MEl HOI) AND SYS TEM FOR CALIBRATING A TUBE SCAJNNKR

This claims benefit of U.S. Provisional Application Set . No. f>0/786,6<> I . tiled on March 28. 20(K.

FIELO OF THE INVENTION

The present invention relates generally to a scanner instrument for collecting and analyzing data describing a tube associated with an oil well and relates more -5PtICItJCaIIy to calibration of the scanner instrument.

BACKGROUND

During the drilling, completion and maintenance of an oil we!!, personnel routinely insert and/υr extract devices such as tubing, tubes, ptpcs, πxis, hollow cylinders, casing, conduit, collars, and duct into the well. For example, a service etew may use a workovet rig or service rig to extrad a siring of tubing and sucker rods from a well that has been producing petroleum. The crew m«y inspect the extracted tubing and evaluate whether one or more sections of thai tuhing should be replaced due to physical wear, thinning of the utbing wall, chemical attack, PJtEUIg- or othei defect The crew typically ieplaces sections that exhibit an unacceptable level of wear and makes note of other sections that are beginning to show wear and may need replacement at a subsequent service call.

As an alternative to manually inspecting tubing, ihe service crew may deploy an instrument to evaluate the tubing as the tubing is extracted from the well and/or ^" insetted into the w ell. The scanning instrument typically remains stationary at the wellhead, and the wotkover rig moves, the tubing through the instrument ^' s raeasutetiient zone. This instrument irta> he called a "tube scanner ^" .

The tube scanner typically measures pitting and wall thickness and can identity cracks in the tuhing wall. Radiation, field strength (electrical electromagnetic, or magnetic), and/or fluid pressure diiϊerential may interrogate the tubing to evaluate these wear parameters. The tube scunner typically produces a raw analog signal and outputs a sampled or digital version of that analog signal.

In other words, Jhe tube scanner typically -stimulates a section of the tubmg using a field, radiation, or pressure and detects ihε tubing ^' s unci action with rac iespon^e to the stimulus. Ati cieraent, such as a transducer _^ cotiverts tϊie .response into an analog eleetricaJ signal. F- or example, the tube scanner may create a magnetic field into which the tubing is disposed, and the transducer may detect changes or permtbaiions HI the field resulting ffoin the presence of ihe tubing and any anomalies of 5ha? tubing.

The analog electrical signal output by the transxiueej am have an arbitrary OJ essentially unlimited number of states or measurement possibilities. That is, rather than having two discrete or binary levels, typical transducers produce signals that can assume any of numerous levels *>i values. As the tubing passes through the mcastireinent field of the instrument, the analog transducer signal vanes in response to variations and anomalies in the wall oϊ the moving tubing.

The tube scannα also typically includes, a system, such as an analog- to-tUgstal converter ("ADCVl ₁ that cotiverts the analog transducer signal into one ot more digital signals suited for reception and. display by a computer. These digital signals typically provide a "snapshot" of the transducer signal Thus, ihe ADC typically output* a numbet, or set of a numbers, thtit represents of describes the attnlog tran&dueet signal at a certain instant in time. Because the analog transducer signal describes ihe sectioo of tubing that is in the tube scaπoer's

measurement zone, the digital signal is effectively a sample ot a snapshot of a parameier-of-ittletest of that tubing section.

The signals generated by the tube scanner may fluctuate or drift over time. Vibrations or mechanical uhoeks that occur, dining, transportation of the instrument may slightly alter the performance of the- tube- scanner. Thermal variance, power fluctuations, or vibrations during the operation of die tube scanner may cause drift or noise in the readings output by the tube scanner These fluctuation, drift, and noise components, of the signals OUt])U! from the tube scanner may lead to inconsistencies of the type that would result m two ililTerent tube scanner outputs from scanning the same pipe at two different times Such inconsistencies arc undesirable when the tube scantier outputs are used for evaluating the we-ar and wear patterns of the tubing and detetnirmrig if pattiouiar sections of tubing should be retained for reuse or otherwise discarded.

To addtess these represents tive deficiencies it) the art, an improved capability for calibrating the lube scunner is needed. A need also exists foi a capability of an oilfield service crew to calibrate the tube scanner in the field. A Airlhei need exists for n capability 1o use one or rαore post-operational calibrations to correct. validate, or flag the UaUi scanned during the operation of the tube scanner.

SUMMARY OF THE INVENTION ^"

The present invention relates to a method tor calibrating a scanner instrument used for scanning tuNrtg that is being placed into att oil veil or being tenioved from the well This scanning πistrnπient tnay be allied a "tube scanner ^'"1 in one aspect of the present invention, a method for calibration of the tube scanner may involve ^canning a lubing standard with known characteristics nnά then computing the relationship between ihe dala from the scat) and the known characteristics of the tubuig standard. This reiattonship beHveeit the expected and actual data may then be used as the calibration function of the tube scanner,

In another aspect of the present invention, a method for calibration of the tube scanner may include adjusting Hie AiUi collected while scanning a string of tube segments based on equalizing the <3«la peaks thai occur in the scan data at the coupling jomts between tube segments. in yet another aspect of the present invention, the dependence of the results of a tube scan upon the speed at which ihe tube moves through ihe scanner is dciermmccl The inventive iuhe scanner calibration may establish typical fast britiL and. slow liin.it metrics for the speed »t "which a tube should be moved through a tube scanner, I he typical speed λould be ihe one where the calibrated scanner repiodυces expected scan values. 3ttost closely and the fas.} limit and slow limit would be the scan speeds where the tube scanner still operates within tolerances., hut rwiveirtent of tubing through the tube scanner that is faster that 1he fast tirait or slower than the slow limit may introduce excessive error into the scan. These limit values cat) be used by the crew to guide their operation of the rig while extracting or inserting lubing through the tube scanner.

