investigation of failed pump components

8/8/2019 Investigation of Failed Pump Components

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- DOE/AL/18536-T1(DE85009648)

INVESTIGATION OF COMPONENT FAILURES IN DOWNHOLEGEOTH ERMA L PUMPING SYSTEMSFinal Report

BYDouglas K.Werner

March 15 ,198 5

Work Performed Under Contract No. AC 04-82AL 18536

Barber-Nichols Engr. Co.Arvada, Colorado

Technical Information CenterOffice of Scientific and Technical InformationUnited States Department of Energy


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DISCLAIMER

Portions of this document may be illegible inelectronic image products. Images are producedfrom the best available original document.


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DISCLAIMER

This report was prepared as an account of work sponsored by an agency of theUnited States Government. Neither the United States Government nor any agencythereof, nor any of their employees, makes any warranty, express or implied, orassumes any legal liability or responsibility for the accuracy, completeness, or use-fulness of any information, apparatus, product, or process disclosed, or representsthat its use would not infringe privately owned rights. Reference herein to any spe-cific commercial product, process, or service by trade name, trademark, manufac-turer, or otherwise does not necessarily constitute or imply its endorsement, recom-mendation, or favoring by the United States Government or any agency thereof.The views and opinions of authors expressed herein do not necessarily state orreflect those of the United States Government or any agency thereof.This report has been reproduced directly from the best available copy.Available from the National Technical Information Service, U. S. Department ofCommerce, Springfield, Virginia 22161.

Price: Printed Copy A03Microfiche A01

Codes are used for pricing all publications. The code is determined by the numberof pages in the publication. Information pertaining to the pricing codes can befound in the current issues of the following publications, which are generally avail-able in most libraries: Energy Research Abstracts (E R A ); Government ReportsAnnouncements and Index (GRA and I); Scientific and Technical AbstractReports (STAR); and publication NTIS-PR-360 available from NTIS at the aboveaddress.


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DOE/AL/18536-T1(DE850O9648)Distribution Category UC66C

- - _ _FINAL REPORT

INVESTIGATION OF COMPONENT FAILURESIN-DOWNHOLE GEOTHERMAL

PUMPING SYSTEMS

Prepared by:

Prepared for :

March 15, 1985Contract DE-AC04-82AL18536

Hugh M. TurpieU.S. Dept. of EnergyAlbuquerque Operations OfficeContracts & IndustrialP.O. Box 5400Albuquerque, NM 87115

Relations Div.

Douglas K. WernerBarber-Nichols Engr. co.6325 W. 55th Ave.

I I Arvada, CO 80002.) -1BARBER-NICHOL

ENGINEERING


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F'CF FINAL REPURT

1. ) INTRODUCT ON2.0 PRESSURIZED MOTORS2.1 OPERCSTING EXPERIENCE2.2 NEED FOR A DOWNWOLE kEGULATOH2.3 DOWNHOLE REGULATOR DEVELOPMENT

3.0 IMPROVED POTHEAD AND PACKOFF CONFIGURATION4.0 PUMP SCALE ACCUMULATIONS5 . 0 PUMP PERFORMQNCE RECCIRD,

CL- . l B I N EXPERIENCE5 . 2 OTHER EXPERIENCE .

. _


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i I1.0 INTRODUCTION

O p e ra t i n g e x p e r i e n c e w i t h downhole geothermal pumps hasd em o n st ra te d t h a t o p e r a t i n g l i v e s o f l e s s t h a n one y ea r a r e v e r ycommon. I n o rd e r f o r l i qu id -do min a ted geo the rma l power sys temst o be e c o n o m i c a l l y v i a b l e , one ye ar o r l onge r con t inuous downho ler u n n i n g t i m e s i n g eo th er m al w e l l s at t e mp e ra t u re s up t o 375"-F a r eneeded. The e f f o r t summarized by t h i s r e p o r t was d i r e c t e d to w a rdi m p r o v in g t h e l i f e o f e l e c t r i c , dow nhole s u b m e r s ib l e pumps. A su se d h e re i n , "pumps" r e f e r t o t h e as se mbl y c o m p r i s i n g t h esubmersible . e l e c t r i c mo to r, mo to r p ro t e c t o r , pu mp in g e l eme n ts ande l e c t r i c po wer c a b le . Pump component r e f e r s o n l y t o t h e p umping.elements.

E x p e r i e n c e w i t h e l e c t r i c downholc sub me rs ib le pumps showedx p e r i e n c e w i t h e l e c t r i c downholc sub me rs ib le pumps showedt h a t i n t r u s i o n o f b r i n e i n t o t h e m o to r o r c a b l e ha s been a commonf a i l u r e mode. I f t h e mo to r and c a b l e c an b e p re s s u r i z e d t op r e v e n t t h e i n t r u s i o n o f b r i n e , t h e o p e r a t in g l i S e OS t h e pumpcan be marked ly inc reased . Th is r e p o r t summar izes Ba rbe r -N i c h o l s ' w ork d u r i n g t h p e r i o d o f Fe b ru a ry 1, 1982 th rough June. 3 0 , 1983 unde r con t rac t number DE-AC04-82AL18536.

T h i s s t u d y i n v e s t i g a t e d component f a i l u r e s i n e l e c t r i c ,h o le subm ers ib le pumps wh ich p reven ted th e a t ta in me n t o f one

1) yea r c on t in uou s downho le run n in g time5 i n g eo th er m al w e l l s a tt e mp e ra t u re s up t o 375"-F. The fo l l o w in g ta sk s were accamp li shed:

-~ ~ ~ - - - - __- - - - - - -_ ~ ~ _ _

I


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. * I 2I

a. Investigated the feasibility of a pressurized motor toprevent brine intrusion into the motor.

b. Investigated improved pothead and packoff designs formore consistent field installation and improved performance.

\.c.\ Investigated brine scale buildup on impeller sleeve


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s - 'shown t h a t comm erc ia l ly a v a i l a b le pumps have an ave rage op e r a t i n gl i f e s l i g h t l y i n excess o f 1 , X ) O hours. T h i s e x p e r i e n c e i s

d iscussed i n g r ea te r d e t a i l i n S e c t i o n 5 . When a downhole motorwas p r e s s u r i z e d w i t h a n e x p e r im e n t a l o i l p r e s s u r i z i n g system , t h ea ve ra ge l i f e t i m e i n c re a s e d t o 4,526 h ou rs . The l o n g e s t o p e r a t i n gl i f e was 7,900 hours. T h i s d ram a t i c immprovement i n op e ra t i ngl i f e i s b e l i e v e d t o be m a i nt ai n edabove ' b r i n e p r e ss u re b y t h e e x t e r n a l o i l p r e s s u r i z i n g s ystem .

