The Petroleum Potential of Some Tertiary Lignites From

8/13/2019 The Petroleum Potential of Some Tertiary Lignites From

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Org. Geochem.Vo l. 17, No . 6, pp. 805-8 26, 1991 0146-6380/91 3.00 + 0.00Printed in Great Britain Pergamon Press plc

T h e p e t r o l e u m p o t e n t i a l o f s o m e T e r t i a r y l i g n i t e s f r o mn o r t h e r n G r e e c e a s d e t e r m i n e d u s i n g p y r o l y s i s a n d

o r g a n i c p e t r o l o g i c a l t e c h n i q u e sMA RTIN G . FO WLER,1 THOMAS GENTZ IS, FARIBOR ZGOODARZI an d ANTHONY E. FOSCOLOS

qnst i tu te of Sedimenta ry and Pe t ro leum Geology, Geologica l Survey of Canada , 3303-33rd St N.W.,Calgary , Alber ta , Canada T2L 2A72Coal Research Centre , Alber ta Research C ounc i l , Devon , Alber ta , Can ada T0C 1E0

3Department o f M inera l Resources Engineer ing , Technica l Universi ty of Cre te , 73133 Chan ia , GreeceAbst rac t - - -Oi l condensa te an d gas have recent ly been d iscovered in the Therm aikos G ulf a rea of n or thernGreece . T he source of these hy drocarbon s i s not know n, a l though there i s a possib i li ty tha t m ore matureequiva lents of ce r ta in Ter t ia ry br own coa ls and l ignites may be responsib le . A c ontr ibu t ion f rom Tert ia ryte rrestr ia l organic mat te r to the Ep anom i o i l i s supported by i t s b iom arker d is t r ibut ions, espec ia lly thep re d o m in a n c e o f t r i te rp e n o id c o m p o u n d s o th e r t h a n h o p a n e s i n t h e m / z 191 mass fragm entogra m. In thisstudy, the hydroc arbon potent ia l of a su i te of Greek T er t ia ry ligni tes i s f i rs t examined using Rock-Ev alana lysis . Three samples a re then fur ther investigated using organic pe t rography, and gas chro matograp hy(GC) and gas chromatography-mass spec t rometry (GC-MS) of the ex t rac ted hydrocarbon frac t ions, aswel l as by hyd rous pyrolysis. An in te rm ontane l igni te (6OG-5) conta ins f luoresc ing hum ini te toge ther w i thresin ite . O n ext rac t ion , th is resin i te i s found to b e of p redom inant ly d ite rpenoid or ig in . Rock-Eval andhydrous pyrolysis support previous proposals that diterpenoid resinite needs a lower activation energyto genera te hydro carbons th an m ost o ther types of organic mat te r . A sample o f a l ign i te deposi ted in adeltaic env iro nm ent (M M- 3) conta ins a more diverse collection of l iptinite macerals with resinite againpredom ina t ing . The resin i te appears to be most ly of t r i te rpenoid and sester te rpenoid or ig in . The besthydro carbon potent ia l i s shown by a sam ple deposi ted in a lagoona l environm ent (KAS-3) . Li t t le d isc reteresin i te is observed in th is sample bu t i t does con ta in abu nda nt f luoresc ing humini te . Al though i t has alow S J S t + 2 ratio, i t gives a high yield on solvent extraction during which a significant fraction of the2 is removed. The fluorescence o f the hum inite after extraction is greatly reduced. T he hyd roca rbon s ofthe extract are believed to be pr edo min antly derived from tri terpen oid resinite . U nlike the pyrolysatesof the o ther two l igni tes but in comm on wi th the E panom i o i l, the t r i te rpenoids in the KA S-3 pyrolysa teare dom ina ted by resin-derived com poun ds ra ther th an hopanes. This and o ther s imi la r it ies be tween thecomp osi t ion of the pyro lysa tes of KA S-3 and the o i l suppo rt the possib i l i ty tha t a m ore mature eq uiva lentof th is l ign i te could b e the source of the Epan omi o i l.K ey w ords - - Greece , hydr ous pyrolysis, l ignites, organ ic petrology, resinite, R ock-E val

INTRODUCTIONO i l , c o n d e n s a t e a n d g a s d i s c o v e r i e s h a v e r e c e n t l yb e e n m a d e i n t h e T h e r m a i k o s G u l f a r ea a b o u t 3 0 k ms o u t h e a s t o f T h e s s a l o n i k i ( F i g . 1 ). O i l w a s d i s c o v e r e db y t h e G r e e k P u b l i c P e t r o l e u m C o r p o r a t i o n a t a d e p t ho f 2 8 0 0 . 5 - 2 8 3 8 . 5 m i n T e r t i a r y s e d i m e n t s d u r i n g t h ed r i l li n g o f t h e E p a n o m i - 2 h o l e i n 1 98 9. A l t h o u g h t h ea c t u a l s o u r c e r o c k s a r e n o t k n o w n , t h e r e i s a s t r o n gs u s p i c i o n t h a t m o r e m a t u r e e q u i v a l e n t s o f c e rt a i nT e r t i a r y b r o w n c o a l s c o u l d b e t h e s o u r c e o f t h e s eh y d r o c a r b o n s . T h e r e h a v e b e e n s e v e r a l r e v i e w s t h a th a v e d i s c u s s e d t h e p o s s i b i l i t y t h a t c o a l s c a n b e o i l -s o u r c e r o c k s ( e . g . D u r a n d a n d P a r a t t e , 1 9 8 3 ; S a x b ya n d S h i b a o k a , 1 98 6; M u r c h i s o n , 1 98 7 ; B e r t r a n d ,1 9 8 9 ) b u t f e w a c t u a l p r o v e n e x a m p l e s .

