00743 copper grounding systems have a negative effect on cathodic protection in production...

7/23/2019 00743 Copper Grounding Systems Have a Negative Effect on Cathodic Protection in Production Facilities (51300-0…

http://slidepdf.com/reader/full/00743-copper-grounding-systems-have-a-negative-effect-on-cathodic-protection 1/13

C O P P E R G R O U N D I N G S Y S TE M S H A V E A N E G A T I V E E FF E C T O N

C A T H O D I C P R O T E C T I O N I N P R O D U C T I O N F A C I L I T I E S

Earl L. Kirkpatr ick , P .E.

E L K E n g i n e e r i n g As s o c i at e s, I n c o r p o r a t e d

8 9 50 F o r u m W a y

F o r t W o r t h , T X 7 6 1 4 0 -5 0 1 7 U S A

F a x : 8 1 7 - 5 6 8 - 8 5 9 0

E - ma i l: e a r l k @ e l k e n g c o r n

M o h a m m a d S h am i m

Un i o n T e x a s P a k i s ta n , I n c o r p o r a t e d

( A w h o l l y o wn e d s u b si d ia r y o f AR CO )

3 a F l o o r B a h r i a Co mp l e x

2 4 Mo u l v i T a mi z u d d i n Kh a n R o a d

G.P .O. Box 3767 , Karach i -74000 , Pak i s tan

F a x : ( 9 2 - 2 l ) 5 6 1 - 0 6 3 4

E-mai l : mshamim@mai l , arco. corn

A B S T R A C T

T h e c o m m o n b o n d i n g o f u n d e r g r o u n d f e r ro u s s t r u c tu r e s t o m a s s iv e c o p p e r g r o u n d i n g g r i d s c r e a te s

p rob lems fo r co r ros io n eng inee r s and the i r a t tem pts to ca tho d ica l ly p ro te c t the f e r rous s t ruc tu res .

Con f l i c t s be tw een co ppe r and fe r rous underg ro und sys tems a re d i scussed and a l t e rna t ives a re p resen ted .

A spec i f i c case h i s to ry conce rn ing p rod uc t ion fac i l it i e s in S indh Prov ince , Pak i s tan i s p resen ted . The case

h i s to ry inc ludes the in i t ia l eng inee r ing eva lua t ion and recom m ende d sys tem change s a s we l l a s the r e su l ts

o f th e r e c o m m e n d e d c h a n g e s o n o v e r a ll p e rf o r ma n c e o f t h e c a t h o d i c p r o t e c t i o n s y s te ms i n mu l ti p le

product ion fac i l i t ies .

I N T R O D U C T I O N

T r a d i ti o n a ll y , m o s t u n d e r g r o u n d s t r u ct u r e s h a v e b e e n e l e c tr i ca l ly b o n d e d i n c o m mo n t o r e d u c e

haza rdous vo l t ages a s soc ia ted wi th l igh tn ing and man-made fau l t cu r ren t s o r induced cu r ren t s in the

opyright

© 2 0 0 0 b y NA CE I n t e r n a t io n a l . Re q u e s t s o r p e r m iss i o n t o p u b l i sh t h is m a n u sc r i p t in a n y f o r m , i n p a r t o r i n wh o le m u s t b e i n w r i t in g t o NACE

In terna t iona l , Conferences Div is ion , P.O. Box 21834 0, Ho uston , Texas 7721 8-834 0. The ma ter ia l p resen ted and the v iews expressed in th is

pap er a re so le ly those o f the au thor s ) and a re no t necessar i l y end orsed b y the Assoc ia t ion . Pr in ted in U.S.A.

00743CORROSION2000

Paper No.



e a rth . A c o m m o n g r o u n d in g s y s t e m p ro v id e s a m o r e e c o n o m ic a l a n d a l o w e r r e s i s t a n c e t o r e m o te - e a r t h

than does the ind iv idua l ea r th ing connec t ions .

T h e U .S . N a t i o n a l E l e c t ri c a l Co d e ( N E C ) ~ d o e s n o t r e q u i re c o p p e r g r o u n d in g ; i n s te a d , i t r e q u ir e s

tha t a pe rmanen t me ta l l ic ea r th ing e lec t rode and conduc to rs mus t be used fo r ea r th ing connec t ions .

Ca th o d i c p r o t e c t i o n i s r o u t i n e ly e m p lo y e d t o o v e r c o m e s o i l i n s t i g a t e d c o r r o s io n c e l l s o n c r u d e o i l a n d

na tu ra l gas p roduc t ion and t ranspor ta t ion fac i l i t i e s . When such a sys tem is d i rec t ly connec ted to a ba re

copp er ea r th ing sys tem, cu r ren t demand m ay inc rease by severa l o rde rs o f mag n i tude . Th is c rea tes a

conf l ic t be tw een ca thod ic p ro tec t ion eng inee r ing des ign and e lec t r ica l sa fe ty des ign . 2 Accep tab le

a l t er n a t iv e s d o e x i s t t o t h e u s e o f b a r e c o p p e r c o n d u c to r s a n d b a r e c o p p e r o r c o p p e r c l ad g r o u n d r o d s . 3

D E S C R I P T I O N O F P A K I S TA N I P R O D U C T I O N F A C I L IT I ES

At the t ime o f the s tudy repor ted on in th i s paper , the co mp any o pera ted s ix (6 ) ma jo r o i l and gas

produc t ion fac i l i t i e s and a number o f smal le r fac i l i t i e s in the Bad in Block , S indh P rov ince , Pak is tan .

Exp lo ra t ion began in 1977 w i th the f i r s t p rodu cer d i scovered a t Khaske l i on Ju ne 16, 1981 . 4 The

produc t ion fac i l i t i e s sepa ra te o i l and gas , knock ou t wa te r , sh ip na tu ra l gas v ia p ipe l ine and s to re o i l and

d is t il l a te p rodu c t ion in abov egrou nd ta nk fa rms fo r la te r t r ansp or t to re f ine ry by tanker t ruck . E lec t r ica l

pow er i s ob ta ined f rom on-s i te genera to r se t s wi th d iese l o r na tu ra l gas p r ime mo vers . S ince al l o f the

produc t ion fac i l i t i e s in S indh P rov ince a re e ssen t ia l ly s imi la r , va ry ing p r imar i ly in overa l l s ize and in the

geom etry o f the layou t , w e wi l l p r imar i ly d iscuss in de ta il , on ly two o f the p rod uc t io n fac i l it i e s in th i s

paper . These p ro duc t io n fac i li t i e s (P .F . ) , des igna ted as P .F . -1 and P .F . -2 , hand le bo th c rude o i l and

na tu ra l gas . P .F . -1 w as b roug h t on- l ine abou t 1988 . P .F . -1 i s a na tu ra l gas p rod uc t ion fac i l i ty tha t

c o n t a in s tw o a b o v e g r o u n d o il s to r a g e t a n k s a n d a v a r i e ty o f p r o c e s s v e ss e ls . T h e r e a r e a t o t a l o f s e v e n

incom ing f low lines in the in take man i fo ld . The P .F . con ta ins a se r ie s o f sepa ra to r vesse ls to knock ou t

wa te r and to sepa ra te d i s t i l l a te f rom the na tu ra l gas . There i s one ou tgo in g gas t ransmiss ion l ine .

