] societyof PetrofeurnEndnaarsI

SPE 27990

New and Expected Developments in Artificial LiftJ.F. Lea, Amoco Production Research, and H.W. VVinkler, Texas Tech U.

SPE Members

Copyright1SS4,S@@ ol petroleumEn@aara, Inc.

Thw papar was prepftmdfor presentationat the Uniwmw of Tulsa CentennialPetroleumEnginaarirwSymposiumheld in Tulea, OK, U.S.A., 2S-31 August1SS4.

Thmpapr was aakmtadror pmentat!! by an SPE Programcommitteetotlowingreviewof informationoontainadin an UXtraCtaubmittadby the aUthOf(a).COntent.9of the paper,as prwanted, have notbean mviawedbythe Sociity 01PetroleumEngineamand are subiw to oorractionby the auttrof(a).The meteriel,aa pmaented,doaa not Mcaaarily rerlectany PoaSionorthe Society01PetroleumEngineer%itaMoam, or membam.Paparaprsaemodat SPE maetingeare aubjeclto publkmtii reviewby EditorialCommittalsot the SoolatytiP~E~iH. PmM@~b~@wtitm dMtitin~ti8.111~ maynorbe aopiad.The abarraot@WLIU-n ~~~ *--of where end by whomthe pep ia praaanted.Write Librarkm SPE.~.o. BOX-, fkhafd~n, TX 7~3-393f3, U.S.A. T@~xI~~~ epE~

ABSTRACTArtificiallift is a broad subject. This paper discusses some

of the new developments in the major areas of artificiallift.Theseare (1) Beam Lift, (2) Electrical Submersible Pumping, (3) GasLift, (4) Hvdraulic Pumping and (5) MiscellaneousTopics.

The beam lift discussion co;cerns a new rod material,downhole measurements for rod loading, unit design and somemiscellaneous topics. The ESP (Electrical Submersible Pump)sadon includesa discussionon solidshandling,downhole sen-sor technology, new motor temperature limitations, motor effi-ciency, and other topics.The gas liftdiscussionincludesmentionof coiled tubing with gas liftvalves internal, a surface controlledgas lift valve concept, and gas lift valve testing and modeling.Hydraulicpumping is used in many locationswith deep pay andfairly small production rates, New hydraulic developments!Rc!udaa @der availabilityof power fluidpumps other than POSi-tive displacement pumps, and smaii jet pumps s@f!di~designed for dewatering gas wells. Some miscellaneousdevel-opments include an insertable PC (progressing cavity) PumPand improved plunger lift algorithms and equipment.

JNTRODUCTIOhlTypically the user has been concerned with reliability,

. .. .

related failure raIes, and ~ian d, ,,,.i-+mning productionrates as high aspractically possible. However, there ia more emphasis now inreducingall costs as much as possible,One way to controlliftingcosts related to lift is to determine what the energy to the liftsys-tem is ve. the output of the liftsystem (Reference 1).

To establish a definitionof the efficiencyof artificiallift,youmust establish a definitionof the useful work that an artificial liftsystem performs. If it is agreed that the down hole pump doeswork equal to the volumetric flow rate times the pressureincrease delivered by the pump, then the followingthree equa-tions can be used for a definitionof the efficiency of an artificiallift system.HPi = ln~ horsepowerto the system . KW/.746

References and illustrationsat end of paper.

HPo = Output horsepowerto the producedfluid= 0.000017 Q DPWhere: DP = The pressure increase throughthe pump, psi

Q = The volumetric flow rate through the pump inbarrels per day

another form of HPo ia:HPo = .00000736 Q LiftWhere: Lift is feet of net lift requiredfor producingthe well.So the resultingdefinitionof efficiencyis:ArtificialUft Efficiency= HPo / HPi

If this isknown,at least approximately,for artificialliftinstal-lations,the user can determine whichwell isdoingthe best job ofconvertinginputenergy into outputwork requiredto lift the fluid.Then, presumably,the user oouldtake measures, if economical,to bringother wells in the field, up to, or above, the field averageefficiency.

This definitionworks equally as well with PC pumps andhydraulic pumps, For gaa lift, one way of determining the HPo~?ightbe ~lculat~ngthef)pequaltothepressure at the fWfOra-tions with no gas lift system minus the pressure at the perfora-tions with a gas lift system. Then the above definition of HPousing Q and DP oouldbe used. The inputpower could be somehorsepowerequivalent of the power to the compressors.