L o w r a n k c o a l s o f T e r t i a r y t o Q u a t e r n a r y a g e a r ew i d e s p r e a d i n G r e e c e . S i x t y l i g n i te - b e a r i n g b a s i n s c o n -t a i n i n g r e s e r v e s o f 5 . 3 x 1 9 t o f lo w r a n k c o a l h a v e*Geological Survey of Can ada N o. 28190.

b e e n d is c o v e r e d t o d a t e ( K o u k o u z a s , 1 9 85 ). M a n y o ft h e s e T e r t i a r y c o a l s a r e r e l a t i v e l y r i c h i n l i p t i n i t em a c e r a l s , e s p e c i a l l y r e s i n i t e , a n d c o n t a i n f l u o r e s c i n gh u m i n i t e ( C a m e r o n et al . , 1 9 8 4 ; G o o d a rz i et al . , 1990)s u g g e s t i n g t h e p o s s i b i l i t y t h a t t h e y c o u l d h a v e b e t t e rh y d r o c a r b o n p o t e n t i a l t h a n i s n o r m a l l y o b s e rv e d f o rc o a l s. M o s t l i g n i t e d e p o s i t s i n G r e e c e w e r e f o r m e d i ni n t e r m o n t a n e b a s i n a l s e t t in g s i n g r a b e n - f i k e s t r u c tu r e s ,a l t h o u g h s o m e w e r e d e p o s i t e d i n n e a r c o a s t a l s e t t i ng ss u c h a s d e l t a s o r a l l u v i a l p l a i n s ( F o s c o l o s et al . , 1989).T h e d i v e r s it y i n t h e d e p o s i t i o n a l e n v i r o n m e n t s isr e f l e c t e d i n t h e s u i t e o f s a m p l e s u s e d i n t h e p r e s e n ts t u d y , t h r e e o f w h i c h w e r e s e l e c t e d f o r m o r e d e t a i l e di n v e s t i g a t i o n s .

T h e 6 O G - 5 s a m p l e c o m e s f r o m V a r v o u t i s M i n ei n t h e F l o r i n a B a s i n , n o r t h w e s t e r n G r e e c e . I t i s o fL o w e r P l i o c e n e a g e a n d w a s d e p o s i t e d i n a n i n t e r -m o n t a n e b a s i n . T h e M M - 3 s a m p l e is o f M i o c e n e a g ea n d w a s d e p o s i t e d i n a n e s t u a r i n e / d e l t a s e t t i n g n e a rM o s c h o p o t a m o s i n t h e K a t e r i n i B a s i n ( F ig . 1 ). I t i st h e l o w e r m o s t o f t h r e e t h i n c o a l s ( a b o u t 6 0 c m t h i c k )

805


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t h a t a r e e a c h s e p a r a t e d b y a b o u t 1 m o f s a n d s t o n e s .T h e K A S - 3 s a m p l e o r i g i n a t e d fr o m a d e p t h o f1 6 85 .5 m i n a w e ll d r i l l e d o n t h e K a s s a n d r a p e n i n s u l aF i g . 1 ). I t i s o f M i o c e n e a g e a n d w a s d e p o s i t e d i n a n

e n v i r o n m e n t i n f lu e n c e d b y m a r i n e b r a c k i s h ) w a t e r s,p r o b a b l y a l a g o o n .

I n t h i s p a p e r w e i n v e s t ig a t e t h e h y d r o c a r b o np o t e n t i a l o f s o m e T e r t i a r y l i g n i t e s f r o m G r e e c e ,c o n c e n t r a t i n g o n t h e t h r e e s a m p l e s d e s c r i b e d a b o v ea n d d e t e r m i n e i f a m o r e m a t u r e e q u i v a l e n t o f o n eo f t h e s e c o a l s c o u l d h a v e b e e n t h e s o u r c e o f th eE p a n o m i o i l .

METHODS

R o c k - E v a l a n d C H N a n al ys isC o a l s w e r e p u l v e r i z e d t o a b o u t 1 00 m e s h i n p r e p a r -

a t i o n f o r R o c k - E v a l , C H N a n a l y s i s a n d e x t r a c t i o n .P r o b l e m s a s s o c i a t e d w i t h R o c k - E v a l a n a l y s i s o f c o a l sh a v e b e e n p r e v i o u s l y d e s c r ib e d e .g . P e te r s , 1 9 8 6 ; L a we t a l . 1 9 8 9 ) . A n e f f o r t w a s m a d e , d u r i n g t h e i n i t i a ls t a g e s o f o u r s t u d i e s o n t h e h y d r o c a r b o n p o t e n t i a l o fc o a l s , t o a r r i v e a t a s e t o f c o n d i t i o n s t h a t p r o v i d e dr e a s o n a b l y a c c u r a t e a n d r e p r o d u c i b l e r e s u l t s f r o mR o c k - E v a l a n a ly s is . W h e n s a m p l e a m o u n t s o f > 5 m gw e r e u s e d , T O C v a l u e s f r o m t h e R o c k - E v a l w e r eu s u a ll y m u c h l o w e r t h a n t h o s e o b t a i n e d f ro m C H Na n a l y s i s w h i c h l e d t o e r r o n e o u s l y h i g h H I v a l u e s.

