a computer simulation model for oil transport and storage problem

8/10/2019 A Computer Simulation Model for Oil Transport and Storage Problem

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A COMPUTER SIMULATION MODELFOR

OIL TRANSPORT AND STOR AGE PROBLEM

B Y D R M U S TA S FA A B D U L A A L

A L F AT A H U N I V E R S I T Y I D E P T . O F C O M P U T E R S C I E N C E S ~ T R I P O L I ~ L I B YA

ABSTRACT

Th is p a p e r s o l v e s t h e p ro b l e m o f a l te rn a t in g t r a n s p o r t o f t w od i ffe ren t k inds o f c rude o i l v ia same p ipe- l ine f rom a d i s tan tp roduc t ion f i e ld to po r t t e rmina l w here i t i s s to red in t anks to beP i c ke d -u p b y s h i p s , s h i p s d o n o t a rr i ve t o p o r t a t d e t e rmi n i s t i ct i m e s . Th e t w o k i n d s o f c ru d e o i l b e l o n g t o d i f f e re n t c o mp a n i e s

a n d d o n o t mi x a t a l l . In t h i s p a p e r w e d e t e rmi n e t h e o p t i mu mtranspor t schedu le fo r the two c rudes depend ing on d i ffe ren tp ro d u c t i o n l e v e l s , a n d w e d e t e r i mi n e t h e o p t i mu m t a n k s t o r a g ecapac i ty to be used by each c rude a t the p o r t t e rmina l und ers t o c h a s t i c o i l p i c k u p b y s h i p s .A c o mp u t e r s i mu l a t i o n t e c h n i q u e i s d e v e l o p e d t o s o l v e t h i s p ro b l e mbased on re levan t h i s to ry da ta . Th e imp lem en ta t ion resu t s o f thes i mu l a t i o n p ro g ra m a re a l s o p re s e n te d a n d i n t e rp re t e d .o p t i u m t r a n s p o r t s c h e d u l e s a n d ma j o r s a v i n g s i n s t o r a g e c a p a c i tyi s c o n c l u d e d .

A. INTRODUCTION

Tw o O i l C o mp a n i e s Zu e t i n a C 1 )a n d A g i p C 2) a re p ro d u c i n gd i ffe ren t c rude o i l a t com mo n f ie ld loca t ion . Oi l p roduced by C1 andC2 i s pum ped f r om f ie ld to the sam e po r t t e rmina l th rougha com mo n p ipe l ine a t a l t e rna t ing schedu le be tween C1 and C2.Each com pany has i t s own s to rage t anks a t po r t , f rom which t ankersh ips l i f t o i l fo r expor t . Also here, com mo n ber th tubes a re used topum p o i l f ro m the d i ffe ren t o i l s to rage t anks to the t anker sh ips . AsCl o i l i s wax f ree and C2 o i l i s waxy, the ber th tubes a re f lu shedwi th C1 o i l a f t e r each loa d ing o f C2 o i l to keep tubes w axf ree .Over the pas t per iod the quan t i ty ~ f o i l p roduc ed by C1 has beenon d ec l ine wh i le tha t p roduce d by C2 has been r i s in g . The s ixs to rage t anks cons t ruc ted by C1 a t po r t severa l years agoappear to be in e xcess o f the cu r ren t needs . S ince the main tenance

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o f s t o r a g e t a n k s , w h e t h e r o r n o t i n u s e , is v e ry c o s t l y, a n dComp any C2 i s in te res ted to buy o r l ease excess t anks o f C1, i t i scons idere d very necessary fo r C1 to f ind the op t imu m num ber o ftanks c o r respo nd ing to i t s cu r ren t and near fu tu re needs . Inadd i t ion , i t i s requ i red to kno w how to ad jus t schedu les o ft ranspo r t ing o i l f rom f ie ld to po r t be tween C1 and C2 as pervarying prod uct io n leve ls o f C1 and C2 and hence th is s tudy isc o n d u c t e d .Th e c o mp l e x i t y o f t h i s p ro b l e m a r is e s f ro m t h e f a c ts t h a t t a n k e rsh ips do no t guaran tee a r r iva l to l i f t o il a t regu la r bas i s to maked e t e rmi n i s t ic s t o ra g e c a l c u l a t i o n . Mo re ov e r, w e a t h e r p ro b l e m s a tpo r t s p reven ts embarked tankers to be loaded fo r unexpec tedper iods o f t ime po r t c lo su re ) .I f regu la r l if t ing o f o i l i s as sum ed and po r t c lo su re i s omi t t ed , i tw o u l d h a v e b e e n a s i mp l e d e t e rmi n i s t ic p ro b l e m b a s e d o nproduc t ion l eve l s. Over es t im at ion o f po r t c lo su re and t ime gapsbe tween tank er sh ips a r r iva l s may resu l t in a cos t ly ove r es t imatednumber o f t ankers .

There fo re , we reso r t to s imu la t ion t echn ique s based on h i s to ryd a t a o f t a n k e r a r r i v a l s a n d p o r t c l o s u re s .