T h e o r i g in a l e l e c t r i c a l g r o u n d in g g r i d w a s c o n s t r u c t e d u t i l i z i n g P V C c o a t e d s t r a n d e d c o p p e r

cond uc to r rang ing in s ize f rom 16ram 2 to 95ram 2 conduc to r . A 16ram 2 con duc to r i s used fo r equ ipm ent

g r o u n d in g . G r id c o n d u c to r s a r e 7 0 r a m 2 o r 9 5 r am 2 a n d a r e c o n n e c t e d t o d r i ve n c o p p e r c l ad g r o u n d r o d s

a t 2 0 0 ( 6 1 m ) t o 4 0 0 ( 1 2 2 m ) f o o t s p a c in g a ro u n d t h e p e r im e te r o f t h e p l a n t w i th s u p p l e m e n ta l g r o u n d

r o d s a t m a jo r e q u ip m e n t . Ca th o d i c p r o t e c t i o n i s s u p p li e d to t h e p l a n t b y T r a n s f o r m e r /Re c t i f i e r ( T /R)

Nu mb er 1 , a 25 vo l t 75 ampere un i t pow er ing a d i s t r ibu ted ve r t ica l anode -bed a round the tw o

produ c t ion tanks . T /R N um ber 2 is a 25 vo l t 75 ampere rec t i f ie r pow er ing a ten - anode , ve r t ica l

c o n v e n t io n a l r e m o te a n o d e - b e d w h ic h p r o v id e s c a th o d i c p r o t e c t i o n t o t h e i n c o m in g f l o w l in e s.

A t s o m e p o in t w i th in t h e f i v e ( 5 ) y e a r s p r i o r t o t h i s s t u d y , a g r o u n d in g s y s t e m u p g r a d e w a s

u n d e r t a k e n t o im p r o v e t h e e l e c tr i ca l g r o u n d in g a t e a c h o f t h e P .F .s . T h i s w a s c o n s id e r e d n e c e s s a r y t o

assu re adequa te fau l t cu r ren t p ro tec t ion shou ld a moto r wind ing o r s imi la r e lec t r ica l e lemen t go to

g r o u n d . T h e g r o u n d in g s y s t e m u p g r a d e c o n s i s te d o f b a re s t r a n d e d c o p p e r 7 0 m m z o r 9 5 r a m 2 c a b le l a id i n

pa ra lle l wi th the ex is t ing insu la ted cab le g rou nd ing g r id . Each ba re co pper g r id was supp leme nted wi th

add i t iona l coppe r g roun drod s and a to ta l o f four deep we l l g roun d beds w ere ins ta lled . The deep we l l

g r o u n d b e d s c o n s i s t o f a c o p p e r p l a te a p p r o x im a te ly l m 2 a n d b u r i e d a p p r o x im a te ly f o u r m e te r s d e e p.

T h r e e s e p a r a t e 9 5 m m 2 s t r a n d e d b a r e c o p p e r c o n d u c to r s w e r e e x o th e r m ic a l l y w e ld e d t o t h e c o p p e r

g r o u n d p l a t e a n d w e r e b r o u g h t u p t o a b u s b a r i n s ta l le d i n a n a b o v e g r o u n d m a n h o le . G iv e n th e l o w

elec t r ica l so i l r e s i s t iv i ty a t th i s s i te , r ang ing f rom 80 to 200 ohm-cm, the g round ing sys tem upgrade d id

no t seem to be necessa ry .



Fol lowing ins ta l l a t ion o f the g round ing sys tem upgrade , co r ros ion fa i lu res were becoming a

p rob lem a t m os t o f the p rod uc t ion fac il it ie s . In a few ins tances , pe r im e te r fenc ing fe ll dow n w hen the

suppor t ing po les co r roded in two a t g rade l eve l o r underg round due to the i r be ing bonded to the ba re

copper pe r im e te r g r id . P r io r to the in i t i a t ion o f th is p resen t s tudy , the c om pany and con t ra c to r pe r sonne l

d i sconnec ted e ssen t i a l ly a l l o f the bonds to the pe r ime te r f enc ing and d i sconnec ted mos t o f the ba re

coppe r pe r ime te r g rou nd lo op f rom the p lan t gr id. Pe r ime te r f ence bond ing is r equ ired a t e l ec tr i cal

gene ra t ing s t a t ions and a t loc a t ions where ex te rna l power i s b rou gh t in to a f ac i li ty v ia ove rhead

conduc to r s . 5 Th i s i s necessa ry in o rde r to p ro tec t pe r sonne l in the even t o f a f al l ing conduc to r . S ince

ne i the r o f these cond i t ions ex i s t a t the p roduc t ion fac i l i t i e s , wi th on-s i t e power gene ra t ion , pe r ime te r

f e n c e g r o u n d i n g i s n o t r e q u ir e d . Ho w e v e r , a p e r i me t e r g r o u n d i n g c o n d u c t o r / e l e c t r o d e s wo u l d b e

benef ic ia l i f one n eeded to low er the r e s i s t ance - to - rem ote ea r th o f the ove ra l l g rid , Tha t i s no t the case

for these product ion fac i l i t ies .

I t was r ep or ted tha t num erous co r ros ion l eaks had been repa ired , mo s t ly on f low l ines due to ac t ive

cor ros ion . In som e ins tances, en t i r e segments o f a p ipe l ine we re r ep laced wi th new p ipe. These

cor ros ion losses w ere r e spons ib le fo r in i t i a t ing the s tudy repor ted in th is pape r .

F A C I L I T Y S U R V E Y S

An n u a l c a t h o d i c p r o t e c t i o n s u r v e y s b y t h e c o mp a n y a n d i n - c o u n t r y s u b c o n t r a c t o r p e r s o n n e l

ind ica ted tha t the ma jo r i ty o f the bur ied p lan t p ip ing (BPP) was no t adequa te ly ca thod ica l ly p ro tec ted ,

exh ib i t ing p ipe - to - so i l po ten t i a l s l e s s nega t ive than -0 .85 vo l t s r e fe renced to copper -copper su lpha te

re fe rence e lec t rode . In la t e summer 1996 , the tw o au thors in co l l abora t ion wi th in -cou n t ry ca thod ic

p r o t e c t i o n s u b c o n t r a c t o r s a n d o t h e r c o mp a n y p e r s o n n e l c o n d u c t e d a d e t a i l e d c a t h o d i c

p r o t e ct i o n /e l e c tr i c al g r o u n d i n g s u r v e y & t h e ma j o r p r o d u c t i o n f a c il it ie s a n d m o s t o f t h e m i n o r p r o d u c t i o n

fac il it ie s in S indh Prov ince . Th i s pape r p resen t s the r e su l ts o f tha t f i e ld inves t iga t ion and the l ead

a u t h o r ' s f o rma l r e c o mme n d a t i o n s . T h e s e r e su l ts a n d r e co mm e n d a t i o n s a r e r e p r e s en t a t iv e o f t h o s e

ob ta ined a t the o the r p rodu c t ion fac i l it i e s in the Bad in B lock .