S a m p l e s i z e s o f 5 o r 1 0 m g h a v e b e e n u s e d i n o t h e rs t u d i e s o f t h e h y d r o c a r b o n p o t e n t i a l o f c o a l s u s i n gR o c k - E v a l e . g. T e i c h m i i l l e r a n d D u r a n d , 1 9 83 ;D u r a n d a n d P a r a t t e 1 9 8 3 ; L i t t k e e t a l . 1989) . Ther e s u l t s fr o m 5 m g a l i q u o t s a r e t h o s e g i v e n i n T a b l e 2 .Tm a~ v a l u e s f r o m t h e 5 m g a n a l y s e s t e n d e d t o b es i g n i f i c a n t ly l o w e r t h a n e x p e c t e d f o r t h e r a n k o f t h ec o a l . M o r e a c c u r a t e Tm ax v a l u e s , t h a t w e r e a b o u t 5 Ch i g h e r t h a n t h e 5 m g a n a l y s i s re s u l t s , w e r e o b t a i n e dw h e n a 2 0 m g a l i q u o t o f s a m p l e w a s u s e d . T h e Tm axv a l u e s g iv e n i n T a b l e 2 f o r t h e o r i g i n a l l ig n i t es a r e f r o m2 0 m g s a m p l e s. U s i n g s u c h s m a l l s a m p l e a m o u n t so b v i o u s l y c a n l e a d t o e r r o r s b e c a u s e o f s a m p l i n g b i a s.H e n c e , a l l s a m p l e s w e r e r u n a t l e a s t i n d u p l i c a t e a n di n s o m e c a s e s , w h e r e u n e x p e c t e d o r w i d e l y d i v e r g -i n g r e s u l t s w e r e o b t a i n e d , a d d i t i o n a l a n a l y s e s w e r ep e r f o r m e d .

A C E C e l e m e n t a l a n a l y s e r w i t h a c o m b u s t i o nt e m p e r a t u r e o f 9 7 0 C a n d a r e d u c t i o n t e m p e r a t u r e o f6 5 0 C w a s e m p l o y e d f o r C H N a n a l y s is . T i n c a p s u l e sw e r e u s e d a n d t h e m a c h i n e w a s c a l i b r a t e d u s i n ga c e t a n i l i d e . S a m p l e s w e r e r u n i n d u p l i c a t e .E x t r a c t i o n a n d f r a c t i o n a t i o n

S a m p l e s w e r e e x t r a c t e d u s i n g a z e o t r o p i c c h l o r o -f o r m : m e t h a n o l 8 7 : 1 3 ) f o r 2 4 h . T h e l i g n i t e e x t r a c t sw e r e f ir s t t r e a t e d w i t h a p p r o x . 4 0 v o l u m e s o f n - p e n -t a n e t o p r e c i p i t a t e t h e a s p h a l te n e s . T h e d e a s p h a l t e d


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Petroleum potential of Tertiary lignitesTable 1. Geochemicaldata on the Epano mi oil

Table 1Gross Composition 1 %Total oi l(% of Recovered Oil)

Satu rate HC s 13.5 (38.5)Arom atic HC s 20.9 (58.5)Resins + asphaltenes 1.5 (3.0)

%Tota l o i lTotal recovered

G asol ine Range2I: Isoheptane index 2.69H: Heptan e index 28.54B : T o l u e n e / n C7 0.83F: nCT/Methylcyclohexane

G C and G C- MS0.86

pr /ph 2.73pr /nCl7 0.61nC17/nC27 0.34r tt t ~ t S / ~ t R 3 0.94, ~ ~ / , , , ~ ,, , ~ ~ ~ 4 0.54C291313(H),17a(H ) 20S dias teran e/ 1.355 (H),14,* (H),17,, (H) 20R -ethyleholestan e

1Determined after column chromatography2Ratios given are th ose u sed b y Thompson (1979, 1983, 1989).I= (2- + 3-methylhexanes)/(1C3-, lt3- , and lt2-dimethylcyelopentanes)H = 100 x n-h ep tan e/( ll cyciohexane through methylcydohexane excludinglc-2-dimethylcyclopentane)3 ,,, ~ t S / ct,, , a R = 5 , , , H ) , 1 4 t z H ) , l T a H ) 2 0 S / 5 a H ) , 1 4 ~ t H ) , 1 7 a H ) 2 0 R - C 2 9s teranes4a131 ~/ a,, = 5,~(H),141~ (H),1713 H) /5 a(H ),1 4a (H ),1 7a (H ) + 5tt (H),141~ H )1713(8)

l i g n it e e x tr a c t s , li g n i te p y r o l y s a t e s a n d E p a n o m i o i lw e r e fr a c t i o n a te d u s in g o p e n c o l u m n c h r o m a t o g r a p h y( 3 /4 a c t i v a t e d a l u m i n a a n d 1 /4 a c t i v a t e d s i l ic a g e l w i t ha n a d s o r b e n t : s a m p l e m a s s r a t i o o f 1 0 0 : l ) . S a t u r a t e sw e r e r e c o v e r e d b y e l u t i n g w i t h 3 . 5 m l o f p e n t a n e / go f a d s o r b e n t . A r o m a t i c s w e r e r e c o v e r e d b y e l u t i n gw i t h 4 m l o f 5 0 :5 0 p e n t a n e - d i c h l o r o m e t h a n e / g o fa d s o r b e n t a n d t h e r e s in s w e r e r e c o v e r e d w i t h 4 m l / go f m e t h a n o l .H y d r o u s p y r o l y s i s