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B . I N P U T D ATA

F o u r k i n d s o f d a t a w h i c h a r e d i r e c t ly o r i n d i r e c tl y r e l e v a n t t o t h es tu d y h av e b een u sed . Th e d a ta Were m a d e av a i l ab le in a v e r y c ru d ef o r m , w i t h i t em s s p r e a d o v e r d i f f er e n t b a c k l o g r e g i s t r y s h e e ts a n df il es . Th e y were id en t i f i ed , ex t r ac t ed an d en te r ed in to th e co m p u te ra s AS C I I d a t a f i le s. Th e i n t e rp r e t a t io n o f d a t a i s a l so d i f f i cu l t a s th ep e o p l e f i l in g a n d a r c h i v i n g t h e d a t a f o r m s a n d r e g i s te r s a r e n o ta w a r e o f t h e t e c h n ic a l it i e s o f t h e i n t e r p r e t a t i o n . H o w e v e r , t h e d a t au sed a r e :

i ) S h i p p i n g D a t a

Th i s i s t h e m o s t r e l ev an t a i id u se ful d a t a f i l e f o r t h e s tu d y. Th eq u a n t i ty o f o i l l i f ted b y each t an k e r a lo n g wi th th e d a t e , t im ea n d d u r a t i o n o f l o a d i n g i s a v a i l a b l e h e r e s i nc e J a n u a r y 1 99 2o n m o r n i n g r e p o r t s h ee t s a n d on m a n u a l r e g i s t ry b o o k s . I t i so b s e r v e d t h a t, b r o a d l y S p e ak i n g, t h e r e w e r e t w o k i n d s o f

s h i p m e n t s f o r C o m p a n y C 1 w h i c h h a v e b e en s t u d i e d a n dt r e a t e d s e p a r a t e l y : -

a

b

Flu s h sh ip m en t to c l ea r b e r th tu b es w i th q u an t i ty f ix ed a t 1 .5M B L L S t h o u s a n d s o f b a r r e l s ).N o r m a l s h i p m e n t w i th m u c h l a rg e r q u a n t i ti e s o f e x p o r t .

i i) P o r t - C l o s u r e D a t a

T h e d a t a r e l a t i n g t o p e r i o d s d u r i n g w h i c h t h e p o r t r e m a i n e d

c lo sed d u e to b ad wea th e r s in ce 1 9 92 h av e b een u sed a f t e rc o l le c t in g t h e m f r o m d a i l y w e a t h e r r e p o r t s . T h e y a r e v e r yr e l e v a n t a n d o f m u c h u s e

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C . A N A LY S E D P R O B L E M D E S C R I P T I O N

Th e m o v em en t o fo i l f r o m th e f ie ld to th e p o r t an d f ro m p o r t t o th etan ke rs i s consid ered in var iou s s tages , as be low :

i Th e o il p ro d u ced b y CI i s t r an s p o r t e d f ro m th e fi e ld to th e p o r tte r mi na l th rou gh p ipe l ine i n ba tch es , i . e . i t flows fo r som espec i f ied hours , and then the p ipe l ine is used fo r the f low of C2o il . Th i s i s m o re o r l e ss a r eg u la r p ro g ram : e .g . 2 0 h o u r s o fCI o i l i s f o l lo wed b y 60 h o u r s o f o i l, a s p e r cu r r en t p ro d u c t io nlevels.

i i ) Th e o i l i s s to red in s to r age tanks a t the por t .

i ii ) O i l t an k e r s a r r i v e a t v a ry in g t im e in t e rv a l s l i ft i ng v a ry in gq u an t i ty o f oi l.

iv

v

ab

An y t an k e r th a t l i ft s C2 o i l h a s to l i f t L5 M BL LS o f C1 o i l t o

g e t t h e b e r th tu b es f lu sh ed .

Du e to b ad we a th e r t h e p o r t i s c lo sed in t e rm i t t en t ly. Wh i l e th ein f lo w o f o il co n t in u es d u r in g th e p e r io d th e p o r t i s clo sed th eo u t f lo w ( sh ip m en t ) i s su sp en d ed cau s in g l a rg e q u an t i t i es o f o i ls to r ed in p o r t t an k s .Th e p e r io d o f c lo su re an d th e in t e r- c lo su re g ap a r e v e ryv a ry in g , h o wev e r, i t i s o b se rv ed th a t d u r in g th e w in te r,c lo su re s a r e m o re f r eq u en t an d fo r l o n g e r p e rio d s th an in o th e rseasons .Th i s l ed u s to s tu d y th e c lo su re -o f -p o r t d a t a sep a ra t e ly fo r t h etwo seasons:No v em b er th ro u g h Ma rch : w h ich we ca ll b ad sea son , an dA p r i l t h r o u g h O c t o b e r : w h c h w e c a l l g o od s e a s o n .To a t t a in accu ra t e m o d e l f it t in g s .


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Keep in g th e ab o v e f ac to r s i n vi ew th e s to r ag e f ac i l it y a t t h e p o r t i s t obe m in im ized p rov id ed tha t i t i s Suffic ien t to cope wi th the ex pec tedp ro d u c t io n s to r ag e u n d e r th e an t i c ip a t ed lo n g p e r io d s o f c lo su re an ddela y in o i l l i f ting . In fa i r weath er, th a t i s when the po r t i s open ,a c c u m u l a t i o n o f o il m a y n o t p o s e s e ri o u s p r o b l e m .

D . T H E P R O P O S E D M O D E L

W e p r o p o s e s i m u la t io n t e c h n iq u e to b e a d o p t e d t o s t u d y t h e p r o b l e ma t h an d . S im u la t io n i s a co m p u te r t e ch n iq u e wh ich g en e ra t e s anes t im a ted sy s t em wh ich i s m o re o r l e ss a p i c tu r e o f a r ea l - l i f e sy s t emu n d e r s t ud y. T h i s i s b a s ed o n a n u m b e r of m a t l e ~ l ~ s t a t i s t i c a lan d lo g ical r e l a t io n sh ip s b e tween th e v a r io u s f ac to r s i n v o lv ed in th esy s t em .

In th i s s tu d y so m e o f th e r e l ev an t fac to r s a r e :

i ) I n p u t To S to r ag e :

Th e e l em en t s o f a b a t ch sch ed u le a r e d i r ec t o u tco m e o fp ro d u c t io n r a t e s ( in p u t t o s to r ag e ) wh ich fu l ly d i c t a t e s th efo l lowing e lements :

a

be

No . o f h o u r s d u r in g wh ich C1 o il i s t r an s p o r t ed th ro u g h th ep ip le l in e f rom the f ie ld to the por t .No . o f hours no t used b y C1 ( i. e . used by C2)R ate o f f low of o il .