To illustrate efficiencies of beam and ESP systems,Figures 1 and 2 show the appnimirmte ie=~ k! sad! system.From Figure 1, it is seen that beam efficienciescould vary quitea bti, but a value in the 50%a is a good value of beam pump sys-tem efficiency.Figure2 chowsa mid size of available ESP squip-ment. It showethat a middle409f0svalue of efficiencyisgood forESP application, etthoughit oan be difficultto obtain.

Other methods of lift may have different values of effi-ciency. PC pumps may have higher obtainable values of effi-ciency than beam pump systems with numbers in the lower60%s.

Hydraulic installationefficienciescan be high if the frictionin injected power fluid lines is not exoessive. Reciprocating

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2 NEW AND EXPECTED DEVELOPMENTS IN ARTIFICIAL LIFT SPE 27990

hydraulicpump systems have higherefficiencythan jet hydraulicpumps. Gas lift efficiency can vary greatly depending on howmuch energy must be generated by compressors. For instance,

. L-!- .- ,Ak...-.,1Aha,,a well producinggas 10Oegin WIVI WUUIU, ,=.43Ei h,W,,e, . .. .. ..=,imh r dfbianrvthan an identicalwell that produces only liquid since more gaswould have to be compressedand injected.Typicallygas lifthasa lower efficiency than some other methods of lift, withinjection-gasslippage and liquidfall back in the tubing contribut-ing to a good portionof the losses.

As far as artificial (power) efficiency is concerned, it maynot be the most important factor. For instance, 9SS 1~ maY bepreferred because of lower frequency of failures and because itis less manpower intensivethan other methods. However, wherepower costs are concerned, determination of efficiency is onemethod to keep track of energy mats for artificialIii systems.

In the followingdiscussionof artificiallift innovations,ft willbe seen that many of the ideas are indeed directedto increasingthe efficiencyof artificiallift.

M PU-Beam pumpingh an old method of Mt. Because of the sup-

posed familiaritywith the subject it iSOftenassumed that th~emay be no significantnew developments in this area. However,some subjects are mentioned here which are not considered asonly minorchanges to the beam pumpingsystem.

Ribbon Rod

Ribbon rod is an invention(Reference 2) which makes useof a graphite compositetape to replace steel rods. It is similartoglass rodsbecause the installationmust includesome steel rodsat the base of the rod string to facilitate rod fall and efiminatebucklingor compressionin the ribbonrod.

Figure 3 shows an edge view of the 1.4x.212 cross sectionribbon rod where it is increased in thickness and bolted into anend fRtingwhich has a standard API pin end attached. Figure 4shows a service truck with a reel of ribbon rod on it runningrodintothe well. In thiscase, some steel rods have already been runintothe well.

Ribbon rod has the followingcurreni properties:The rnod-UIUSof elasticityis 16.4x1($ psi. The weight is .127 Ibs/ftand thedensity is 100 lbs/f@.

The advantagea of the graphitefiber compositerod includecorrosion resistance and a very high tolerance to fatigue com-pared to other rods. Also one n\che seems to be in the area ofallowing a higher produtilon rate for beam pump wells that arealready loaded to the maximum with existing steel roo Sytierns.Although a static analysis indicates that lighter rode do notreduce gearbox loading,dynamic mnsiderations and rod stretchresuttin system that does has lower gearbox loadingwhen Rib-bon rod is installed.

Ribbon Rod Example:

Consider 600 bpd from 6000 ft. A steel rod system is an1.75 in. pump, an 86 md sting, 12.2 spm~a 64 hp motordemand(use 75 hp) and a 912-365-144 unit. This is compared to a rodstringof 3000 ft ribbonrod, 2000 ft 7/8s and 1000 ft 1.0 in. rods.Futiher optimization in the ribbon rod design is probably possi-ble.

This shows there is a potentiai to increase prodiictkm artcflow~i atraa GR ?he ~- ~y.~an components using the light.. - -w-eight mmposite rod. Fiberglass could be used, but, again, itdoes not have the resistance to fatigue as does graphite com-posite material (Reference 2).

atQdEQmmQ MwamumQqOGear Box Load 98 59

% Rod Load 102 94

Production,bpd 591 683

Concerningefficiency,the losses along the rod stringweremeasured to be less than withthe steel rode. However, the usualsituationmeasured was a beam unit that was signifiitly underloaded after the hwtallationof Ribbon rod, and Reference 3 indi-cates that under loaded units can drop off sharply in efficiency.This may explain why most efficienciesof beam systems usingRibbon rod only a showed slight Increases in overall power effi-ciency.