Re s i s t a n c e - to - Re m o t e E a r t h Me a s u r e me n t s

An a t t empt was made to measure the combined p lan t / e lec t r i ca l g round ing g r id r e s i s t ance - to - remote

e a r th a t P F . - 1 v i a t h e I E E E f al l & p o t e n t i a l me t h o d . 6 A r e m o t e c u r r e n t p in ( C - l ) wa s e s ta b l is h e d 8 ,5 0 0

fee t sou th o f the sou th f ence o f the PF . The po ten t i a l p ins were e s tab l ished by d r iv ing a ga lvan ized i ron

r o d a p p r o x i ma t e l y 5 , 3 0 0 f e e t s o u t h o f t h e s o u t h f e n c e o f t h e p l an t . T h e s e p i n s we r e c o n n e c t e d b a c k t o

the C-1 and P -1 t e rmina l s o f the low res is t ance AC ra t io ohm m ete r wi th ind iv idua l 1 .5mm 2 insula ted

coppe r conduc to r . Di rec t con nec t ion was m ade to the p lan t g roun d ing g r id v ia add i tiona l t e s t l eads f rom

the C-2 and P -2 t e rmina l s o f the AC ra t io ohm mete r . The re s i s t ance - to - re mo te ea r th o f the ex i st ing

c o mp o s i t e g r o u n d i n g g r i d a n d p l a n t p i p i n g n e t wo r k wa s s o l o w a s t o p r e c l u d e me a s u r e me n t w i t h t h e

ava i lab le ins t rumenta t ion . Ne i the r o f the AC ohm mete r s ava i l ab le a t the time o f the su rvey cou ld

accura te ly measure a va lue o f l e s s than 0 .005 ohms .

There fo re , an a l t e rna t ive DC m ethod was used . The d i f fe rences in po ten t i a l (AE) be tw een the on

and the ' oË rem ote p ipe - to - so i l po ten t i a l s measured whi le s imul taneous ly cyc l ing T /R Nu mb er 1 and

T/R Number 2 were used to ca lcu la te the r e s i s t ance o f the en t i r e p lan t g round ing g r id to r emote ea r th .

These me asurem ents we re t aken us ing a sing le , r em ote copper -c oppe r su l fa te r e fe rence e lec t rode

es tab li shed a t 8 ,500 (2 ,590m ) fee t r emote f rom the p lan t si te . W hen the in te r rup ted p ipe - to - so i l po ten t i a l



su rvey was conduc ted , the c lose p ipe - to - so i l po ten t i a l and the r emote p ipe - to - so i l po ten t i a l were

measured and recorded a t each t e s t s i te wi th the T /Rs in bo th the on and in the o f f cond i t ion . An

average o f the r em ote p ipe - to - so i l AEs was d iv ided by the por t ion o f the T /R ou tpu t s tha t were

con t r ibu t ing ca thod ic p ro tec t ion cu r ren t to the p lan t p ip ing on ly . Th i s p rocedu re d i s rega rded the

ca thod ic p ro tec t ion cu r ren t tha t was app l i ed to the f low l ines . The ca lcu la ted re s i s t ance o f the g round ing

gr id and p lan t p ip ing a t P .F .-1 was 0 .001145 ohms .

L o c a l c o n t r a c t p e rs o n n e l we r e t h e n e m p l o y e d to d i g u p a n d s e v er c o n n e c t i o n s o n t h e b a r e c o p p e r

g r o u n d i n g gr id wh e r e v e r t h is wa s t h o u g h t t o b e p r a c ti c al . Af t e r r e mo v i n g a s mu c h c o p p e r f r o m t h e

sys tem as was cons ide red p rac t i ca l , the p lan t g round ing g r id r e s i s t ance - to - remote ea r th was r emeasured

us ing the same DC techn iques . Th i s t ime , the ove ra l l g round ing g rid me asured 0 .001 2 o hm s- to - rem ote

ea r th . Th i s r ep resen t s l es s than a 5 pe rcen t inc rease in ove ra ll p lan t r e s is t ance bu t d id p rov ide a

s ign if i can t dec rease in the load on the ca thod ic p ro tec t ion sys tem. For on-s i t e e lec tr i ca l pow er

genera t ion , ove ra l l p lan t g round ing re s i s t ance in the r ange o f 5 to 25 ohms i s cons ide red adequa te and

safe. There fo re , the ex tens ive g roun d ing sys tem upgrade w as no t necessa ry .

The ex i s t ing ca thod ic p ro tec t ion sys tem in bo th P .F . s were p re fe ren t i a l ly p ro tec t ing the f i r e wa te r

loop and no t p rov id ing enough ca thod ic p ro tec t ion cu r ren t f low to the va r ied p lan t p ip ing which con ta ins

the va luab le p rodu c t ion f lu ids and gases . Du r ing the e lec t r ica l g roun d ing sys tem d ig -ou t s , de l ibe ra te

c ross bond s were m ade be tw een f i r e wa te r p ip ing and p lan t p ip ing and be twee n insu la ted p lan t g round ing

gr id conduc to r s and bur ied p lan t pip ing. Th i s was don e to a s su re adequa te e lec t r i ca l con t inu i ty be twe en

the va r ious sys tems ; tha t i s , g round ing g r id conduc to r s , bu r ied p roduc t ion p ip ing and va r ied f i r e wa te r

ma ins . Th i s i s imp or tan t to ov e rcom e ca thod ic in te r fe rence p rob lem s be tw een va r ious segm ents o f the

underg round sys tems . Ca th od ic in te r fe rence was n o ted a t mo re than one loca t ion wi th in the p lan t s it e.

No tab ly , th i s was usua l ly occur r ing on the g round ing g r id which had no t p rev ious ly been de l ibe ra te ly

c o n n e c t e d t o t h e BP P b u t w a s i n t e r c o n n e c te d o n l y v i a a b o v e g r o u n d c o n n e c t i o n s .

Resu l ts o f the Inv es t iga t ions

Approx ima te ly 800 (244m) l inea l f ee t o f add i t iona l l a rge d iamete r ba re copper g round ing

c o n d u c t o r a n d t h r e e g r o u n d we l l s we r e p h y s i ca l ly d i s c o n n e c t ed a t P .F .- 1 . T h e s e c o n d s e t o f o n - o f f '

c lose p ipe - to - so i l po ten t i a l da ta a t P .F . -1 d id no t show an inc rease in po ten t i a l s a~e r r emova l o f

add i t iona l ba re copper . 7 Th i s was due to T /R N um ber 2 (w hich is ded ica ted to p ro tec t io n o f p lan t p ip ing)

go ing in to ha l fwave rec t if i ca t ion due to a b low n d iode in the rec t i f ie r b r idge . Va l id da ta w ere ob ta ined

fo r the change in the ove ra l l g r id r e s i s t ance - to - remote ea r th , bu t improvement in p ipe - to - so i l po ten t i a l s

cou ld no t be de mo ns t ra ted s ince we had no t ime to r epa i r the r ec t i f i e r b r idge p r io r to condu c t ing the f ina l

su rvey . Resu l t s o f the secon d su rvey a t P.F .-1 d id show e l imina t ion o f the ca thod ic in te r fe rence tha t was

in it i al ly no ted du r ing the f ir s t su rvey . Ca thod ic in te r fe rence had been p rev ious ly no ted o n bo th BPP and

on the g ro und ing g r id .