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ii)

a

bc

defg

iii)

Output From Storage:

The following stochastic variables are the most important andrelevant factors governing the output from the storage tanksand have therefore been used in the model:

Gap in hours) between twosuccessive closures during bads e a s o n

Period in hours) of closures during bad season.Gap in hours) between two successive closures during goodseason.Period in hours) of closures during good season.Gap between two successive flush shipments lifting 1.5 MBLLS.Gap between two successive normal shipments.Quantity lifted in the normal shipments.

Initial Stock:

This is the initial quantity in C1 storage tanks at the port atsome base period, to avoid unrealistic system generat ion of

future daily stock levels that would in the absence of this initialvalue, start with Zero stock level.

E. ANALYSIS OF THE DATA

Each of the seven stochastic variables enumerated above has beenanalysed using the collected and then computerised) data files to givethe following statistics:a

bcdefg

Minimum value,

Maximum value,Mean or the average,V~riance,Beta 1,Beta 2, andFrequency distribution.

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Sev e ra l co m p u te r p ro g ra m s h av e b een wr i t t en fo r t h e ab o v e s t a t i s t ic swh ich a r e n ecessa ry to sp ec i fy th e p ro p e r m o d e l t o r ep r e se n t t h ed i f f e r en t v a r i ab le s . Th e p ro g ram s a r e :

a cl.ex e . . .wh ich com putes the above s ta t i s t ics fo r :i ) du ra t io n o f por t c losed hours fo r :

a ) good season ,b} bad season ,

i i ) gap ( in hou rs) between consecutive closures in :a) good season,b) bad season ,

b out big , exe .. .wh ich co m p u te s th e r e l ev an t s t a ti s t ic s f o r :i ) q u an t i ty o f o i l l i f t er b y n o rm a l sh ip m en t ,i i ) gap ( in hours) be tween two consecu t ive no rm al

sh ip m en t s .

c outs m, exe . ..

wh ich co m p u te s th e r eq u i r ed s t a t i s t ic s f o r :i ) gap ( in hours) be tween two consecu t ive f lush sh ipm ents .

(No te th a t t h e q u an t i ty l i ft ed b y flu sh sh ip m en t s b e in g f ix ed a t 1 .5M B LL S n eed n o t b e in v est ig a ted in to , an y fu r th e r ) .

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Fr o m th e s tu d y o f t h e f r eq u en cy d i s t r ib u t io n s an d o th e r s t a t i s t i c s i t

h a s b e e n i n f e r r e d t h a t t h e g e n e r al i se d g a m m a d i s t r ib u t i o n m a y b ee m p l o y e d t o a p p r o x i m a t e t h e u n k no w n d i s t ri b u t io n o f t h e v a r i a b l e su n d e r s tu d y. Th i s i n f e r en ce i s a lso in co n fo rm i ty wi th th e ex p e r i en ceo f o p e ra t io n s r e sea r ch p r ac t i ce s in such f i e ld s o f ap p l i ca tio n .

Th e p ro b ab i l i t y d en s i ty f un c t io n o f t h e g en e ra li zed g am m ad i s t r ib u t io n i s o f t h e fo rm :

f (x ) =1 r~x ^ ( r- l ) / G ( r ) ~ exp ( - l ~x )

wh e re G i s t h e g am m a fu n ct ion , an d o th e r n o ta tio n s a r e ex p la in edbelow.

G am m a d i s t r ib u t io n in i t s g en e ra l f o rm , d ep en d in g o n th e v a lu es o f i t sp a r a m e t e r s , i n c lu d e s v a r io u s o t h e r i m p o r t a n t p r o b a b i l i t yd i s t r ib u t io n s co m m o n ly u sed in su ch s tu d ie s su ch a s :

i Neg a t iv e ex p o n en t i a l d i s t r ib u t io n :Th e p ro b ab i l i t y d en s i ty f u n c tio n o f t h i s d i s t r ib u t io n h as th e

fo rm :

f (x) = 1 ~ exp (-lx)

wh ere x is t h e ex p o n en t i a l ) ' a r i a t e , 1 i s t h e p a r a m e te rand exp s tan ds fo r e to the pow er . ..

s t an d s fo r m u l t ip l i ca t io n .

ii) E r l a n g d i s t r i b u t i o nTh e p ro b ab i l i t y d en s i ty f u n ct io n o f th i s d i s t r ib u t io n is :

f (x ) = 1 ^ r ~ x ^ ( r - 1 ) ~ e x p ( - l ~ x )

w h e r e x is t h e E r l a n g v a r i a t e,r a n d 1 a r e t h e p a r a m e t e r s , a n d

s t an d s fo r f ac to r i a l s ig n ,^ s t an d s fo r ' t o t h e p o we r ' .

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_

_

Th e sy s t em i s f i r s t co n s t ru c ted o n h o u r ly b as i s f o r w h o les im u la t io n p e r io d wi th in fo rm a t io n o n : p o r t - c lo sed / o p en ,in f low, ou t f low ( f lush + normal) the ho ur ly s to ck i s c rea t ed .Al l t h i s i s d o n e in s id e th e Co m p u te r an d th en th e h o u r lys t ru c tu r e i s r em o d e l l ed in to d a i ly s t r u c tu r e . Assu m in g th eg i v e n c a p a c it y o f a t a n k t o b e 5 40 M B L L S t h e n u m b e r o ft an k s n eed ed to s to r e th e s to ck a t t h e p o r t i s co m p u ted eachd ay. Th e g iv en v a lu e o f 5 40 MB LLS can ea s ily b ec h a n g e d i n t h e p r o g r a m .