\th r e s u l t o f t h e m otor b e in g

The p r o t o t y p e o i l p r e s s u r i z i n g system u se d f o r our t e s t s a tt h e E a s t Mesa f a c i l i t y was added t o a n . e l e c t r i c s u bm e r s ib le Redapump u se d t o p ro v i d e geothC rma1 b r i n e f o r t h e 500 kW d i r e c tc o n t a c t h e a t e xc ha ng er p i l o t p l a n t . The p r e s s u r i z i n g sy ste mschemat ic i s shown i n F i g u r e 1, "Downwell Motor O i l P r e s s u r i z i n gSystem." ' 6s shown i n t f i g u r e , a p i p e l e n d s f r om t h e dow nw ellmo to r t o t h e s u r f a c e mou e d o i l s ju pp ly s ys te m. A s the downho lep r e s s u r e v a r i e d w i t h w e l l p r o d u c t i o n and t i m e , t h e v a r y i n gpr es su re was sensed b t h e b u b b l e t u b e p re s s u re me a s u r i n gequ ipmen t and th e p ress ; on th e su r fa ce ad jus ted . I n t h i smanner, t h e p re ss ure i n t h was ma in ta in ed a t 7 t o 10 p s iabove t h e w e l l p r es s ur e . akage o f o i l o u tw a rd f r o m t h emotor was th e n re p il f rom t h e sur fa ce . When t h e w e l lpr es su re was decrease e p r e s s u r e i n t h e mo t o r w a s

a r e l i e f v ven ted o i l f r om t h e t o p o f t h e

1n c a r p a r a t e d as - the


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J

I


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. .6

p Tr zp r e s s u re s o u rc e r a t h e r t h a n a motor-dr iven pump 5 0 t h a t o i l

p re ssu re was ma in ta ine d d u r i n g power ou tages . A b a t t e r y p o w e rs u p p l y p r d v i d e d e n er gy f o r t h e c o n t r o l s ys te m d u r i n g powero utag es . D u r i n g e x t r e m e l y r a p i d i n c r e a s e s o f d ow nh ole w e l lp r e s s u r e ( w h i c h was p o s s i b l e d u r i n g e l e c t r i c a l power o u t a g e s ) ,t h e b u b b le t u b e pres su re co u ld no t keep up w i t h t h e i n cr e as e i nd ow nh ole p r e s s u r e and t h e p r e s s u r e i n t h e m o tor was m a i n ta i n e dabove we1 1 pre ss ur e by a be l ow s assembly mnunted on t h e bo t tomo f t h e e l e c t r i c m otor. A s i s f u r t h e r d isc us se d i n S e c ti on 5.1 o ft h i s r ep o r t: , t h i s s ys te m o p e r a te d f o r 7,900 h o u r s w h ic h, a t t h et i m e , r e p r e s e n t e d a r e c o r d f o r e l e c t r i c , dow nhole s u b m e r s ib lepumps opera t ing w i t h 35OQ-F b r i n e .

2.2 NEED F O R A DOWNHOLE REGULATOR

A d i sadvan tage o f t h i s system i s encountered w i t h pumps

Th i s sys tem is s i m i l a r t o t h e p r e v i o u s l y d is cu ss ed c o n f i g u r a t i o n- - w i t h t h e a d d i t i o n of a - dawnhole presm..~re r e g u l a t o r i n t h e oil


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. . !! 7i1

s u p p l y t u b e b etw ee n t h e s u r f a c e and t h e m o tor .

The o p e r a t i o n o f t h i s s yste m i s a s f o l l o w s : The o i lr e s e r v o i r on t h e s u r f a c e (known a s t h e a c c um u l a to r v e s s e l ) i sm a i nt a in e d a t c o n s t a nt p r e s s u re by r e g u l a t i n g t h e gas p r e s s u ref ro m a n i t r o g e n b o t t l e . A n i t r o g e n b o t t l e i s used so t h a t o i lp r e s s u r e c a n b e m a i n ta i n e d i n t h e e v e nt o f an e l e c t r i c a l poweroutage. The pr es su re i s s e l e c t e d t o m a i n t a i n t h e dow nhole m o to ro i l s u p p ly p r e s s u re above t h e b r i n e p r e s s u r e r e g a r d l e s s o fo p e r a t i n g c o n d i t i on s . T h i s h i g h p re s su re o i l is c on ne ct ed t o adow nhole p r e s s u r e r e g u l a t o r w hic h m a i n t a i n s t h e p re s s u r e on t h edownstream side of t h e r e g u l a t o r a p r e s e t v a l u e above a mb ie ntw e l l p r e s s u r e . T h i s r e g u la t e d o i l p r e ss u re i s t h e n c o nn e cted t othe mo to r . cls t h e w e l l p r e s s u r e i n c r e a s e s ( s a y d u r i n g d ec re as edpump f l o w ) t h i s r i s e i n p r e s s u re i s s ensed b y t h e r e g u l a t o r w hic ha d m i t s a s m a l l a d d i t i o n a l a mount o f o i l t o t h e m o to r t o m a i n ta int h e p re s % ju re abo ve b r i n e p r e s s u r e. D u r i n g O p e r a t i n g c o n d i t i o n s

5

when t h e w e l l p r e s s u r e i s r e du c e d ( s u ch a s d u r i n g pump s t a r t o ru r i n g i n c r ea s e s i n mp f lo w r a t e ) , t h e p re s su re i n t h e w e l l i s

reduced and escess p ressu r i n t h e m o to r is v e n t e d t h r o u gh t h edownhole r e l i e f v a lv e . A n exbe low ' the mot" g i v e " i n t h e o i l volumb e ll ow s a l s o m a i n t a i e ss ur e s l i g h t l y above b r i n ep r e s s u r e i n case of o i l s up p ly s ys tem f a i l u r e .

w i t h t h e mo to r p ro v id es some

- _ __ -. ._ - - A n o i l - - f l o w . m e t e r - . - . i 5 p r o v i d e d an t h e - s u r f a c e to m o n i t o r -


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. .

downhole pump oilgauge is providedconvenience.

1 8

pressurizing system performance and a levelon the oil accumulator vessel for operator

This improved downwell pump pressurizing system is suitable+or installation in both shallow and deep settings. The downholepressure regulator is not commercially available and hence, wasdeveloped during this program. Additional details of thedownhole regulator are discussed in Section 2.3.

. . 2 .3 DOWNHOLE REGULATOR DEVELOPMENT

The performance specifications f.or the dow'nhole regulatorassembly are shown in Table 1, Downhole . Regulator .Spec f cat ons. We are unaware of com'mercially availablepressure regulators which meet all the requirements of Table 1.Therefore, B/N's first step to develop the regulator was toprocure a commercially available pressure regulator valve. Thisvalve wa5 believed to meet the flow requirements, but not thepackaging or metallurgical'requirements, This valve was thenconnected to a commercially available diaphragm-type relief valveto make a ' lieving" type pressure regulator which wasresponsive to t h increases and decreases in brine pressure. A s

gram confirmed the fl w performance of the regulator -and identified some material problems, the failed components werereplaced with those made of superior materials. The long term


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. . I

w i t h i n a f i v e - i n c h d ia m e r p i p e and co nt r u c t i t f ro m m a t e r i a l sc o m p a t i b l e w i t h th e geothermal env i ronment . Two va lv es soc o ns tr uc te d , were i n s t a l l e d i n t h e B a rb e r- N ic h ol s l a b o r a t o r y w e l lc as in g s i m u l a t i o n t e s t r i g . M o b i l SHC 639 s y n t h e t i c h y d r o c a r b o no i l was p r e s s u r i z e d b y a h y d r a u l i c pump b e fo r e p a s s i n g t h r o u g ht h e r e g u l a t o r v a lv e . The r e g u l a t o r and r e l i e f v a l v e s and an o i lchamber ( t o s imu1ht.e t h e downhole motor and be l lo w s assem bly)were l o c a t e d i n s i d e a h e at ed , w a t e r - f i l l e d , p r e s s u r i z e d chamber

i,

t o s im u la te th e downhole env i ronmen t . The wa te r p res su re wasc y c l e d t o s i m u l a t e d ow nh ole c o n d i t i o n s d u r i n g pump o p e r a t i o n .The o i l s u p p ly p re s su re t o t h e . r e g u l a t o r was m a i n ta i ne d a t aminimum o f 369 psig' . .