There fo re , da ta p resen ted he re in Tab le 1 i s on ano the r p roduc t ion fac i l i ty , des igna ted a s P .F -2 ,

where va l id in i t ia l and f inal su rvey da ta po in t s were ob ta ined . P .F . -2 p lan t cons t ruc t ion w as s t a r t ed abou t

1990 . I t i s p r imar i ly a gas f ac il ity . Ap prox im a te ly 890 (271m ) l inea l f ee t o f add i t iona l l a rge d iamete r ba re

copper g rou nd ing co ndu c to r were phys ica l ly d i sconnec ted f rom th i s p lan t g r id . W hi le p r io r e f fo r t s by the

c o mp a n y h a d d i s c o n n e c t e d s o m e s e g me n t s o f t h e p e r i me t e r c o p p e r g r o u n d i n g g r i d f r o m p l a n t fe n ci n g,

c ross connec t ions s t il l ex i st ed . As a r e su l t o f the add i t iona l excava t ion w ork ca r r i ed ou t du r ing these

s tud ies , ne i the r the pe r ime te r f enc ing nor the pe r ime te r ba re copper g round ing loop remained connec ted



to the p lan t g r id . Seve ra l o f the da ta po in t s a re marked F .W. , des igna t ing the f ir e wa te r sys tem. The

repor ted da ta po in t s have been se lec ted f rom ac ross the p lan t s i te and a re r ep resen ta t ive read ings. Al l

r ead ings shown in Tab le 1 th rough Tab le 7 a re c lose p ipe - to - so i l po ten t i a l s measured to a sa tu ra ted

copp er -copp er su lpha te r e fe rence e lec t rode . Tab le 1 l is t s s t eady on and imm edia te o f f va lues to

dem ons t ra te the vo l t age sh if t f rom the in te r rup ted pow er source . Al l o the r t ab le s show s teady on p ipe -

to - so i l po ten t i a l s unde r the s t a ted cond i t ions .

U pon rev iew o f these da ta , o ne wi l l no te tha t the p ipe - to - so i l po ten t i a l s on a l l o f the F .W . read ings

have a l l dec reased in magn i tude , wh i le the BPP te s t po in t s a l l showed an inc rease in magn i tude in p ipe -

to - so i l po ten t ia l s . The o ve ra l l r e su l t i s m ore un i fo rm p ipe - to - so i l po ten t i a l s th ro ug hou t the f ac il ity . In

add i t ion , the o f f p ipe - to - so i l po ten t i a l s a re more un i fo rm, ind ica t ive o f improve d e lec tr i ca l con t inu i ty

be tween the va r ious underg ro und s t ruc tu res . In i ti a lly , the T /Rs ded ica ted to p r o tec t ion o f p lan t p ip ing

were p rov ided wi th the lowes t r e si s t ance connec t ions to the F .W. loop . There appea red to be more

res i s tance in the nega t ive con nec t ions to the B PP. There w ere no d i rec t connec t ion s f rom the T /Rs to the

p l a n t g r o u n d i n g g ri d . Ho w e v e r , t h e r e we r e n u m e r o u s c r o ss c o n n e c t i o n s b e t we e n t h e g r o u n d i n g g r id a n d

the BPP.

The reason fo r the dec rease in p ipe - to - so i l po ten t i a l magn i tudes on the F .W. l ines i s because o f

de l ibe ra te c ross bond ing be tween the F .W. sys tem, the bur ied p lan t p ip ing and the e lec t r i ca l g round ing

gr id . S ince we can no t t ake the g round ing g r id ou t o f the equa t ion , a be t t e r cho ice i s to bon d the g r id in

common wi th the ba lance o f the p ip ing sys tem to e l imina te s t r ay cu r ren t ca thod ic in te r fe rence p rob lems

and to p rodu ce mo re un i fo rm p ipe - to - so i l po ten t i a ls . The ne t r e su l t o f the imp roved c ross bond ing and

t h e e l i mi n a t i o n o f s o me o f t h e b a r e c o p p e r g r o u n d i n g i s mo r e u n i f o r m p i p e - t o - s o i l p o t e n t i a l s o n t h e

bur ied p lan t p ip ing and e l imina t ion o f ca thod ic in te r fe rence be tw een va r ious e lemen ts o f the und erg roun d

system.

At P .F . -2 , the re a re th ree func t ion ing T /R un i t s . T /R N um bers 1 and 2 po w er a to ta l o f th i r ty (30)

ve r t i ca lly ins ta l l ed d i s t r ibu ted anodes a rou nd the pe r ime te r o f n ine p rodu c t ion t anks . T /R N um ber 3

pow ers a conven t iona l r em ote ve r t ica l anode-bed and i s ded ica ted to ca thod ic p ro tec t ion o f the incoming

f low l ines and t runk l ines f rom rem ote p ro duc t ion fac il it ie s . Al l th ree o f these T /R ' s a re r a ted a t 25 v o l t s

75 amperes DC. Ca lcu la ted re s i s t ance - to - rem ote ea r th o f P .F . -2 was 0 .001294 ohm s p r io r to r emov ing

the add i t iona l copper g round ing and was 0 .00139 ohms a f t e r r emoving the add i t iona l copper g round ing .

Th is r ep resen t s a 7 .7% inc rease in ove ra l l p lan t r e si s t ance . Ho we ver , th e f ina l ove ra l l p lan t r e s i s tance i s

s ti ll more than th ree o rde r s o f m agn i tude low er in r e s i s tance - to - rem ote ea r th than i s r equ i red to ope ra te a

s af e sy s te m. A r e v i e w o f th e c o mp a n y ' s e a r ly c a th o d i c p r o t e c ti o n d a t a wo u l d p r o b a b l y s h o w t h a t th e

ins ta l led T /R c apac i ty was adequa te to ca thod ica l ly p ro tec t ea ch o f the p rodu c t ion fac i l it i e s p r io r to

ins ta ll a t ion o f the g rou nd in g sys tem upgrade .

S imi la r su rveys were ca r r i ed ou t a t the r ema in ing fac i l i t i e s by loca l C.P . consu l t an t s a s pe r

p rocedu res p rov ided by the l ead au thor . O ne o f these ou t f i t s was t r a ined fo r th i s work by invo lv ing them

in the su rveys in PF-1 and PF-2 . Var ious amounts o f copper conduc to r was e l imina ted f rom the

ground ing g r id a t these o the r p rodu c t ion fac il i ti e s a l so .

Seve ra l cu r ren t r equ i remen t t e s t s were conduc ted a t one o r more loca t ions th roughou t the l a rge r

p lan t s i t e s to a s s i s t in de te rmin ing the add i t iona l T /R and anode-bed capac i ty r equ i remen ts fo r each

fac il ity . In some ins tances , a com ple te anode-bed was s imula ted u t i li z ing t em pora ry d r iven rods o r

ex i s ting i so la ted und erg rou nd fac il i ti e s , such a s road wa y cu lve rt s , a s an anod e-bed e lemen t . In o the r



in s tances , a s ing le d r iven g roundrod was ene rg ized a t inc rementa l amperage va lues to de te rmine e lec t r ica l

g rad ien t f ie lds a round each impressed cu r ren t anode .

R E C O M M E N D A T I O N S

Ba s e d u p o n t h e e x t e n s iv e i n v e s ti g a t io n s c a rr i ed o n t h r o u g h o u t t h e B a d in b lo c k p r o d u c t i o n f a ci li ti e s,

s p e ci fi c c a th o d i c p r o t e c t io n s y s t e m u p g r a d e r e c o m m e n d a t i o n s w e r e m a d e f o r e a c h fa c il it y . T h e s e

u p g r a d e s r a n g e d f r o m a f e w z in c a n o d e a n d t e s t l e a d in s t a ll a t io n s i n o n e r e m o te p r o d u c t i o n f a c il i ty t o t h e

ins ta l la t ion o f a s many as two add i t iona l and mu ch la rge r T / R un i t s a t som e o f the la rge r fac i li t ie s .

