of the invention and should not be used to limit the disclosed invention. 
     Unless otherwise indicated, parts that are connected or coupled may be directly or indirectly connected and may have other devices interposed therebetween including devices known to persons of ordinary skill in the art. 
       FIGS. 1-3  show views of a pump motor lead protector in accordance with the present invention  100 ,  200 ,  300 . A pump motor lead is omitted from  FIGS. 1, 3  for clarity and is shown in  FIG. 2  (See e.g.,  202 ). 
       FIG. 1  shows a pump motor lead protector  200  mounted alongside a pump  104  and motor  102  assembly  103  that may be suspended from production tubing  110  for producing product from a reservoir, such as a subterranean oil well and/or reservoir  113  to a receiving facility  115 , such as a production shut-off valve. Flow arrows showing inlet flow from the reservoir and pump outlet flow  112  indicate typical production of liquids such as oil or crude oil. In various embodiments, the pump and motor assembly is an electric submersible pump and motor assembly. 
     Applications include production facilities with an outer casing such as casing  108  into which the pump  104  and motor  102  are inserted. As skilled artisans will recognize, the pump and motor assembly may also be used in a hole or well-bore that has no casing. And, as skilled artisans will recognize, the pump may be above the motor as shown, or the pump may be below the motor when designed for such use. An upper end of the pump  166  may, in various embodiments, be coupled with a string of production tubing  110 . 
     When the pump and motor are moved in a confined space like the casing  108 , the motor lead protector  200  assists in protecting the motor lead  202 . For example, the motor lead protector covers the motor lead (See  FIG. 2 ) such that it is not rubbed against or snagged by adjacent and/or fixed structures such as the casing inside side wall  124  during pump  104  and motor  102  insertion into or removal from the casing. 
     A head guard of the motor lead protector  210  covers the motor lead  202  where it passes through a motor sidewall  122 . Some embodiments of the head guard include a head guard front or head guard front section  212  with a forward sloped or wedge-like nose  205  that guides pump  104  and motor  102  when moved in the casing. Locating the motor lead protector and in particular the head guard front section between the motor and the inside side wall of the casing  124  spaces the motor apart from the casing  121 . 
     In various embodiments, connection of the pump motor lead protector  200  with the motor  102 , pump  104 , and production tubing  110  is by fasteners and/or other restraints. For example, bolts may be used to affix the head guard  210  to the motor and straps or bands  106  may be used to affix the trailing guard  220  to the motor, pump and/or production tubing. As skilled artisans will recognize, embodiments provide a motor lead protector that extends at least from a motor lead entryway  120 , and in the direction of the receiving facility  115 . 
       FIG. 2  shows an enlarged side view of the motor lead protector of  FIG. 1 . Among other things, this view shows a motor lead  202  that is covered by the motor lead protector. And,  FIG. 3  shows an enlarged top view of the motor lead protector of  FIG. 1 . 
     The motor lead protector  200  includes the head guard  210  and the trailing guard  220 . The head guard includes a head guard front section  212  and a head guard rear section  214 . Like the trailing guard  220 , the head guard  210  provides motor lead  202  protection. For example, a hollowed out head guard provides a protected space for a motor lead  202  which has an exemplary motor lead head end  203 . Here, the motor lead head end is shown entering the motor lead entryway  120  through the motor entryway sidewall  122 . 
     In some embodiments, the motor lead  202  connects with a lead termination block  160  such as an electrical terminal block or receptacle that is accessible on the motor exterior. And in some embodiments, a motor lead plug  162  interconnects with a mating lead termination block, for example a bayonet plug and socket or another suitable arrangement may be used. The terminal block may extend from a sunken motor surface portion providing a low profile motor terminal block. In various ones of these embodiments, the motor lead need not pass through a motor lead entryway, a feature that may enable better sealing of the motor internals against contaminants outside the motor. 
     In various embodiments, head guard  210  features include the head guard front  212  section with a hollowed out interior  240  for receiving a motor lead  202 , and motor fastener means such as peripheral bolt holes  205 . In some embodiments bolts passing through front guard peripheral bolt holes are anchored in matched threaded holes of the motor. For example, bolt holes in a motor used to mount a traditional motor lead entryway cover might be reused when the front guard replaces the traditional cover during pump motor lead protector installation. 
