Patent Publication Number: US-2023132716-A1

Title: Over-the-line modular weight bar

Description:
RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Application No. 63/002,012, filed on Mar. 30, 2020 titled “Over-the-Line Modular Weight Bar.” 
    
    
     BACKGROUND OF THE INVENTION 
     Generally, when drilling and completing a subterranean well for the production of fluids, minerals, or gases from underground reservoirs, several types of tubulars are placed downhole as part of the drilling, exploration, and completions process. These tubulars can include casing, tubing, pipes, liners, and devices conveyed downhole by tubulars of various types. Each well is unique, so combinations of different tubulars may be lowered into a well for a multitude of purposes. 
     A subsurface or subterranean well is drilled through one or more formations. The formation is a body of rock or strata that contains one or more compositions. The formation is treated as a continuous body. Within the formation hydrocarbon deposits may exist. Typically a wellbore will be drilled from a surface location, placing a hole into a formation of interest. Completion equipment will be put into place, including casing, tubing, and other downhole equipment as needed. Perforating the casing and the formation with a perforating gun is a well-known method in the art for accessing hydrocarbon deposits within a formation from a wellbore. 
     During drilling and completing a well, and throughout the complete well&#39;s life, tools of various types may be lowered into and retrieved from the well by use of a cable or wireline. These tools are often combined into a tool string that includes multiple tools in series. A wireline can provide both mechanical support for conveying the tools in and out of the well and electronic communication between the surface and any tools in the well. A wireline that does not provide electrical communication or power between the surface and a tool is often referred to as slickline. Electrical power and communication may be provided by a wireline that ties into a cable head at the top of a tool string. The electrical signal may have to travel through several components, subs, and tools before it gets to a particular tool. 
     The top of a tool string may include a cable head connecting the tool string mechanically and/or electrically to the wireline. The top of a tool string often also includes a fishing neck to facilitate fishing, or retrieval of the tool string, if the wireline is compromised. 
     A weight bar (also known as a sinker bar or stem) is sometimes added to a tool string to facilitate conveyance of the tool string into the well. For example, the weight bar may overcome wellhead pressure and friction when introducing the tool string into the well bore. An over-the-line (OTL) weight bar is a type of weight bar with no electrical feed through and is inserted above the cable head with the wireline itself running through the inner diameter of the weight assembly. Typical OTL weight bars require that the wireline or cable be disconnected from the cable head and then reconnected to the cable head (reheading) for installation of the weight bar to the tool string. This is a potentially time consuming process that introduces opportunity for errors or malfunctions. 
     An object of the present invention is to enable the addition of weight to a tool string conveyed by wireline without reheading the wireline or cable. 
     SUMMARY OF EXAMPLE EMBODIMENTS 
     An example embodiment may include a weight bar for use on a downhole tool string conveyed by a wireline comprising: a) a longitudinal axis substantially in line with the wireline, b) a weight section comprising: a weight section top end comprising male threads distal from the tool string, a weight section bottom end proximate the tool string comprising female threads in a bottom end bore. a weight section outer surface extending more than degrees about the longitudinal axis between the weight section top end and the weight section bottom end, a cable borehole along the longitudinal axis, a longitudinal slot extending from the weight section bottom end to the weight section top end of the weight section parallel to the longitudinal axis comprising: a first longitudinal slot side wall substantially parallel to the longitudinal axis, and a second longitudinal slot side wall substantially parallel to the longitudinal axis and the first longitudinal side wall, a first longitudinal slot shoulder extending substantially orthogonal from the first longitudinal slot side wall into the longitudinal slot, a second longitudinal slot shoulder extending substantially orthogonal from the second longitudinal slot side wall into the longitudinal slot, a bottom end bore face in the bottom end bore substantially orthogonal to the longitudinal axis, a locking pin slot in the bottom end bore face; c) a slot closure bar, fitting in and substantially filling the longitudinal slot in the weight section, comprising: a slot closure bar top end distal from the tool string, a slot closure bar bottom end opposite the top end, a slot closure bar outer surface extending less than degrees about the longitudinal axis from the slot closure bar top end to the slot closure bar bottom end, a slot closure bar inner surface engaging the first and second longitudinal slot shoulders, a first slot closure bar side wall substantially parallel to the longitudinal axis, a second slot closure bar side wall substantially parallel to the longitudinal axis, a locking pin extending from the first and second slot closure bar side walls substantially orthogonal to the longitudinal axis and engaging the locking pin groove in the weight section bottom bore; and d) wherein the slot closure bar top end has a slot closure bar top end outer surface closer to the longitudinal axis than the male threads on the weight section top end, and slot closure bar bottom end has an inner surface farther from the longitudinal axis than the female threads in weight section bottom end. A further example embodiment may include the locking pin slot extends circumferentially about the longitudinal axis from the first longitudinal slot side wall to the second longitudinal slot side wall. 