The discussion of tube scanner calibration presented in this summary is for illustrative purposes only. Various aspects of the present invention in ay be more clearly understood and appreciated froni a review of the following detailed descoplion of the disclosed embodiments aad by sefcrmce to the drawings, and any cleitns. (hat may follow. Moreover, other sspecls systems methods featutes advantages, and objects of the present invention W)I! become apparent io one with skill in the. art trpon examination of the following dtavvirigs and detailed des.crijλt<>n. H is intended that all such asjKcts. systems, πiethods, tenUa-es. advaiilug.es, and objects are to be

included \v ilhin this άn.fci iption aie Io IK V\ tthm the .jcopc ol lhe pceseul un anion and aie Io Ix* protected tn am aetompans mg claims

BRI E F DESC 85FI IOIN OF THE DRAWINGS 1 iguj c 1 is an ilhiϊluihon of an exemplar λ stem foi >eπ icing an ml well wheic the *% stem sa<ms tubing as She titbmg is extracted liom or inserted into ihe well tn aeeouiαnee w iih an ovemplan embodiment of the ptesient tm entiun figure 2 w a Junctional block diagtatn ot .tn c xemplan swem tor c anning tubing that is being maci tcd tnto ot e\tiJn ted iTottt an ι>il 'twil tn accordunce αitli an t'\eκtpian utnbtxlmtcnt ol the ρjc-.ent uiv eituon S tautc ^■ ϊλ tllu-^Uttlcϊ, a v ecltca) cni^s-st-viion ol an e\ctnρ)αn tube sUtodau! tot u-v in otibt.rting a tube ϊcanπci in aceouitmce \s tiit an cwmi'lsn cmhtxlunoii of ih.u pi c^cni im (,'trit(>)t

I ttiittc >H illivslfstc _* <t hoEiλinUtl cross- vectfoit <>i ϊhn rotait(>it<tlK uuiαttt icjjμiit oϊ αti c\ι;(iiplar\ tube støndaid d3s>μ(> ^ι vJ dltin α eijuilai M Iλ\ υf 1ian*<!iioα elαπeitts yj acewdaiiei; ^^ sill an e\oitpLt!λ eπib(>d(mcnt of the picstfnt im entmn Figtire 4 j;, a fkn\ehan uf an exomplan proees>s> lot scanning tubniy that is being inserted tnto m t-\!xtiete4 ti om dii oil well and l or calibrating fhe lube ^ annei nsmg a fubt- standard m ai cordance with tin exenipl.in einbcdimern of the present tm etition

) tjisuc 5 is a ilouchart ot att e\enipictn p)oet;s.s Jut ea!tbt.3ttng a Uibt; scaimet u->mg J tuK; siatidatd .and .jioied ιtt!oπt)αtκ ^ι n <tlκiul the stancLnd in yccoidance \\tl)t an t:\eπtp!;j) \ embodiuiott ol the pjc-vnt ifi\ ettito)t I iμiuc (> is a flowchart uf an y\enφ!<m pnve^s fot scanning tubtnμ llωt is bcmg inserted tntu ut extiatied from an oil v.eU viEiii l(>i (.ahhiaUtija the tube senitfier bnsetϊ on the ^canned inttiimaUon. in aecoiUain.e VMth Mi cxenipiatλ eiπbiidtinent nt the piesent nf. eiti)un

MOJU a^peeis ol the present tm ention can be boiiet imdersiooj w ith tcference io the abm e drd^tng-v

The components in the >iraw ing< are nut tveess&πh Iu scale emphasis tn^tead being placed upon ele-ai h ilUiiti tihng fhe pπncipkN o! e\«nplan einbixhnieriH oJ Jhc ptcsenf inv eniion Moi ein ei , m the draw ings tetcreiu-e muiicrals designaie like oi eori e--ρonding, but not neιevκiith identical, demenls thuHighout the stneral

DETAILED DϊλγRIPTION OF EXEMPLARY E M BO IH Vl E (N TS t he pieseni U3\ enttoit suppiiii^ vi 3\ιcιlκ>d i<n cthbuaat" a lobe scαtmet used to *e<ti3 Uibma hewψ placed into Oi being ivnuned Uom α well An exemplar method aid s\ >tcm foi calibrating the tube scanner will iw lie de^cπbed more fulls hcretnaficr vuth reterence Iu Vigwe-v l~^ 1 luse iigmcs <ho\% repres^nUtis e embodiments ot the present im enUoii 1 tgυre S depict < a \\orko\ ei nμ mov ing uthirtg λatugh a tube ^ctraner m a iepre^enUUne oper ting cn\ Honment tor one embodiment of fhe ptesent inv ention Fignre 2 pto\ κies a block diagiant ol a lube -icannei Jha) momtoi i, senses, or ehataueπ/es lubing .ind tlut \ .t!κlates >ind intetpieH fubmg data Figw e ^" i depKls. tin exemplar tubing standtBd ioi e.itibt.rting the lube ^c.sitnec ilUnHated m Vigtst: 2 Pigates -1 5 and u pto\ idt; tlo« dwyrαtns of nxeilwds Jot etdtbiynttt ¹ a tube suinttuig tnsttutnettl

The tin cntiott can be embodied in mans dtl teient fotni-> and should not be constt ued as htnitcd h> the embodiment* »et forth li«em mthcj thase cmKidMHeiris JSC pm\ided so thnt ilus dise.U>s«re vvill be thoiouyh and uwplele. and w ill iulh convex the scope ot the tn\entκ>t) to one ha\ ing oiduiai s skill m the art Purtheitnoic all

"CXaDIj)IfS" or "exemplary embodiments' ^* given herein are intended to i>e non-limiting and among others ^upporied by representations of the present invention.