T w o h y d r o u s p y r o l y s is m e t h o d s w e r e u s ed . O n e w a sa s m a l l - s c a le m e t h o d , b a s e d o n t h a t u s e d b y E g l i n t o ne t a L 0 9 8 6 ) w h i c h h a s p r e v i o u s l y b e e n u s e d to s t u d yc o a l s i n t h is l a b o r a t o r y ( v o n d e r D i c k e t a L , 1989).T h i s w a s e m p l o y e d to l o o k a t t h e h y d r o c a r b o np o t e n t i a l o f t h r e e o f t h e G r e e k c o a l s. E x p e r i m e n t sw e r e c a r r i e d o u t i n p u r p o s e - b u i l t s t a i n l e s s s t e e l

b o m b l e t s ( v o l u m e 3 5 m l ) . A b o u t 2 g o f th e c o a ls a m p l e ( u n e x t r a c t e d o r p r e - e x t r a c t e d ) w a s u s e d i n

35.8

807

e a c h e x p e r i m e n t t o w h i c h 2 0 m l o f d i s ti l le d w a t e r w a sa d d e d . T h e b o m b l e t w a s th e n p u r g e d w i t h n i t r o g e n tor e m o v e a i r b e f o r e b e i n g s e a l e d . T h e b o m b l e t s w e r ep l a c e d i n a c o m m e r c i a l l y a v a i l a b l e 1 l i t r e p r e s s u r er e a c t o r ( P a r r I n s t r u m e n t C o . ) , a l s o p a r t l y f i l le d w i t hw a t e r ( t o m i n i m i z e t h e p r e s s u r e d i f f e r e n t i a l a c r o s s t h eh o m b l e t w a l l a n d t o r e d u c e t e m p e r a t u r e g r a d i e n t si n t h e s y s t e m ) , w h i c h w a s i n t u r n s e a l e d a n d c h e c k e df o r l e a k s a t b e t w e e n 1 5 0 0 a n d 2 0 0 0 p s i h e l i u m . T h et e m p e r a t u r e o f t h e r e a c t o r w a s r a i se d b y a h e a t i n gj a c k e t w i t h t e m p e r a t u r e a c c u r a t e t o a b o u t 5 C .S a m p l e s w e r e e i t h e r h e a t e d t o 3 0 0 o r 3 3 0 C a n d h e l di s o t h e r m a l f o r 7 2 h a f t e r w h i c h t i m e t h e v e s s e l w a sa l l o w e d t o c o o l p r i o r t o o p e n i n g . T h e g a s e s p r o d u c e dd u r i n g t h e e x p e r i m e n t w e r e n o t c o l l e c t e d a n d w e r ea l l o w e d t o l e a k o ff . T h e p r o d u c t s i n t h e b o m b l e t s w e r ee x t r a c t e d u s i n g d i c h l o r o m e t h a n e . T h e p y r o l y s a t e s w e r ed e a s p h a l t e d a n d f r a c t i o n a t e d a s d e s cr i b e d a b o v e . T h ee x t r a c t e d r es i d u e s w e r e a n a l y s e d b y R o c k - E v a l , C H Na n d o p t i c a l t e c h n i q u e s .


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Petroleum potential of Tertiary lignites 809The Kassandra coa l sample was fu r the r i nves t i ga t ed

w i t h a l a r g e r s c a le e x p e r im e n t . T w o l u m p s o f c o a l,b o t h w e i g h i n g a r o u n d 1 0 g ( t o ta l c o m b i n e d w e i g h t= 1 9 .7 4 g ) w e r e p l a c ed i n a 3 0 0 m l P a r r B o m b w i t h1 00 m l o f d i s ti ll e d w a t e r . T h e b o m b w a s p u r g e d w i t hh e l i u m a n d c h e c k e d f o r l e a k s a t b e t w e e n 1 5 0 0 a n d2 0 0 0 p s i h el iu m . T h e b o m b w a s f ir s t h e a t e d t o 3 0 0 Ca n d h e l d i s o th e r m a l f o r 7 2 h . A t t h e e n d o f t h is p h a s eo f th e e x p e r i m e n t t h e b o m b w a s a l lo w e d t o c o o la n d t h e o i l o n t h e s u r f ac e o f t h e w a t e r w a s r e c o v e r e da s a n e x p e l le d o il f r a c ti o n . A n a d d i t io n a l 2 0 m l o fd i s t i l l e d w a t e r w a s a d d e d t o t h e b o m b a n d t h e s a m es a m p l e w a s h e a t e d t o 3 3 0 C a n d h e l d i s o t h e r m a l f o r72 h . Th e expe l l ed o i l f rom th i s phase o f t he expe r i-m e n t w a s a l s o r e c o v e r e d . I n a d d i t i o n , t h e c o a l r es i d u ew a s e x t r a c t e d u l t r a s o n i c a l l y w i t h d i c h l o r o m e t h a n e .These expe l l ed o il s, an d t he ex t r ac t , we re f r ac t i ona t eda s a b o v e .GC and GC -MS ana l ys i sG a s c h r o m a t o g r a m s o f t h e s a t u r at e f r a c t io n s w e r ea c q u i r e d o n a V a r i a n 3 7 0 0 F I D g a s c h r o m a t o g r a p h( G C ) u s i n g a 3 0 m D B - 1 c o l u m n w i t h a t e m p e r a t u r ep r o g r a m o f 6 0 - 3 0 0 C a t 6 C / m in . G a s c h r o m a -t o g r a p h y - m a s s s p e c t r o m e t r y ( G C - M S ) d a t a w e r ec o ll e ct ed u s in g a V G 7 0 S Q h y b ri d M S - M S u n d e rt h e c o n t r o l o f a V G 1 1 -2 50 d a t a s y s t e m . D a t a w e r ec o l l e c t e d u s i n g a 1 0 0 p A t r a p c u r r e n t a n d 7 0 e Vi o n i z a t i o n v o l t a g e . T h e g a s c h r o m a t o g r a p h w a s f it te dw i t h a 2 5 m D B - 5 c o l u m n w h i c h w a s c o u p l e d d i r e c t lyt o t h e i o n s o u rc e a n d t e m p e r a t u r e p r o g r a m m e d f r o m5 0 t o 3 1 0 C a t 4 C / m i n . T h e i o n s m o n i t o r e d i n e a c he x p e r i m e n t w e r e rn/z 177.1638, 191.1794, 217.1950,218 .2028 , 231 .2106 and 259 .2262 . Fu l l scan da t a , fo rp e a k i d e n ti f ic a t io n b y c o m p a r i s o n o f m a s s s p e c t r a,w e r e o b t a i n e d b y s c a n n i n g f r o m m / z 650 to 50 and1 s /decade .