The test r i g was o p e r a te d 2 4 h ou rs -a -d ay f o r s i x days a weekw i t h t h e " w e l l " p r e ss u r e c y c l e d betw een 209 p s i g and 300 p s i g .The va l v es ma in ta ine d th e s im u la t ed mo tor chamber 14 t o 35 p s iabove t h e s i m u l a te d b r i n e p r e s su re . The h i g h e r o i l p r e s s u r eo c c u r r i n g d u r i n g h i g h e r b r i n e p r e ss u re c o n d i t i o n s . A f t e r s i xda ys o f e r a t i o n , t h e t e s t rig was shut down and t h e v a l ve s. I n s p e c t i o n t h e v a l v e com pon en ts showed n o s i g n s o fwear o r d i s t r e s s .

m bled and a d j u s t e d and t h e t e s t r i g1 days of o p e r a t i o n , (19 days

d iaphragm of t h e r e l i e f v a l v ef a i l e d . The f a i l u r e was t r a c e d t o i m p u r i t i e s i n t h e w a te rc a u s i n g the d i a p h r a g m - to . - bcome b r i t t l e and. f a i l d u r i n g v a l v e -


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c y c l i n g . The b r o nz e d ia p hr ag m s o f b o th v a l v e s w ere r e p l a c e d w i t hd iaphragms manufac tured f rom 316 s t a i n l e s s s t e e l . I t wasr e c og n iz e d t h a t 316 s t a i n l e s s s t e e l would p r o b a b l y n o t bes u i t a b l e f o r many w e l l e n v ir o n m e n ts b ec au se o f i t s s u s c e p t i b i l i t yt o c h l o r i d e s t r e s s c o r ro s io n c ra ck in g . I t d i d r e p r e s e n t ane x p e d ie n t r ep la c em e nt f o r t h e l a b o r a t o r y t e s t i n g .

The v a l v e s w ere re a ss em b le d and t h e v a l v e t e s t i n g c o n t i n u e dw i t h S25P-F h o t w a te r. The v a l v e s w ere t e s te d f o r 32 days whent h e w a te r t e m p e ra t u re s e t p o i n t was i n c r e a s e d f r o m 325"-F t o 380-Ft o p r o v i d e a m o r e s ev ere t e s t o f t h e p re s su re r e g u l a t o r c o n t r o land r e l i e f v a lv e . The v a l v e s ' m a i n ta i ne d t h e m ot or c a v i t yp r e s s u r e 7.7 to 25.3 p s i above t h e s i m u l a t e d w e l l p r e s s u r e w hic hi s s l i g h t l y h i g h e r t h a n d e s i r e d . The p r e s s u r e s c o u l d b e changed-- . ,

_ _ m o d i f i c a t i o n s w ere made t o the v a l v e a t t h i s t im e t a - - d e t e r m i n e


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t h e l i f e o f t h e o r i g i n a l s o f t T e f l o n s ea ts . The m e ta l- to -m e ta ls e a t s o f t h e p r e s s u r e r e g u l a t g v a l v e showed n o d i s t r e s s .

The va lves w ere r ea s se m b le d an d i n s t a l l e d i n t h e t e s t r i gwhic,. was op era -ed a t 580"-F and t h e o i l s u p p l y p r e s s i tr e was 5ie-a t a p p ro x im a t e ly -300 ps ig . The s imu la te d mo to r p res su re wasm a i n ta i n e d t h r e e t o e i g h t p s i ab ov e s i m u l a te d we1 l \. p re s s u re . Thet.ec,t r i g o p e r a t e d c o n t i n u o u s l y - fo r 137 d ay s u n t i l t h e system wass h u t dawn becau se o f a p r e s s i t r e r e l i e f v a l v e l e a k . Teardowni n s p e c t i o n showed t h e v a l v e s e a t a r e a t o be p a r t i a l l y cove redw i t h a b la .c k m a t e r i a l w h ic h p r e v e n t e d t h e v a l v e f ro m s e a t i n gt i g h t l y . Sam ples o f t h e b l a c k m a t e r i a l , new ' o i i and use d o i lwere sent t o t h e M o b i l O i l l a b o r a t o r y f o r a n a l y s is . T h e i r

- a n a l y s i s showed t h e u se d o i l s am ple c o n t a i n e d (3.2% water wh ich i sn o t c o n s id e r ed e x c e ss iv e f o r us ed o i l . The used o i l sample dl50c o n ta i n e d 30 ppm s i l i c o n w h ic h i 5 an i n d i c a t o r o f wear w i t h i n t h esys tem. The b l ac k m a te r i a l removed f rom th e va l v e sea t wasp r i m a r i l y com posed o f n i c k e l and alum inum f i n e s w i t h t r a c e s o fi r o n and 5 i l i c o n . Q u ot in g f ro m t h e M o b i l O i l r e p o r t , " i t appearst h a t a pump o r o t h e r p i e c e o f equipment i s ex pe r i e nc ing wear andt h e d e b r i s i s a c cu m u la t i ng a t t h e p re ss rju re r e l i e f v a lv e " .

h e t e s t p ro gr am we r e b u i l t a n o i l pump w h ic h c o n t a in e d a nctnger. A pp ar en t l y th e pump wear m a te r i a l foun de t e s t l o o p and t o t h e r e l i e f v a l v e s ea t where

,

i t a cc um u la te d, p r e v e n t i n g t h e v a l v e f ro m c l o s i n g .

.. - . The- mod i f i e d p r e s s u r e r e g u l a t o r was t e s t e d f o r 3,200 t o t a l


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iThours . W i t h p r o p e r m o d i f i c a t i o n and a d d i t i o n a l d ev elo pm en t,th es e components can be packaged i n a m anner s u i t a b l e f o ri n s t a l l a t i o n w i t h a downhole submersible pump.

3.0 IMPROVED POTHEAD ClND PACKOFF CONFIGURATIONS

B a r b e r- N ic h o ls e x p e r i e n c e w i t h d ow nh ole pump i n s t a l l a t i o n s '.h as shown t h a t c a b l e end t e r m i n a t i o n s h av e a h i g h r a t e o f f i e l df a i l u r e s . The e l e c t r i c a l c a b le t e r m i na t i on a t t h e m otor i s knownas t h e p ot he a d w h i l e t h e t e r m i n a t i o n a t t h e s urfa ce -m ou nte dwe l l head i s c a l l e d t h e p a c k o ff .

.The p re sen t po thead p ro v id ed by Reda i n co rp o r a t es an

e l as t o m e r s e a l t o - p r e v e n t t h e e n t r a n c e o f b r i n e i n t o t he . m otorc a v i t y . T h i s s e a l m u s t b e c o m p a t i b l e w i t h b o t h h o t o i l and h o twa te r . I n g e n e r a l , h i g h t e m p e r a tu r e ( a p r o s i m a te l y 350a-Fc a p a b i l i t y ) e la s to m e rs w hic h a r e e x c e l. le n t f o r u se w i t hh yd ro ca rb on o i l s a r e n o t c o m pa t i bl e w i t h h o t w a te r and v i c eversa . Hence t h e e laEjtomer in co rp or a t ed i n t h e p r e s e n t p o th e adc o n f i g u r a t i o n is a comp A m e t a l h e r m e t i c s h e a ths u r r o u n d in g t h e e l e c t r a1 c o n d uc t o rs w ou ld e l i m i n a t e t h e needf o r t h e e l as t om e r ic 5e

uc ing an improved po thead andc a b l e c on f i g u r a t i o n w a s m ine t h e c o m m e r c i a l ly a v a i l a b l ec a b l e i n s u l a t i n g m a t e r i a l t h a t c o u l d b e i n c o rp o r a t e d i n a m e ta l

-sheath. Communicat ion w i t h w i r e m a n u f ac t u re r s d e te rm i ne d t h a t a


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I 14c

e f l o n - i n s u l a t e d c o p pe r c o n d u c to r most met ou r go als . However a te l e v a te d t e m p e r a tu r e s , a T ef l o n - i n s u l a t e d c op pe r w i r e i s n o tc a pa b le o f s u p p o r t i n g i t s own w e i gh t f o r l e n g t h s g r e a t e r t h a na p p r o x i m a te l y 800 f e e t . I t i s n ec es sa ry t o s u pp o rt t h e w i r e b ymeans o t h e r t h a n l o c a l c l am p i n g o f t h e T e f l o n i n s u l a t i o n b ec au set h e T e f l o n c an " c o l d f l o w " away f r o m t h e c la m p in g p r e s su r e .Numerous tech n ique s and p o t e n t i a l vendo rs were eva lua ted i n t h i sregard .