Moreover, although art exemplary embodiment of the invention is described with respect to ealibraiirig a tube seatmei m a measurement zone adjacent to a wellhead, one skilled in the art will recognize that the invention ma\ be employed or utilized in connection with a vaήeh of applications in the oilfield or anofhet operating environment.

Figure i illustrates a system MO for servicing an oil well 175 The svstem 100 scans the tubing 125 US the tubmg 125 is extracted froin or inserted into the well 175 according to an exemplary embodiment of the present invention The oil "well 175 includes a hole bored or drilled into the ground to teach an oii-bearing formation. The borehole of the well 175 i* encased bv a tube or pipe (not explicitly shown in Figure 1 V known as a "easing/ ^" thai is cemented to down-hole fotnintions and thnt protects the well trora unwanted fluids and debris within the formation.

Within the casing is a tube ( 25 that carries oil, gas, hydrocarbons, petroleum products, and/or other formation fluids, such as water, to the surface, In operation, a sucker rod string tnot explicitly shown in Figure 1 1 disposed within the tube 125. forces the oil uphole. Driven by strokes from ail uptiole machine, such as a ^■ Tucking'" pump jack. Jhe -sucker rod moves up and down to communicate reciprocal inoJion to a dowrthole pump i not explicitly shown πi Pigiire ) ). Wuh each stroke, the downhole puπrp moves oil up the tube 1.25 towards the wellhead. As shown in Figure 1 , a service crew u>es> a work over or service rig J 40 to service the well 175. During the illustrated ptoetxϊure. the etew pulls the tubing 125 front the vvell. for exsxnpk to repair OF replace the downhole purap ^' lhe tubing I 25 includes a sttitig of sections, each of which may be referred to as a ' ^' JoJnI, ^" 1ha1 typically range in length from 29 to 34 feet (about 8,8 to i <\3 meters). The joints screw together viu collars, unions, tubing joints, or threaded conneciiotis. The crew uses the workovcr rig 140 to extract tlie tubing 125 in increments or steps, typically two joints per increment The rig 140 includes a derrick or boom 145 and a cable 105 thai the crew temporarily fastens to the tubing siring 125. A motor-driven red 110. drum, wtnch, oi block and tackle pulls the cable H)S theieby hoisting or lifting the tubing string 125 attached (hereto. The crew lifts the tυbitig siring 125 a vertical distance that appropriately equals the height of the derrick 145. typically about sixty feet ot two joints. Moτe specifically, the crew atuiches the table M)5 to Jhe Hibwg string 125. which is vertically stationary during the- attachtneut procedure The αvw then life the tubing 125, generally in a continuous motion, so that two joints are extracted from the well 175 while the portion of the tubing string 125 below those two joints remains in the well 175. When those two joints are out oi ^' the well 575, the operator of the reel ! 10 stops the cable l§>. thereby halting upward motion ot ^' the tubing 125 The crew then separates or unscrews the two exposed joints from the remainder ot ^" the tubing string 125 that extends into the well 175. A clamping apparatus grasps the tubing string 125 while ihe crew unscrews the two exposed JOHIIS, thereby preventing the string 125 from dropping into the we!) 175 when those joints separate horn the main siring 125.

The crew repeats the process of lifting and separating two-joint sections of tubing from the well 1.75 and arranges the extracted sections in a stack of vertically tiispo&ed joints, known as a "stand" of tubing. After extracting the full tubui^ string 125 from the we!) 175 and servicing the purap, the crew reverses the step-wise

tube-extraction piocess to place the tubing string 125 back in the- well 175. In other words, the crew uses the rig l-tθ to reconstitute the tubing siring 125 by threading ot ' ^' making up ^''" each joint and incrementally lowering the tubing siring 125 into the welt 175.

The sv srtem 100 incorporates a tube scanner for monitoring, scanning, assessing, or evaluating the tubing ϊ25 as the tubing 125 moves into or out of die well 175. The tube scanner 150 obtains information or data about the portion of the Uibing 125 that is in the tube scanner's J SO sensing or measurement zone 155. ^' Vis a ditla link 120, an encoder 115 provides the tubing scanner ^" ISO with speed, veiocitv. and/or positional information about the tube 125 For example, the encoder 115 may be mechanically Jinked to the reel i 10 Eo determine motion and/or position of the tubing 125 as the tubing 125 moves through the measurement zone 155. As an alternative io the illustrated encoder 115, some other form of positional or speed sensor cart determine the detrick^ block speed or the tig engine ^' s rotational velocity in. revolutions per minute (" ¹ F(PM" ), fot example.