Th e co m p le t e g en e ra t ed sy s t em fo r t h e wh o le s im u la t io n p e r io di s th en d i sp lay ed o n sc r een o r p r in t ed o n p r in t e r a t w i l lsh o win g :

[ da y c losed in ou t d -s t oc k no . tnks ]

in

o u t

w h e r e

day . .

c losed . .

i s t h e se r i a l n o . o f t h e d ay f ro m 1 u p to th e l a s t d ayof the s imu la t ion per iod .

sh o ws th e n u m b er o f h o u r s th e p o r t i s c lo sedo n th a t d ay u s in g th e sy m b o l s :

mean ing do sed fo r 1 to 6 hours ,+ mean ing do se d fo r 7 to 12 hours

meaning closed for 13 to 18 hoursx mean ing do sed fo r 19 to 24 hours ,

is the qua nti t y o f inf low of oi l f rom the f ie ld to the pog~.

i s th e q u an t i ty o f ou t flo w o f o i l f r o m th e p o r t b y th et an k e r s .

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cl-stock..

no. tuks..

is the closing-stock of oil left in the storage tanks on theday.

In case the re is zero stock it is indicated by -0.0.

is the nu mb er of tanks requi red to store the closing stock.It has been worked out taking a tan k s capacity to be 540MB LL S. To be realistic it appea rs as 1 even when thestock is Zero.

H. IMPLEMENTATION

The ma in simulatio n prog ram (Sim. Exe.) has been valid ated an dexecuted several times. Several implem entati on aspects should beobserved :

i In respect of randomization, the simulation progra m (SIM) hastwo options for the initial yalue of seed for rand omis atio n is :

a not r ese t i t mean ing that eve ry t ime the p rogram i s execu tedthe same set of random n umbe rs would be generated causingthe rec onstruc tion of the same system for the same inp ut. Thisis suitabl e if results are to be compa red for differe nt sets ofparameters.

b reset : mea nin g that every time the progra m is exectued a newset of random num ber s is generated and a different simulatedsystem is constructed. Although different, all the gener atedsystems re pre sen t the possible outcomes / pictures of the system

un de r study with the same parameter s. This is often used tocompare results obt ain edf or the same set of parameter s, afacility which makes the prog ram very general an d useful.

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ii) In respe t o f t im e v a l id i ty o f t h e m o d e l , s in ce th e m o d e l i s

b ased o n d a ta f r o m 1 9 9 2 to Ap r i l 1 99 9, an d b e in g a d i sc r e t es i m u l a t i o n m o d e l , i t is v a l i d a t e d t o g e n e r a t e s t o r a g er e q u i r e m e n t v i a s i m u l a t e d o p e r a t i o n o f p r o d u c t i o n f l ow -i n / fl o w - o u t f o r a n y p e r i o d s t a r t i n g fr o m d a y 1 o f 9 9 a n de x t e n d s p r a c t i c a l l y t o m o r e t h a n 3 y e a r s ( t h e o r e t ic a l l y t o a n yn u m b e r o f y e a r s ). M o r e r e c e n t d a t a i s n e e d e d t o e x t e n d t h ed u r a t io n v a l id i ty o f t h e m o d e l . As d a ta en d s in 3 0 /04 /9 9,s i m u l a t i o n c a n a c t u a l l y s t a r t an y d a y f r o m 01 /0 5 /9 9 . P r o g r a mS I M a s k s f o r t h e l a s t d a y b e f o re s i m u l a t i o n s t a r t a n d fo r t h el e n g th o f t h e s i m u l a t i o n p e r io d i n d a y s. O v e r l a p p e r i o d o f d a t aa v a i l a b l e a n d s i m u l a t e d d a t a i s o n l y u s ed f o r v a l i d a t i o np u r p o s e s . S i m u l a t i o n a f t e r t h e p e r i o d o f d a t a a v a i l a b l e i s t h eac tu a l f o r eease .

i ii ) S I M a l so r e q u i r e s d a i l y p r o d u c t i o n a s a n i n p u t p a r a m e t e r , b u ti t i s r ep r e s en ted in t e rm s o f d a i ly f lo w r a t e a lo n g th e p ip e l in e( a v e r a g e d a t 1 2 M B L L S p e r h o u r ) , a n d t h e d u r a t i o n o f f l ow(d u ra t io n o f C1 b a tch es an d C2 b a tch es ), e .g . i f cu r r e n t

p ro d u c t io n r a t e i s ab o u t 6 0 MB LL S th en in ( 60 /12 = 5 ) f i v eh o u r s d a i ly, t h is p ro d u c t io n can b e b a tch ed l eav in g 1 9 h o u r sd a i ly f o r C2 b a tch . A b a tch cy c le o f 4 d ay s wi l l sp l i t b a t ch es inth e r a t i o o f 2 0 :7 6 b e tween C1 an d C2 r e sp ec t iv e ly.

Cu r r en t ly th e r a t io i s 2 0:8 0 , ad ju s t in g th e p ip e l in e f lo w r a t ewh en ev e r p ro d u c t io n l ev el d o es n o t f i t t h e b a t ch sch ed u le . I nS I M , b o t h p i p e l in e f lo w r a t e a n d b a t c h d u r a t i o n a r e i n p u tp a r a m e t e r s d e c i d e d b y t h e u s e r a c c o r d i n g t o t h e p r o d u c t i o nlevel .

I n t h e a p p e n d i x be l ow, a p r i n t - o u t o f t h r e e v a r i o u s c a s e sg e n e r a t e d f r o m S I M fo r d i f f er e n t i n p u t p a r a m e t e r s . A l l t h r e ecases s im u la t e 1 2 0 d ay s o f 1 99 9 u s in g th e av e rag e p ip e l in e f lo wr a t e o f 12 M B L L S .

