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BACKGROUND OF THE DISCLOSURE 
       [0001]    1. Field of the Disclosure 
         [0002]    The present disclosure generally relates to a method for makeup evaluation visualization to automatically detect acceptable or unacceptable connections during tubular makeup. 
         [0003]    2. Description of the Related Art 
         [0004]    In wellbore construction and completion operations, a wellbore is formed to access hydrocarbon-bearing formations (e.g., crude oil and/or natural gas) by the use of drilling. Drilling is accomplished by utilizing a drill bit that is mounted on the end of a drill string. To drill within the wellbore to a predetermined depth, the drill string is often rotated by a top drive or rotary table on a surface platform or rig, or by a downhole motor mounted towards the lower end of the drill string. After drilling to a predetermined depth, the drill string and drill bit are removed and a string of casing is lowered into the wellbore. An annulus is thus formed between the casing string and the formation. The casing string is temporarily hung from the surface of the well. A cementing operation is then conducted in order to fill the annulus with cement. The casing string is cemented into the wellbore by circulating cement into the annulus defined between the outer wall of the casing and the borehole. The combination of cement and casing strengthens the wellbore and facilitates the isolation of certain areas of the formation behind the casing for the production of hydrocarbons. 
         [0005]    A drilling rig is constructed on the earth&#39;s surface or floated on water to facilitate the insertion and removal of tubular strings (e.g., drill pipe, casing, sucker rod, riser, or production tubing) into a wellbore. The drilling rig includes a platform and power tools, such as an elevator and slips, to engage, assemble, and lower the tubulars into the wellbore. The elevator is suspended above the platform by a draw works that can raise or lower the elevator in relation to the floor of the rig. The slips are mounted in the platform floor. The elevator and slips are each capable of engaging and releasing a tubular and are designed to work in tandem. Generally, the slips hold a tubular or tubular string that extends into the wellbore from the platform. The elevator engages a tubular joint and aligns it over the tubular string being held by the slips. One or more power drives, e.g. a power tong and a spinner, are then used to thread the joint and the string together. Once the tubulars are joined, the slips disengage the tubular string and the elevator lowers the tubular string through the slips until the elevator and slips are at a predetermined distance from each other. The slips then reengage the tubular string and the elevator disengages the string and repeats the process. This sequence applies to assembling tubulars for the purpose of drilling, deploying casing, or deploying other components into the wellbore. The sequence is reversed to disassemble the tubular string. 
       SUMMARY OF THE DISCLOSURE 
       [0006]    The present disclosure generally relates to a method for makeup evaluation visualization to automatically detect acceptable or unacceptable connections during tubular makeup. In one embodiment, a method of connecting a first threaded tubular to a second threaded tubular includes: engaging threads of the tubulars; and rotating the first tubular relative to the second tubular, thereby making up the threaded connection. The method further includes, during makeup of the threaded connection: measuring torque applied to the connection; measuring turns of the first tubular; and detecting a shoulder position. The method further includes: displaying the measured torque and turns; overlaying a reference curve onto the display; evaluating the threaded connection by comparing the measured torque and turns to the reference curve; and graphically displaying the evaluation. 
         [0007]    In another embodiment, a tubular makeup system includes: a power drive operable rotate a first threaded tubular relative to a second threaded tubular; a torque cell; a turns counter; and a programmable logic controller (PLC) operably connected to the power drive and in communication with the torque cell and turns counter. The PLC is configured to control an operation including: engaging threads of the tubulars; and rotating the first tubular relative to the second tubular, thereby making up the threaded connection. The operation further includes, during makeup of the threaded connection: measuring torque applied to the connection; measuring turns of the first tubular; and detecting a shoulder position. The operation further includes: displaying the measured torque and turns; overlaying a reference curve onto the display; evaluating the threaded connection by comparing the measured torque and turns to the reference curve; and graphically displaying the evaluation. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments. 