λnoihef dnta link 135 conneds the tube scanner 150 to a computing device or computer 130, which can be a laptop, a handheld, personal digital assistant fPDλ' ^' j. a e-ellukr system, a portable radio, a personal tnesSuging system, a wireless, appliance, or a stationary personal computer r'PL" ^' \ for example. The computer 130 displays data that the tube scanner 150 has obtained ftoin the tubing 125. The compute! OO can present the tubmg data graphically, for example m a trend format. The service crew monitors or observes the displayed data on the corupuiet iSϋ or other display device to evaluate the condition of the tnbing 1.25. ¹ I he service cre-w can therein' grade the tubing .1.25 according Io its fitness for continued service, for example The communication link 135 cat) include a dirvet link or a portion of a broader communication network that carries information among oihei devices or simitar systems Jo the sy stem 180. Moreover, the communication link OS can include a pnth through the itifeτnet, an iπiranet, a private iietwoik. a telephone network, an interne! protocol (,"JP") network, a packet- switched network, « circuit-switched network, a loeaϊ area network ( ^"'" LAN ^'" ,!, a wide area network (. ^" WAH ^-' ' ). a metropolitan area network the public switched telephone network (" ^" PSITs" ^" ), a wireless network, or a cellular -system, tor example The eotnmunieation hnk ϊ33 can also include a signal paih that is optical fiber oplk, wired, wireless, wire-line, vvaveguided. or satellite-based, to name a tew possibilities. Signals transmitting over the link 135 can carry or convey data or information digitally or via analog transmission. Such signals can include modulated electrical, optical, microwave, radiolϊequeney ultrasonic, or eiectMinagrtciic energy, among other energy forms.. The compute! OW typically includes, haidwvue and softwnre, lhat httrdλvurε πι«y iiieiude various computer components, such as disk storage, disk drives, microphone^;, random access memory t"RAM"\ read only memory (. ^" ROM"), one or more microprocessors, power supplies, a video controlier, a system bus, a display monitor, a communication intwface. and input devices. Further, the computer 130 can include a digital controller. a microprocessor, or some other implementation of digital logic, for example The computer ^' I SO executes -software Jha). may include an operating system and one or more software modules for managing data. The operating system can be the softvvate product that Microsoft Corporation of Redmond, Washington sells under the registered trademark WINDOWS, .tor example. The data management module can store, sort, and organize data and eatt also provide a capability for graphing, plotting, charting, or trending sϊatø. The data management raodule can be or include the softvvme product thttt Microsoft Corporation sells under the registered trademark HXChL, for trample.

in owe exemplify embodiment of the present invention, a rαuiutaskiϋg computer functions, as the computer IMi. Multiple programs can execute in an ovet lapping tirnelrame ot in a manner that appears concurrent or simultaneous to a human observer. Multitasking operation can include time slicing or ώtteshating. Jot example, The data management module can include one ot more computer programs or pieces; of computer executable code. To name a few examples, the data management module can include one or more of a utility, a module or object of code, a software program, an interactive program, a ^" "plug-in, ^1* an "applet. ^" ' a script, ;i "soriptlct," an operating system, a browser, an object handler, a standalone program, a language, a program that is Tiot a standalone program, a program that runs a computer, a program that performs maintenance or general purpose chores., a program that is launched to enable a machine or iruman user to interact with data, a progtarn that creates or is used to create another program, and a program that a»tsis a user in the performance of a task such as database interaction, word processing, accounting, of file management.

Turning now to Mgure 2, this figure illustrates a functional block diagram (it ^* an ifistruπieτitatioti sysieπi 2ftO for scanning tubing ( 25 that is being inserted into or extracted from an oil well 175 according to one exemplary embodiment of the present invention. One skilled in the information-technology, computing, signal processing, sensoi, or electronics arts will lecogiiixe that (lie components and functions that ate illustrated as individual blocks m Figure 2, and ret ^' creneed as such elsewhere herein, are not necessarily strictly separate modules. Furthermore, the contents of each block are not necessarily positioned in one phvsieal location, in one embodiment of the present invention, certain blocks represent virtual modules and the components, data, and functions may be physically dispersed. Moreover, iti some exemplary embodiments, a single physical device may perforin two or more functions thai Figure 2 illustrates in two or more distinct block,'.. For example, the function of the computer 130 eat) be integtated into the tubing scanner 150 1o j)j-(>vide a unitary (>r commonly-housed hardware and sort ware element that acquires and processes data and displays processed data in graphics! form for viewing by an operator, technician, or engineer The tubing scanner 151 ⁾ may include a rod-wear sensor 2tl3 and a pitting sensor 255 for determining parameters relevant to continued use ot ^' the tubing ϊ23 ^" llie rod-wear semor 205 assesses relatively large tubing defects ot features such as wall Ihinraua, Wall thinning tnav he due to physical w eat or abrasion between the tubing ϊ.25 and the sucker .tod that is reciprocates therein for example. Meanwhile, the pitting sensor 255 detects or identifies smaller defect* or features, such as pitting that stems from corrosion or some other form of chemical attack within the well 175. These small flaws may be visible to the naked eye or rtmy have microscopic features, ibi example Pilling can occur on the inside surface of the tubing 125. the so-called "inner diaraetei, ^" or on the outside of the tubing 125

The inclusion of the rod-wear sensor 205 and the pitting sensor 255 in the tubing scanner ! 50 is intended to be illustrative rather than Hunting. The tube scanner 150 can include additional sensors or measuring apparatus thai may be sailed to a particular application. For example, the instrumentation -system 200 can include a collar locator 275, a device that detects tubing cracks or splits, a temperature gauge, a camera, a hydrostatic tester, etc. In (M)C exemplary embodiment of the present invention, the tube scaniiet 150 includes or is coupled to an inventory counter,, sucli as one of the πiveniory counting devices disclosed in U S Patent Application Publication Number 2004/01 %CS?2.