I t was le ar ne d t h a t Ha lpen En g in ee r ing Company has at e c h n i q u e w hereby T e f l o n - i n s u l a t e d i n s t r u m e n t c a b l e s a r e c o v e re dw i th a l l o y 629 welded sheaths . Th.is te ch n iq ue can co nc e iv ab ly bee xten de d t o p ow er c a b l e s w h i c h a r e much l a r g e r t h a n t h ei n s t r u m e n t c a b l e s . H ow ever, c o s t l y n'ew t o o l i n g i s r e q u i r e d t o

a t e t h e l a r g e r w i r e s iz e . A s p a r t o f t h i s concep t, t h et h r e e s he ath ed w i r e s w ou ld be j o i n e d t o t h e mo to r w i t h a s p e c i a lpo thead. The shea th wou ld be p ro te c te d f rom ab ra s ion and o t he rmechanical damage b y a w rap o f g a l v a n i z e d s t e e l a rm or s i m i l a r t o

y a pp l i e d t o downho le pump power cab les .

u se t h e m e ta l s he at hs a r e n o t drawn t i g h t l y a g a in s t t h e

e l e c t r i c a l i r ju la t ion e r e i s a s m a l l d is c o n ti nu o u s a nn ulu sa th .T h i s a n n u l u s m b e p r e s s u r i z e d

q u id t o p r e v e n t i n i n g r e s s o f b r i ne . I f o i lp r e s s u r i z e t h e a n nu lu s, it c o u l d a l s o be used t o

p r e s s u r iz e t h e m oto r c a v i t y b y s im p l y a d m i t t i n g o i l t o t h e m o t o rt h r o u g h __.h e p ot he -a d _. -F or i n s t a l l a t i o n h a v i n g deep- s e t t i n g - d e p t h s


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a nd l a r g e w e l l d r aw d o wn s , t h e c o lu m n o f o i l i n s i d e t h e c a b l ew o u l d d e v e l o p e x c e s s i v e p r e s s u r e i n t h e motor a n d a p r e s s u r e -t i g h t p o th e a d a l o n g w i t h a d ow nh ol e r e g u l a t o r s y s t e m isr e q u i r e d . CS c o n c e p t u a l d e s i g n of t h e i mp ro ve d p o t h e a dc o n f i g u r a t i o n f o r a s h a l l o w s e t t i n g d e p t h is sh ow n i n F a r b e r -N i c h o l s d r a w i n g PC F-001, C o n c e p t - C a b l e F e e d t h r o u g h . T h e a s s e m b l yof t h e i n s u l a t e d c o nd u c t o r i n t h e m e t a l l i c s h e a t h is known a s t h eMSC. T h e MSC e n t e r s P s t a n d a r d Sw ag e lok t u b e f i t t i n g made b yC ra wf or d F i t t i n g Company w h e r e i n t h e s h e a t h is t e r m i n a t e d . T heSwagelol.: : c o n n e c t o r f orms a metal-to-metal b a r r i e r b e tw ee n t h eg eo th er ma l b r i n e an d t h e o i l . The i n s u l a t e d e l e c t r i c a l c o n d u c t o rc o n t i n u e s t h r o u g h a metal t u b e t o t h e p o t he a d c o n n e c t o r w hi chi n t e r f a c e s w i t h t h e motor h ea d. T h i s c o n f i g u r a t i o n p r o v i d e s goods e a l i n g o f t h e b r i n e a n d o i l w h i l e b e i n g s u i t a b l e f o r e x i s t . i n gmotor p o t he a d c o n f i g u r a t i o n s . T h i s c o n c e p t is s u i t a b l e f o ri n s t a l l a t i o n w h e r e t h e motor d i r e c t l y t h r o u g ht h e MSC. T he c o n c e p t is a l s o a m e n i a b l e t o d e ep s e t t i n g pumps

h e motor is p r e s s u r i z e d t h r o ug h a s e p a r a t e o i l s u p p l yP r e s s u r i z e d o i 1 w o ul d t h e n b a ck u p t h r o u g h

a n o i l - f i l l e d c a b l e t o a l e v e l a b ov e t h e water l e v e l i n t h ew e l l . The o i l l e v e l w i l l b e m n i n tb e c a u s e of t h e lower s p e c i f i c g r a v Y of t h e 011. T he s h e a t h .c o u l d b e m ad e o f M o ne l, a1 l o y


21/43

I

I 16I,

4.C) PUMP SCALE ACCUMULATIONS

Many g eo th er ma l b r i n e s h a v e t h e p o t e n t i a l t o f o r m c a lc a r b o n a t e s c a l e o n pump p a r t s . I f s c a l e is f or me d i n s i d e

Many g eo th er ma l b r i n e s h a v e t h e p o t e n t i a l t o f o r m c a lc a r b o n a t e s c a l e o n pump p a r t s . I f s c a l e is f or me d i n s i d e

c i u mP LmP

i m p e l l e r s , s l e e v e b e a r i n g s or t h r u s t w a t e r s , t h e pump o p e r a t i n gt o r q u e may b ecom e e x c e s s i v e a n d resjult i n r e d uc e d o u t p u t o re l e c t r i c a l o v e r 1c a d s .

T w o m e t h o d s of e l i m i n a t i n g . t h i s s c a l e may b e i n c o r p o r a t e d


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' ' 17

g r e a t l y i n c r e a s e d a t e l e v a t e d t e m p er a t u r e s . What may b e as u i t a b l e i n h i b i t o r a t room t e m p e t a t u r e s may b e c o m p l e t e lyi n a d e q u a t e a t t h e t e m p e r a t u r e s e n co u n te r ed i n a h o t g e o t h e r m a lw e l l .