     And, in various embodiments, head guard features include a head guard rear section  214  with a box  218  extending from the front section and peripheral or flanged fastening means  216  to either side of the box. The box may be in the form of a closed box or a box with an open side(s). In some embodiments, the box is a rectangle with an open side or side portion adapted to receive the cross-sectional shape of a mating end (See e.g.  410 ) of the trailing guard  220 . And, in some embodiments the box is adapted to fit and/or fittingly receive the cross-sectional shape of a mating end of the trailing guard as where the box and the mating end have equal numbers of sides. Fastener means such as bolt holes  213  may be used with peripheral or flanged fastening means. 
       FIG. 3  shows, inter alia, a dorsal top side  219  of the head guard  210 . Dimensions include an overall length “a 1 ” and a width such as a maximum width of “a 2 .”  FIG. 2  shows, inter alia, a side view of the head guard with a head guard front section  212  height of “a 3 ” which is less than a head guard rear section  214  height of “a 4 ”. In various embodiments, a head guard major aspect ratio is (a 1 /a 2 ) with values greater than two. And, in various embodiments, the head guard rear section with height a 4  is depressed with respect to the adjacent head guard front section with height a 3 . 
     And, in some embodiments a head guard minor aspect ratio is (a 1 /a 3 ) with values greater than four. In these embodiments, the lead protector head guard may be described as a “low profile” lead protector. 
       FIG. 4  shows an enlarged perspective view  400  of an embodiment of the head guard of  FIG. 2 . As seen, the head guard  210  is ready for mating with an adjacent trailing guard portion  220 . In an embodiment, a head guard box  218  includes a box mouth  211  that is for receiving a free end  410  of the trailing guard assembly. Skilled artisans will appreciate this “pin and socket” joint arrangement might be reversed in some embodiments. 
     Also shown is a head guard  210  end  404  revealing a curved interior or curved ventral surface portion  402  of the head guard. Curved with a radius “R,” the head guard may be designed to snugly interface with a similarly curved motor  102  exterior surface  150 . Other portions of the head guard such as the head guard rear section  214  may be similarly shaped for similar reasons. 
     The embodiment shown has a head guard front  212  with a wedge-like forward slope along its longitudinal axis (e.g., t 1 &lt;t 2 ). In some embodiments, the head guard front section has a raised exterior rib  406  that extends about parallel to a head guard longitudinal axis. And, in an embodiment, a dorsal rib such as a bumper rib or a central bumper rib that extends along at least a portion of the head guard and in a direction that is somewhat parallel to the head guard longitudinal axis. 
     As skilled artisans will appreciate, head guards with a wedge-like forward slope provide means to reduce the leading cross-sectional area  420  and thickness t 2 , attributes lowering the risk of frontal impacts with fixed structures that may tend to move the head guard relative to the motor  102 . Where the rib is included, otherwise deleterious effects of side impacts and friction with the head guard and the casing inside sidewall  124  may be further reduced. 
     Turning now to consider the trailing guard  220 , the head guard  210  is for assembly with the trailing guard  220 . Some head guard embodiments provide for a box-like connection wherein a trailing guard  220  is mated with and/or inserted in a box mouth  211  of a head guard box  218 . 
     In various embodiments, the trailing guard is in the form of a tube, partial tube, or channel-like structure  220  and corresponding slots  230  in opposite sidewalls of the trailing guard provide a means for strapping or banding  106  the trailing guard to secure it against one or more of the pump, motor, and production tubing (See also  FIG. 1 ). In an embodiment, bands secure the trailing guard to at least one of the pump  104  and the motor  102 . And, in an embodiment, bands secure the trailing guard to the pump and the motor. And, in an embodiment bands securing the trailing guard include bands that encircle the production tubing  110 . 
       FIGS. 5-7  show an embodiment  500 ,  600 ,  700  of the trailing guard  220  of  FIG. 2 . 
     In various embodiments, including the embodiment of  FIG. 5 , the channel may be described as having multiple sides, for example 7 sides, one of which  502  is open. Here, a channel ridgeline  510  is the juncture of first sidewalls  512 ,  522  forming a somewhat flattened “A” frame like structure. Adjoining respective legs of the “A” as first leg extensions are second sidewalls  514 ,  524  forming an obtuse angle with respective first sidewalls. Adjoining these first leg extensions are second leg extensions/third sidewalls  516 ,  526  forming near right angles with respective first sidewalls. 
