Design of Drill Pipe

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the design of the drillpipe for use in oil well drilling operation

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<ul><li><p>b-fspg~;q~t- -, l.,.,</p><p>DRILL PIPE</p><p>The Design and Performance Characteristics ofAluminum Drill Pipe</p><p>.,</p><p>Abstract</p><p>.</p><p>t?,G, BOICER. S, DALRYMPLE I</p><p>This paper outlines the approach atz~ solutions to theproblems associated with - the design and deve!optnent ofaluminum as a drill stem. for rotary drilling. A current</p><p> field history on tdumitsutn as a drilling tool is includedto assist the reader in judging the selection of engi-neering compromises [n the light of present field perform-ance and to acquaint the reader with. the present status ofaluminum dril! stetn in the drilling art.</p><p>Following proof of satisfactory operation of the firstcduminum drill string; 25, more strings (ske TabIe 1] have</p><p>~gone into. worldwide operational ttse. A study ,of theirperformance indicates: (1) no operational disadvantages,</p><p>(2) compatibility wfth. present drilling muds, (3J mlxed-</p><p>REYNOLDS MS7ALS CO.RICHMOND, VA.</p><p>1</p><p>transfer of stresses and a satisfacto~y fatigue life. Thisand other design and performanc~ considerations are dealtwith in this report.</p><p>After the development of a satisfactory aluminum drillpipe it was necessary to demonstrate the eeonomic ad-vantage of this tool, This too has been accomplished anddata are available to show the competitive position ofaluminum drill pipe.</p><p>Acceptance of ahsminum drill pipe is attested to bydemonstrated success i and by re-orders by present users:Five users have purchased their second strings of alum-inum drilI pipe. One user has purchased his fourth string.</p><p>Statement of Theory</p><p>I</p><p>i</p><p>.</p><p>. .</p><p>string operat(onir are successful, (4) hand and power slipsare operational{ (5) .no failures in the tool-joint area, (6)tioproblems it? fishing or other special USCS,(7) normalwear on. pipe body comparable to steel and (8) less thant~rmal wear on tool jo[nts.</p><p>These facts about the. present operational status ofalutnin?tni drill pipe de-mcmstrate that successful drillingtools can be designed and constructed of aluminum. Fieldand laboratory studies are continuing in order to improveand expand the u,veof aluminum jor.drill pipe. </p><p>,.</p><p>Introduction , .</p><p>To make functional drill pipe from aluminum requiredmore than a casual selectior, of engineering compromises.The target was a d@ling tool that would substantiallymeet the physical characteristics of Grade E steel drillpipe but, if possible, also incorporate the many desirablecharacteristics found in low-allov steel drill Ltiue(Grade D)such as toughness, concentric w%ar,and, lowembrittlementrate.</p><p>If aluminum could be successfully fabricated into de-pendable dr~ll stem, the advantages of this light materialshould reduce drilling costs. A few of the readily apparentareas of improved economy are: (1) rig investment, (2)transportation, (3) wireline life, (4) hoisting fuel savingsand ~(s) hoisting time reduction. </p><p>On the theory that aluminum drill pipe would lowerdr~lling costs, a project was initiated about 14 years ago,</p><p>TABLE 1REYNOLDS DRILL STRINGSJULY 1, 1963</p><p>length mn~cw:(ftl WNe% L%h locatlm,</p><p>41/..1. F+t)-</p><p>;</p><p>i:::</p><p>.27.</p><p>t;,</p><p>148,361106,2S010)::;</p><p>3s:2546S,00036,17656,58319,:00</p><p>-, ...,..,r.</p><p>15 9,89023 4,62016 6,350</p><p>6,563!4 9,550 8 8,500</p><p>4,5001! 4,650</p><p>~1/2 1 S,po.</p><p>from: Texas. Cal If,Okla.ChileN.E, TexasN.Z. TexasAlberta, CanadaAlberta, CamdaN.E. Texas, Calif.</p><p>It was recognized early in the aluminum drill pipe pro-,. -.,W11. 11,620 77,000 9 8,55072,</p><p>N .E , Texas12,000</p><p>gram that aluminum alloys could not be beat utilized in a ,, IS. ,~~::,61,634 5 12,300, La., Miss.39,013 3,900 Ok&amp;OmO</p><p>dbsign that copied the then available steel driil pipe. It14. 11;355 ,! 1T ,:5515, S:olo 15,000 Mont.