G a s o l i n e - r a n g e h y d r o c a r b o n s w e r e a n a l y s e d u s i n gt h e m e t h o d o f S n o w d o n a n d O s a d e t z ( 19 8 8) .Microscopy

Sam ple s o f t he o r ig ina l coa l s , t he ex t r ac t ed coa l sa n d t h e h y d r o u s p y r o l y s i s r e s i d u e s w e r e p r e p a r e da s p e l l e t s a c c o r d i n g t o t h e m e t h o d d e s c r i b e d b yM a c k o w s k y ( 1 9 82 ). R e f l e c ta n c e m e a s u r e m e n t s i n o il(n o = 1 .518 a t 24C) we re de t e rm ined us ing a Ze i ssM P M I I r e fl e ct e d li g h t m i c r o s c o p e f it te d w i t h h a l o g e nand f l uo re scen t (HBO) l i gh t source s . The o r ig ina la n d e x t r a c t e d c o a l s w e r e p h o t o g r a p h e d u s i n g w a t e rimmers ion and f l uo re scen t l i gh t ( f i l t e r s : exc i t a t i on4 5 0 - 4 9 0 n m , b e a m s p l i t t e r 5 1 0 n m a n d b a r r i e r5 20 n m ) . M a c e r a l a n a l y si s w a s p e r f o r m e d u s i n g aS w i f t M o d e l F a u t o m a t i c p o i n t c o u n t e r a t t a c h e d t ot h e m e c h a n i c a l s t a g e o f t h e m i c r o s c o p e .

EP NOMI OIL

A s i n d i c a t e d b y t h e w h o l e o i l g a s c h r o m a t o g r a m[Fig . 2 (a ) ] , t he Epanomi o i l i s l i gh t wi th on ly am i n o r p o r t i o n ( 3 5 . 8 % ) r e c o v e r e d a f t e r f r a c t i o n a t i o n .

g 6 3 7 -

5 0 5L ~ ;~5

~ l i l i l i i i l l l . .|01 151 201 251 30 351 401 451 501 55~ 507 7 8 0 0 5

5 0 O r t 01 1 5 2 0 ~ i 3 0 3 5 4015 7 4 4 -

i l l l J L j jT im e ( r a i n )

Fig. 2. Gas chrom atograms of the Epanomi oil : (a) wholeoil; (b) gasoline range (C6, C7, Cs are n-hexane, n-heptaneand n-octane respectively, B is benzene, MCY C6 is methyl-cyclohexa ne and T is toluene); and (c) C~0+ saturate hydro-carbons. Pr is pristane and numbers refer to n-alkanes in(a) and (c).I t c o n s i s t s a l m o s t e n t i r e l y o f h y d r o c a r b o n s w i t h ap r e d o m i n a n c e o f a r o m a t i c s o v e r s a t u r a t e s ( T a b l e 1 ).Gaso l ine - range ana lys i s [F ig . 2 (b ) ] sugges t s t ha t t heo il h a s n o t b e e n b i o d e g r a d e d o r w a t e r - w a s h e d . U s i n gg a s o l i n e - r a n g e p a r a m e t e r s p r o p o s e d b y T h o m p s o n(1979, 1983, 1987), g iven in Table 1 , the oi l is m atu reexcep t i n t he ca se o f t he i sohep t an e va lue w hichind i ca t e s t he o i l i s supe rma tu re .