I t is p r e f e r a b l e t o a d d t h e a c i d t h r o u g h t h e p r o d u c t i o nt u b e of a shutdown pump r a t h e r t h a n a d d i n g i t t o t h e a n n u l u sf o r m e d b e t w e e n t h e p r o d u c t i o n t u b e a nd t h e w e l l c a s i n g . Theq u a n t i t y of c a r b o n a t e s c a l e i n t h e a n n u l u s i s d i f f i c u l t t oe s t i m a t e a n d h e n c e , i t is d i f f i c u l t t o d e t e r m i n e how much a c i d is

d . T he b r i n e i n t h e p r o d u c t i o n t u b e h a s b ee n p r e s s u r i z e di n g t h e e v o l u t i o n o f c a rb o n d i o x i d e , t h e r e f o r e t h e amount

o f s c a l e o n t h e p r o d u c t i o n c u b e wall w ou ld b e e x p e c t e d t o b em i n i m a l . If t h e a c i d is a d d e d to t h e w e l l . a n n + i l u s , i t may s implyf l o w down p a s t t h e pump and clean' t h e w e l l c a s i n g w h i l e n o tr e m o v i n g t h e pump i n t e r n a l s c a l e .

n g t h e pump t o u g h t h e p r o d u c t i o n tube r e q u i r e si n s t a l 1a t on . Pumps norm a l 1y .

i n c o r p o r a t e a b et we en t h e pump d i s c h a r g e a n d t h epump is t o b e a c i d i z e d t h ro u g h t h e

h o u l d n o t be i n s t a l l e d a t t h e1s o p e r a t i n g e x p e r i e n c e

p s s i n c e No vember 1979 h a s shownq u i r e d i n a r t e s i a n w e l l s .

.___Ahalternative--tcr-aridiaing.caled - pumps- w o u l d be t o a d d --


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II 18

sm a l l amoun ts o f an t i - sc a l an t chemica ls such as those produced byPf z e r t o t h e c o n t i n u o u y o p e r a t i n g pump. T h i s chemica lt r e a t me n t p ro c e du re w o ul d a l s o s e rv e t o p r o t e c t d ow ns tre ameq uipm ent f ro m c a l c i u m c ar b on a te o r s i l i c a s c a l i n g .

B a r b e r - N i c h a l s ' e x p e ri e n ce w i t h b r i n e pump s e i z i n g a f t e rremo v al f r o m t h e w e l l may b e o f i n t e re s t . D u r i n g remo v al an dsubsequent d isassemb ly o f geo therma l b r i n e pumps a t the Eas t Mesageotherm al t e s t f a c i l i t y , i t was common f o r t h e p u m p t o t u r nf r e e l y upon i n i t i a l r em ov al. Upon e xp os ure t o a i r t h e pumpsw ould b i n d and become d i f f i c u l t o r i m p os s ib le t o r o t a t e b yhand. T h i s phenomenon was ob se rve d even when t h e pump was

\\. 'i

. .

f l o o d e d w i t h w ate r o r D i e s e l f u e l . It i s b e l i e v ed t h a t s c a l e d i db u i l d up on i m p e l l e r s and b e a r i n d u r i n g n orma l pump o p e ra t i o n , ,

t h i s s c a l e d i d n o t s i g n i f i n t l y e f f e c t pump p erform an ce.Upon e x po su re t o a i r , t h i s s c a l e was c h e m i c a l l y a l t e r e d c a u s in gi t t o expand and t h e r e b y c a us i t h e r o t a t i n g e le m en ts t o b i nd .T he n a t u r e o f t h e chem ica l change i s unknown, b u t i s b e l ie v e d t o

bon d i o x i d e o r oxygen t h e a i r a c t i n g on

i

5 .0 PUMP PERFORMANCE RECORD

e r a t i n g e x p e r i e e l e c t r i c , downhole s u b m er s ib lepumps i s summarized in t i n . Ba rbe r -N icho ls ' e x p e r i e n c ea t t h e E as t Mesa ge othe rm al t e s t f a c i l i t y i s ' d i s c u s se d f i r s t .


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19

5.1 BARBER-NICHOLS EXPERIENCE

'The c o n f i g u ra t i o n o f t h e pump d iscussjed be low co n s i s ts o f am u l t i s t a g e v e r t i c a l REDA pump connected t o a th ree-phas e, 80 hpm otor t h r o u g h a p r o t e c t o r w hic h c o n t a i n s t h e s h a f t s e a l s r e q u i r e dt o i s o l a t e t h e m o to r f r om t h e h o t b r i n e . The pump p r o v i d e sbetw een 175. and 235 gpm o f SSO'-F geo the rma l b r i ne . Pcwer i spro v ide d t o t h e downho le m o to r by means of an armored ca b le wh ichc o n s i s t s o f c op pe r c o n d u c t o r s i n d i v i d u a l l y w ra pp ed w i t h a ra m i df a b r i c , EPDM rub be r and lead. The th re e w i r e s a r e then wrappedt o g e t h e r w i t h a g a lv a n i z e d s t e e l arm or t o make a f l a t c a b l e w h ic hc o n t a i n s n o s p l i c e s b etw een t h e p ot he ad and p a c k o f f . A q u a r t e r -i n c h d ia m e te r c ar bo n s t e e l b u b b le tu b e was l o c a t e d s l i g h t l y a bove.t h e .p u m p s u c t i o n t o measure t h e downhole p r es su re a t th e pumpi n l e t .

B a r b e r - N i c h o l s e x p e r i e n c e i s summarized i n Tab le 11. Thet a b l e sum marizes t h e i n s t a l l a t i o n number f o r i d e n t i f i c a t i o n ,

a te , f a i l u r e an d r e a1 d a te s , w e l l num ber, pumpg e oth er m a l b r i n e t e m p e r a tu r e , and a b r i e f

n of t h e run and f a i l u r e . A d d i t i o n a i n f o r m a t i o n a bo ut

u r e s is found below.

T h i s pump was i n s t a l l e d o n 7 /21 /7 9 , b u t was n o t s t a r t e d.. - u n t i l 8/14L74 b ec au se t h e r e m a i er- a+ t h e - + a c i l i t y was -not


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WellNo.-8-

8-18-16-26-2

6-2I

6-26-26-2

I

6-2 :

6-2

6-2

20

' TABLE I1BARBER-NICHOLS WWNHOLE PUMP EXPERIENCE

InstallationDate(Start Date)Surface Commentsailure Setting OperatingDate Depth Time( Removal (Feet (HoursDate)

Bui IdNo.-1

Temp.{OF)

92 79 - ' 620(f0%4/793. 315 333333

3333 0350

3503503503 0

350

Motor burned oWellhead incipifailureMotor contained. # gallon waterleak path unknoPackoff failure

11/16/79(11/17/79) 5/05/80 620(5/19/80) 40523 6/25/806/26 80

8/21/80(8/22/80)9/18/80(9/18/80

8/26/80 620(9/22/80) 14811 8/26/80 762 100(9/17/80) Packoff failure2 12/18/80 731(1/15/81) 2184 Same unit as 6-pected incipiencable failure

Packoff failuredr leaking wellhLeaking wellhea

Build # l e SUS-

1/16/81(1/17/81) 336/31/81 762(2/03/81) *2/06/81(2/06/81)2/10/81(2/10/81)3/17/81( 3/18/81)

2/06/81 731 si(2109/81)2/11/82 700(2117181 Pot head crack6/27/81 729(7/24/81) 2352 Wet cable. .WetSuspected pothewater leak5 9/04/81(9108181 9/14/81 739 136(9/22/811 BIN oil pressurizing system.Oil supply tubefailure. Pothead O-ringshaved

BIN oil pressurizing system.Sand wore outpump elements10/23/81 9/22/82 615 7900 350

1016182(10/07/82)7 B/N oil pressur-izing system.Damaged well cascaused pump to bcome stuck

1/04/83 . 6155/25/83 1152 350

- .