     Another example embodiment may include a weight bar for use in a downhole tool string conveyed by a wireline comprising: a) a longitudinal axis substantially in line with the wireline; b) a weight section comprising: a weight section outer surface, a cable borehole along the longitudinal axis, a weight section top end distal from the tool string, a weight section bottom end proximate the tool string, a longitudinal slot extending from the cable borehole through the weight section outer surface, c) a slot closure bar fitting within the weight section longitudinal slot comprising: a slot closure bar top end, a slot closure bar bottom end, d) a slot closure bar top end retainer restricting movement of the top end of the slot closure bar relative to the weight section in at least one direction; and e) a slot closure bar bottom end retainer restricting movement of the bottom end of the slot closure bar relative to the weight section in at least one direction. In a further example embodiment the weight section further comprises: male threads on the weight section top end. In yet a further example embodiment the weight section further comprises: a bottom end bore in the weight section bottom end. In a further example embodiment the weight section further comprises: female threads in the bottom end bore in the weight section bottom end. In a further example embodiment the weight section outer surface extends more than 180 degrees about the longitudinal axis between the weight section top end and the weight section bottom end. In another example embodiment, the longitudinal slot extends from the weight section bottom end to the weight section top end parallel to the longitudinal axis and comprises: a first longitudinal slot side wall substantially parallel to the longitudinal axis; and a second longitudinal slot side wall substantially parallel to the longitudinal axis and the first longitudinal side wall. In another example embodiment, the slot closure bar top end retainer comprises: a first longitudinal slot shoulder extending substantially orthogonal from the first longitudinal slot side wall into the longitudinal slot. In a further example embodiment, the slot closure bar top end retainer further comprises: a second longitudinal slot shoulder extending substantially orthogonal from the second longitudinal slot side wall into the longitudinal slot. In another example embodiment, the slot closure bar bottom end retainer comprises: a locking pin slot in the bottom end bore face and a locking pin in the slot closure bar. In a further example embodiment the weight section further comprises: a bottom end bore face in the bottom end bore substantially orthogonal to the longitudinal axis. In a further example embodiment the locking pin slot is in the bottom end bore face. In another example embodiment, the slot closure bar fits in and substantially fills the longitudinal slot. In another example embodiment, the slot closure bar comprises: a slot closure bar outer surface extending less than 180 degrees about the longitudinal axis from the slot closure bar top end to the slot closure bar bottom end. In another example embodiment, the slot closure bar comprises: a slot closure bar inner surface engaging the first and second longitudinal slot shoulders; a first slot closure bar side wall substantially parallel to the longitudinal axis; and a second slot closure bar side wall substantially parallel to the longitudinal axis. In a further example embodiment the slot closure bar retainer comprises: a locking pin extending from the first and second slot closure bar side walls substantially orthogonal to the longitudinal axis and engaging a locking pin groove in a weight section bottom bore. In another example embodiment, the slot closure bar top end has a slot closure bar top end outer surface closer to the longitudinal axis than the male threads on the weight section top end, and slot closure bar bottom end has an inner surface farther from the longitudinal axis than the female threads in weight section bottom end. 