The who le o i l ch roma togram [F ig . 2 (a ) ] i nd i ca t e st h a t t h e n - a l k a n e s h a v e a b i m o d a l d i s t r i b u t i o n . T h el o w e r m o l e c u l a r w e i g h t C10---C12)n - a l k a n e s a r e i nm u c h h i g h e r c o n c e n t r a t io n s t h a n t h e ir C ~ 5 + h o m o -l o g u e s . A d i s t i n c t s e c o n d m a x i m u m o c c u r s a r o u n dnC27 . Th i s , and t he h igh p r i s t ane t o phy t ane r a t i o(2 .7 ) a re ev idence fo r a con t r i bu t i on t o t h i s o i l f romsource rocks con t a in ing t e r r e s t r i a l l y de r ived o rgan i cma t t e r (Powe l l and M cK i rdy , 1973) .

T h e s t e r a n e d i s t r i b u ti o n o f t h e E p a n o m i o i l[F ig . 3 (a )] i s dom ina t ed by C29 com po nen t s wi thm u c h l o w e r a m o u n t s o f C27 and C2s ste ranes, ad i s t r ib u t i o n c o m m o n l y r e p o r t e d i n o il s d e r i v e d f r o ms o u r c e r o c k s c o n t a i n i n g p r e d o m i n a n t l y t e rr e s tr i al ly -d e r i v e d o r g a n i c m a t t e r ( e . g . H o f f m a n n et al. 1984;Broo ks , 1986; Ph i lp and Gi lbe r t , 198 6) . S t e ranem a t u r a t i o n r a t i o s i n d i c a t e t h e o i l t o b e m a t u r e b u tthey have no t r e ached t he i r endp o in t va lue s (Tab l e 1 ).

Te rpanes a re p re sen t i n much h ighe r concen t ra t i onsthan s t e ranes . The m / z 191 f r agm ento gram [F ig . 3(b )]i s u n u s u a l i n t h a t i t i s n o t d o m i n a t e d b y h o p a n e s .


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810 MARTIN G. FOWLERet al

a )

7

9 D S

9 S

i9 R

b)

Fig . 3 . a ) Mass f ragm entogra ms of the Epan om i o i l hydrocarbo ns : a ) m / z 217 showing s te raned is t r ibu t ion 27DS and 29D S a re 13f l H) , 17 a H) 20S C27 and C29 diasteranes, 29R and 29S are C295c~ H),14~ H), 17~ H) 2 0R and 20S steranes); b) m / z 191 showing t r i te rpane d is t r ibu t ions H is 17~ H),21fl H)-hopane and O is o leanane) .


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Petroleum potential of Tertiary lignites 811A l l t h e m a j o r p e a k s are C3 pen tacyc l i c t e rpanes t ha th a v e s i m i l a r m a s s s p e c t ra . T h e y a l l s h o w a m o l e c u l a ri o n o f m / z 4 1 2 , a n M + - 1 5 m / z 3 9 7 ) f r a g m e n t a n da b a s e f r a g m e n t o f m / z 1 9 1 . T h e p e a k m a r k e d O i nF i g . 3 ( b ) c o - e l u t e s w i t h , a n d s h o w s t h e s a m e m a s ss p e c t r u m a s a n 1 8 ~ ( H ) - o l e a n a n e s t a n d a r d . T h e p e a km a r k e d H i s t h o u g h t t o b e 1 7 ~ ( H ) - h o p a n e f o r si m i la rr e as o n s . H o p a n e s o f o t h e r c a r b o n n u m b e r s a p p e a r t ob e p r e s e n t i n c o n s i d e r a b l y l o w e r a b u n d a n c e . A c o n -t r i bu t ion t o t h i s o i l f rom Ter t i a ry t e r re s t r i a l o rgan icm a t t e r i s s u p p o r t e d b y t h e p r e se n c e o f o le a n a n e a n ds e v e r a l o t h e r n o n - h o p a n o i d t r i t e r p e n o i d s .

HYDROCARBON POTENTIAL OF LIGNITES

Rock-Eval analysisBefore l ook in g in de t a il a t t h ree sam ples , a su i t e o f

G r e e k l i g n i t e s w a s s u r v e y e d f o r t h e i r h y d r o c a r b o np o t e n t i a l u s i n g R o c k - E v a l a n a l y s i s . T h e r e s u l t s o ft h e se a n a l y s e s a r e s h o w n a s a p l o t o f H y d r o g e n I n d e xv s O x y g e n I n d e x i n F i g . 4 . A s e x p e c te d , m a n y o f t h el ign i t es p lo t nea r t o t he Typ e I I I cu rve . A few samplesp l o t c l o s e r t o t h e T y p e I I c u r v e a n d h a v e h i g h e r H Iv a l u e s s u g g e s t i n g t h a t t h e y h a v e b e t t e r h y d r o c a r b o np o t e n t i a l . H o w e v e r , e v e n t h e s e s a m p l e s h a v e H Iv a l u e s c o n s i d e r a b l y l o w e r t h a n m o s t c o n v e n t i o n a ls o u rc e r o c k s. T h e K A S - 3 s a m p l e f r o m t h e K a s s a n d r awe l l , and a sample f rom the nea rby Pos-1 we l l , showt h e b e s t h y d r o c a r b o n p o t e n t ia l . B o t h o f th e s e c o a lsa r e t h o u g h t t o h a v e f o r m e d i n n e a r - m a r i n e l a g o o n a ld e p o s i t i o n a l s e t ti n g s. M M - 3 , t h e c o a l d e p o s it e d i n a nes tua r ine env i ronment , ha s s ign i f i can t ly l e ss po t en-t ia l . These samples have Tmax va lues app rox im a te lyc o n s i s t e n t w i t h t h e i r m a t u r i t y a n d l o w P r o d u c t i o nInd ices (Tab le 2 ) .

m

E ~ZI. 4

W e

m

0

I

11 IIj

OXYG N IN EXFig. 4. HI vs OI plot of Greek lignite samples. and II ,S2/TOC and S~ +S 2/T O C for diterpenoid resinite-richsamples, respectively; 0 , S2/TOC for other l ignite samples.