fhe luiw scanner LSW also includes a controller 250 that may process signals, from the rod-wear sensor 205 and the pitting sensor 255. In one exemplary embodiment, the controller 250 processes signals according to a speed measurement .12*) from the eneodet 115. The controller 250 can include a computer, a nitcroptocessor 290, a computing ice, or some other implementation of. pjogrammahle or hardwired digital logic In one exemplary embodiment, the controller 250 includes one oi more application specific uiiegπtled ciieuits; t^ASICS") or digital signal processing (-'DSP") chips. Calibration module 225 may include executable code stored on ROM programmable ROM ("1 ^"5 ROM"). RAM ^' , an optical disk, a hard drive, magnetic niedsa, tape, papei, or -some othet machine readable medium. calibration module 225 maybe implemented in programmable or hardwired electronics, or some combination of hardware and executable software code The speed measutcπtent OO from the encoder 115 may be used m owe aspect of calibrating tube scanner

159 that relates to the dependence of the teuifc of a tube scan upon the speed 120 at which the tube moves through the 1uhe scanner 150. The cnlibrntion module 225 may establish typical, fast limit, and slow liπni πieUies lbi the speed at which a tube 125 should be moved through n 1uhe scanner 150, The lypieal speed would be the one where the calibrated tube scanner 150 reproduces expected scan values most closely and the fast limit and s.lmv limit would be ihe scan speeds where the tube scanner 150 still operates within tolerances, but movement of tubing 125 through the tube seamier 150 that is fastet that the fast limit or slower than the slow limit may introduce excessive error into the scan. ^' These limit values can be used by the crew to guide their operation of the τ»g 140 while extractma or inserting tubing 125 ttøou&h the tube scantier 15ft.

The tod-weat sensoi .205 may include a transducer 210 that outputs an electrical signal containing information about the section of tubing 125 that is m the measurement /one 155. Sensor elec ironies 22« may amplify, condition, and digitize the output lVom transducer 210 nnd then j>rovide controller 25ft whtt samples or snapshots (>f the waif thickness of the portion of the luhiπg J.25 that is situntei in the measurement zone 155.

Similar to the tod-wear sensor 205. the pitting sensor 255 include a. pitting transducer 26ft Sensor electronics 270 may amplify, condition, and digitize the output from transducer 26ft and then provide controller 250 wiili samples or snapshots of the amount and nature of pitting m the walla of She portion of the tubing 125 thai is -situated in the measurement zone 155

The transducers, such as lift and 26tt may respond to stπtnth wuhin the meas.uvem.ent zone iSS such as electromagnetic, mechanical Ouid pressure diffcrcuiial, sonic, ulttasonic. ot optieaiλ'isiiai.

A collar locator 275 includes a collar censor 277 and sensor electronics. 28«. The s.ensoτ 277 may include a tneehnnieaϊ switch, electromagnetic transducer, optknl iteeetor. or other sensor fox tng when H coupling joint collar is within measuteinent zone 155. Sensor electronics 280 may amplify, condition, and digitize the output from sensor 277 and then provide controller 250 with information regarding the presence of a coupling joint collar within the measurement zone 155 of collar locator 275 in tube scanner 150 or even outside of the tube scanner 15« but as part of sen-ice rig system Itø). can provide controller 250 and/or computer 131) with information regarding the location of couplings or collars at the points where tube 125 sections or joints connect to one another within the uihina string .

The calibration module 225 can use signals from sensors, such as 205 and .255, and indications lϊoπt the opetating ctevv as inputs to one or more calibration processes. These calibration processes can deteπtutie corrective calibration functions that rau.)- lyanstomi the signals output by the sensors, such as 205 aad 255, to snore accurately represent signals that are descriptive of the actual tube 125 heui$ scanned These calibration functions

may be tcquircd due to drift, offset, noise, ot other errors or artifacts introduced itno the signals iiont seniors., >uch as 205 and 255. Once these calibration functions are determined, the calibration module 225 of eunttolk-t 250 rπa\ apply the calibration functions to the signals received from sensors, such as 205 and 255, in order to achieve data that is mote jeprvsentϋtive of the actual tube 125 being analyzed One ofordinary skill in the art will appreciate that the calibration functionality, described lor otic exemplary enihodbnenl as a calibration module 225 of controller 2SfK may, without departing from the scope or spirit of the present invention, be located and/or partitioned otherwise, for example as functional] ty of computer 130. controller 25ft, or electronics within sen.sors, such as 205 or 255 An exemplary tubing standard for use in calibration as well as some exemplary calibration process flowcharts are described hereinafter. Figute 3λ illustrate.-; a vertical cross- sect ion of an exemplary tubing standard 3(Hf used to calibrate the tube scantier J.50 of Figures 1 arid 2. Refetring now to Figute* 2 and 3 A, the exemplary standard 300 can he manufadυred with a known se1 of physical eliarncterisiies. The stnndard 3WO rαa\ thus be expected to stimulate sensors 205, 255 inside of tube senrmer 150 to produce known response signals according to the known physical properties of the tuning standard 300. This can be considered ihe "expected scan" of standard 300, When the tube scunner 15ft is used to scan the standard 300. the resulting signals from the sensors 205, 255 can be considered the "actual -scan ^" of the standard 300 by those semors 205, 255 at that time. Deviation between the ^■ 'expected scan ^" and the "actual scan" represents the drift, offset, error, noise, artifacts, or other aberration exhibited bv the sensors 205, 255 wtihin the tube scanner 15ft. This deviation is what is sought to he teinovecL at substantially minimized, by the application of a calibration function by the calibration module 225. A region 330 of the slandatd 300 having various wall thicknesses may be used Iy exercise and calibrate the rod-wear sensor 2!>5. A tegion 360 of the staπdatd 3rø having various depths, widths, and structures of w«H- pittirtg fealutes or grooves (nay he used to exercise and calibrate the pitting sensor 255. While regions 330 and 360 of the tubing standard 31)0 may he substantially circularly symmetrical, region 370 of the tubing standard 300 may contain vertical features or grooves which introduce a. rotational aspect to the tubing standard 300, Thm the expected scan ot ^' the tubing standard 300 will ds t ^' fer as a function of Jhe angle at which tubing standard 300 is drawn through tube scantier 150. This nationally variant tube region 370 3-5 discussed in more detail below and illustrated in Figure >B.