The availability and cost of the Ribbon rod is yet to bedetermined. There are possibilitiesfor ribbonrod types of mate-rialswMch allow a beam pump systemto performwith increasedCapabilities.

Down Hofe Load Meaauring ToolIn conjunctionwith some of the Ribbonrodtesting,a down-

hole tool (Reference 4) was used inthe rod stringto measure rodloadswhile the unitwas running.This unitcontainedstraingagesconnected to the walls of the tool with 7/8 in. pin end connntions.The measured loadswere recordedwith a small computerin the tool at times selected and controlledby a down hole clock.The resultscould then be played out when the tool was broughtto the surface.

Later this tool was used more extensively on more weflswith steel and fiberglassrods.The resultswere comparedto pre-dictive and diagnostic wave equation models in Reference 5.Some results did not compare well to some of the modeischecked.

Additional work in this area could possibly settle manydesign issues in the area of beam pumping analyticalwork. Forinstance more down hole measurements correlated againstmodel developmentmuld:.

l

.

l

l

Eetablkshimproved models for rodfluidhubing drag.Determinethe load at the junctionof steel and fbr glass rode.t)~e~ine the variables affect on mmpr~sion on the bottomrod to fmaiiyaiiow a KXlibaSiSf~r $iZifigW?ker*rS (if indeedneeded).Determine measured results of the piston muplhg effect toallow better modelingof this problem.Could be used in deviated wells to confirm existing modek(Reference 6) of rod drag in deviated wells.

The above are just a few items that could be settled with avolume of good down hde data directed at aolvfng these andother issues. The results should further improve predictive anddiagndlc tools in the area of beam pumping.

Hew UniteCommon units are the conventional, Ma* IL air balance,

and some conventional types of units with offsets (phasedcranks) to improve the torque profile. Also tower units like theRot&Flex have been used to take advantage of some of the longstroke characteristics.In addition,there are many hydrauliccon-cepts, potteble units, iow PtiIe Unhj *.

Fiiure 5 SilOWS Ii new uiiiqii dSS@ Wd?ich eii!!?i!?ates thewefking beam. The unit is claimed to show increases in overalleffloiencyand is more compact. It is operationaland available to

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SPE 27990 J. F. Lea and H. W. Winkler 3

the industry: This unit has counter-rotating weights for thecounter balance effect.

Just how far can unit design be carried to practicallytakeadvantage of all possibilities to smooth torque and reducepower? Reference 7 discusses a tower unitwhich uses numeri-cal controland a highefficiencymotor.High efficiencyvalues areclaimed.

Additionally,Figure 6 (Reference 8) shows a schematic ofa proposalto use a high efficiency NEMA B motor attached to aflywheel with a variable speed drive which is controlledto main-tain a constant torque on the motor. Thjs would allow the motorefficiencyfor the cycle to be in the low 90%s. For a conventionalunit~tha NEMA D motorthe peak efficiencyisabout 86%. How-ever, the total cycle efficiency is closer to 76-SO%. So this con-cept would increase the motoreffiiency about 14 percent. Shwethe VSD would consume some energy, this would somewhatdecrease the efficiency. This proposal is not without some con-ceptual problems, includingthe fact that some special provisionswould have to be made for starting.

So far industryor government organizationshave not gen-erally seen fii to fund development of beam systems which maybe more energy efficient, but which are more complicated andcostly. If they are funded, tested, and foundto work refisbly,thenan effective efficiency increase of about 10% seems poselble. Itmay be that these types of more sophisticatedpumpingunitswillnotsee general applicationconsidering*E! large mimktwC4mittalready in operation and the fact that many companies are oper-ating strictlywith used equipment when needed.

su~Wtih the combination of centrifugal pumps, electrical

motors, seal chambers, special Makes and separators, surfacecontrols,cables, and new materialstechnologies,there seems to~~ay~ be somethingnew in the area of ESPS.