</p><p>1;:*was necessary to balance the design, alloy choice, spength, 16, 4,020 9,f7017,</p><p>Ulnh.5,010</p><p>corrosion and, wear resistance of aluminum alloys into a.* *.</p><p>18.CaIif.</p><p>7,020 4,55s 1 Colo.19. 4,740 57,351 7,:90</p><p>workable tool, one. ctspable of sustainigg_the; spe$ses ~f, ~ ~o.. _._u,s~o. ~.-z#.l.?.o._ -1&amp;l,: 10,OSO..._. N$, .roxm .,. -.N. Okla.rotary diiilhi-gr - -- 4.in. PiOe</p><p>The application of steei tool jaints to aluminum pipe ,21, 11?5z0 113,427 19 5,950 MIs.:, posed many problems in ofder to achieve a satisfactory, ,, 2Z !J1~.1. pipe</p><p>7,020 20:,:S7; ~33 6,100 La., Miss., Tex.23:.</p><p>OrfginsS manuscript received fn Soelety of Petroleum Engineers oflh?e7,500 * *</p><p>24. 6,000SWdlArabia</p><p>5:800 Aug. S,. 1963. Revieed manuscript received Oct. 80, 106S. Paper me. 1$:;$ .* ,,-~ :</p><p>Aleska</p><p>sented at SPE FsL1 Meting held h New Orleans, Ott, 6.9, 196$. &amp; ,l</p><p>Cqllf..*, Uhzh</p></li><li><p>,/</p><p>which has today progressed to a point of full-scale magnL-tude throughout the world,</p><p>Acturil field operation (25 strings) ot ahvninum drillpipe has brought to light other advantages and savingswhich were not apparent at the outset: 2 (1) pipe main-tenance and life, (2) drilling fuel, (3) tool joint life, (4)pumping fuel, (.5) safety and (6) less flow resistance inannuhts.</p><p>Description of Test Eqsdpmetit</p><p>Fsstigue TestA rotating, cantilever betun-type fatigue test tnachinc</p><p>is maintained in the Reynolds Richmond, Vs., labora-tories for full-scale fatigue testing of drill p~pe and drillpipe-tool joint assemblies. The machine has a drive</p><p>mechanism in the head which provides a controlled con-tinuous rotation.</p><p>A deflecting mechanism is located approximately 7 ft,from the head and is equipped with rollers to provide ro-tating support of the test section. The machine is capableof subjecting a test specimen to a bending moment of200,000 in.-lb during a typical test. Fig. 1 shows a schem-atic of the test machine.Tension and Torsion Test</p><p>A, combirai?ion, tension and. torsion testing machine ismaintained at the Reynolds Extrusion Milt in Phoenix,Ariz., for testing full-scale specimens of various shapes,.including drill pipe with tool joints. The machine is sxtp-able of a 750,000-lb tensiIe pull, and the heads can berotated 3600 in either direction. Fig. 2 shows a sketch of.the arrangement,.</p><p>Application of Test E&amp;ipm*</p><p>Fntigue Testing -</p><p>Sufficirmt background has been developed in the fatiguetesting of hand-applied tool joints on steel pipe to providegood fatigue life pnrameters. Most of the tests on the 41.4in, steel drill pipe were run at 300 rpm under a bending</p><p>lRefevences given 21L end of p,auer.</p><p>,</p><p>COLLiRTOOL JOINT&gt; DRILL PIPE&gt; 1</p><p>MECHANISM80~ I</p><p>-+&amp;</p><p>II I</p><p>,.</p><p>F-ig. lDrill pipe assembly fatigue testmachine.</p><p>HYDRAULIC ,MOTORS &amp; WORM GEARS</p><p>FOR ROTATING HEADSTENSION ~YL[NDER { TOOL DRILL \TOOL</p><p>.!</p><p>.!</p><p>.-. .</p><p>,</p><p>Fig. ZDrill pipe assemldy tension imd torsion testing.</p><p>l , *</p><p>.-</p><p>moment of 1S0,000 in.-lb to produce a bending stress ofabout 35,000 psi at the base of the upset, The deflection of41/2-in, stee] pipe with a lever arm length of 80-in. iS about7/s -in. which is maintained during rotation. Exprience withGrade E drill pipe and hand-applied tool joints indicatean average fatigue life of 400,000 to 600,000 turns orcycles.</p><p>Today, aluminum drill pipe specimens give long con-sistent runs in the million cycle range with. test specimensselected at random from production. Breaks usually OC-cur 4 to 36 in. from the tool joint, which indicate maxi-mum efficiency of the tool joint-drill pipe assembly.</p><p>The tests on 41X-in, aluminum pipe are also run at300 rpm under a bending moment of 150,000 in.-lb whichproduces a bending stress of about 16,000 ,Psi at the endof ihc tool joint shoulder. The deflection of the 41A-in.aluminum is double that of steel or about 13A in. for a Ieverarm length of 80 in, and a 150,000 in.