When insetted into the tube scantier 150 for calibration purposes, the standard 3Of! may be aligned using an index marker 3J.0, I he index marker 310 allow*, the standard 300 to be scanned in a consistent ettariner that is beneficial to the calibration ptoccss because the aeJuai stun can be synchronized with, ot matched up Kt, 1he expected scat) more readily. The index ronrkeτ 310 πIHY be paiiried onto, molded or ninchined into, ot externally affixed to the standard 300. One skilled in the mechanical or manufacturing arts will appreciate various other embodiments of the index marker 310, the «s.e of which would not depart lYvtm the scope or spirit of the invention. Additionally . the standard 300 may by operated without alignment via the index marker 310 and synchronization may be achieved by controller 250 or computer 130 using correlation to watch up expected features of the standard 3110 as identified within ihe scan data

Pigute 3B illustrates a botizornal crews-section of the roiationally variant region 370 of an exemplary tubing standard 300 disposed with a eirculat array of transducer elements 380 A -11 Referring now to Figures 2, 3 A and 3B _> the rotational aspect region 370 of exemplary standard 300 cart be manufactured with vertical features or grooves. 390. These vertical sμooves 390 introduce a rotational! > ^■ variant scan of the standard 300 in the region

3?β of rotational variance. Ti)IS. is in contrast to tegiotts 330 and 360 of tubing standard 3i>0 which may substantia!!)- display circular symmetry. Sensor transducers, such as 210 arid 260 shown in Figure 2 may be phy sically arranged as an array of transducer elements 380A-H disposed arcnintl the measurement zone 155, Vertical grooves 390 m tubing standard 300 may be used to isolate the response of each of the tranϋdueej element?; 380A-H. Fur example, in the orientation illustrated in Figure JB, (lie giυove 390 would be detected as a thinner wall measurement at transducer clement 3S0E compared to the other seven transducer elements 380A-D. 380F-H However if ihe tubing ϋt&πdatd 300 were being insetted or extracted at an orientation totaled ninety degrees clock Wi w (as viewed in Figured SB) then groove 390 would he detected by transducer 3B0G. This rotational variance in the scan of region 370 of tubing standard 3i>0 may he used to individually calibrate the sensor elements 380A-H circularly disposed around the measurement zone 155. Rotational variance HI the scan of region 370 of the tubing standard 300 may also be used to identify individually malfunctioning or faulty sensot elements 380A-H. ϊ ^: urther exploitation of these rotatoria! varinnees in the calibration scanning are elnlxMHted in the process flowchart illustrated in Figure 5 belo .

The physical design of the tubing standard 3W) is specifically intended to represent features, spanning the full range of pits, grooves and wall thickness that are measurable by the sensors 205, 255 within the tube scanner 150. When used as a calibration standard, these vatied qualities may allow the ^" tube scanner 150 to be calibrated over its full domain of operation. The two sensors 21)5, 255 oϊ the tube -scanner 150 are intended to he exemplary and ncsi limiting The tube scanner 150 may include other tube scanning sensot.s in various combinations without departing ftom the spirit ot scope of the present invention. Sitnilatiy, the etrculat disposition of sensor elements 380 A-H is intended to be exemplary and non- limiting. Sensor arrays of more ot less, than eight elements ot arrangements other that) the eireuku example may be employed within tube scanner 150 without departing iVom the spirit or scope of the present invention.

Processes for an exemplary embodiment of the present invention will he discussed below with reference to figures 4, 5 and 6. λn exemplary embodiment of the present invention euti include one or more computer programs or coπiput.er-iniptemented methods that implement functions or steps described herein ant.! illustrated in the exemplary flowchart!! ot ^" Figures 4, 5 and 6. However, it should be apparent that (here could be many different ways of implementing ihe inveimon in computer programming and the invention should not be construed as limited to any one set of computer ρrogta.fit instructions. Further, a skilled programmer would be able to write such, a computer program to implement the disclosed invention without difficulty based on the exemplary system architectures and flowcharts atrf the associated description m the application. ?ex?. tor example.

ThereiVtJe, disclosure ot ^' a particular set of program cade instructions is not considered necessary tor an adequate understanding of how to make and use the invention. The inventive functionality of any claimed process, method, or computer program will He explained in more detail in the following description in conjunction, with the remaining figures illustrating representative functions and program flow Certain steps in the processes described below must naturally precede others for the present invention to function as described. However, the present invention is riot limited to the order of the steps described if such order or sequence does nøi alter the functionality of the present invention HI an undesirable manner. That is. it is τee«grιi;?ed that some steps may hύ performed before ot after other steps or in parallel with other steps without iiepmling from the scope mid spirit of the ptesent invention.

fuming now to Figure 4. this figure illustrates a flowchart of an exemplary process 400 for scanning tubing that is being insetted into or eN traded ftυm an oil well 175 and for calibrating the tube sesnnet 150 us>mg a tube standard 3<tO within the operating environment of the exemplar" workovet rig 140 and tube scarinet 150 of Figures 1 and 2 Now referring to Figures j , 2 and 4, the exemplary method 400 begins at the START step and proceeds; to sitep 420A where an oil field service crew calibrates the tube scanner 150 using the tubing standard 3(Ml. This calibration is elaborated betmv in sub-process 420 ol ^" Figure 5.