Dewn !h!e SensersFigures 7 and 8 show two versions of improveddown hole

sensor systems for ESP operation (Reference 9). Althougheachsystem has some special features, they both advertise that it ispossible to get an intake and a discharge pressure. If thisbecomes rekbfe practiced technology, this could result in sev-eral major design improvementsfor the industry. In general, theimprovements from obtaining both intake and discharge pres-sure would include:l Effectsof free gas throughthe pump under a variety of cond~

tions would be measured allowing the determination of muchbetter models for this type of situation.

l Effects of viscosityon pump performancewould be measuredunder down hole conditions, again allowing development ofhn~ar m~als in ttils area.e,,, ,.. ---

. The eff~ of pump performance could be separated fromeffects of tubing perftimance.

l Tubing pressure drops with multiphase flow could be mea-sured with various fluidsand inclinationsallowinga volume ofdata to be obtained to validate against multiphaaeflow pres-sure prediion programs.

Also, if wellbore fluidtemperature could be taken below themotor and at pump intake and discharge, heat flow models orcorrelationsmuld be evaluated.

High Temperature ESP Motors:Consideringhot conditions,Figure 9 shows a pictureof one

concept of a hightemperature motorwith the surface Injectedoilline attached to the motor.This assists in coolingand motor pro-

tection.This motorisestimated to be able to operate inthe upper400F range. Anothercompany also has achieved significantruntimes with high temperature rated motors in high temperaturewells. This company uses a longer motor protectoror seal sec-tion, with improved insulationand other features. Some of thesehightemperature tests are reported in Reference 10.

ESP Solids HandlingSand has long been a problem with ESPS. Down thrust

causes wear through the phenolic wear washers and metal.Radial wear can occurwhich loosensup the shaft in itsbushingsand vibrationbegins.

Figure 10 showsone companysconcept with a sand resis-tant thrust module with several stages (4 to 11) suppated by athrustbearing and a hardened sleeve for radial thrust. Also theyare offering tungsten catbide on tungsten Catilde radial wearbushingsfor pumps, gas separators, etc.

Figure 11 showaanother companysZirconiaceramic bear-ing for use in their ARZ sand-resistantpumps as well as for usein intakesand gas separators (see Reference 9). The compliantmountingsystem isdesigned suchthat shock loadswllnotcrackthe bearing whkh is seven times more resistantto breakingthanSificon Carbide. This concept centers more on radial wear pmtection. However, they do have a double thickness hi-tempera-ture thrust washer and 2 pedestals for down thrust wearresistance se well as other features.

A third mmpsnys Sand Handler uses a floater configura-tion with hardened inserts in every atage to resist radial andthrust.The inae~ are available ina variety of resistantmaterials.A hardened diffuser mushroom surface and impeller flangesleeve provide down thrust resistance. A hardened impeller huband cliffuser mushrmm contact surface provides radial resis-tance to wear. They also have a compression pump to put allthrust on an isolated thrust bearing to prevent impelleddtiusercontact w%.

W Pump@ SS9 k%torsTwo companies are pursuing development of an ESP

motor driven PC pump. This has been offered in the past byanother ESP manufacturer for a short period of time. The con-cept eliminatesrodon tubingwear, rodWNJ+PV and shorteningof the rodswhen they wind up. Also it would be suitablefor devi-ated wells.

On the minusside, the motormust be geared down and thegear box becomes another element which must be protectedfrom down hole renditions and is subjectto failure. Also there isthe possibilityof vibrationfrom the PC pumps which can aggra-vate seafing of the motor and gear box.

One company is pursuingdevelopment with a motorMlchhas asynchronous speed of 1600 rpm. Another company is pur-

~ . l .4 hne ++a ~~qm~ synchronoussuingdevelopmentwith a mutol Lh=b,,W. .speed (woo rpm) as a conventionalESP (see Figure 12).

If these is developad successfully,the applications couldbe deeper typical PC pump applbations. However, the draw-backs of current PC pumps such as gasses and chemicalsattackingthe elastomer stator still remain.

Motor EfficiencyMotor efficiencies around 90% are claimed by one ESP

mmufacturer. This ishigherthan mostbutthere is stillsome con-cern in the industryon uniformmotor testing. Also there is a con-cern on how motorsare rated and re-rated.