           [0009]      FIG. 1A  is a partial cross section view of a connection between threaded premium grade tubulars.  FIG. 1B  is a partial cross section view of a connection between threaded premium grade tubulars in a seal position formed by engagement between sealing surfaces.  FIG. 1C  is a partial cross section view of a connection between threaded premium grade tubulars in a shoulder position formed by engagement between shoulder surfaces. 
           [0010]      FIG. 2A  illustrates an ideal torque-turns curve for the premium connection.  FIG. 2B  illustrates an ideal torque gradient-turns curve for the premium connection. 
           [0011]      FIG. 3A  is a perspective view of a tong assembly in an upper position.  FIG. 3B  is a block diagram illustrating a tubular makeup system, according to one embodiment of the present disclosure. 
           [0012]      FIGS. 4A and 4B  illustrate operation of a graphical evaluator of the tubular makeup system for an acceptable connection. 
           [0013]      FIGS. 5A and 5B  illustrate operation of the graphical evaluator for an unacceptable connection due to violation of a final torque criterion. 
           [0014]      FIGS. 6A and 6B  illustrate operation of the graphical evaluator for an unacceptable connection due to violation of a delta turn criterion. 
           [0015]      FIGS. 7A and 7B  illustrate operation of the graphical evaluator for an unacceptable connection due to violation of a reference curve criterion. 
           [0016]      FIGS. 8A and 8B  illustrate operation of the graphical evaluator for an unacceptable connection due to violation of a delta gradient criterion. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]      FIG. 1A  illustrates a connection  1  between premium grade tubulars  2 ,  4 . The tubulars  2 ,  4  may be any oil country tubular good, such as production tubing, casing, liner, or drill pipe. The connection  1  may include a first tubular  2  joined to a second tubular  4  through a tubular coupling  6 . Each of the tubulars  2 ,  4  and the coupling  6  may be made from a metal or alloy, such as plain carbon steel, low alloy steel, high strength low alloy steel, stainless steel, or a nickel based alloy. The end of each tubular  2 ,  4  may have a tapered externally-threaded surface  8  (aka a pin) which co-operates with a correspondingly tapered internally-threaded surface (aka box)  10  on the coupling  6 . Each tubular  2 ,  4  may be provided with a torque shoulder  12  which co-operates with a corresponding torque shoulder  14  on the coupling  6 . At a terminal end of each tubular  2 ,  4 , there may be defined an annular sealing area  16  which is engageable with a co-operating annular sealing area  18  defined between the tapered portions  10 ,  14  of the coupling  6 . Alternatively, the sealing areas  16 , 18  may be located at other positions in the connection  1  than adjacent the shoulders  12 , 14 . 
         [0018]    During makeup, the box  10  is engaged with the pin  8  and then screwed onto the pin by relative rotation therewith. During continued rotation, the annular sealing areas  16 ,  18  contact one another, as shown in  FIG. 1B . This initial contact is referred to as the “seal position”. As the coupling  6  is further rotated, the co-operating tapered torque shoulders  12 ,  14  contact and bear against one another at a machine detectable stage referred to as a “shoulder position”, as shown in  FIG. 1C . The increasing pressure interface between the tapered torque shoulders  12 ,  14  cause the seals  16 ,  18  to be forced into a tighter metal-to-metal sealing engagement with each other causing deformation of the seals  16  and eventually forming a fluid-tight seal. 
         [0019]      FIG. 2A  illustrates an ideal torque-turns curve  50  for the premium connection.  FIG. 2B  illustrates an ideal torque gradient-turns curve  50   a  for the premium connection. During makeup of the tubulars  2 ,  4 , torque and turns measurements may be recorded and the curves  50 ,  50   a  displayed for evaluation by a technician. Shortly after the coupling  6  engages the tubular  4  and torque is applied, the measured torque increases linearly as illustrated by curve portion  52 . As a result, corresponding curve portion  52   a  of the differential curve  50   a  is flat at some positive value. 