I n t e r m o n t a n e l i g n i t e s f r o m t h e F l o r i n a B a s i n s u c ha s 6 O G - 5 b e h a v e v e r y d i f f e r e n t l y f r o m t h e a b o v es a m p l e s. T h e y a r e v e r y i m m a t u r e ( a r o u n d 0 . 2 5 % R o )b u t g i v e m u c h h i g h e r S l v a l u e s a n d P r o d u c t i o nInd ices t han the o the r samples ( e .g . 6OG-5 , Tab le 2 ) .These samples a re a l so cha rac t e r i zed by the i r ve rylow Tmax va lues o f be tween 365 and 368C. The i r $2peaks a re ve ry j agged . V ery l ow Tma va lues have beenprev ious ly obse rved in coa l s wi th a h igh re s in i t e con-t e n t ( v o n d e r D i c k et al., 1 9 8 9 ) a l t h o u g h n o t a l w a y sa s s o c i at e d w i t h h i g h P r o d u c t i o n I n d i ce s . B e c a u s e t h eSl va lues a re so h igh , i t seems rea sonab le t o cons ide rthe t o t a l hy dro ca r bo n po t en t i a l o f the se li gn it es andno t j us t t ha t r epre sen t ed b y the $2 peak . H I va luesc a l c u la t e d t h e n o r m a l w a y (S 2 / T O C ) a n d a H Iv a l u e c a lc u l a t ed b y c o m b i n i n g t h e S ~ a n d $ 2 a m o u n t s( S , + S 2 / T O C ) h a v e b o t h b e e n p l o t te d o n F i g . 4 . F o rsamp le 6OG -5 , t he add i t i on o f the S~ peak ra ise s t heH I v a l u e b y a r o u n d 2 5 % , m a k i n g i t c o m p a r a b l e t ot h a t o f t h e K a s s a n d r a s a m p l e ( T a b le 2 ) .Ato mic H /C ra t ios , de r ived f ro m e l ementa l ana lys is ,i n d i c a t e t h a t 6 O G - 5 h a s t h e b e s t h y d r o c a r b o n p o t e n -t ia l o f t h e t h r e e c o a l s fo l l o w e d b y K A S - 3 a n d t h e nM M - 3 ( T a b l e 2 ). T h e r e a s o n w h y e le m e n t a l a n a l y si ss h o w s 6 O G - 5 w i t h b e t t e r h y d r o c a r b o n p o t e n t i a l t h a nK A S - 3 , w h i l s t R o c k - E v a l s u g g e s ts t h e r e v e rs e , m i g h tb e d u e t o t h e ir d i f f er in g m e t h o d s o f p r o d u c t d e t e c t io n(Pe t e rs , 1986) . 6O G-5 i s ve ry imm ature a nd a s i nd i -ca t ed by i ts O I va lue , ve ry oxygen r ich . The F ID of t heR o c k - E v a l o n l y r e s p o n d s t o c a r b o n m a s s a n d C - - Hb o n d s w h i l s t a c o m m o n p y r o p r o d u c t s u c h a s w a t e r( w h i c h w o u l d b e e x p e c t e d t o b e a m o r e i m p o r t a n tp r o d u c t f r o m 6 O G - 5 ) i s n o t i n c l u d e d i n t h e H I b u ti s measured by e l ementa l ana lys i s (Pe t e r s , 1986) .Organic petrology

S a m p l e 6 O G - 5 f r o m t h e i n t e rm o n t a n e F l o r i n a B a s i nis a t y p i c a l im m a t u r e T e r t i a ry h u m i c c o a l . I t c o n t a i n san a bun danc e o f wo od y ti ssues (humin it e) , f l uoresc ingy e l lo w - b r o w n to d a r k b r o w n a n d m o d e r a t e a m o u n t sof hum ode t r in i t e an d ph lobap h in i t e [P l a t e l( a ) ].The au to - f luore scence o f t he humin i t e i n t h i s ve ryi m m a t u r e s a m p l e i s p r o b a b l y p r i m a r y f l u o r e s c e n c einhe r i t ed f rom the o r ig ina l p l an t s t ruc tu re s (S tou tand Bens l ey , 1987) . Ph lo baph in i t e i s a cha rac t e r i s t i cc o n s t i t u e n t o f T e r t i a r y c o a l s f o u n d m a i n l y i n b a r kt i ssues , and i s t hough t t o be de r ived f rom t ann inson the dea th o f the plant (Teichmii ller, 1982) . Thissample was a l so r i ch i n r e s in i t e which occurs a s ova lto rounded bodies f i l l ing ce l l t i ssues. They exhibi t aye l low to l i gh t o range f l uore scence . A sma l l amounto f m i c r o s p o r e s a n d l i p to d e t r in i t e w a s a l s o o b s e r v e dbu t no i ne r t i n i t e was ev iden t [P l a t e l ( a ) ] .