Redatedto motor rating is a question of how the voftagaehwld be adjusted on an installationwhere the motor is not fully

341

.Figure 19Figure 18

SPOOLABE GAS LiH VALVE

FLow BYPASS-

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INSTALLATION sET INSERTABLE~p PJMP,_dk,

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IIH!ll1-114Jel PUMP

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SW

4 NEW AND EXPECTED DEVELOPMENTS IN ARTIFICIAL LIFT SPE 27990

loaded. There issome conflictinginformationon thissubjectfromdifferentvendors. Currently, it appears that the best method is toset the voltage for an under loaded motorto the pointwhere theamps are at a minimum. Unfortunatelythis takes several stopsand starts which could conceivably cause damage. Hopefullysome of these concerns will be resolved up to the operatorssat-isfactioninthe near future. Recent attentionhas been focusedonthe subject.ESP Needed Developments

Opinionson needed developments muld vary greatly fromvendor to vendor and operator to operator. Efficiencytakes the&I -- ~ l-. i. ECDI. frnm +hta n~mnq th~rnseivx. CM this beUlggusl Ivan Ill I-UK 0 88,,s. ~ ...r% -.improved by a alicke~ finishfrom a better more uniformmanu-facturing process and from better stage hydrodynamicdesign?Motor improvements have pointed the way to operation in hightemperatures.

The shaft seais in the seal or protector sectionscan allowleakage especially if vibrationis present. This leads to a wish!!s!Ofba!a~~ed non-vibratingequipmentwithshaft seais deAgned toresist ieakage from iaterai vibration.

Sensor packages, with no failure modes to stop pumping,should help design and anaiysis as previouslymentioned.

Improved cable technologycombinedwith good cable run-ning procedureswili get the most out of cable installations.lnde-pendent testing to establish rating procedures (Tulsa University,and ERA in the U.K. for instance) shouldassist the user with theseletilon process.

Power could be saved if power factor capacitors could bemounted down hole, but this currentlyappears to take too muchspace and could be a failure mode.

The ESP controllercould have logic to calculate and die-play overall efficiency.This would be a good methodfor compar-ing one well to another for best efficiency.

.- --.L. ---~ i*s- nf rptor perfgrn~~~eOp&aIQTS eoiiid IJI-RW~- uu~ w, , .-. 0

curves at various loads and voltages if they were available. Alsopump thrust curves at various ratea and at higher HZ can be,- ,=.1:- -1.:-- 4--:..:-

. . #-.*di. whathe~ !Q ~n ~!J~~s OUtrwpwi m meirwng u~l=lvn= Iew=, ,,,g ... .-w.of the normal recommended ranges.

Gas lift is one of the most reliabie methods of iift. It is gen-erally the least man power intensiveand can be advantageous inremote areas. It will generally continue to produce with littleattention,butto get the optimumfrom a gas liftwell requiresengi-neering, attention, testing and other detailed analysis, as is thecase with other methods of lift.

Valve Testing

One of the newer developments inthe fieid of gas iiftis per-formance testing of gas lift valves. Results of this kind of workcan be found in References 11 and 12. The assumptionfor manyinstallationdesigns and operations is that the valve acts as anorificewiththe area equal to fullyopen seat. However, valve test-ing takes into account the valve load rate and the interactionofthe ball near the seat which may restrict the flow =i- (sssFigure 13) throughthe seat area.

A conventional casing pressure operated valve can betested with constanttubing pressure (see resultsin Figure 14) or

------- r:... ... d~! Lffi*u*P nn~- SIwith constantcasing pr~sure (sew rl~u, w I t. ,,- .-,, -. .*- -satisfactory method of testing has been established, the userneeds to develop an accurate valve model whiohwili predicttheinjection-gas throughput when the up and down stream pres-sures and dome pressure are input.

Once a valve model is developed, it becomes possible topredict flow rates through the valves during the unioading pr-cess and at the final depth of gas injection. Reference 13 indi-cates a step by step procedure for design using a valve model.Reference 14 showsdetails usinga computermodelwithtime asa variable and presents results of some example dynamicallycalculated results. Figure 16 shows some example output fromsuch a model.

Shown in Figure 16 is the rate throughthe three top valves~so~rne d~rin~ a dynamically simulated unloading sequence.From this plot you can see the flowthroughthe valves as a func-tion of time. Also you can sea how an upper valve does not quitfl~wing untilthe next lower valve bagins to flow. This is a desir-able sequence for the unloadingprocess. In this particularexam-ple, the thkd valve is the injection valve which assumes aconstantflow rate with time after it is uncovered. These calcula-tionsallowthe userto estimate whether a valve designwill,orwillnot, unload in advance of the field installation.