         [0020]    During continued rotation, the annular sealing areas  16 ,  18  contact one another causing a slight change (specifically, an increase) in the torque rate, as illustrated by point  54 . Thus, point  54  corresponds to the seal position shown in  FIG. 1B  and is plotted as the first step  54   a  of the differential curve  50   a.  The torque rate then again stabilizes resulting in the linear curve portion  56  and the plateau  56   a.  In practice, the seal condition (point  54 ) may be too slight to be detectable. However, in a properly behaved makeup, a discernable/detectable change in the torque rate occurs when the shoulder position is achieved (corresponding to  FIG. 1C ), as represented by point  58  and step  58   a.  The torque rate then again increases linearly as illustrated by curve portion  60  and the plateau  60   a  until makeup of the connection is terminated at final torque  62 . 
         [0021]      FIG. 3A  is a perspective view of a power drive, such as tong assembly  100 , in an upper position. A group  140   g  of clamps has been removed for illustrative purposes. The tong assembly  100  may include a power tong  102  and a back-up tong  104  located on a drilling rig  106  coaxially with a drilling center  108  of the drilling rig  106 . The assembly  100  may be coupled in a vertically displaceable manner to one or more guide columns  110  (two shown) arranged diametrically opposite each other relative to the drilling centre  108 . The guide columns  110  may be connected to a chassis  112  which by wheels  114  and hydraulic motors (not shown) may be displaced horizontally on rails  116  connected to the drilling rig  106 . In the operative position, the assembly  100  may be located immediately above the slips  118  of the drilling rig  106 . 
         [0022]    The power tong  102  may include a power tong housing provided with a through aperture that corresponds to the guide columns  110 , and an undivided drive ring connected via a bearing ring (not shown). The bearing ring may have a toothed ring (not shown) in mesh with cogwheels (not shown) on one or more hydraulic motors (not shown), such as two. One of the motors may be a spinner motor (high speed, low torque) and the other motor may be one or more torque motors (high torque, low speed). The toothed ring may be coupled to the drive ring by screw-bolt-joints (not shown). The hydraulic motors may be arranged to rotate the drive ring about the drilling centre  108 . The two hydraulic motors may be disposed on diametrically opposite sides of the drive ring. A cover may be provided to cover the power tong housing. 
         [0023]    In the drive ring and co-rotating with this may be two crescent-shaped groups  140   g  (only one shown) of clamps. Each group  140   g  of clamps may be provided with one or more, such as three, clamps distributed around the drilling center  108 . Each clamp may include a cylinder block provided with one or more, such as three, cylinder bores arranged in a vertical row. In each cylinder bore may be a corresponding longitudinally displaceable piston that seals against the cylinder bore by a piston gasket. A rear gasket may prevent pressurized fluid from flowing out between the piston and the cylinder bore at the rear end of the piston. 
         [0024]    The pistons may be fastened to the housing of the group  140   g  of clamps by respective screw-bolt-joints. On the part of the cylinder block facing the drilling center  108  there may be provided a gripper. The gripper may be connected to the cylinder block by fastening, such as with dovetail grooves or screw-bolt-joints (not shown). Surrounding the drive ring there may be provided a swivel ring that seals by swivel gaskets, the swivel ring may be stationary relative to the power tong housing. The swivel ring may have a first passage that communicates with the plus side of the pistons via a first fluid connection, a second passage that communicates with the minus side of the pistons via a second fluid connection, and a further passage. The cylinder and the piston may thereby be double acting. The swivel ring, swivel gaskets and drive ring may together form a swivel coupling. 
         [0025]    The backup tong  104  may also include the clamp groups. The back-up tong  104  may further include a back-up tong housing with guides  176  that correspond with the guide columns  110 , and a retainer ring for two groups of clamps. At the guides  176  there may be cogwheels that mesh with respective pitch racks of the guide columns  110 . Separate hydraulic motors may drive the cogwheels via gears. A pair of hydraulic cylinders may be arranged to adjust the vertical distance between the power tong  102  and the back-up tong  104 . 