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Ini tia l stock in all cases is assume d to be 500 MBLL S while infact it was only 338 MBLLS. These three cases impose ver ysevere test of the simulation model SIM as they repre sent thecur ren tly known typical case, and the two radical cases of highdrop and high increase in C1 product ion.

case i): Using the curre nt production average of 60 MBLLSbatch ed in 20:80 schedule. Stock level is shown not toexceed the need for only three tanks. This result can beverified from the first 120 days o f 1999 existing data.

case ii): Using half of the cur ren t produ ction rate 30 MBLLS)which al ters the ba tch cycle as follows:30/12 = 2.5 hours for C1 daily batch, leaving 21.5 hou rsfor C2 daily batches. There fore, the 4 days cycle splitsinto 10:86 b atch hours for the C1 and C2 respectively.With this very low produc tion rate, SIM generates stocklevels of not more than two tanks which is veryconsistent.

case iii): Using high produc tion rate tha t equally splits the batchcycle with C2 into 24:24 hours, SIM consisten tlygenerates the correspo nding hig h need for up to sixtanks.

The pro gra m gives results which app ear to be absolutely realistic.At the cu rre nt rate of inflow, we find that normally three storagetanks would be needed by C1 in the worst case of the cu rre nt

practical and realistic situ atio m This means a fourth tan k is to beavailable as a spare for main tena nce purposes. Rarely, if ever, dueto delayed ship ment the fo ur th tan k may be needed, a situationwhich may even be avoided by invited shipmen ts or by slowing downthe C1 batches.

3


16/22

16

I. C O N C L U S I O N

A s im u la t io n t ech n iq u e to d e t e rm in e th e o p t im u m tan k cap ac i ty inp o r t t o s to r e in co m in g o i l f r o m f ie ld su b jec t t o p o r t - c lo su re an d n o n -u n i fo rm l i f ti n g o f oi l b y sh ip s was d ev e lo p ed an d im p lem en ted .

Th i s . co m p u te r s im u la t io n m o d e l can b e u sed fo r m o re th an o n e

p u r p o s e :

a ) to op t imize schedule a t the cu r ren t s i tua t ion ,b ) t o f in d o p t im u m s to r ag e Ceq u ir em en t s a t p r e sen t ,c ) to p lan fo r ba tch schedul ing wi th changed da ta in fu tu re ,d ) t o e s t im a te s to r ag e r eq u i r em en t in f u tu r e w i th ch an g ed

inform at ion on p roduct io n o r in f low schedule-

A v e r y im p o r t an t o b se rv a t io n i s t h a t t h e p r e sen t s tu d y i s b a sed o nd a ta av a i l ab le w i th u s f o r t h e p as t f ew y ea r s . I n o r d e r t o k eep th esy s t em v a l id an d wo rk ab l e f o r an y p e r io d o f t im e in f u tu r e it wo u idn o t b e n e cessa ry to r ewr i t e t h e wh o le sy s t em .

W h a t w o u l d b e n e e d e d w il l b e c o m p u ta t i on o f n e w p a r a m e t e r s b a s e do n m o re r ecen t d a t a r e f lec t in g ch an g e in th e p a t t e rn o f t h e v a r io u sf ac to r s an d in co rp o ra t in g th em in th e p ro g ram .

32


17/22

A P P E N D I XCASE (i)

b a s e - d a t e . . 1 2 3 1 ; b - s t o c k :r a t e o f i n f l o w / h r : 1 2 . 0; p d - o f - s i md a y c l o s e d i n

1 x 120 . 02 x 120 . 03 x 0 0

0 0

5 7 2 . 06 1 6 8 . 07 0 . 08 0 . 09 * 24 . 0

1 0 x 2 1 6 . 011 x 0 . 01 2 x 0 . 01 3 0 . 01 4 2 4 0 . 01 5 0 . 01 6 0 . 01 7 X 0 . 0

1 8 2 1 6 . 01 9 2 4 . 02 0 + 0 . 02 1 + 0 . 02 2 1 6 8 . 02 3 7 2 . 02 4 0 . 02 5 0 0

2 6 1 2 0 0

2 7 1 2 0 . 02 8 0 . 02 9 0 . 03 0 7 2 . 03 1 1 6 8 . 03 2 0 . 03 3 0 . 03 4 + 2 4 . 03 5 + 2 1 6 . 03 6 0 . 03 7 , 0 . 03 8 0 , 03 9 2 4 0 . 04 0 0 0

4 1 0 . 0

4 2 x 0 . 04 3 x 2 1 6 . 04 4 + 2 4 . 04 5 0 . 04 6 0 . 04 7 1 6 8 . 04 8 7 2 . 04 9 0 . 0

,~ ~ 50 0 .05 1 1 2 0 . 05 2 1 2 0 . 05 3 0 . 05 0 0

5 5 7 2 . 05 6 1 6 8 . 05 7 0 . 0

b o o ]33

5 0 0 . 0 ; n h r - C li n d a y s :

o u t

0 . 00 . 00 . 0

4 9 4 . 7

2 4 5 . 30 . 00 . 01 . 50 . 00 . 00 . 00 . 00 . 00 . 00 . 00 . 00 . 0

5 5 4 . 48 3 . 1

0 . 00 . 00 . 01 . 5

5 5 9 . 50 . 00 . 00 . 00 . 00 . 0

3 1 2 . 00 . 00 . 00 . 01 . 5n . O0 . 0

1 1 6 . 42 9 0 . 1

0 . 01 . 50 . 00 . 00 . 01 4 50 . 00 . 00 . 0

2 9 1 . 02 0 6 . 0

0 . 0O 0O 01 5O 0O 0O 0O 0

0 . 0

: 20 ; nhr - C21 2 0

c l - s t o c k

620 0740 0740 0245 3

72 0240 0240 02 3 8 . 52 6 2 . 54 7 8 . 54 7 8 . 54 7 8 . 54 7 8 . 57 1 8 . 57 1 8 . 57 1 8 . 57 1 8 . 5