At step 440. the crew operates the tube scanner 150 Operating the Ribe scanner 130 may include scannaπg tube segments 125 being extracted froriL or inserted into, Jhe well 175 Scanning tube segments 125 typicalh' includes collecting, within cot nrt) tier 2SiL computer 130, or both, the digitized signals ftoin sensot electronics, such as 220 or 270 Mechanical speed velocity, or positional tnlaonation may also be collected from the encoder 1 15. This mechanical information may assist in relating the collected sensor data with the phvsical area of tubing 125 lieitig sampled and each snap-shot The calibration module 225 may , in real-time, apply the calihraiioii function obtained during Jhe initial calibration 420A to 1he scan data collected during the scaunei operation in step 440. λi step 420B, the crew calibrates the tube scunner ISO using the tubing standard 300. This calibration is elaborated below in sub-proees-s 420 of Figure 5 λt step 480 _ the calibration module 225 may use this post- operaiaon calibration to validate that Jhe- tube scanner ISO is stall in cahbraϋoii and was thus likely Eo have remained m calibration throughout the tube scanning operation of step 4-lβ. ! f the post-operationa) eaiibratkm 4208 Ludicales lhat the lube .scanner ^" J SO has drifted out of calibration, the calibration module 225 may adjust the data collected during the tube scanning operation in step 440 according to tlie new calibration or the calibration module 225 may siatψly flag the data collected during the tube scanning operation in step 440 to be examined more closely in light of the post-operation calibration 420B.

Proe-ess 4 ⁽ M) may provide for improved data collection during tube scanning operation 440 since the tube scanner 151 ⁾ is calibrated in step 42J ⁾ A just prior to being operated and then calibrated again in ^tep 426B just after operation. After the post-operational calibration, the calibration module 225 may verify that the tube scanner 150 is still in calibration and it may react accordingly if tube -scanner 150 has drifted out ot ^' calibration. It should be appreciated that m addition to this, exemplary embodiment where ealibistion occurs before operation, arid aftei operation, the calibration steps πisv take place one or more times during the operation of the lube scanner 150 at the same well without departing trora (he spirit of scope of the present invention. Such seannet calibration can be employed in lhe field when, for example, the service erew has an increased need for sctin accuracy, or is concerned that the tube scanner ϊ5i> is not maintaining calibration lor extended periods of operation due to. for example, vibraiiom or thermal iluctuaiiotis.

Turning ΏOW to Figure 5, this iϊgure illustrates a tlowehart of an exemplary sub-process 420 for calibrating a tube scanner 150 using a tube -standard 300 and stored information a.bout the standard. This e-xeinplary sub-proce-ss elϋ borates the steps described in the calibmJion steps 420A and 420B ot ^' Figtffe 4.

Al &tep SM) the uύ .tick} service ciew inserts tubing calibratioa stamiatά 3SK) «no tube seacinet 150. Al step 5.20 the tubing standard 3iKl is aligned suth the tube scanner ϊ5S> using the index marker 310 of tubing standard 300. One.: the standard 300 is aligned into the tube scanner 150, the process proceeds at step 5-tft where the crew draws the calibration, tubing sumdarsi 300 thsough the tube scanner 150 white the tube scanner 150 samples scan data describing the tubing standatd 30ft. This i.am data may be considered the "actual s.eaiv ^" in

contrast Us stored information describing the known physical characteristics of standard 3TO. l.his stored information may be considered the ^" expected s*a» ^' as it rept events an idealization of what tube scanner 150 would, when perfectly calibrated, semi from the standard tubing 3!)(*.

At decision step 543, it is determined if additional partial totatfoos of tubing standaui 300 are required. As discussed above and illustrated in Figure 3B _> partial rotation of the- tubing standaul 300 relates to Uie vertical feature 390 and to the isolation of individual transducer elements 380λ-H within a sensor transducer (such its 210 or 2&h arranged as a circiiiitr array If the circtilat arriiv of transducer elements 380A-H includes eight elements, as illustrated in Figure 3B. and it is desirable to isolate each dement Jhen each partial rotation may be of 45 degtees and there may be seven such partial rotations interleaved between a total of eight scans of the tubing staudacά 3(M) ihtough tube seaunet 150. For vatving nuπtbers of circulady disposed transducer elements 38<S, the nutnber of partial rotation* and s*a»s may be the s>ame as the number of transducer elements 380 (as in the example just given ^" i Alternatively, the numl>er of partial relations may be more or kss than the number ol ^* trmsducer elements 380. Whatever the total number of partial rotations, intended to fully exercise the tuber scanner ISO, decision step 543 evaluates it ^" the toUil number of partial rotations has been completed or if additional partial rotations are required to be scanned

IT decision step 543 determines that no additional paitial rotations are required, then the "NO ^" bianeh is followed to step 351 ⁾ , otherwise, the "YKS" branch is followed to step S-W, where the partial rotation is earned out by the crew prior to beginning the next lube scan by returning Us step 510. The amount of each partial rotation is, in the simplest preferred implementation, three hundred and sixty degrees divided by the total nurø.i>er of partial rotations. Tbi> approach would evenly spate the partial rotation ^eans around the circle describing the horizontal cross-section <>! ^' the measurement z(>ne 155. Such even spacing of scans around the standard tubing 3rø is exemplary and πon-liitniiπg. Other measures <>i ^" partial rotation can be acceptable or even desirable