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-~ ~

- .1 2 1 j

iready . T h is pump was ma nu al ly shu t down on 8/22 /79 a f t e ro p e r a t i n g f o r e i g h t days. W h il e a t te m p t in g t o r e s t a r t t h e pumpon 9/25/79, t h e pump shu t down due t o ove r load . Whi le t h e pumpwas s t i l l d ow n wr ll , a meggar i n d i c a t e d a s h o r t c i r c u i t f r om a

. phase co nd uc tor t o ground. The pump was removed fro m t h e w e l l on10/24/79. The motor and o i l sm el led burned. A t o t a l o f tw op i n t s o f wa te r were removed f rom th e moto r and p r o te c t o r andt h e r e was e v id e nc e o f b r i n e le a ka g e a c ro s s t h e s h a f t s e a l l o c a t e di ' n t h e p r o t e c t o r . S ubsequent i n s p e c t i o n showed t h e u n i t f a i l e ddue t o m oto r b u r n ou t w hic h o c c u rr e d i n a s t a t o r w i n d i n g s l o t . I na d d i t i o n , a l ea d w i r e between th e po thead and s t a t o r w ind ing hadme1 ted.

Inspec t4o n o f th e w e l l head showed th e R T V rubb er used- t osea1 around t h e p ro d u c t i o n tu be was decomposed.

P u i l d # 2 , Wel l 8-1

T h i s pump was i n s t a l l e d 11 /16 /79 and s t a r te d 11/17 /79 . I to p er a te d a lm o st c o n t i n u o u s l y u n t i l 5/05/80 when t h e pump shutdown au to m a t i c a l l y due t o ove r load . The ca b le and mo to r weremeggared and showed 1 0 0 K res i s tance phase - to -g round . A r e s t a r twas at tem pted , b u t th e pump 5hut down because o f ove r load . Asecond meggar re a d in g showed 0 ohms ph as e- to -g ro un d. Whenrem oved f r o m t h e w e l l on 5 /1 9 /8 0 s i g n i f i c a n t c a rb o na t e b u i l d u pwas d i sc ove red on th e pump i n l e t sc reen . The mo to r and p ro te c to rt u rn e d - f r e e l y , b u t t h e pump showed re s i s t a n c e ' t o t u r n i n g . The


27/43

moto r co n t a in ed abou t 1 /2 g a l l o n o f w a t er . The r e s i s t a n c ebetween t h e condcrctors and motor ca se was 8 K ohms, whichi n d i c a te d a w et d i e l e c t r i c . The p o th e ad m eggared a t 2 0 M ohms.A l l b u t one s h a f t s ea l i n t h e p r o t e c t o r r e r e i n e x c e l le n tc o n d i t i o n and a l l were s t i l l s e a l in g . The p r o t e c t o r and m otorb e a r i n g s w e re i n good c o n d i t i o n , b u t t h e pump b e a r i n g s a nd wearr i n g s c o n ta i n e d some s c a l e . The m o to r r e s i s t a n c e wasd e t e r i o r a t i n g and i t was f e l t i t would have been a s h o r t t i m eb e f o r e m o to r a r c i n g and ' burnout wou ld o c c u r , even w i t h a d r ymotor .

b u i l d #3 . W e l l 8-1

Th is pump was. i n s t a l l e d 6 /25 /86 i n w e l l 8-1. O n 8 /26 /80t h i s pump Shut down a u t o m a t i c a l l y b ec au se o f an e l e c t r i c a lo v e r lo a d . I n s p e c t i o n o f t h e c a b l e d u r i n g r em o v al showed w a te rbetween th e l ea d and th e EPDM i n s u l a t i o n i n t w o o f t h e c o n d uc t o r sb e lo w t h e p a c k o f f . S ub se qu en t t e s t i n g o f t h e pump a nd c a b l eb elo w t h e p a c k o f f i n d i c a t e d t h e y w e r e . s t i l l good ( t h e c a b lemeggared between 1 and 13:)O meggaohms), b u t one phas e wasd e t e r i o r a t i n g and f a i l u r e was e xp ec te d t o o cc ur s h o r t l y . flte ar do wn o f t h e p a c k o f f showed t h e w at er c i r c u l a t i o n b a r r i e r wasn o t i n p l a c e . T h i s b a r r i e r p re ve nts t h e n a t u r a l c i r c u l a t i o n o f

i n t o t h e p ac ko f a re a. I t s need was i d e n t i f i e d i n t h eGPTF p o r t a b l e pump t e s t 5. F u r t he r & y - e , t h e r e Wasp 3 a s t i c t a p e on one p ha se c o n d uc tor a nd f i b e r g l a s s t a p e on a l l._~hr_ee,_~__There.was;.nn.ater .-. n . . t h e p r o t e c t o r , b u t t h e r e - w a s some-


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. .* I

23

water i n t h e m otor i n d i c a t i n g t h e s h a f t s e a l s were work ingp ro p e r l y , a nd t h e r e was a l e a k p a t h d i r e c t l y b etw ee n t h e moto rand w e l l . T h i s was t h e l a s t i n s t a l l a t i o n i n w e l l 8-1.

E k i i I d # 1 , We11 6-1

T h i s pump was i n s t a l l e d 8 /21 /80 and s ta r t e d 8 /22 /80 . Th isr e pr e se nt s t h e f i r s t i n s t a l l a t i o n i n h i g h e r t e m p er a tu r e w e l l 6 -2. T h i s pump sh ut down a u to r n t i c a l l y on 8/20/30 ue t o ane l e c t r i c a l o v er lo a d . D u r i n g r em o v al , we c u t t h e c a b l e j u s t belowth e pa ck o f f . The measured re s i s t an ce be tween th e phase w i re s andground i n t h e pa cko f f showed two phases sho r ted t o g round.Measured re s is ta n ce o f downbole cab le and motor was 2 0 M ohm phaset o ground, i n d i c a t i n g t h e e l e c t r i c a l f a i l u r e o c c w r e d ' i n t h epa ck of f . When t h e pa ck of f was d isassembled, i t w a s d i s c o v e r e dt h e w ater c i r c u l a t i o n b a r r i e r i n t h e p a c k o f f e x t e n s i o n w a smis s ing and the l e ad shea th had been removed f ro m t h e c a b l e n ea r


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.24IJ - / \

o hm s b e t w ee n c o n d u c t o r s a n d g r o u n d . B e f o r e removal o n 1/15/81 i t

24IJ - / \o hm s b e t w ee n c o n d u c t o r s a n d g r o u n d . B e f o r e removal o n 1/15/81 i tw a s rneggared a t 500K ohms. Thre w a s n o water i n t h e p r o t e c t o ra nd o n e p i n t o f water i n t h e motor. Motor o i l w a s y e l l o w - w h i t ea n d f o am y w i t h n o b u r n e d s m e l l . I t w a s b e l i e v e d t h a t t h i s u n i tw a s f a i l i n g b e c au s e o f a s h o r t i n t h e c a b l e .

B u i l d #3 . W e l l 6-2'\\

T h i s p u m p w a s i n s t a l l e d 1/16 /81 a n d s t a r t e d t h e n e x t d a y .T h i s pump s h u t dowm a u t o m a t i c a l l y o n 1/31/81 d u e t o u n d e r l o a d .A t t h i s t i m e i t meggared a t 70K o h m s p h ase t o g r o u n d , w h i c h i 5

. . i n c o n s i s t e n t w i t h t h e u n d e r l oa d s hu td ow n. On F e b r u a r y 2, 1981,b r i n e l e a k a ge w a s o b s er v ed a r o un d t h e c o u p l i n g w eld ed i n t o t h ew e l lh e a d f l a n g e . A n e w c o u p l i n g w a s w e l d e d t o t h e w e l l h e a df l a n g e t h e n e x t da y, The pump w a 5 l i f t e d o n e p ro d u c t io n t u b ej o i n t a n d a n ew p ack o f f w a 5 made u s i n g l u b r i c a n t t o h e l p s e a t t h es e a l i n g b l o c k s ,

The pump w a s r e s t a r t e d o n 2/6 /81 . A f t e r o n e ha l f - h o ur ofo p e r a t i o n , a l e a k w a s o b s e r v e d at t h e w e l l h e a d c o u p l i n g. Thew e l d h a d f a i l e d d u e t o p o o r w el d p e n e t r a t i o n i n t h e c o up l in g .D u r in g t h e s u b se q u en t r e p a i r w o r k , t h e c a b l e w a s a c c i d e n t l ydamaged and t h e pump w a s r a i s e d 30 f e e t t o p r o v i d e enough c a b l et o r e m a k e t h e p a c k o f f .