~,gtije I ~ sh~~~=some additiona! data from this type ofmodel, showing both annulus and tubing levels from examplecalculationvs. time duringthe unloadingprocess.

Further use of a valve model will allow the user to predictfluidand gas velocitiesduringunloading,and alsoto predot backflow into the formation. The user can then attempt to makeadjustments in suggested unloading procedures in advance tominimize undesirableeffects.

Coiled Tubing Gas Lift InstallationsThe advent of common coiledtubingoperationshas lead to

the innovationof placingvalves insidecoiledtubingbefore inetal-Iation.This aliowsquickinstallationby just runningthe coiledtub-ing and the valves inside which are already instailed. Thismethod does restrict the flow in the vicinity of the valve (seeFigure 18). There is no external enlargement of the coiledtubingto restrictstandard spoolable runningoperations.The spoolablesystem is now available in 2 3/8s coiled tubing (seeReference 15). Another W=Y t~ dU {,,,= 1,,, -w, -- .---..= ----- lM- ,,Ath ~ml!d tI Ihinn is toband valve installationsto the coiled tubing as it is run.

Swfec4 Cwmo!!wf Va!veA concept of an electricallycontrolledvalve forthe injetilon

valve is discussed in Reference 16. This would allow surfacecontrol of the flow rate through the injectionvalve for changingwell condtions. It remainsto be seen what kind demand there isfor close controlof the injtiton valve from the surface.

Hydraulic jet and reciprocatingpumping have not seen asmuch use as some other methods in recent years. A survey indkcates that many ofthe currentinstallationsof hydraulicsare deep(-10,000 ft) wells producing small amounts of fluid(-1 00-300 bpd). There are exceptionsto these average vaiues.

Problems in the past have centered on too much effort tomaintain clean fluidsfor the surface and down hole pumps. Alsoit isdifficultto handle large amountsof fluidin some locations.Onthe plus side, some installationscan be aeiected to allow circu-ia~ng ~ faii~ pump t~ the surface w~ho~ pulli~ tubhg. Furtherit is easy to vary the productionrate if the surface power fluidpump has the capacity.

The use of horizontal ESPs for power fluid or other powerMM centrifugal pumps helps hydrauiic pump installationsthatexperience wear in the surface pump due to solids.This type ofinstallationbecomes much more solids resistant if the hydraulicpump is a jet. However a centrifugalpump at the surface with ajet pump downhcrleleads to a lees ~lcient system.

S42

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SPE 27990 J. F. Lea and H. W. Winkler 5

Small hydraulic powered jet pumps are available forde-watering gas wells. One vendor of pumps offers a pump withless than .75 in. OD, and lengths of less than 12 in. This smallpump allows it to be run in highly deviated holes (seeReference 17).

With this smaller jet pump, coiled tubing can also be usedas the power fluidstringwith OD sizes startingat 1 in. The smalljet pump can be circulatedIn and out of the well insidethe coiledtubing. The small coiled tubing string can be run inside produc-tion tiibm~ VAtll,11=~l--c-- ------ -- ......= --. : _ .. :+h +ha rWAI i d fllji~q ~fi~inn ba~ up the powerfluid/productionstring. The gas can be producd up the casingannulus.

Figure 19 (Reference 18) illustratesa jet run insideproduc-tion tubing on coiled tubing. TM padcular illustrationis for an1-1/4 in. jet pump.

PC pumps have been used invarious applicationsin recentyears. Some of the more favorable conditions include takingwater off coal seam wells, pumpingviscoussandy crude in shal-low wells. They have been tried in highwater cut W. Texas wellsat around 4000 ft depth (see Reference 19).

Weak points have been the fact that gasses such as I-&and C02 attack the rubber stator and it can swell or harden withtime thus leading to pump failure.Insertable PC Pump

One new innovationdeveloped in S. America is an insert-able PC pump. This pump allows the stator to be pulled with therotor. It has a lower productioncapacity. No data is available onthe run life experiences using this form of lift, but the conceptwarrants future consideration, especially for de-watering gaswells. See Figure 20 for a schematic of this concept.%iifiger L?ft

Plunger lift seems to be seeing increasing applications.This may be attributedto the advent of microprocessorcontrol-lers taking out some of the manual adjustment required in the~?. A ~adety of p!ungersexist with the brush plunger (brbtleecan wear) and the expanding blades giving the best fluid seal.One innovationhas a seal under the expanding blades.