W e r e c o m m e n d e d t h e i n s t a ll a t io n o f tw o a d d i ti o n a l T /R u n i t s i n P .F .- 1 . P r o p o s e d T /R N u m b e r 3

was ins ta l led on the wes t s ide o f the p lan t a s two sp l i t segments o f a conven t iona l d i s t r ibu ted hor izon ta l

anode-bed in c lose p rox im i ty to the p rocess p ip ing . T /R N um ber 4 was ins ta l led on the eas t s ide o f the

p lan t a s one long con t inuous conven t iona l semi- remote anode-bed .

Re c o m m e n d a t i o n s w e r e m a d e f o r tw o a d d i ti o n a l T /R in s t a l la t io n s a t P .F . - 2. T /R N u m b e r 4 i s a 1 0

vo l t 100 amp ere un i t pow er ing a sp l it ho r izon ta l anode-bed con ta in ing 11 anodes . I t i s in s ta lled on the

we s t s ide o f the p lan t. Th is anode-bed i s no t t ru ly a rem ote anod e-bed bu t a lmos t cou ld be cons ide red a

d is t r ibu ted ins ta l la t ion . T /R N um ber 5 i s a 10 vo l t 150 ampere o i l coo led T /R on the eas t s ide o f the

p lan t. Th is un i t pow ers a 16-anode hor izon ta l anode-bed wh ich i s d i l ly rem ote f rom th e p lan t p ip ing .

S im i la r r e c o m m e n d a t i o n s w e r e m a d e f o r o th e r f a c il i ti e s a ls o . T a b l e 2 p r e s e n t s a s u m m a r y o f t h e

recommended ca thod ic p ro tec t ion upgrades a t va r ious fac i l i t i e s .

I n a dd i ti o n , w e m a d e r e c o m m e n d a t i o n s f o r a d d it i o na l c r o ss b o n d s a n d f o r r e m o v a l o f s om e o f t h e

r e s is t o r j u n c t i o n b o x e s ( R I B) t h a t w e r e u s e d t o c r o s s c o n n e c t s o m e o f t h e p l a n t p ip in g . S o m e o f t h e

RJB s a re appropr ia te to con t ro l p ipe - to -so i l po ten t ia l s on f low l ines and o the r i so la ted p ip ing . Ho wev er ,

wi th in the p lan t s i te i t se l f , these RJBs in t roduce unaccep tab ly h igh res i s tances in the bond ing c i rcu i t s .

Th is leads to uneven p ipe - to -so i l po ten t ia l s and a lways p resen ts the poss ib i l i ty o f ca thod ic in te r fe rence on

s o m e o f th e u n d e r g r o u n d s t r uc tu r es .

R E S U L T S O F T H E C A T H O D I C P R O T E C T I O N U P G R A D E S

T h e f i e l d i n s t a l l a t i o n w o r k f o r t h e r e c o m m e n d e d C .P . s y s t e m u p g r a d e s s t a r t e d a t t h e e n d o f 1 9 9 7

and f in i shed by the end o f 1998 in th ree fac i l i t i e s , v iz . PF-1 , PF-2 , and PF-4 . No upgrade in ICCP

capac i ty was deem ed n ecessa ry fo r the re st o f the ma jo r fac i li t ie s . Jus t rem oving excess ive ba re cop per

g round ing a t these fac i l i ti e s was su f f icien t to re s to re e f fec t ive leve ls o f ca thod ic p ro tec t ion . Tab le 3

p r e s e n ts s o m e o f t h e d a t a f r o m P F - 1 c o l l ec t e d a f t e r co m m is s io n in g th e I C CP s y s t e m u p g r a d e . T h e d a t a

show s s ign i f ican t imp rovem ent in the leve l o f po ten t ia l o f the bur ied p ip ing a t t e s t po in t loca t ions w hich

are d i f f icu l t to p ro tec t due to the i r c loseness wi th bur ied ba re copper conduc to rs .

T a b l e 4 p r e s e n t s s o m e o f t h e CP p o t e n t ia l d a t a f o r P .F . - 2 a f t e r c o m m is s io n in g th e r e c o m m e n d e d

I CC P u p g ra d e s . T a b l e N u m b e r s 5 t h r o u g h 7 p re s e n t s im i l a r d a t a f o r P .F .- 4 . T h e s e d a t a a l so s h o w

s ig n if i c an t im p r o v e m e n t i n t h e C P p o t e n t i a l o f m o s t o f t h e t e s t p o in t s o n b u r i e d p l a n t p ipin g.

N ote th a t the re s t i ll a re a smal l pe rce n tage o f low p ipe - to -so i l po te n t ia l s a t so me o f the fac il i t ie s

a f te r f ina l da ta . Al l o f the f ina l da ta a re ga the red wi th in a w eek o f comm iss ion ing the upg rade a t each



f aci li ty . I t is f e lt tha t co n t inu ing po la r i za t ion ove r the nex t fo ur to e igh t week s w i ll r e su lt in p ro tec ted

po ten t i a l s a t mos t o r a ll o f the low po ten t i a l si te s. I t no t, supp lementa l ca thod ic p ro tec t ion in the fo rm o f

po in t anodes w i ll be em ployed .

A C K N O W L E D G E M E N T

The au thors g ra te fu l ly acknowledge the suppor t and pe rmiss ion o f Un ion Texas Pak i s tan Inc . and

t h e i r j o i n t v e n t u r e p a r t n e r s ( O i l a n d G a s D e v e l o p me n t C o r p o r a t i o n L i m i te d a n d Oc c i d e n t a l P e tr o l e u m

Pak is tan Inc , ) fo r p repa ra t ion and p resen ta t ion o f th i s pape r.

R E F E R E N C E S

.

NFPA 70-1996 , Na t iona l E lec t r i ca l Code , Na t iona l F i re P ro tec t ion Assoc ia t ion , Qu incy , MA. ,

1996.

.

E . L . K i rk p a t ri c k , a n d M. S h a mi m, T h e Co n f l i ct Be t w e e n Co p p e r G r o u n d i n g S y s t e ms a n d CP ,

M ate r ia l s Pe r fo rman ce , 38 , 9, N A CE In te rna t iona l , Ho us ton , TX, 1999 .

. E . L. Ki rkpa t r i ck , Al te rna t ives to Cop per Gro und ing in S i t e s Requ i r ing Ca thod ic P ro tec t ion ,

M ate r ia l s Pe r fo rm ance , 25 , 9. Na t ion a l Assoc ia t ion o f Co r ros ion Eng inee r s , Ho us ton , T X, 1986 .

.

G. A. Pe tze t, Un ion Texas Hope s to Repro duce it s Pak i s tan Bad in Exper ience , Oi l & Gas

Journal , 95, 44, Tulsa , OK , 1997.

.

AN S I / I E E E S t a n d a r d 8 0 - 1 98 6 I E E E Gu i d e f o r S a f e ty i n S u b s t a ti o n Gr o u n d i n g , T h e In s t it u te

o f E lec tr i ca l and E lec t ron ics Eng inee r s , Inc ., Ne w York , NY , 1986 .

.