The pump w a s s t a r t e d o n 2/9/81 and ' w a s l e f t pumping.- - ~ o v e r n i g h t at abo 200 gpm, T he n e x t m or ni ng , w h i l e c h a n g i n g t h e


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f l o w c o n t r o l va l ves , t h e pump f l o w inc rease d and th e pump shu tdown on ov er loa d. The moto r and c a b le were meggared a t 3K ohmsand t h e pump was p u l l e d on 2/10/81. The p a c k o ff was okay. Acrack was found i n t h e s o l d e r j o i n t betw een t h e p ot he ad and t h eca bl e armor. About one g a l l o n was water and was dr a i ne d f r om t h emotor. The motor t h r u s t be ar in g was sco red and one o f i t s'.t i l t i n g pqd5 was jammed. The motor head and s t a t o r were found t ob e ru s t y . Th e 'w a te r had a p p a re n t l y le a k e d i n t o t h e mo to r t h ro u g ha v o i d i n t h e p o t h e a d c a s t i n g .

B u i l d #4 , Wel l 6-2 . ,. .

T h i s pump was in s t a l l e d 3/17//81 and s t a r t e d t h e f o l l o w i n g.day. The pump s h u t down on 6/27 /81 due t o a power outa ge. Thepumped was meggared a t 5OK ohms a f t e r s i t t i n g i d l e o ve r t h eweekend. No r e s t a r t was at te m pt ed . The pump was removed on7/24/81. A f t e r re mo va l, t h e p r o t e c t o r and pump t u rn e d s mo o t h lyb u t t h e mo to r t u rn e d ro u g h l y and one p i n t of water was dr a i ne df ro m t h e mo r. The motor had a broken le ad w i r e wh ich may havebeen b roken du r in g th e remova l o f t h e po thead . An' o i l samplet a k e n f r o m th e . mo to r showed many p a r t i c l e s su sp en de d i n t h e o i l ,i n c l u d i n g p a r t i c l e5 t o be r u s t , d i r t , and p i e c e s 0.fe l e c t r i c a l i n n i n sp ec t io n showed t h e mo to rt h r i t s t washers ha been overhe ated and were crac ked andcrumbly. The motor s h a f t w a s b l u e n e ar t h e mo to r ro t o r s . Thec a b le was wet i t s f u l l l e ng th , b u t s t i l l passed a 2(:M v o l t h i g hp o t e n t i a _ l _ t e s t , _ Th e pafhead __


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. .26

I

was c on cl ud ed t h a t t h e f a i l u r e o f t h i s pump w a s caused by watere n t e r i n g t h e c a b l e a nd m oto r t h r o u g h t h e po th e ad .

B u i l d #5, Well 6-2

REDA pump #5 was t h e f i r s t i n s t a l l a t i o n t o u s e t h e BIN motor\o i l p r e s s u r i z a t i o n system .'\, T h i s c o n s i s t e d of a sur face-mounted

a i l s u p p l y syste m c on ne cte d t o t h e m otor b y an o i l l i n e , a5d is cu s se d i n S e c t io n 2.0 . The pump was i n s t a l l e d on 9 /6 4/8 1 ands t a r t e d on 9 /08 /81 a f t e r t h e Labor Day weekend.

. .The pump wa5 shut down' on 9 / 1 4/ 8 1 t o p e r f o r m m a in te na n ce on

t h e e l e c t r i c a lt h e mo tor p ress u r i z i . ng system was ou t o f o i l . A d d i t i o n a l l y t h e rewas an e l e c t r i c a l s h o r t f ro m t h e phase c o n d u c t o rs t o g ro un d i nt h e ca b l e and /o r mo tor . Du r in r emova l on 9 /22 /81 , t h e packo f fw a s f ou n d t o b e okay. I n s p e c t i o n r e v e a l e d t h a t t h e 304 s t a i n l e s ss t e e l a i l l i n e had b ro ke n b elo w t h e w e ll he a d due t o s t r e s s

o r r o s i o n c r a c k in g . A d d i t i o n a l l y t h e O - ri ng s e a l be tw ee n t h ep o th e a d an d m o to r ha d b een sh ave d d u r i n g i n s t a l l a t i o n and tw o o ft h e t u b u l a r c o n n ec t or s on t h e end o f t h e m o to r l e a d w i r e s w erel o o se . They had been i m p r o p e r l y i n s t a l l e d a t t h e f a c t o r y . M o to r

nce was fou nd t o be 8 0 M ohms, i n d i11 i n t a c t and c o u l d b i e d out. T h r e e q u a r t

w ere d r a i n e d f r o m t h e m o to rhand. A n o i l s am ple t a ke n f ro m t h e p r o t e c t o r c o n t a i n e d w ate r.


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. .

B u i l d M 6 . Well 6-2

T h i s i n s t a l l a t i o n a l s o i n c o r p o r a t e d t h e downwel l o i lp r e s s u r i z i n g s y s t e m . T he pump was i n s t a l l e d 1(3/2.3/81 a nd s t a r t e dt h e same d a y . I t r a n f o r a p p r o x i m a t e l y 7900 h o u r s u n t i l i t w a sr e m o v e d O c t o b e r 4 , 1982. T h i s 7900 h o u r s r e p r e s e n t s as i g n i f i c a n t i m p r o v em en t i n p u m p o p e r a t i n g i m e . D u r in g t h e r u n ,pump head a nd f l o w d e g ra d e d c o n t i n u o u s l y a5 s ct rn ma ri ze d i n F i g u r e3. T h e p e r f o r m a n ce d e c r e a s e d t o a p o i n t w h e r e t h e pump c o u l d n o ts u p p l y t h e 500 kW p i l o t p l a n t n e ed s . Upon remova l o f t h e pumpa nd i n s p e c t i o n a t t h e Keda B a r t l e s v i l l e f a c i l i t y , i t . was f o u n dt h a t t h e pump i m p e l l e r s h ad l i t e r a l l y worn o u t b e c a u s e of smalla m o u n t s of s a n d i n t h e w e l l . T h e s a n d h a d worn t h e i m p e l l e rt h r u s t b a l a n c i n g 5edlS a1r u b a g a i n s t t h e i r s t a t o r s , t h e r e b y c a u s i n g a d d i t i o n a l wear. T h emotor i n s u l a t i o n w a s i n e x c e l l e n t c o n d i t i o n a nd t h e meggar s ho we d

. -- -- b ri n e r em o ve d t h e - p h o ~ i p h o r o u s additives from t h e l u b r i r a t i n. -- -- b ri n e r em o ve d t h e - p h o ~ i p h o r o u s additives from t h e l u b r i r a t i n


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I

'C

Ic

8 2 T\M.