         [0026]    In operation, when the tubular joint  2  is to be added to tubular string  20  (already including tubular joint  4 ), the assembly  100  may be displaced vertically along the guide columns  110  by the hydraulic motors, the gears, the cogwheels and the pitch racks until the back-up tong  104  corresponds with the pin  8  of the tubular string  20 . The box  10  of the coupling  6  may have been made up to the pin  8  of the joint  2  offsite (aka bucking operation) before the tubulars  2 ,  4  are transported to the rig. Alternatively the coupling  6  may be bucked on the joint  4  instead of the joint  2 . Alternatively, the coupling  6  may be welded to one of the tubulars  2 ,  4  instead of being bucked on. 
         [0027]    The vertical distance between the back-up tong  104  and the power tong  102  may be adjusted so as to make the grippers correspond with the coupling  6 . The clamps may be moved up to the coupling  6  by pressurized fluid flowing to the first passage in the swivel ring and on through the first fluid connection to the plus side of the pistons. The excess fluid on the minus side of the pistons may flow via the second fluid connection and the second passage back to a hydraulic power unit (not shown). 
         [0028]    The grippers may then grip their respective pin or box while the hydraulic motors rotate the drive ring and the groups  140   g  of clamps about the drilling center  108 , while at the same time constant pressure may be applied through the swivel ring to the plus side of the pistons. The power tong  102  may be displaced down towards the back-up tong  104  while the screwing takes place. After the desired torque has been achieved, the rotation of the drive ring may be stopped. The clamps may be retracted from the tubular string  20  by pressurized fluid being delivered to the minus side of the pistons via the swivel ring. The assembly  100  may be released from the tubular string  20  and moved to its lower position. 
         [0029]    When a joint  2  is to be removed from the tubular string  20 , the operation is performed in a similar manner to that described above. When tools or other objects of a larger outer diameter than the tubular string  20  are to be displaced through the assembly  100 , the grippers may easily be removed from their respective clamps, or alternatively the groups  140   g  of clamps can be lifted out of the drive ring. 
         [0030]    Alternatively, other types of tong assemblies may be used instead of the tong assembly  100 . 
         [0031]      FIG. 3B  is a block diagram illustrating a tubular makeup system  200 , according to one embodiment of the present disclosure. The tubular makeup system  200  may include the tong assembly  100 , a tong remote unit (TRU)  204 , a turns counter  208 , a torque cell  212 , and the control system  206 . The control system  206  may communicate with the TRU  204  via an interface. Depending on sophistication of the TRU  204 , the interface may be analog or digital. Alternatively, the control system  206  may also serve as the TRU. 
         [0032]    A programmable logic controller (PLC)  216  of the control system  206  may monitor the turns count signals  210  and torque signals  214  from the respective sensors  208 ,  212  and compare the measured values of these signals with predetermined values  223 - 230 . The predetermined values  223 - 230  may be input by an technician for a particular connection. The predetermined values  223 - 230  may be input to the PLC  216  via an input device  218 , such as a keypad. 
         [0033]    Illustrative predetermined values  223 - 230  which may be input, by an technician or otherwise, include minimum and maximum delta gradient values  223 , a shoulder threshold gradient  224 , a dump torque value  226 , minimum and maximum delta turns values  228 , minimum and maximum torque values  230 , and reference curve data  231 . The minimum and maximum torque values  230  may include a set for the shoulder position and a set for the final position. The torque values  230  may be derived theoretically, such as by finite element analysis, or empirically, such as by laboratory testing and/or analysis of historical data for a particular connection. The dump torque value  226  may simply be an average of the final minimum and maximum torque values  230 . During makeup of the connection  1 , various output may be observed by an technician on output device, such as a video monitor, which may be one of a plurality of output devices  220 . A technician may observe the various predefined values which have been input for a particular connection. Further, the technician may observe graphical information such as the torque rate curve  50  and the torque rate differential curve  50   a.  The plurality of output devices  220  may also include a printer such as a strip chart recorder or a digital printer, or a plotter, such as an x-y plotter, to provide a hard copy output. The plurality of output devices  220  may further include an alarm, such as a horn or other audio equipment, to alert the technician of significant events occurring during makeup, such as the shoulder position, termination, and/or a violation of a criterion. 