-lb moment. Thispoints up the fact that the aluminum drill pipe can de-flect about twice as much as steel driIl pipe and still be</p><p>, within safe stress limits, ,,,</p><p>Tension and Torsion Test</p><p>The background ,dftensile t&amp;thtg on 4~z in. Grade Epipe indicates an average value of 450,000 to 500,000lb. Aluminum drill pipe shows an average tensiie strengthof 488,000 lb, ranging from 473,000 to 503,000 lb ineight joints selected at random from production prior torelease of the first string. Tests were made which putthe, tension load through the tool joint assembly. FuII.length joints were u~ed (30 ft). No failures occurred in ornear the. tool. joint area. The break areas ranged from4 1/3 to 9 ft from the end of the joint. The test wasmade by gripping the ,outside of the tool joints. The tensileload did not pass through the working, connections of thejoints.) Very limited torsion test data on steel drill pipe wereavailable for comparison.</p><p>A field specimen with a service history of 148,000 ftof hole was given an initial tensile pull of 150,000 lbafter which one emi was rotated 180 clockwise with re-spect to the opposite end. N.o failure occurred. The torquewas then backed off to 120 displacement and the tensiontest continued to a tlnai pLdi of 365,000 lb, at whichpoint a typical tension break occurred in the body, of thepipe. These tests dramatically illustrate the tough tension .and torsion properties of aluminum drill stem, in the Par-ticular design, and its ability to accept abuse.</p><p>Design ObjectivesInitial design objectives for alumisium drill stem con-</p><p>templated physical characteristics comparable to GrtRie Edrill pipe. The design should be compatible With presentrig practices, drilling methods, fishing operations, drillingfluids and all other well drilling operatiofis.Phase One -</p><p>,.</p><p>1, To prevent compounding the problems associated .with the irstroduotion, of a new product, a decision was ~made to provide steel tool joints with API working con;nections for the aluminum drili pipe. It was aiso assuthed </p><p>. th.at.;@gE,@@bJg.rns~oV~!ved.~m.!b~.gPP!ica!iOn..qC.9Ygi!?hl$. ., ;,...steel tool joints .to ahsm~num drif.1.pipe would be easier . and quicker to solve than the development of new types,for example, aluminum )001jtipt% . t</p><p>2. lf possible, the field application and remotial fea; tures of present hand-applied .~ool ,joint designs would bcretained. . . .</p></li><li><p>&amp;.</p><p>.</p><p>.,</p><p>.-,</p><p>.</p><p>,.</p><p>F</p><p>3. It would also be destrable to provide a design whichwould be compatible with present field methods of hard-banding.</p><p>4. The first phase of the development program wason 41%-in. cfrill pipe. Upon successful completion of thiswork, 3Y2- and 4-ki. drill pipes were designed and fieldtested.</p><p>5, Due to the increased popularity of the internal-flush drill pipe, all design considerations evolved aroundthe external upset configuration. Selection of this type ofheavy end would also provide better iinherent propertiesfor the solution of slip placement, tool joint applicationand fatigue problems,</p><p>6. Because of the recent interest in the subject of an-nulus flow, external ,streamlining around the tool joint as-sembly was a part of the design? although not mandatory,and certainly not at the expense of other more importantdesign considerations?</p><p>Phase TwoThe secmtd-phase design objectives, depending on ini-</p><p>tial phase findings, included the following.1. The development ~f a bore coating for aluminum</p><p>drill pipe, (The same methods and processes which havebeen successful for bore coating steel pipe were not com-patible with aluminum.)</p><p>2. The development of larger sizes of dr,ill pipe,namely S, 5% and 6% in.</p><p>3. Consideration of a drill pipe size below ~% in.4, Development of field inspection methods for ahtmi-</p><p>num drill pipe.5. Development of the all-aluminum strin~, leading to</p><p>. .</p><p>,1-.,.,-g.-1~;;1... . ..:_,._.,.- .3. . .. ./,. ,.