RYBeam pumping may benefit from better models resulting

fromtechniques measuring down hole rod loads while the unit isrunning.Althoughsophisticatedconcepts exist for more efficientbeam pumping systems, they may be expensive to develop andmarket. It is likelythat the use of existingequipmentwillcontinuewith practical improvedcontrols,better materials (possiblydras-tically different) for rods, stuffing boxes, possibly pumpbalkdseateand other components.

Electricalsubmersiblepumpsshouldbenefitfrom improveddown hole sensors for critical installations. High temperaturemotorsindicatethat motor life improvementsare possible. Leak-age around seals is a problem when vibration is present.Improved sand handlingdesigns may pointthe way to improvedgeneral use pumps wtich do not have as much wear and vibra-tions, thus leading to longer total system life. Motors are behgadverthd with improved efficiency. Pump efficiency mayimprovewith smootherfinish manufacturingtechniquesand bet-ter hydraulicdesign with time.

Gas lift techniques, especially higher volume wells, mayshow improvement in design, analysis, and operation with theadvent of models of gas lift valves resulting from gas lift valvetesting. Using the valve models, the unloadkrgprocess can be

examined with respectto flow of gas or liquidthroughthe valves,and also with respect to effects on the formation during theunloadingprocess, Gas lift valves with coiled tubing (mountedon the insideor the outside) may add to the ease of applyinggaslift.

Hydraulic lift developments include the advent of small jetpumps utilizingsmall stringsfor de-watering gas wells. Horizon-tal ESPs for power fluid show better life in solids mntaminatedfluids but exhibit lower efficiency than positive displacementpumps.

PC pumps are used in sandy, viscous, or solids producingwells. The rubber statore are still susceptible to some gassessuch as H@ and C%. Downhole motors are being examinedtilch if successful, could extend PC operation to deeper wellsand into more deviated wells. An insertable PC pump has beendeveloped for lower volume producingwells.

1.

2.

3.

4.

5,

6.

7.

8.

9.

10.

11.

12.

343

Lea, J. F. and fulhisssle:Beam Pumps Surpass ESP Effi-ciency; Oil and Gas Journal, May 18, 1992, p. 72 to 75.Hensley, H. N., et. al.: Ribbon Rod Development for BeamPumping Applications, Forty-First Annual southwesternPetroleum Short course, April 20-21,1 g94, p. 44 to 55.,TexasTech University,LubbodGTX.BYrd, J. P. and Beaeley, W. L.: pr~l~n9 pfime MoverRequirements, Power Costs, and Electrical Demand forBeam Pumping Units; CIM Paper No. 374035 presented atthe 25th Annual Meeting of Petroleum Society of CIM, inCalgary, May 7-10,1974.Albert, G.: Downhole Dynamometer Tool: Proceedings ofFo~-First Annual Southwestern Petroleum Short Course,Lubbock,TX, April20-21, 1994, p. 1 to 3.Ott, R. T., and Mendanhall, G. L.: Maldngthe Most of RodDesign - A Comparison of Measured Rod String stressesEmphasizing Fiberglass Rod% Forty-First Annual South-western Petroleum Short Course, April 20-21, 1994, p. 91to 105.Gibbs, S. G.: Design and Diagnosis of DdatedRod-Pumped Wells; Journal of Petroleum Technology,Vol. 44, No. 7, p. 774 to 781, July 1992, SPE 22787.Li, Y., Zhu, S.: PromotingSubsurface Pump EfficiencyandDeveloping Working Conditionsof Mechanical Oil Produc-tion System by Means of Real-Time Numerical ControlTechnology; 67th Annual SPE Technical Conference,Washington DC, Proceedhgs of Production Operations &Engineering,p. 1017 to 1024, SPE 24947, April4,1992.Butlin, D.: Constant Torque for Beam Pumps driven byElectricMotor%a proposalsubmittedto DOE, 1989.Lea, J. F. and Winkler, H. W.: Whats New in ArtificialUftvWorid Oil, March 1994, p. 44 to 51.Fickee. B., Fuller, D., and Dowdy, R.: ElectricalSubmerg-ible Pumping Systems Applied in High Temperature Envi-ronments, 1994 Electrical Submersible Pump Workshop,April,27-29, Houston,Texas.Nieberding, M. A. et. al.: Formalization of Nitrogen-LoadedGas-Lift Valve Performance Data; SPE 20673 presented atthe 1990 SPE AnnualTechnicalConference and Exhibtion,New Orleans, Sept., p. 23 to 26.Decker, K. L.: Gae-Uft Valve Performance Testing andData Correidlom SPE Production & Facilftfee,May 1993,p. 101 to 107.