     Another example embodiment may include an apparatus for use downhole comprising: a tool string; a cable head connecting the tool string to a wireline; a fishing neck top sub attached to a top end of the tool string at a bottom of the fishing neck top sub; a cable head bottom adapter attached to the fishing neck top sub opposite the tool string; a weight bar comprising: a) a longitudinal axis substantially in line with the wireline; b) a weight section comprising: a weight section outer surface, a cable borehole along the longitudinal axis, a weight section top end distal from the tool string, a weight section bottom end proximate the tool string, a longitudinal slot extending from the cable borehole through the weight section outer surface, c) a slot closure bar fitting within the weight section longitudinal slot comprising: a slot closure bar top end, a slot closure bar bottom end, d) a slot closure bar top end retainer restricting movement of the top end of the slot closure bar relative to the weight section in at least one direction; and e) a slot closure bar bottom end retainer restricting movement of the bottom end of the slot closure bar relative to the weight section in at least one direction. In a further example embodiment the weight section further comprises: male threads on the weight section top end. In yet a further example embodiment the weight section further comprises: a bottom end bore in the weight section bottom end. In yet a further example embodiment the weight section further comprises: female threads in the bottom end bore in the weight section bottom end. In another example embodiment, the weight section outer surface extends more than 180 degrees about the longitudinal axis between the weight section top end and the weight section bottom end. In a further example embodiment the longitudinal slot extends from the weight section bottom end to the weight section top end parallel to the longitudinal axis and comprises: a first longitudinal slot side wall substantially parallel to the longitudinal axis; and a second longitudinal slot side wall substantially parallel to the longitudinal axis and the first longitudinal side wall. In another further example embodiment the slot closure bar top end retainer comprises: a first longitudinal slot shoulder extending substantially orthogonal from the first longitudinal slot side wall into the longitudinal slot. In a yet further example embodiment the slot closure bar top end retainer further comprises: a second longitudinal slot shoulder extending substantially orthogonal from the second longitudinal slot side wall into the longitudinal slot. In another further example embodiment the slot closure bar bottom end retainer comprises: a locking pin slot in the bottom end bore face and a locking pin in the slot closure bar. In a yet further example embodiment the weight section further comprises: a bottom end bore face in the bottom end bore substantially orthogonal to the longitudinal axis. In a yet further example embodiment the locking pin slot is in the bottom end bore face. In another further example embodiment the slot closure bar fits in and substantially fills the longitudinal slot. In another further example embodiment, the slot closure bar comprises: a slot closure bar outer surface extending less than degrees about the longitudinal axis from the slot closure bar top end to the slot closure bar bottom end. In a yet further example embodiment the slot closure bar comprises: a slot closure bar inner surface engaging the first and second longitudinal slot shoulders; a first slot closure bar side wall substantially parallel to the longitudinal axis; and a second slot closure bar side wall substantially parallel to the longitudinal axis. In a yet further example embodiment, the slot closure bar retainer comprises: a locking pin extending from the first and second slot closure bar side walls substantially orthogonal to the longitudinal axis and engaging a locking pin groove in a weight section bottom bore. In another further example embodiment, the slot closure bar top end has a slot closure bar top end outer surface closer to the longitudinal axis than the male threads on the weight section top end, and slot closure bar bottom end has an inner surface farther from the longitudinal axis than the female threads in weight section bottom end. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a thorough understanding of the present invention, reference is made to the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings in which reference numbers designate like or similar elements throughout the several figures of the drawing. Briefly: 
         FIG.  1    shows a perspective view of components at the top end of a tool string without a weight bar. 
         FIG.  2    shows a perspective view of components at the top end of a tool string without a weight bar with the fishing neck disconnected. 
         FIG.  3 A  shows a perspective view of components at the top end of a tool string during attachment of a modular weight bar. 
         FIG.  3 B  shows detail view of a perspective view of components at the top end of a tool string during attachment of a modular weight bar. 
         FIG.  4    shows a perspective view of components at the top end of a tool string during attachment of a modular weight bar. 
         FIG.  5    shows a perspective view of components at the top end of a tool string during attachment of a modular weight bar. 
         FIG.  6 A  shows a perspective view of components at the top end of a tool string during attachment of a modular weight bar. 
         FIG.  6 B  shows a perspective view of components at the top end of a tool string during attachment of a modular weight bar. 
         FIG.  7    shows a perspective view of components at the top end of a tool string during attachment of a second modular weight bar. 
         FIG.  8    shows a perspective view of components at the top end of a tool string during attachment of a second modular weight bar. 
         FIG.  9    shows a cross section view through the middle of a modular weight bar. 
         FIG.  10    shows a perspective view of a bottom end of a modular weight bar. 
         FIG.  11    shows a cross section view through the bottom end of a modular weight bar. 
         FIG.  12    shows a perspective view of weight section of a modular weight bar. 
         FIG.  13    shows a perspective cross section view of weight section of a modular weight bar. 
         FIG.  14    shows a perspective view of weight section of a modular weight bar. 
         FIG.  15    shows a perspective cross section view of weight section of a modular weight bar. 
     
    
    
     DETAILED DESCRIPTION OF EXAMPLES OF THE INVENTION 
     In the following description, certain terms have been used for brevity, clarity, and examples. No unnecessary limitations are to be implied therefrom and such terms are used for descriptive purposes only and are intended to be broadly construed. The different apparatus, systems and method steps described herein may be used alone or in combination with other apparatus, systems and method steps. It is to be expected that various equivalents, alternatives, and modifications are possible within the scope of the appended claims. 
     Downhole tool string components are typically assembled along a common longitudinal axis because they must typically transit a narrow cylindrical borehole. In the examples of  FIGS.  1 - 8    this longitudinal axis is represented by the wireline  600 . 