3 8 0 . 13 2 1 . 03 2 1 . 03 2 1 . 04 8 9 . 05 5 9 . 5

- 0 . 0- 0 . 0

1 2 0 . 02 4 0 . 02 4 0 . 02 4 0 . 0

- 0 . 01 6 8 . 01 6 8 . 01 6 8 . 01 9 0 . 54 0 6 . 54 0 6 . 52 9 0 . 1

- 0 . 02 4 0 . 0238 , 52 3 8 . 52 3 8 . 545 4. 5.4 7 7 . 04 7 7 . 04 7 7 . 06 4 5 . 04 2 6 . 02 2 0 . 02 2 0 . 03 4 0 . 04 6 0 . 04 5 8 . 54 5 8 . 55 3 0 . 56 9 8 . 56 9 8 . 5

698 . 5

: 8 0

n o . i n k s

2221

1111111112222

1111121111111

1i1111111111111121111111122

2


18/22

d a y

6 16 26 36 4656 667

6 86 97 07 17 27 37 47 57 67 77 87 98 0

8 18 28 38 48 58 68 78 88 99 09 19 29 39 49 59 69 79 89 9

1 0 01 1

1 0 21 0 31 0 41 0 51 0 61 0 71 0 81 0 9i i 0i i i1 1 21 1 31 1 41 1 51 1 6

1 1 71 1 81 1 91 9 N

c l o s e d

+

xx

X

X

i n

0 . 00 . 00 . 0

2 4 0 . 00 . 00 . 00 . 0

2 1 6 . 02 4 . 0

0 . 00 . 0

1 6 8 . 07 2 . 0

0 . 00 . 0

1 2 0 . 01 2 0 . 0

0 . 00 . 0

7 2 . 0

1 6 8 . 00 . 00 . 0

2 4 . 02 1 6 . 0

0 . 00 . 00 . 0

2 4 0 . 00 . 00 . 00 . 0

2 1 6 . 02 4 . 0

0 . 00 . 0

1 6 8 . 07 2 . 0

0 . 00 . 0

1 2 0 . 01 2 0 . 0

0 . 00 . 0

7 2 . 01 6 8 . 0

0 . 00 . 0

2 4 . 02 1 6 . 0

0 . 00 . 00 . 0

2 4 0 . 00 . 00 . 00 . 0

2 1 6 . 02 4 . 0

0 . 0

o u t

0 . 00 . 00 . 01 . 50 . 00 . 00 . 0

0 . 00 . 01 . 50 . 00 . 0

2 9 2 . 51 9 7 . 0

0 . 00 . 00 . 01 . 50 . 00 . 0

8 7 . 33 2 0 . 1

4 6 . 10 . 00 . 00 . 00 . 00 . 00 . 00 . 01 5

0 0

3 7 9 82 7 0 7

0 . 00 . 00 . 00 . 00 . 00 . 00 . 01 . 50 . 0

2 3 2 . 84 0 3 . 7

0 . 00 . 00 . 01 . 50 . 00 . 00 . 01 . 5

2 0 3 . 73 8 6 . 3

0 . 0

34

c l - s t o c k

4 5 1 54 5 1 54 5 1 56 9 0 06 9 0 06 9 0 06 9 0 0

9 0 6 09 3 0 09 2 8 . 59 2 8 . 5

1 0 9 6 . 58 7 6 . 06 7 9 . 06 7 9 . 07 9 9 . 09 1 9 . 09 1 7 . 59 1 7 . 5

9 8 9 . 5

1 0 7 0 . 27 5 0 . 17 0 4 . 07 2 8 . 09 4 4 . 09 4 4 . 09 4 4 . 09 4 4 . 0

1 1 8 4 . 01 1 8 4 . 01 1 8 2 . 51 1 8 2 . 51 3 9 8 . 51 4 2 2 . 51 0 4 2 . 7

7 7 2 . 09 4 0 . 0

1 0 1 2 . 01 0 1 2 . 01 0 1 2 . 01 1 3 2 . 01 2 5 2 . 01 2 5 2 . 01 2 5 2 . 01 3 2 4 . 01 4 9 0 . 51 4 9 0 . 51 2 5 7 . 7

8 7 8 . 01 0 9 4 . 01 0 9 4 . 01 0 9 4 . 01 0 9 2 . 51 3 3 2 . 51 3 3 2 . 51 3 3 2 . 51 3 3 1 . 01 3 4 3 . 3

9 8 1 . 09 8 1 . 0

n o . t n k s

1112222

2222322222222

2222222233333322222233333333233

. 3

333333


19/22

A P P E N D I X

CASE (li)

b a s e - d a t e : 1 2 3 1; b - s t o c k : 5 0 0 . 0 ;r a t e o f i n f l o w / h r :d a y c l o s e d

1 x2 x3 x

456789

10 xII x12 x13 *141516

17 x181920 +21 +2 22 3242 52 6272 8293 0313 23 33 4

35 +3 6

37 *3 8394 O41 +42 X43 x44 +4 54 64 74 84 95 051525 3545 556

l 7~

1 2 . 0 ; p d - o f l s i m i ni n

120 00 . 00 0

0 . 0120 0

0 . 00 00 . 0

1 2 0 00 . 00 00 . 0

1 2 0 00 . 00 . 00 . 0

1 2 0 . 00 . 00 . 00 . 0

1 2 0 . 00 . 00 . 00 . 0

1 2 0 . 00 . 00 . 00 . 0

1 2 0 . 00 . 00 . 00 . 0

1 2 0 . 00 . 00 . 00 . 0

1 2 0 . 00 . 00 . 00 . 0

1 2 0 . 00 . 00 . 00 . 0

1 2 0 . 00 . 00 . 00 . 0

1 2 0 . 00 . 00 . 00 . 0

1 2 0 . 00 . 00 . 00 . 0

120 . 0 135

n h r - C 1 : i 0 ; n h r - C 2d a y s : 1 2 0

o u t c l - s t o c k

0 . 0 6 2 0 . 00 . 0 6 2 0 . 00 . 0 6 2 0 . 0

0 . 0 6 2 0 . 00 . 0 7 4 0 . 00 . 0 7 4 0 . 00 . 0 7 4 0 . 01 . 5 7 3 8 . 50 . 0 8 5 8 . 50 0 8 5 8 . 50 . 0 8 5 8 . 50 . 0 8 5 8 . 50 . 0 9 7 8 . 5