         [0034]    Upon the occurrence of a predefined event(s), the PLC  216  may output a dump signal  222  to the TRU  204  to automatically shut down or reduce the torque exerted by the tong assembly  100 . For example, dump signal  222  may be issued in response to the measured torque value reaching the dump torque  226  and/or a bad connection. 
         [0035]    The comparison of measured turn count values and torque values with respect to predetermined values is performed by one or more functional units of the PLC  216 . The functional units may generally be implemented as hardware, software or a combination thereof. The functional units may include one or more of a torque-turns plotter algorithm  232 , a process monitor  234 , a torque gradient calculator  236 , a smoothing algorithm  238 , a sampler  240 , a database  242  of reference curves, a connection evaluator  252 , and a target detector  254 . The process monitor  234  may include one or more of a thread engagement detection algorithm  244 , a seal detection algorithm  246 , a shoulder detection algorithm  248 , and a graphical evaluator algorithm  250 . Alternatively, the functional units may be performed by a single unit. As such, the functional units may be considered logical representations, rather than well-defined and individually distinguishable components of software or hardware. 
         [0036]    In operation, one of the threaded members (e.g., tubular  2  and coupling  6 ) is rotated by the power tong  102  while the other tubular  4  is held by the backup tong  104 . The applied torque and rotation are measured at regular intervals throughout the makeup. The frequency with which torque and rotation are measured may be specified by the sampler  240 . The sampler  240  may be configurable, so that an technician may input a desired sampling frequency. The torque and rotation values may be stored as a paired set in a buffer area of memory. Further, the rate of change of torque with respect to rotation (hereinafter “torque gradient”) may be calculated for each paired set of measurements by the torque gradient calculator  236 . The smoothing algorithm  238  may operate to smooth the torque-turns curve  50  and/or torque gradient curve  50   a  (e.g., by way of a running average). These values (torque, rotation, and torque gradient) may then be plotted by the plotter  232  for display on the output device  220 . 
         [0037]    The values (torque, rotation, and torque gradient) may then be compared by the connection evaluator  252 , either continuously or at selected events, with predetermined values, such as the values  223 - 230 . Based on the comparison of the measured and/or calculated values with the predefined values  223 - 230 , the process monitor  234  may determine the occurrence of various events and the connection evaluator  252  may determine whether to continue rotation or abort the makeup. The thread engagement detection algorithm  244  may monitor for thread engagement of the pin  8  and box  10 . Upon detection of thread engagement a first marker is stored. The marker may be quantified, for example, by time, rotation, torque, the torque gradient, or a combination of any such quantifications. During continued rotation, the seal detection algorithm  246  monitors for the seal condition. This may be accomplished by comparing the calculated torque gradient with a predetermined threshold seal condition value. A second marker indicating the seal condition may be stored if/when the seal condition is detected. At this point, the torque value at the seal condition may be evaluated by the connection evaluator  252 . 
         [0038]    For example, a determination may be made as to whether the turns value and/or torque value are within specified limits. The specified limits may be predetermined, or based off of a value measured during makeup. If the connection evaluator  252  determines a bad connection, rotation may be terminated. Otherwise, rotation continues and the shoulder detection algorithm  248  monitors for the shoulder position. This may be accomplished by comparing the calculated torque gradient with the shoulder threshold gradient  224 . When the shoulder position is detected, a third marker indicating the shoulder position is stored. The connection evaluator  252  may then determine whether the torque value at the shoulder position is acceptable by comparing to the respective input torque values  230 . 