     An example set of components at the top end of a tool string is shown in  FIG.  1    showing a wireline  600  that extends from the surface through a fishing neck  500  and a cable head bottom adapter  400  (shows in dashed lines to allow visibility of other components) to a cable head  300 . In this example, the cable head  300  and bottom adapter  400  are attached to the tool string  100  though fishing neck top sub  200 . Typically these parts are threadably attached, but may also be bolted together, attached with set screws, attached with any other attachment mechanism, or any combination of methods. In the example of  FIG.  1   , the fishing neck  500  threads onto the bottom adapter  400  and is also secured with a cup point set screw  501 . 
       FIG.  2    shows the example set of components at the top end of a tool string of  FIG.  1    with the fishing neck  500  detached from the bottom adapter  400  for attachment of a modular weight bar  900  to the tool string  100  over the wireline  600 . This is an example of the first step in adding a modular weight bar to a tool string without reheading the cable or wireline  600  into a cable head  300 . 
     An example insertion of a modular weight bar is shown in  FIGS.  3 A through  15   . In this example, a weight section  700  is placed over the wireline  600  between the fishing neck  500  and the bottom adapter  400  as indicated by the arrow. This example weight section  700  has a longitudinal slot  705  leading from the weight section outer surface  703  to a cable borehole  704  from the weight section top end  701  to the weight section bottom end  702 . The cable borehole is sized to accommodate the wireline  600  along the longitudinal axis. The longitudinal slot  705  allows the weight section  700  to be placed over the wireline  600  while the wireline is still attached to other components at each end. In this example, weight section top end  701  has male threads  714  for engaging complimentary threads in fishing neck  500 , though these components could be attached through other mechanisms as mentioned above. In this example, weight section bottom end  702  has female threads  713  for engaging complimentary threads in bottom adapter  400 , though these components could be attached through other mechanisms as mentioned above. In this example, the weight section bottom end  702  is proximate the tool string  100  and the weight section top end  701  is distal from the tool string  100 ; however, this direction could be reversed by appropriate modification of the attachment mechanisms of either the weight bar  900  and/or adjacent components. In this example, weight section bottom end  702  has a bottom end bore  710  including female threads  713 . In this example, there is a bottom end bore face  711  in the weight section bottom end bore  710  substantially orthogonal to the longitudinal axis and the locking pin slot  712  is in the bottom end bore face  711 . 
     The example of  FIGS.  3 A through  15    also show a slot closure bar  800  for insertion into the longitudinal slot  705 . In this example, the slot closure bar  800  has a slot closure bar bottom end  802  proximate the tool string  100  and a slot closure bar top end  801  distal from the tool string  100 . This slot closure bar has a locking pin  812  for restricting movement the slot closure bar bottom end  802  relative to the weight section  700 . In this example, the locking pin  812  engages a locking pin slot  712  in the weight section bottom bore  710 . This allows the slot closure bar  800  to be attached to the weight section by hooking the locking pin in the weight section bottom bore  710  and/or locking pin slot  712  and rotating slot closure bar top end  801  toward weight section  700 . Slot closure bar top end  801  is then be captured and held against weight section  700  by threading fishing neck  500  onto weight section top end  701 . Weight bar  900  is then be attached to bottom adapter  400  by threading weight section bottom end  702  onto bottom adapter  400  and secured with cup point set screws  401  and  501 . 
       FIGS.  6 B and  8    show the insertion of a second weight bar  900 ′ between weight bar  900  and fishing neck  500  through the same methods and mechanisms described above with respect to the insertion and attachment of weight bar  900  where weight bar  900 ′ is attached to weight bar  900  rather than bottom adapter  400 . 
       FIG.  9    is a cross section view through the middle of an example weight bar  900 . The example of  FIG.  9    shows the weight section  700  with outer surface  703 , cable borehole  704 , a first longitudinal slot side wall  706 , a second longitudinal slot side wall  707 , and first and second longitudinal slot shoulders  708  and  709  respectively. In this example, the first and second longitudinal slot side walls  706  and  707  are substantially parallel to the longitudinal axis of the weight section  700 . In this example, the first and second longitudinal slot shoulders  708  and  709  are substantially parallel to the longitudinal axis and orthogonal to and extending from the longitudinal slot side walls  706  and  707  into the longitudinal slot  705 . As shown in the example of  FIG.  9    the longitudinal slot shoulders  708  and  709  restrict slot closure bar  800  from intruding into cable borehole  704 . In this example, the weight section outer surface  703  extends more than 180 degrees about the longitudinal axis centered in cable borehole  704 . 