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- 3%- -34

32c

3a

a * 'd240

2-20


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. .30 - 1

o i l . T h i s p ho sp ho ro us com bined w i t h c a l c i u m i n t h e b r i n e t op ro du ce c a l c i u m p ho sp ha te w hic h p r e c i p i t a t e d o u t o f t h e l i q u i d .Much ca l c i um phosphate was found ups t ream o f th e f i v e m ic ro nd ow nhole o i l f i l t e r . T h i s c o m bi na ti on o f ph os ph oro us i n t h e o i land ca l c i um i n t h e b r i n e i s a150 su sp ec te d t o be t h e re as on fart h e r e l i e f v a l v e p lu g g in g o f t e n found i n used downhole geothermalp r o t e c t o r s.

, A n o p e r a t i o n a l p r ob le m was p l u g g i n g o f t h e b u b b l e t ub es .I n s p e c t i o n o f t h e b u b b le t ub e a f t e r 79C)O h o u rs o f o p e r a t i o nshowed t h e l owe r end t o b e p lugged w i t h a w h i t e s c a l e . I t i sb e l i ev e d t h a t t h e d r y n i t r o g e n gas used f o r t h e b u bb le t u b ecaused t h e b r i n e i n s i d e t h e b ub ble t u b e t o b e s l o w l y e va po ra te d

. l e a v i n g b e h i n d a c a l c iu m c a r bo n a te d e p o s i t .

B u i l d #7, W e l l 6-2

T h i s pump was i n s t a l l e d 10/6/82 a n d s t a r t e d 19/7/82, I t r a nu n t i l 11/24/82 when i t was sh ut down because t h e b r i n e was nol o n g e r r e q u i r e d . D u r i n g i n s p e c t i o n o n 1 /4 /8 3 a m eggar showed 1ZKohms ph as e-t o-g rou nd and t h e pump was n o t r e s t a r t e d . D u r in g t h e

a t te m pt t o p u l l t h e u n i t o n 2 /8 /8 3 , we d i s c o v e r e d t h e p r o d u c t i o ntu be was s t uc k i n t h e 1. A s t r e t c h t e s t o f t h e p r o du c t i o ntube showed i t t o b e s t u c k a p p r o x i m a t e ly 3 46 f e e t b e lo w t h ewel lhead. It was b e l i e v e d t h e t u b wa5 r e s t r a i n e d b y s c a l e o r adamaged w e l l c as ing . A t t h e t i m e, i t a pp e ar ed t h a t s c a l e was t h em are l i k e l y c au se b ec au se t h e well had been produced by S l o w i n g


36/43

1 0 0 gpm o f b r i n e f r o m t h e a n nu l ou s f o r 60 hou rs . S u f f i c i e n t k i l lf l u i d was pumped i n t o t h e w e l l t o f i l l t h e a nn ulo us . The f l u i dd i d n o t f l o w o ut t h e t o p o f t h e w e l l i n d i c a t i n g t h e r e was s t i l lan opening past the pump.

O n 4/18/83, 500 g a l lo n s o f i n h i b i t e d 10% a c e t i c a c i d waspumped i n t o t he w e l l annu lous. The wo rkove r r i g p u l l e d andt w i s t e d t h e p r o d u ct io n t u b e t o l oo se n i t . A t o t a l o f 240 f e e t o fp ro d u c t i o n t i ib e was, removed. On 4/20/83, ano the r 500 g a l l o n s o fa c e t i c a c i d was added, bu t no a d d i t i o n a l t ub in g was removab le .The w e l l a n nu lo us was f i l l e d w i t h f r e s h w a te r w h i l e t h e w ork ov err i g wa5 used on ano the r we l l . O n 4/25/83, 1500 g a l l o n s o f 30%i n h i b i t e d a c e t i c a c i d was a dded t o t h e w e l l . However, t h ew ork ov er r i g was s t i l l . n o t a b l e t o rem ove t h e pump. O n

. 5/29/83, a s e t o f j a r s were used t o "hammer" t h e equ ipment ou to f w e l l . The pump c mponent was f u l l of sand and b ro ke n pumpp i e c es . The re were t w o g a l l o n s o f w a te r i n t h e mo to r and t h epothead was c racked. The motor , p r o t e c t o r o r pump d i d n o t t u r n

The mo to r w ind ings were sh o r t ed t o t h e mo to r case.e pump was removed f ro m th e w e l l , a lo gg in g t o o l wou ld

no t go be low 315 f e e t .

5 .2 'EHATING EXP ENCE O F OTHERS

The be s t documenta t ion a f t h e o p e r a t i n g e s pe r ie n ce w i t he l e c t r i c d ow nho le s u b me rs i b l e pumps a v a i l a b l e i n t h e p u b l i c

a5 p re p ar ed f or .. t h e E l e c t r i c P ow er-Research I n s t i t u t e


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~~~ _I_-,- I. .

I1 32u nd er p r o j e c t #HF'195-8 by Pe te r F. E l l i s and P.F. Greene ofRad ian Corpo ra t i on , Au s t i n , Texas u nd er t h e d i r e c t i o n o f EPHIp r o j e c t manager Evan Hughes. With EPRI and Rad ian 's k indp e r m i s s i o n , t h e o p e r a t i n g e x p e r ie n c e o f t h e o t h e r g e ot he rm a lpumps i s summarized i n Tab le 11.1 o f t h i s r e p o r t . The i n f o r m a t i o ne n cl os e d i s fr om t h e d r a f t copy o f t h e EPRI r e p o r t .

There i s one o t h e r pump i n s t a l l a t i o n i n c l u d e d i n o urstudy. Because o f t h e d ra m at ic : s u cc e ss o f t h e B a r b e r - N i c h o l s o i lp re s s u r i z e d system, REDA design ed and assembled an o i lp r e s s u r i z i n g system f o r a 300 hp subm ers ib l e pump i n we l l 44-7 a tt h e Magma s i t e . The o i l s u p p l y s ys te m wa5 a p r o p r i e ta r y d e s i g nc a l l e d POSILIFE. C o n si de r ab le d i f f i c u l t y wa5 e nc ou nt er ed d u r i n gt h e i n s t a l l a t i o n of t h i s p r o t o t y p e sytem. A f t e r t h e pump hadbe en i n s t a l l e d , t h e ' r e s i s t a n c e b e tw een p ha se c o n d u c to r s andground was 150 megaohms. The pump s u c t io n s e t t i n g de pth was1388.5 f e e t . The pump opera te d f o r ap pro x im ate ly two weeks ands h u t down due to an e l e c t r i c a l ove r l oad . The pump was p u l l e d and

d t o B a r t l e s v i l l e , 0wi tness ed by Ba rbe r -N i cho l s eng inee rs . The pump and p ro te c to rwere i n good co nd t i on and co uld be reused. The tandem mo torswere wet w i t h wate r , bu t i t w ou ld b e p o s s i b l e t o d r y them o u t andt h e y a l s o c o u l d b e re us ed . Th cab le had been mechan i ca l l y abusede i t h e r d u r i ng t h e i n s t a l l a t i o n o r re m o va l. The p ot he ad ha d b lo wnup ( l i t e r a l l y ) and a pp ro xi m at el y o ne -h al f o f i t was miss ing . I ti s h y p o th e s i z e d t h a t w a te r g o t i n t o t h e p o th e a d a re a. The

-- r e s u l t i n g s h o r t c i r c u i t caused a spark - and some o f t h e w a t e r -


38/43


39/43

.

. -fi


40/43

35

TABLE I11.GEOTHERMAL PUMPING EXPERIENCE S U W Y : ELECTRIC SWHERSIBLES

Table I11 is reproduced from EPRI Project #RP195-8by Peter El l i s and P.F. Greene of Radian Corp.


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42/43


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I! 38i

.a-

investigation of failed pump components

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