</p><p>. Fig. 3-Ckoss-sectional views of drill pipe: (lef&amp;) pipe ex-truded and machined, (center tool joint assembiy~</p><p>1 i(right) completed joint of n umimsm drill pipe...</p><p>nwrm~new T06*. -</p><p>-,.</p><p>. . . -.</p><p>1,, ,,, I</p><p>,.</p><p>the design of aluminum tool joints or other methods ofjoining the aluminum drill stem.</p><p>6. Development of the internal upset pipe to be fabri-cated into 4M - and 5-in. full-hole and extra-hole drillpip? types,</p><p>Data available today indicate that all of the initial de-sign objectives have now been reached with a minimumamount of diversion fr.m the original concept,</p><p>Fig. 3 shows present pipe (A), tool joint assembly (B)and complete drill pipe joint (C). One of the second de-sign objectives has been completed, that of the bore coat-ing for aluminum drill pipe and the formal @ering of</p><p>, the 51%-in, size to the trade is in the immediat~ future.Also, soon to be announced, and to be available to the</p><p>trade, is a new and impfoved inspection method designedfor use on aluminum drill pipe in the field. Other secondphase design objectives are in process, , .</p><p>Pres@Xion of Design Development ?,.; I</p><p>Alloy SekxtionInitial studies of alloys for aluminum drill pipe led to</p><p>the se[ection of alloys 6061, 2014 and 7075 as possibili- ties, with final selection depending on laboratory and en-gineering studies in conjunction with proposed tool-jc?intdevelopments. Typical tensile strengths are shown on Fig.4. Fig. 5 compares strength-section properties.</p><p>The alIoy 6061 was eliminated early in the programsince engineering studies indicated the physical propertiesof this alloy would dictate very heavy sections. Alloys2014 and 7075 were carried through laboratory studies,prototype and ffeId developments in various cordlgurations,leading to a final conclusion and selection of 2014-T6 asbeing the most suitable aluminum alloy for fabrication ofaluminum drill pipe at this time. J</p><p>Principal among. the factors leading to this decision wasthe fact that fatigue endurance of 707S-T6 alloy, as re-ported, in AN C:5 (see Fig, .6) was slightly inferior to2014-T6 in complete stress reversals at 500 million cycles,showed a wider and mdre uncontrolled scatterband of re-si.dts, equal-to-inferior fatigue properties in ptill-pull fa-tigue and definitely inferior properties at elevated tempera-</p><p>ULTIMATE TENSILE STRENGTH</p><p>.,</p><p>.</p><p>- -4..-H-. , - .</p><p>-, . .-~,</p><p>.,, ., ---- ,.-., ,.~... ,:-.</p><p>.,</p><p>. ...-. . . . . . . . . . . . . . ... ---- . .. . . . . . . ... . . :. ..-= .: .. -..--..-+ . . . . .,. :.. !</p><p>-. ..-. . . . . . . ..--. ; -. ~...- .:---- ...:. ... . . ... .:.</p><p>-= - .--.{: - :.. :&gt; : : :. .;.,.;</p><p>. . I. .. .! .- . .-.-. - _,.. ,-., ,. ---. . . .. . .. -., .. -.</p><p>. . . ,.</p><p>:.:.;,...-..</p><p>1707&gt;,</p><p>rig. 4-4Jnit tensile propertied... . .</p></li><li><p>, </p><p>-! -------.,</p><p>-..</p><p>tures (Figs. 7 and 8). Of almost equal consideration werenotch sensitivity and susceptibility to stress corrosioncracking in the full section (both fact~rs being more</p><p>favorable to 2014-T6 than 7075-T6). I</p><p>Design of Pipe Body</p><p>Although 7075-T6 alloy displays a higher unit strengththan 2014-T6, it does not follow that this factor wouldprovide advantages in a drill-pipe design of 7075-T6 alloyintended to have physical characteristics similar to GradeE. To match the physical characteristics of Grade E withthe 7075-T6 alloy dictates a body cross section comparableto Grade E. The resulting relatively thin wall greatly influ-ences rMll pipe life. Fig. 9 clearly Ulustratq the dkadvan-</p><p>yJTKJN ARSA</p><p>O.D. INS ,</p><p>I.D. INS.</p><p>TENSIONYIELD-15.</p><p>ULTIMATE-LB.</p><p>ACTUAL-LS.</p><p>TORSIONYIELD-IN-LB</p><p>-</p><p>.-</p><p>4,540 6.440 4+407</p><p>4.625 4.600 4.500</p><p>3.951 3/500 3.S26.</p><p>319,000 373,000 330,000</p><p>363,000 412,000 440,000</p><p>. . . . 4ss,000 490,000</p><p>363,000-J__</p><p>396,000 372,000... . </p><p>Fig. 5Strength-section comparison.</p><p>g o.%</p><p>g 20v) d</p><p>10</p><p>010 10 104 105 10 1(7 10 lo</p><p>C...</p></li></ul>