         [0039]    Upon continuing rotation, the target detector  254  compares the measured torque to the dump torque value  226 . Once the dump torque value  226  is reached, rotation may be terminated by sending the dump signal  222 . Alternatively, the dump signal  222  may be issued slightly before the dump torque  226  is reached to account for system inertia. Once the connection is complete, the connection evaluator  252  may calculate a delta turns value based on the difference between the final turns value and the turns value at the shoulder condition. The connection evaluator  252  may compare the delta turns value with the input delta turns values  228 . Similarly, the connection evaluator may compare the final torque value to the respective input torque values  230 . The connection evaluator  252  may calculate a delta torque value based on the difference between the final torque value and the torque value at the shoulder condition. The connection evaluator  252  may calculate a delta gradient value using delta torque and delta turns values and compare it with the respective input values  223 . If either criteria is not met, then the connection evaluator  252  may indicate a bad connection. 
         [0040]    Alternatively, a delta turns value may be entered instead of the dump torque  226 . The target detector  254  may then calculate a target turns value using the shoulder turns and the delta turns value (target turns equals shoulder turns plus delta turns). 
         [0041]      FIGS. 4A and 4B  illustrate operation of the graphical evaluator  250  of the tubular makeup system  200  for an acceptable connection  1 . For the sake of clarity, the curves have been simplified relative to actual field data. The graphical evaluator  250  may be operable to overlay one or more (two shown) reference curves onto the torque-turns curve during makeup of the threaded connection. The graphical evaluator may retrieve the reference curves from the database  242 . The database  242  may include torque-turns curves of previously assembled good connections and the reference curves may be the maximum (reference curve  1 ) and minimum (reference curve  2 ) curves of the previously assembled good connections. The database may include curves from laboratory assembled connections and/or field assembled connections. 
         [0042]    Alternatively, the reference curves may be constructed by averaging data of the previously assembled good connections to create an average reference curve (not shown). The average reference curve may then be overlayed onto the torque-turns plot or the first and second reference curves may be constructed using a standard deviation of the average curve. Alternatively, the reference curves may be theoretically constructed and may or may not be empirically calibrated. 
         [0043]    The graphical evaluator  250  may also partition the torque-turns plot into one or more regions using the database  242  and respective input values  228 ,  230 , such as a reference region, delta turns region, shoulder torque region, and a final torque region. During makeup and/or after termination of the connection, the graphical evaluator  250  may compare the torque-turns curve and determine if the curve is within the reference region. If the torque-turns curve is within the reference region, the graphical evaluator  250  may fill the region with a favorable color, such as green (depicted with cross hatching). If the torque-turns curve exits the reference region, the graphical evaluator may fill the reference region with an unfavorable color, such as red ( FIG. 7A , depicted with cross hatching). The graphical evaluator  250  may also receive comparisons for the other regions from the connection evaluator  252  and may fill the respective regions red or green based on the comparisons. The graphical evaluator  250  may then make a recommendation to the technician either accepting or rejecting the connection. The graphical evaluator  250  may display the recommendation as well as the reason(s) for rejection, if applicable. The technician may also easily comprehend the reason(s) for rejection based on the color fills of the respective regions. 
         [0044]    The graphical evaluator  250  may also be operable to overlay the shoulder threshold  224  onto the torque gradient curve ( FIG. 4B ) and to display a delta gradient region using the input values  223 . The graphical evaluator  250  may receive a comparison for the delta gradient region from the connection evaluator  252  and may fill the delta gradient red or green based on the comparison. The torque gradient curve may be displayed in alignment (based on turns) with the torque-turns curve. Alternatively, the torque gradient curve may be inverted and share the turns axis with the torque-turns curve. 
         [0045]    Once the connection  1  has been accepted, the torque-turns curve may or may not be added to the database  242 . 