6 NEW AND EXPECTED DEVELOPMENTS IN ARTIFICIAL LIFT

13. Winkler, H. W. and Eads, P. T.: Applyingthe Baeic Perfor-mance Corwep*S of Shg!e-E!ement, Unbalanced Gas-LiftValves for Installation Desigm SPEPE Journal, August1993, p. 211 to 216.

14. Capucci, E. C., and Serra, K. V.: Transient Aspects ofUnloading Oil Wells Through Qae-Lift Valve%SPE 22791,presented at the 66th Annual Technical Conference of theSPE in Dallas, TX, October 6-6,1991.

15. Lea, J. F. and Wlnkler, H. W.: Whats New in Artificiall-ift:World Oil, May 1993, p. 41 to 45.

16. Schnatzmeter, M. A., Yonker, J. H., Pool, C. M., Goiffon,J. J.: Developmentof a Surface ControlledElectricGas LfffValve; JPT, May 1994, p. 436 to 441.

17. Martin, J. M., and Coleman, W. P.: Innovative Jet PumpDesign Proves Beneficial in Coafbed Methane De-WateringApplications? presented at the 4f)th Annual SouthwesternPetroleum Short Course, Lubbock, TX, April 21-22, 1993,p. 34-43.

18. Teit, H.: Hydraulic Pumping Systems ArtificialLift for Ver-ied LifMg Requirements, presented at the 40th Annualsouthwestern Petroleum Short Course, Lubbock, TX,April21-22, 1993, p. 106-114 and Trico Bulletin PB 9-171-1/4 Jet FreePump.

19. Wright, D. and Adair, R.: Progressive Cavity PumpsDeliver Highest Mechanical Efficiency/Lowest OperatingCost in Mature Permian Basin: p. 151 to 157, FortiethAnnual Southwestern Petroleum Short Course, April 21-22,1993, Texas Tech University,LubbockTX.

SPE 27990

Figure 1

Typical Beam Pump Losses

)+&JQ~y,,:,,iciencyHigher SPM,

.: More Losses L Gearbo:K, Belts,Bearings.

Units Lc)aded =Better Efficiency

f

AH STANDARDRIBBONROD ~

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Figure 2

Typical Losses for ESP Installation

Surf LOSS = 2.9%

(T \

Puly8\;ssHp, Useful= 46.6 ~0

;;-:: ~d!

20:30 bad

L 7

\MotorCable Loss

Loss ==5.8?40= 16.4Y0

5.5 Casing Equipment

Figure 3 Rlbbun rodl End Connection Figure 4Ribbon rod Reeled on Smflce Truck at Well Site

Figure 6

Ffgure 5 New Pumping Unit Concept

Schematic of Beam Pumping System__ -..~ ._rcglh

%+replacefixedspeedprimemover withvariable speed constant torque= SJ@em

.. .

Figure 7: hMtf-Chonnel Sensor System for ESPS

-. .

Figure 5:Schematic of Multi-Channel ESP Sensor System

- Bolt On Head- Discherge

Pra8sure/lemper$ ture- Pump

- protector

_ SignalCable

Motor

Motor

Downhola Monitoring

Tool

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Figure 10

.

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Figure 11:Zirconia Bearing System for ESP SandResistance

Figure 9Hi-Temp Motor with Surface InjectIon Une forMotor Oil

347

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Figure 12 Two Concepts for Downhoie Motorfor PC Pumps

+ 1PO NiTROGEN DOME

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Figure 13: Gas-i.fft Vaive Schemaffc

ma, ..A 1Arl~w-w *-

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I

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l 450 0900950 0525 m 936A600 q 975

X 675 l 1000v 750 q 1050

J ~A..o 500 1000 1500 2000 2500

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