     In the example of  FIG.  9   , the slot closure bar  800  has an outer surface  803  that extends less than 180 degrees about the longitudinal axis of the weight bar  900  and weight section  700 . The slot closure bar of this example also has a first and second side wall  806  and  807 , respectively and an inner surface  804 .  FIG.  9    shows the slot closure bar fitting within and substantially filling longitudinal slot  705 . 
       FIG.  10    shows an example bottom end of weight bar  900 , including weight section bottom end  702  and slot closure bar bottom end  802 .  FIG.  10    shows bottom bore  710  in weight section bottom end  702  and bottom bore face  711  and female threads  713  in bottom bore  710 . Bottom bore face  711  is substantially orthogonal to the longitudinal axis. This example also shows an example locking pin slot  712  as a slot in bottom bore face  711  circumferentially about the longitudinal axis from first longitudinal slot wall  706  to second longitudinal slot wall  707 . Alternatively, locking pin slot  712  could be a straight slot orthogonal to the longitudinal axis or a slot in an outer wall of bottom bore  710  adjacent to or through female threads  713 . Also seen in the example of  FIG.  10    is slot closure bar bottom end  802  with an inner surface  811  that is farther from the longitudinal axis than female threads  713  so as to avoid interference with complementary threads. This example also shows locking pin  812  in locking pin slot  712 , restricting the movement of slot closure bar  800  relative to the weight section  700  both radially relative to the longitudinal axis and toward the weight section top end  701 . Locking pin  812  can extend from either or both of slot closure bar side walls  706  and  707  or be integral with them. 
       FIG.  11    is a cross section of an example weight bar  900  through the locking pin  812  orthogonal to the longitudinal axis through the center of wireline  600 . This example shows relative positions of wireline  600 , weight section  700 , slot closure bar  800 , locking pin  812 , locking pin slot  712 , and first and second longitudinal slot shoulders  708  and  709 . 
       FIG.  12    is a perspective view of an example weight section  700  from the bottom end showing the relative positions and arrangement of weight section top end  701 , weight section bottom end  702 , weight section outer surface  703 , longitudinal slot  705 , female threads  713 , and male threads  714 . 
       FIG.  13    is a perspective cross-section (parallel to the first longitudinal slot wall  706  and parallel to and through the longitudinal axis) view of an example weight section  700  from the bottom end showing the relative positions and arrangement of weight section top end  701 , weight section bottom end  702 , weight section outer surface  703 , first longitudinal slot wall  706 , first longitudinal slot shoulder  708 , female threads  713 , and male threads  714 . 
       FIG.  14    is a perspective view of an example weight section  700  from the top end showing the relative positions and arrangement of weight section top end  701 , weight section bottom end  702 , weight section outer surface  703 , longitudinal slot  705 , female threads  713 , male threads  714 , and second longitudinal slot shoulder  709 . 
       FIG.  15    is a perspective cross-section (parallel to the second longitudinal slot wall  706  and parallel to and through the longitudinal axis) view of an example weight section  700  from the top end showing the relative positions and arrangement of weight section top end  701 , weight section bottom end  702 , weight section outer surface  703 , second longitudinal slot wall  707 , second longitudinal slot shoulder  709 , female threads  713 , and male threads  714 . 
     Although the invention has been described in terms of embodiments which are set forth in detail, it should be understood that this is by illustration only and that the invention is not necessarily limited thereto. For example, terms such as upper and lower or top and bottom can be substituted with uphole and downhole, respectfully. Top and bottom could be left and right, respectively. Uphole and downhole could be shown in figures as left and right, respectively, or top and bottom, respectively. Generally downhole tools initially enter the borehole in a vertical orientation, but since some boreholes end up horizontal, the orientation of the tool may change. In that case downhole, lower, or bottom is generally a component in the tool string that enters the borehole before a component referred to as uphole, upper, or top, relatively speaking. The first housing and second housing may be top housing and bottom housing, respectfully. In a gun string such as described herein, the first gun may be the uphole gun or the downhole gun, same for the second gun, and the uphole or downhole references can be swapped as they are merely used to describe the location relationship of the various components. Terms like wellbore, borehole, well, bore, oil well, and other alternatives may be used synonymously. Terms like tool string, tool, perforating gun string, gun string, or downhole tools, and other alternatives may be used synonymously. The alternative embodiments and operating techniques will become apparent to those of ordinary skill in the art in view of the present disclosure. Accordingly, modifications of the invention are contemplated which may be made without departing from the spirit of the claimed invention.