AN S I / I E E E S t a n d a r d 81 - 1 9 8 3 , I E E E Gu i d e fo r Me a s u r i n g E a r th Re s i s ti v it y Gr o u n d I mp e d a n c e ,

and Ear th Sur face Poe ten t i a l s o f a Gro und Sys tem, The Ins t i tu te o f E lec t r i ca l and E lec t ron ics

Eng inee r s , Inc . , N ew Yo rk , NY , 1983 .

.

E . L . K i r k p at r ic k , Re p o r t o f Ca t h o d i c P r o t e c t io n a n d Gr o u n d i n g S t u d y o n Oi l a n d Ga s

Prod uc t ion Fac i li t ie s in Pak i s tan , EL K E ng inee r ing Assoc ia te s , Inc . , 1750 , 21 M arch 1997 .



T A B L E 1

E F F E C T O F B A R E C O P P E R R E M O V A L O N C P P O T E N T I A L O F B U R I E D P I P I N G in P . F .- 2

S E L E C T E D P I P E - T O - S O IL P O T E N T I A L S M I L L I V O L T S T O C u -C u SO 4

B E F O R E C O P P ER R E M O V A L A F T E R C O P P E R R E M O V A L

D E S C R I P T I O N

F . W . - W a l e r C a n n o n M - 7

F . W . - P u m p D i s c h a r g e

2 F r e s h W a t e r L i n e

10 T .R . In l e t L ine

W a t e r I n j e c t i o n P u m p S u c t i o n

L i n e

4 B r i n e L i n e - W e s t E n d

3 L i n e t o T a n k S - 2 1 2

C L O S E O N C L O S E O F F

-1245

-980

-755

-720

-760

.-685

-735

-745

-635

-540

-580

-539

-565

C L O S E O N

-1005

- 8 2 0

-785

- 7 5 0

- 7 8 0

- 6 9 0

-955

- 9 7 0

C L O S E O F F

-660

-645

-645

-570

-580

-550

-560

B P P

-

47 -545 -475 -560 -485

F . W . - F i r e C a n n o n M - I 1 - 1 1 6 0 - 7 7 0 - 9 2 0 - 6 3 0

F .W. - P . I .V . H -7 -1200 -770 -980 -670

B P P

-

38 - P l a n t S ide -665 -560 -690 -575

F .W. - F i r e H y dra n t H -6 -1225 -775 -995 -660

8 D r a i n L i n e a t S k i m P o n d - 6 4 0 - 5 3 5 - 6 4 0 - 5 5 0

T A B L E 2

S U M M A R Y O F R E C O M M E N D A T I O N S

F O R M A J O R P R O D U C T I O N F A C I L I T IE S

F a c i l i t y

I d e n t i f i c a t i o n

P F - I

PF -2

PF-3

P F - 4

P F - 5

P F - 6

F a c i l i t y N a m e

T u r k

G a s F a c i l it y

G o l a r c h i

G a s F a c i l it y

B u k h a r i

G a s F a c i l i ty

M a z a r i

O i l / G a s F a c i l i ty

L a g h a r i

O i l Fa c i l i t y

K l m s k e h l i

O i l Fa c i l i t y

E x i s t i n g C P S y s t e m

T / R s G . B e d s

T W O T W O

O N E T W O

T W O T W O

T H R E E T H R E E

T W O T W O

T H R E E F O U R

A d d i t i o n a l E q u i p m e n t U p g r a d e

R e c o m m e n d a t i o n s C o m p l e t i o n

T / R s G . B e d s

T W O T H R E E J u ly '9 8

T W O T W O M a y ' 9 8

N I L N I L

T H R E E * T H R E E N o v ' 9 8

N I LI L

N I L N I L

* O n e o f t h e t h r e e T / R u n i t s r e c o m m e n d e d i s r e p l a c e m e n t o f o n e o f t h e e x i s t i n g T / R w i t h h i g h e r o u t p u t u n it .



T A B L E 3

C A T H O D I C P R O T E C T I O N D A T A A F T E R C O M M I S S I O N I N G

I C C P U P G R A D E F O R P . F . -1

I n i t i a l D a t a

S t a r t -u p D a t a

F i n a l D a t a

D a t e T / R 1 T / R 2 T / R 3 T / R 4

1 2 - 1 3 M a y ' 9 8

1 4 - 1 5 M a y ' 9 8

1 6 - 1 7 M a y ' 9 8

O N O N

O F F

O F F

O N O N O N O N

O N O N O N * O N *

S E L E C T E D P I P E - T O - SO I L P O T E N T I A L S M I L L I V O L T S T O C u -C u SO 4

L o c a t i o n D e s c r i p t io n

B U R I E D P L A N T P I P IN G 0B PP )

4 S O U T H E A S T OF M C C

I n i ti a l D a t a S t a r t - u p D a t a

-831

F i n a l D a t a

- 7 7 9

S O U T H E A S T O F M C C - 8 02 - 7 54

T O D E G A S E R - 82 4 - 80 2

D R A I N - 8 4 4 - 7 62

D R A I N F R O M T A N K S - 8 50 - 7 9 2

V -512 -823 -742

S T U B U P - 7 6 6 - 7 0 2

T O B U R N P I T - 1 05 3 - 9 45

T O B U R N P I T - 1 2 0 5 - 1 05 7

F R O M V - 1 2 10 - 6 9 0 - 7 8 2

N E A R V - 1 2 0 0 - 8 2 9 - 7 48

A T K H O R E W A H R E C E I V E R - 78 5 - 70 8

8 S S G C M E T E R I N G S KI D

IA A T I N C I N E R A T O R

T e s t P o i n t

B P P N O .

B P P 6

B P P 6 A 4

B P P 2 4

B P P 2 A 4

B P P 1 4

B P P 7 2

B P P 8 2

B P P

A 4

B P P B 4

B P P C 2

B P P 4 4

B PP 5 1

B P P 9

B PP 10

B PP 16

BPP 11

B PP 12

B PP 13

B PP 14

BPP 15

G - N O . G R O U q

G -1

G - 2

G - I I

G - 1 2

G - 1 3

G - 1 4

G - 1 5

G - 3 E - 5 0

G - 4 V - 5 0 5

G - 5 D - 5 0 1

G - 6 S - 5 0 1 A

G - 7 T R - 1

8 S S G C M A N I F O L D

~ O U N D I N G C A B L E S

-535

-530

-539

-536

-558

-542

-529

-632

- 6 7 8

-545

-504

-499

-1126

- 6 7 0

-850

-535

-533

-521

-521

-607

- 5 0 7 ]

- 9 1 0 1

-917

-998

-738 I

-700 I

-496

-506

- 5 3 0

-473

-166 j

A l l po te n t i a l s a re S t e a dy on

F L P 5 1 1

-1401

- 1 0 5 8

- 1 6 0 2

-1064

-786

- 7 8 6

-789

-789

-819

-675

- 1 6 4 2

-1408

-1136

-1419

-1251

-774

-774

-772

-772

N E A R M C C

* O N , bu t se t a t r e duc e d ou tpu t .