     Some trailing guard cross-sections may be referred to as “n” shaped cross-sections, more particularly as four or more adjoining panels forming an “n” shaped cross-section and yet more particularly as 6 adjoining panels forming an “n” shaped cross-section. 
       FIG. 6  shows the channel  220  cross-section of  FIG. 5 . A channel overall height “h” and a channel overall width “w” are shown along with a channel interior  602 . The channel open side  502  faces an adjacent structure  604  such as the motor  102 , pump  104 , or production tubing  110 . 
     In various embodiments a strap or band  106  and a motor lead  202  pass through the channel interior via corresponding channel slots  230  with exemplary major “s 2 ” and minor “t 2 ” slot dimensions selected to accommodate the band. Here, a motor lead  202  is located beneath the band such that a protective clearance “c” exists between the strap or band and the motor lead. A benefit of the protective clearance is relieving the motor lead as a strap or band bearing point and using the channel instead to transmit forces to the structure via its two leg extensions  516 ,  526  without bearing on the motor lead. Yet another benefit of the protective clearance is the avoidance/mitigation of strap or band to motor lead chafing. 
       FIG. 7  shows mating ends  702 ,  704  of respective trailing guards depicted as channel sections  220 ,  720 . As shown here, the pin like end  704  of one trailing guard  720  is for insertion into the socket-like end  702  of another trailing guard  220 . As skilled artisans will appreciate, trailing guard mating ends may be configured as needed to accommodate varying trailing guard cross sections. And, as skilled artisans will appreciate, trailing guard sections with mating ends provide a means of adapting trailing guard length to accommodate varying applications. 
     Materials of construction for the head guard  210  include metals and dense plastics. For example, a metal such as stainless steel and a plastic such as polyether ethyl ketone (“PEEK”), known for its toughness and low coefficient of friction, might be used according to the application. As indicated by the choice of application, materials, cost, schedule, and availability, head guards may be machined, cast, or produced by other suitable methods such as powder metallurgy or sintering. In an embodiment, the head guard is made from stainless steel. 
     Materials of construction for the trailing guard  220  include metals and dense plastics. For example, a metal such as stainless steel and a plastics such as polycarbonate and polypropylene might be used according to the application. As indicated by the choice of application, materials, cost, schedule, and availability, trailing guards may be machined, cast, extruded, rolled, or produced by other suitable methods such as powder metallurgy or sintering. In an embodiment, the trailing guard is made from stainless steel. 
     In operation, embodiments of the lead protector provide a lead cover affixed to a pump and motor assembly, for example via a band like clamping system. For example, protection is provided during insertion of the pump and motor apparatus in a surrounding such as a casing, during operation of the pump and motor apparatus, and during extraction of the pump and motor apparatus from a surrounding such as a casing. The lead protector shields the covered lead(s) from damage such as damage caused by rubbing, pulling, scraping, and the like. Among other things, embodiments of the invention provide a lead protector of a length that protects the motor lead from damage occurring in the annulus between a casing and the pump and motor apparatus. 
     Example: In an oil well application with a well casing, the pump motor lead protector was installed on a 3.75 inch outside diameter pump and motor assembly. The head guard was dimensioned to fit within the annulus between the motor and the casing inside wall. As described above, a wedge-like front guard and a mating trailing guard with slotted sidewalls was installed via metal bands passing through the slots and around the pump and motor assembly. Bolts passing through front guard peripheral bolt holes and anchored in matched threaded holes of the motor secured the head guard to the motor. Channel cross-section, channel slot locations, and motor lead dimensions provided a protective clearance between the motor lead and banding passing through the channel interior. The assembly was inserted in the casing and lowered 1100 feet into the reservoir for fluid production. During lowering, the assembly navigated the route through the casing, including casing bend radii on the order of 3 to 4 degrees. In operation, the pump and motor surfaced fluid normally. This evidence shows the pump motor lead protector prevented debilitating rubbing and snagging damage to the motor lead and further that the protective clearance prevented debilitating rubbing, chafing, and compression damage between the band and the motor lead. 
     While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. It will be understood by those skilled in the art that various changes in form and details can be made therein without departing from the spirit and scope of the invention. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.