λt step 546, the erevv may gauge the angle of the partial rotation using an external instrument, or by using angle markings on or within lube scanner 150, tubing standard 3<M). or index marker 316. The angle of partial rotation separating each scan of a rotational set may be entered or verified by the crew using the computer 130 This angular displacement information inay be used by Jhe ealibration module 225 in making the calibration computations. Alter ihe .first transition through step 543, the second and later passes through step 540 within the same totattonaJ set ol ^' scans may be simplified to only include scanning the vertical feature tegiou 37(! of tubing standard 30W through the tube scannet 15W. This simplification may lie possible because only the vertical feature region 37U of the tubing standard 3WO varies, with rotational nnale. OKtfira.ng subsequent sαras to this iegiott 37β can reduce the toiat amount of time retμiired to cajibrale the tube s.eaiHier ISiϊ.

λt step 550. calibration module 225 computes a transform that am act upon the uet.ua! s.ean to yield, or approximate, the expected scan. This transfomi can he considered a calibration function for the lube scanner iSft For example, if Jhe values in the actual scan are all five less than the expected scan, then a calibration Junction may be to add five to all measured values. As a second example, if values in the actual scan are one third of those in the expected scan, a calibration functKsn tnav be to multiply all ineastutxl vahxes. by thtec. These lineat examples, of caltbralton functions are intended to be e\.ein.ρlan' atxt not limiting. One skilled in the control systems or signal processing arts will appreciate thai the calibration function may be linear or nonlinear, may operate in time, frequency, phase, or other domain ^■ , may be static: or may he adaptive according. Io the

minimization o! ^" one or more of various, adaptation metrics, without departing from the scope or spirit of the present invention.

At step 57!K the iranstbmi. or calibration function, computed at siep 550 may he stored fot use by the calibration module 225 and may be applied to data scanned during operation of the tube- scanner 150. Application of the calibration function to data scanned by the tube scanner 150 may remove, or reduce, deviation from (lie ideal operation of the tube scanner 150. 11ms. tube scanner ISf) may b« considered to be calibrated. As. such, operation of tube scanner ISO upon the tubing slaπdatd 300 would result in acim datit substantially approximating the expected scan data, in this calibrated state, the tube -scanner ISO may generate scan data during a -scan of a tubing segment 125 that is substantially indicative of the actual physical properties of the tuhina segment 1.25 and noi including drift, noise, offset, or otfaet artifact components to an extent thai the scan data wouki be Jess useful fot decision making regarding the tubing segment 125. f ^' uruing now to Figure 6, (his figure illustrates n flowchart of an exemplary process 6rø for calibrating a tube scanner ISO us. ing coupling joints in a string of tubing 125. instead of relying upon a calibration standard tubing 3W), proems ftOft may use the scan data from the actual tubing 125 being operated upon by the tubo scanner 150 to calibrate Jh« tube seamier 150. It shoυlύ be appreciated that tttbmg standard calibration, such as illustrated m processes 400 and 420 and coupling joint calibration, such as illustrated by process 600, are not nuitualiy exclusive calibration lechnujues and they may be used m combination or alternatively at different phases of scanner operation

Now referring to Figures 1. 2, and 6, the exemplary process 6SK) begins at step 610, where the tube augments being scsuned are drawn, by the crew, thtough the tube seaunet J.50 while the tube scsunet J.50 collects, within controller 250, computer 130. or both, the digitized signals, from sensor electronics, such aw 22β or 270, Mechanical speed, veloeily. or positional information may also be collected ftom the encodet I tS, This mechanical information may assist it) relating the collected sensor data with the physical area of tubing being sampled and each snap-shot. At decision step 620, calibration module 225 determines whether or not a collar locator JS in use. A collar locator 275 JS an instrument that indicates when a coupling joint collar is being scanned If a collar locator 275 is m use, the ^" YKS ^" branch is followed to step 630. where the calibration module 225 uses the indications ft on) the collar locator 275 Us identity' the coupling joints within the data scanned at step 610. IT a collar locator 275 is not in use, the "NO"' branch is followed to siep 640 where the calibration module 225 identifies the coupling joints in the scan data using peaks, in the data occurring at approximately thirty toot intervals. L-lach tubing segment is approximate!)- thirty feet long arid the scan data will penk. or saturate, nt the times in the scan when a collar, or coupling joint, is passing within the measurement zone 155.

Once the coupling joints are identified within the scan data «t either step 630 or 640, the process 600 continues to step 66ϋ where Jhe scan data is scaled up or down to equalize the- scan amplitudes of all of the scanned coupling joints. Since Jhe tube scanner 150 may saturate ami provide a peak measuretnent at a coupling joint, sealing the data as to equalize all of (he coupling jouii tegions may remove any drift error;, introduced in the data during the scanning operaltort.

Using either the tubing standard process 400 (aiotig with tubing standard 300) or the coupling joint equalization process 6(StK tire present invention can calibrate » tube scanner 150. Use of such a. calibrated tube scanner 150 can increase correctness mid consistency in the scanning of tubing 125 over the use <, ^■ <{ a non-

ealibiated tube scanner Coπectπcss and consistency can benefit the art when the results of tube scans ate ased m making important decisions concerning λvhether or not a segment υf tubing need be discarded due iυ yscεssive wear or in 3i"takiιig dccisiciis Uie iype and amomits of ciietnicals used in a well.