5 2 3 . 8 4 5 4 . 73 9 5 . 2 5 9 . 5

0 . 0 5 9 . 5

0 . 0 1 7 9 . 51 , 5 1 7 8 . 00 . 0 1 7 8 . 00 . 0 1 7 8 . 00 . 0 2 9 8 . 00 . 0 2 9 8 . 01 . 5 2 9 6 . 50 . 0 2 9 6 . 51 . 5 4 1 5 . 00 . 0 4 1 5 . 0

0 0 4 1 5 . 00 . 0 4 1 5 . 0

2 0 3 . 7 3 3 1 . 33 3 1 . 3 - 0 . 0

0 . 0 - 0 . 00 . 0 - 0 . 00 . 0 1 2 0 . 01 . 5 1 1 8 . 50 . 0 1 1 8 . 50 . 0 1 1 8 . 50 . 0 2 3 8 . 50 . 0 2 3 8 . 50 . 0 2 3 8 5I . 5 23 7 00 . 0 3 5 70 . 0 3 5 7 00 . 0 3 5 7 01 . 5 3 5 5 50 . 0 4 7 5 50 . 0 4 7 5 50 . 0 4 7 5 5

4 7 5 . 5 - 0 00 . 0 1 2 0 . 00 . 0 1 1 2 0 . 00 . 0 1 2 0 . 00 . 0 1 2 0 . 01 . 5 2 3 8 . 50 . 0 2 3 8 . 50 . 0 2 3 8 . 50 . 0 2 3 8 . 5

0 . 0 i 3 5 8 . 50 . 0 3 5 8 . 5

: 8 6

n o . t n k s

222

2222222222111

1111111111111111I11111111111111111

111

11

11


20/22

d a y

6 16 26 36 46 56 6

6 76 86 97 07 17 27 37 47 57 67 77 87 98 08 18 28 38 48 58 68 78 88 99 O9 19 29 3

9 49 59 69 79 89 9

I 0 01 0 11 0 21 0 31 0 41 0 51 0 6

1 0 71 0 81 0 91 1 0I i i1 1 21 1 31 1 41 1 51 1 61 1 71 1 81 1 91 2 0

c l o s e d

+

xx

++

i n

1 2 0 . 00 . 00 . 00 . 0

1 2 0 . 00 . 00 . 00 . 0

1 2 0 . 00 . 00 . 00 . 0

1 2 0 . 00 . 00 . 00 . 0

1 2 0 . 00 . 00 . 00 . 0

1 2 0 . 00 . 00 . 00 . 0

1 2 0 . 00 . 00 . 00 . 0

1 2 0 . 00 . 00 . 00 . 0

1 2 0 . 0

0 . 00 . 00 . 0

1 2 0 . 00 . 00 . 00 . 0

1 2 0 . 00 . 00 . 00 . 0

1 2 0 . 00 . 0

0 . 00 . 0

1 2 0 . 00 . 00 . 00 . 0

1 2 0 . 00 . 00 . 00 . 0

1 2 0 . 00 . 00 . 00 . 0

36

o u t

0 . 00 . 00 . 01 . 50 . 0

3 7 8 . 31 8 8 . 7

0 . 00 . 01 . 50 . 00 . 01 . 50 . 00 . 00 . 00 . 01 . 50 . 00 . 00 . 0

3 2 0 . 11 8 5 . 4

0 . 00 . 00 . 00 . 00 . 00 , 00 . 01 . 50 . 00 . 0

0 . 01 . 50 . 00 . 0

1 1 6 . 43 6 0 . 6

0 . 00 . 00 . 00 . 00 . 00 . 0 '1 . 5

0 . 00 . 01 . 50 . 00 . 00 . 0

4 7 7 . 00 . 00 . 00 . 01 . 50 . 00 . 00 . 0

c l - s t o c k

4 7 8 . 54 7 8 . 54 7 8 . 54 7 7 . 05 9 7 . 02 1 8 . 7

3 0 . 0

3 0 . 01 5 0 . 01 4 8 . 51 4 8 . 51 4 8 . 5

2 6 7 . 02 6 7 . 02 6 7 . 02 6 7 . 03 8 7 . 0385 53 8 5 . 53 8 5 . 55 0 5 . 51 8 5 . 4

- 0 . 0- 0 . 0

1 2 0 . 01 2 0 . 01 2 0 . 01 2 0 . 02 4 0 . 02 4 0 . 02 3 8 . 52 3 8 . 53 5 8 . 5

3 5 8 . 53 5 7 . 03 5 7 . 04 7 7 . 03 6 0 . 6

- 0 . 0- 0 . 0

1 2 0 . 01 2 0 . 01 2 0 . 01 2 0 . 0

. 2 4 0 . 02 3 8 . 5

2 3 8 . 52 3 8 53 5 7 . 03 5 7 . 03 5 7 . 03 5 7 . 0

- 0 . 0- 0 . 0- 0 . 0- 0 . 0

1 1 8 . 51 1 8 . 51 1 8 . 51 1 8 . 5

n o . t n k s

11112111

1111

I11111111111111111111

111111I111111

11

11111111I111


21/22

b a s e - d a t e : 12 3 1;r a t e o f i n 1 o w / h r :d a y U c l o s e d

1 x2 x3 x456789 *

I0 x11 x1 2 x13 *14151617 x1 81920 +21 +2 22 32 42 52 6272 82 93 0

3 13 23 334 +35 +3 6373 83 94 041 +42 x43 x

44 +4 54 64 74 84 950 ~. . .5 15 25 35 45 55 65 7

5 8

A P P E N D I X

CASE i i i )

b - s t o c k : 5 0 0 . 0 ;1 2 . 0 ; p d o f s i m

i n

1 8 0 . 01 0 8 . 01 8 0 . 01 0 8 01 8 0 01 0 8 01 8 0 01 0 81 8 01 0 8 01 8 0 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 0