         [0046]      FIGS. 5A and 5B  illustrate operation of the graphical evaluator  250  for an unacceptable connection  1  due to violation of a final torque criterion. The graphical evaluator  250  may receive an alert from the connection evaluator  252  that the maximum final torque has been exceeded, fill the final torque region red, and reject the connection  1  with explanation. The graphical evaluator  250  may fill the reference region, the shoulder torque region, the delta turn region, and the delta gradient region green based on its own comparisons and those from the connection evaluator  252 . 
         [0047]      FIGS. 6A and 6B  illustrate operation of the graphical evaluator  250  for an unacceptable connection  1  due to violation of a delta turn criterion. The graphical evaluator  250  may receive an alert from the connection evaluator  252  that the maximum delta turns value has been exceeded, fill the delta turn region red, and reject the connection  1  with explanation. The graphical evaluator  250  may fill the reference region, the shoulder torque region, the final torque region, and delta gradient region green based on its own comparisons and those from the connection evaluator  252 . 
         [0048]      FIGS. 7A and 7B  illustrate operation of the graphical evaluator  250  for an unacceptable connection  1  due to violation of a reference curve criterion. The graphical evaluator  250  may determine that the torque-turns curve has exited (two places) the reference region, fill the reference region red, and reject the connection  1  with explanation. The graphical evaluator  250  may fill the delta turn region, the shoulder torque region, the final torque region, and the delta gradient region green based on its own comparisons and those from the connection evaluator  252 . 
         [0049]      FIGS. 8A and 8B  illustrate operation of the graphical evaluator  250  for an unacceptable connection  1  due to violation of a delta gradient criterion. The graphical evaluator  250  may receive an alert from the connection evaluator  252  that the minimum delta gradient was not reached, fill the delta gradient region red, and reject the connection  1  with explanation. The graphical evaluator  250  may fill the reference region, the shoulder torque region, the final torque region, and delta turn region green based on its own comparisons and those from the connection evaluator  252 . 
         [0050]    As discussed above, the delta gradients  223  may be input separately from the reference curve database  242 , thereby providing independent criteria for evaluating the connection. Alternatively, the delta gradients may be derived from the reference curve database  242  which may result in the criteria being dependent or independent depending on how the delta gradients are derived from the database. 
         [0051]    Additionally, the graphical evaluator  250  may include a menu of options for the technician to configure the reference curves. 
         [0052]    Additionally, the control system  206  may include a storage device  221 , such as a hard drive or solid state drive, for recording the makeup data. The stored data may then be used to generate a post makeup report. Additionally, the graphical evaluator  250  may include a comments field for allowing the technician to enter notes for each individual connection and the notes may be recorded on the storage device  221  for inclusion in the report. Additionally, the technician may accept or reject the connection according to or in spite of the graphical evaluator&#39;s recommendation and the technician may enter an explanation for the acceptance or rejection in the comments field. Additionally, the graphical evaluator  250  may alert the technician of any detected anomalies in real time during the makeup using the alarm, such as by an audio alert and/or graphical alert. 
         [0053]    Additionally, the graphical evaluator  250  may have the capability to plot selected connection graphs simultaneously—for example to spot trends in make-up performance which might be attributable to changes occurring in the machinery of the tongs (component wear, slow hydraulic leak, changes in temperature affecting hydraulics, etc.) or drift of the performance of the various sensors. 
         [0054]    Alternatively, the tubular makeup system power drive may be a top drive instead of the tong assembly. 
         [0055]    While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope of the invention is determined by the claims that follow.

Summary:
A method of connecting a first threaded tubular to a second threaded tubular includes: engaging threads of the tubulars; and rotating the first tubular relative to the second tubular, thereby making up the threaded connection. The method further includes, during makeup of the threaded connection: measuring torque applied to the connection; measuring turns of the first tubular; and detecting a shoulder position. The method further includes: displaying the measured torque and turns; overlaying a reference curve onto the display; evaluating the threaded connection by comparing the measured torque and turns to the reference curve; and graphically displaying the evaluation.