-930

-779

-1408

-1178 -1070

-1565 -1118

-1691

-983

-726

-782

- 8 3 9

- 8 2 9

- 1 1 2 0

-1434

-900

- 6 6 9

-714

-795

-752

-470



T A B L E 4

C A T H O D I C P R O T E C T I O N D A T A A F T E R C O M M I S S I O N I N G

I C C P U P G R A D E F O R P .F . -2

D a t e

I n i t ia l D a t a

S t a r t - u p D a t a

F i n a l D a t a

1 2 - 1 3 M a y ' 9 8

1 4 - 1 5 M a y ' 9 8

1 6 - 1 7 M a y ' 9 8

T / R 1 T / R 2 T / R 3 T / R 4

O N O N O F F O F F

O N O N O N O N

O N O N O N * O N *

S E L E C T E D P I P E - T O -S O I L P O T E N T I A L S M I L L I V O L T S T O C u- Cu SO ~

T e st P o in t L o c a t i o n D e s c r i p t i o n I n it ia l D a ta S t ar t -u p D a ta

G - 8 K H O R E W A H R E C E I V E R .-478 - 7 72

G - 9 E A S T O F V - 5 1 2 - 5 77 - 9 5 7

G - 1 0

T - N O .

T - 5 0 1

N E A R F H ( 5 )

S T O R A G E T A N K S

N O R T H

E A S T

S O U T H

W E S T

-607

-1132

- 9 5 8

- 1 1 5 6

-1148

-955

-1451

- 1 3 1 8

- 1 4 5 9

-1455

F i n a l D a t a

-681

-852

-868

-1165

-1065

-1156

-1179

T ~ 5 0 2 N O R T H - 1 2 2 5 - 1 4 9 5 - 1 1 5 9

E A S T - 1 1 5 8 - 1 4 6 4 - 1 1 0 4

S O U T H - 1 1 5 7 - 1 4 4 1 - 1 1 1 0

W E S T - 1 1 51 - 1 4 2 5 - 1 1 2 0

F W L -N O . F I R E W A T E R L O O P

1 A R E A - 2 - 8 5 6 - 1 8 9 2 - 1 4 63

2 A R E A - 2 - 6 6 7 - 9 6 5 - 1 0 6 5

2 A A R E A - 2 - 8 6 7 - 1 1 5 5 - 9 2 2

3 A R E A - 2 - 1 1 2 2 - 1 7 7 0 - 1 4 5 9

4 A R E A - 2 - 9 1 0 - 1 3 2 5 - 1 2 4 4

A R E A - 2

ArU~A-2

-984

-873

A R E A - I - 8 O 4

A R E A - I - 8 4 6

A R E A - 3 - 7 7 5

A R E A - 3 - 8 1 3

A R E A - 3 - 8 1 0

A R E A - 3 - 8 5 2

A R E A - 3 - 8 4 9

A R E A - 3 - 8 4 4

-1559

A

- 1 3 8 0

-1476 -1210

-1409 -1256

-1530 -1344

-990 -1095

-1064 -1248

-1066 -1224

-1105 -1353

- 1 1 0 8 - 1 3 4 6

-1068 -1288

6

6 A

7

7A

7B

8 A

8

9

9A

10A

10

3 A

O N . bu t se t a t

A R E A - 3 - 1 0 5 8 - 1 2 8 2 - 1 4 9 6

A R E A - 3 - 8 5 6 - 1 0 9 6 - 1 3 0 3

A R E A - 3 - 8 5 0 - 1 0 9 0 - 1 3 1 4

A R E A - 3 - 1 2 8 6 - 2 0 8 9 - 1 8 0 2

r e d u c e d o u t p u t. A l l p o t e n t i a l s a ~ s t e a dy o n



T A B L E 5

C A T H O D I C P R O T E C T I O N D A T A A F T E R C O M M I S S I O N I N G T H E I C C P U P G R A D E F O R P . F . - 4

D a t e

S T E P - 1 1 3- 14 N o v ' 9 8

S T E P - 2 1 6- 17 N o v ' 9 8

S T E P - 3 1 9- 20 N o v ' 9 8

T / R 1 T / R 2 T / R 3 T / R 4 T / R 5

O F F O F F O F F O N O N

O N O N O N O N O N

O N * O N * O N * O N * O N *

S E L E C T E D P I P E - T O - S O I L P O T E N T I A L S M I L L I V O L T S T O C u -C u SO 4

T e s t P o i n t

B P P N O .

L o c a t i o n D e s c r i p t i o n

B U R I E D P L A N T P I P IN G ( B P P )

I n i t i a l

D a t a

S T E P - 1

S T E P - 2

B P P 8 2 ½ G A S T O I N C I N E R A T O R - 45 1 - 80 3 - 9 33

B P P 8 2 A 1 /2 G A S T O I N C I N E R A T O R - 44 3 - 77 3 - 8 9 8

B P P 8 1 A 2 W A T E R - 4 50 - 7 6 2 - 8 95

B P P 8 1 3 W A T E R - 4 5 2 - 7 7 1 - 9 0 9

B P P 7 8 8 D I A T O S K I M P O N D - 4 5 0 - 8 22 - 9 3 9

B P P 7 9 1 - 1 /2 T O B U R N P I T - 4 5 2 - 7 8 7 - 8 9 4

B P P 8 0 2 C R U D E O I L - 4 52 - 7 8 8 - 8 9 6

B P P 7 9 A 1 -1 /2 G A S A T B U R N P I T - 4 68 - 7 9 9 - 9 1 7

1 3P P 8 0 A 2 C R U D E O I L - 4 6 8 - 7 7 9 - 9 1 9

B P P 3 8 8 S A L E S G A S L I N E ( L I N E / P L A N T ) - 4 42 - 77 1 - 9 2 9

B P P 3 6 D R A I N T O S K I M P O N D 2 F R O M - 45 3 - 7 53 - 8 9 4

V - 6 1 2

B P P 3 5 D R A I N T O S K I M P O N D 2 F R O M - 53 6 - 7 20 - 8 67

V - 6 0 5

B P P 3 7 2 D I A - 4 4 6 - 7 3 7 - 8 5 7

B P P 4 4 4 S T U B U P - 4 53 - 7 1 5 - 8 5 7

B P P 4 2 1 T O B P P - 4 1 - 4 43 - 7 1 8 - 8 5 7

B P P 4 1 1 T O T - 6 0 1 - 4 8 6 -6 7 7 - 7 8 8

B P P 4 0 2 T O T - 6 0 1 - 4 6 7 -6 9 3 - 8 1 3

B P P 4 3 4 S T U B U P - 4 33 - 7 1 3 - 8 53

B P P 3 9 4 S T U B U P - 4 4 9 - 7 5 8 - 9 0 4

B P P 1 2C 1½ - D I A D I E S E L L I N E F R O M - 4 5 0 - 8 81 - 1 0 81

D I E S E L T N K

B P P 1 2B 1 D I E S E L R E T U R N - 4 5 4 - 8 29 - 1 01 6

B P P 1 2 2 D I E S E L S U P P L Y E R - 6 - 4 5 7 - 8 33 - 1 0 2 7

B P P 1 2A 1 F R O M D I E S E L E N G I N E - 4 44 - 8 40 - 1 0 30

13PP 11 2 D I A -382 -677 -651

B P P 9 2 F R O M A I R C O M P R E S S O R - 4 27 - 6 96 - 8 3 9

B P P 1 0 1 - I / 2 F . G . F R O M S C R U B B E R G A S - 4 3 4 - 7 02 - 86 1

E N G .