1 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 81 8 0 01 0 81 8 0 01 0 81 8 0 01 0 81 8 0 . 0

1 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 0 ~ .1 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 0 137

n h r - C li n d a y s : 1 2 0

o u t

0 . 00 . 00 . 0

6 4 0 . 21 9 2 . 8

0 . 00 . 01 .50 . 00 . 00 . 00 . 0

4 6 5 . 61 2 1 5 . 9

0 . 00 . 00 . 01 . 5

4 9 4 . 71 1 6 . 3

0 . 00 . 0

4 3 8 . 03 3 9 . 3

5 1 . 70 . 0

3 9 6 . 90 . 00 .00 . 0

0 . 00 . 00 . 0

1 1 7 . 93 7 8 . 3

3 5 . 30 . 00 . 00 . 01 .50 . 00 . 00 . 0

8 7 4 . 511 8 . 04 9 4 . 72 1 3 . 3

0 . 00 .0

5 1 3 . 08 7 . 3

4 3 7 . 71 .50 . 00 . 00 . 00 . 00 . 0

: 2 4; n h r - C 2 :

c l - s t o c k

6 8 0 07 8 8 o9 6 8 04 3 5 84 2 3 05 3 1 07 11 08 1 7 59 9 7 5

11 0 5 51 2 8 5 51 3 9 3 511 0 7 9

-o o180 02 8 8 . 04 6 8 . 05 7 4 . 52 5 9 . 82 5 1 . 54 3 1 . 55 3 9 . 52 8 1 . 5

5 0 . 21 7 8 . 52 8 6 . 5

6 9 . 61 7 7 . 63 5 7 . 64 6 5 . 6

6 4 5 . 67 5 3 . 69 3 3 . 69 2 3 . 77 2 5 . 47 9 8 . 19 7 8 . 1

1 0 8 6 . 11 2 6 6 . 11 3 7 2 . 61 5 5 2 . 61 6 6 0 . 61 8 4 0 . 6

1 0 7 4 111 3 6 17 4 9 47 1 6 18 2 4 1

1 0 0 4 15 9 9 16 9 1 . 83 6 2 . 15 4 0 . 66 4 8 . 68 2 8 . 69 3 6 . 6

1 1 1 6 . 61 2 2 4 . 6

24

n o . t n k s

222111222333311112111111111111

2222222333344232222221222233


22/22

dayl|

616263646 5

666768697O7 1727 3747 576777 8

7 980818 28 3848 5868 78 8899 09 19 29 3949 59 69 79 89 9

I 0 0i 0 11 0 21 0 31 0 41 0 5

1 0 61 0 71 0 81 0 9i i 0I i i

21 1 3

1 1 4

1 1 5

1 1 6

1 1 7

c l o s e d

+

xx

X

X

i n

1 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 0

1 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 0

1 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 0i 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 0

1 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 0

_. 1 8 0 . 01 0 8 . 01 8 0 . 01 0 8 . 01 8 0 0

o u t

3 7 8 . 31 5 8 . 7

0 . 01 . 50 . 0

0 . 00 . 08 7 . 3

4 6 4 . 71 . 50 . 00 . 0

5 2 5 . 3I ~ I 2

0 . 00 . 0

4 9 4 . 01 . 5

0 . 00 . 00 . 00 . 01 . 5

2 3 2 . 85 3 3 . 2

0 . 00 , 00 . 00 . 00 . 01 . 50 . 00 . 0

4 0 7 . 44 2 . 1

0 . 00 . 00 . 0

6 3 3 . 00 . 0

4 6 5 . 61 2 3 . 49 8 9 . 42 4 1 . 6

0 . 0

2 6 3 . 4315. 1

0 . 03 5 0 . 76 7 9 . 81 4 4 . 0

0 . 01 . 50 . 00 . 00 . 0

292 5

c l - s t o c k

6 5 7 . 36 0 6 . 67 8 6 . 68 9 3 . 1

1 0 7 3 . 1

1 1 8 1 . 11 3 ~ I . i1 3 8 1 . 81 0 9 7 . 11 2 0 3 . 61 3 8 3 . 61 4 9 1 . 61 1 4 6 . 31 1 1 3 . 11 2 9 3 . 11 4 0 1 . 11 0 8 7 . 11 1 9 3 . 6

1 3 7 3 . 61 4 8 1 . 61 6 6 1 . 61 7 6 9 . 61 9 4 8 . 11 8 2 3 . 31 4 7 0 . 11 5 7 8 . 11 7 5 8 . 11 8 6 6 . 12 0 4 6 . 12154 .12 3 3 2 . 62 4 4 0 . 62 6 2 0 . 62 3 2 1 . 22 4 5 9 . 12 5 6 7 . 12 7 4 7 . 12 8 5 5 . 12 4 0 2 . 12 5 1 0 . 12 2 2 4 . 52 2 0 9 . 11 3 9 9 . 71 2 6 6 . 11 4 4 6 . 1

1 2 9 0 . 71 1 5 5 . 61 2 6 3 . 61 0 9 2 . 9

5 2 1 . 15 5 7 . 16 6 5 . 18 4 3 6 ~

951.6 ,1 1 3 1 . 61 2 3 9 . 61 1 2 7 1

n o . t n k

22222

3333333333333

33444

43344

4

4

555555665555333

33331222233

3

a computer simulation model for oil transport and storage problem

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