* O N , bu t se t a t r e duc e d ou tpu t . A l l po te n t i a l s a re s t e a dy on



T A B L E 6

C A T H O D I C P R O T E C T I O N D A T A A F T E R C O M M I S S I O N I N G T H E I C C P U P G R A D E F O R P . F . - 4

D a t e

S T E P - I 1 3- 14 N o v ' 9 8

S T E P - 2 1 6-1 7 N o v ' 9 8

S T E P - 3 1 9- 20 N o v ' 9 8

T / R I T / R 2 T / R 3 T / R 4 T / R 5

O F F O F F , O F F O N O N

O N O N O N O N O N

O N * O N * O N * , O N * O N *

S E L E C T E D P I P E - T O -S O I L P O T E N T I A L S M I L L I V O L T S T O C u -C u SO 4

I n i t i a l


B U R I E D P L A N T P I P I N G ( B P P )

T e s t P o i n t

B P P N O .

B P P 8 3

B P P

84

B P P

85

B P P 86

B P P 8 7

B P P

3 8 A

B P P 1 8 B

B P P 45

B P P

46

13PP

4 5 A

B P P 4 6 A

B P P 8 8

B P P

8 8 A

B P P

89

B P P 3 2 6 D I A

B P P 3 1 4 D I A

B P P

3 0 2 W A T E R

B P P

29

13PP

2 8 2 G A S

B P P 2 7 8 O I L

B P P 2 6 8 O I L

B P P

1 9 8 D I A

B P P 2 0 8 D I A

B P P 2 1 2 D I A

B P P 2 2 2 ; ' D I A

B P P 2 3 2 D I A

B P P 2 4 4 D 1 A

B P P

2 5 6 ; ' D I A

B P P 8 9 A 8

B P P 1 8A 3 D I A

B P P 18 4 D I A

B P P 17 ] 4 D I A

B__PP 16 ] 4 D1 A

O N ,

bu t se t a t r e duc e d ou tpu t .

D a t a

8 D I A F R O M T - S 21 1 ( B P P - 8 9 A )

S T E P - I S T E P - 2

3 W A T E R F R O M F . W . P O N D - 4 7 6 - 7 79 - 1 21 1

6 W A T E R F R O M F . W . P O N D - 4 70 - 8 26 - 1 2 25

6 W A T E R / P L A N T T O F . W . P O N D - 4 75 - 86 1 - 1 2 5 7

3 W A T E R F R O M B P P - 8 3 T O M Z - 2 - 4 87 - 78 1 - 1 25 0

6

F R O M B P P - 8 4 - 5 4 5 - 7 51 - 1 1 4 5

S S G C A T P L A N T ( S S G C S I D E ) - 8 72 - 7 90 - 1 0 00

3 D I A S T U B U P ( N o t c o n n e c t e d t o - 5 0 5 - 5 0 7 - 5 51

C P )

6

D I A F R O M T - S 2 1 1 - 4 4 8 - 5 8 8 - 9 6 5

8 D I A F R O M T - S 2 1 1 - 4 50 - 5 8 9 - 9 6 9

C O N T I N U A T I O N O F B P P -4 5 - 44 9 - 61 8 - 94 5

C O N T I N U A T I O N O F B P P -4 6 - 44 2 - 6 12 - 9 42

3 W A T E R T O E V . P O N D - 45 3 - 5 9 0 - 9 26

3 W A T E R ( C O N T I N U A T I O N O F - 48 3 - 6 36 - 96 1

B P P - 8 8 )

- 4 4 5 - 6 3 7 - 9 9 2

-441 -632 -993

-447 -633 -992

-445

-447

- 4 4 7

- 4 4 6

-62 l

-627

- 6 2 9

- 6 3 0

-985

2 A I R F R O M A I R C O M P R E S S O R -983

- 9 8 6

- 9 8 7

-446 -630 -990

-431 -619 -1033

-431 -621 -1027

-433 -611 -1008

-431 -615 -1008

-434 -614 -1008

-434 -617 -1011

-433

-433

I A ' IF ( A B O V E G R A D E )

-619

-615

- 1 0 1 8

-1001

-439 -613 -910

-431 -589 -853

-421 -598 -867

-418 -607 -893

A l l po te n t i a l s a re s t e a dy on

S T E P - 3



TABLE 7

C A T H O D I C P R O T E C T I O N D A T A A F T E R C O M M I S S I O N I N G T H E I C C P U P G R A D E F O R P .F . - 4

D a t e

ST EP -1 13-14 Nov'98

ST EP -2 16-17 Nov'98

ST EP -3 19-20 Nov'98

T / R I T / R 2 T / R 3 T / R 4 T / R 5

OFF OFF" OFF ON ON

ON ON i ON ON

i

ON

ON* ON* ' ON* ON* ON*

SELECTED PIPE-TO-SOIL POTENTIALS M1LLIVOLTS TO Cu-CuSO4

T e s t P o i n t

B P P N O .


B U R I E D P L A N T P I P IN G ( B P P )

BPP 61

I n i t i a l

D a t a

S T E P - I

S T E P - 2

S T E P - 3

BPP 15 4" DIA -418 -602 -897

BPP 14 6" DIA -4i 8 -602 -900

BPP 13 8" D1A -417 -601 -902

BPP 90 2" GAS -421 -865 -996 -979

BPP 91 i 2 AiR FROM AIR COMPRESS OR -422 -874 -984 -978

BPP 53 6" OIL -421 -847 -952 -957

BPP 92 4" GAS -423 -875 -979 -969

BPP 93 4" AI R -422 -857 -957 -961

BPP 52 8" GAS -420 -840 -945 -949

BPP 94 2" AIR FROM AIR COMP RESSOR -421 -833 -942 -946

BPP 51 6" OIL -418 -808 -999 -902

BPP 50 8" OIL -413 -790 -876

BPP 54 6" STUB UP -415 -769 -859

BPP 55 4" STUB UP '415 -767 -851

BPP 56 1" OIL DRA IN FROM LIAR I PIG -414 -753 -840 -641

REC.

BPP 57 2" FROM LIA RI PIG REC. -424 -776 -876

BPP 58 2" FROM MAT LI PIG REC. -420 -774 -873 -876

BPP 59 1" DRA IN FRO M MAT LI PIG REC. -413 -752 -840 -841

-751 -843 -850" OIL FROM DHAB I PIG REC. TO

BPP-51

BPP 62

-417

-401

-402

PP 63

-693

-697

1" DRAIN F ROM DHAB I PIG REC.

-757

-760

" FROM DHABI PIG REC.

-758

-761

BPP 64 2" FRO M S. MAZ ARI PIG REC. -400 -697 -763 -763

BPP 65 " DRA IN FROM S. MAZ ARI PIG -399 -680 -748 -748

REC.

BPP 67 4" OIL FROM ER-11 (Disconnected) -413 -718 -819 -819

4" DRAIN TO PIT

PP 70

BPP 68

BPP 69

BPP 71

-418

-418

-433

-412

-400

-405

-408

BPP 72

BPP 73

BPP 77

-711

-718

-747

-707

-683

-683

-686

I" STUB UP (RF.MOVED FROM ER-

11)

2 S T U B U P ( R E M O V E D F R O M E R -

l l )

8" OIL TO V-800 FROM SDV-5000

A&B

-792

-802

-839

-794

-757

-759

-771

1 D I A

6" TO V-700 (REMOVED) OIL

8" FROM INLET MANIFOLD

-793

-806

-844

-796

-756

-762

-773

* ON, but set at reduced output. All potentials are steady on

00743 copper grounding systems have a negative effect on cathodic protection in production...

Documents