T h e e s t u a r i n e c o a l M M - 3 f r o m M o s c h o p o t a m o si s a l so a hum ic coa l , cons i s t i ng o f humote l i n i t e ,l ip t i n it e , pyr i t e and ve ry l ow am oun t s o f i ne r t in i t e(Tab le 4 ) . The l i p t i n i t e componen t s , which a re ea s i l yrecogn i sed unde r u .v . exc i t a t i on , cons i s t o f r e s in i t e ,exsudat ini te , cut ini te , sporini te , f luorini te (der ivedfrom essential plant oils) and liptodetrinite [Plate l(b)].


8/22


~ ' ~ c ~ ~ , ~

o

I

0

~ ~ i ~ . ~

.f

a

0 ~ O

u 0 O


9/22

Pla te 1 . Pe trograph ic charac te r is t ic s o f Greek l ign i te samples under u .v . l igh t , wa te r immers ion (f i l te rs ,exc i ta t ion 450-490 nm, beam sp l i t te r 510 nm and ba rr ie r 420 nm). Th e long ax is o f each pho togr aph is230 m. (a ) Sample 6OG-5 . F ie ld o f v iew consis ts m os t ly o f f luoresc ing hum in i te (H) with some res in i te(R) f i ll ing cav i t ie s. (b ) Sam ple M M-3 . F ie ld o f v iew shows bands o f f luoresc ing res in i te (R) , exsuda t in i te(E) and f luor in i te (F) . Humin i te (H) on ly weak ly f luoresces . Note o i l d rop le t (O) s ta r t ing to fo rm frome x s u d a tin i te . ( c) S a mp le K A S -3 . S h o w n h e re a re b a n d s o f f luo re s cin g h u mo te l in it e (H T ) a n d h u mo c o l l in i t e(HC). A lso p resen t is some mo re in tensei~ t iuoresc ing l ip t in i te (L) . (d ) Sam ple KAS -3 . Bands o f f luoresc ingh u mo te l in i t e (H T ) a n d h u mo c o l l in i t e (H C ) a re a g a in s h o w n . P h lo b a p h in i t e (P h ) o c c u r s w i th in th ehum ote l in i te . L ip to de tr in i te (Ld) is a lso p resen t. C is a ca rbona te c las t . (e ) Samp le KAS -3 a f te r ex trac t ion .Co mp ared to (c ) o r (d) the f luorescence o f the humin i te is g rea tly reduced . Exsuda t in i te (E) and py ri te(P) now obse rvab le .

813


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Plate 2 . Residues o f G reek l ign i tes af ter hydro us pyro lysis a t 300C for 72 h un der incide n t whi te l igh t ,o i l imm ersion . Magnif icat ion same as P late I . a) KA S-3 or ig inal l ign i te res idue af ter hydrous pyro lysisat 300C for 72 h . V i t r in i te- l ike V) f ragments con tain ing devolat i l izat ion vacuoles Va) are p resen tind icat ing that sam ple was reactive du r ing pyro lysis. b ) KA S-3 pre-ex t racted l ign i te res idue af ter hydrou spyro lysis a t 300C for 72 h . Fuse d rou nded v i t r in ite- l ike V) f ragments show ing no d evolat i l izat ionvacuoles. c) KA S-3 or ig inal l ign i te res idue af ter hydrous pyrolysis a t 330C for 72 h . R oun dedvi t r in i te- like f ragme nts V) and some pyr i te P) are p resen t . d ) 6OG-5 or ig inal coal res idue af ter hydrouspyro lysis a t 300C for 72 h . V i t r in ite- l ike f ragments 0 D conta in ing some re mn ant mo rphology o f aroun ded resin i te body R) . e) MM -3 or ig inal l ign i te res idue af ter hydrou s pyro lysis a t 300C. Suban gularv i t r in i te- like f ragmen ts V) showing rem nan t o f cu t in i te Cu) morphology .

814


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Petroleum pote ntial of Tert iary lignites 815Table 4. M aceral analysisof original ignitesamples based on ~00 point-countsunder bo th white light and u .v. excitation.Numbers in parentheses are calculatedon a mineral free basis

Table 4

Maeerals KAS-343.0

Samples60G-5

24.0MM- 3

Humotelinite 65.0Humoeollinite 7.0 16.0 2.0Humodetrinite 9.0 21.0 2.0

59.0 84.3) 61.0 65.6)4.0

Tot al Huminlte 69.0Sporinite 3.0Resin ite 7.0 15.0Cutinlte 1.0 2.0 2.0Liptodetrinite 5.0 9.0 9.0Exsud atinite 1.0 1.0Alginite 4.0

2 2 .0 2 3 .7 )1.0 15.7)

10.0 10.7)

To tal LiptiniteSemifusinite

30.01.0

Fusinite 10.0Tot al Inertinit e 1.0Mineral M atter 30.0 7.0

T h e h u m i n i t e m a t r i x a l s o e x h i b i t s a w e a k b r o w n i s hf l u o r e s c e n c e . R e s i n i t e s h o w s a b r i g h t y e l l o w f l u o r -e s ce n c e a n d o c c u r s in l a rg e > 2 0 0 p m l e n g t h ) m a s s e sp a r a l l e l t o t h e b e d d i n g p l a n e r a t h e r t h a n a s t h e i s o l a t e d

~ 2 0 p m l e n gt h ) b o d i e s o b s e r v ed i n th e 6 O G - 5s a m p l e . B r i g h t l y f l u o r e s c in g e x s u d a t i n i t e o c c u r s f i ll i n gc r a c k s a n d f i s s u r e s p e r p e n d i c u l a r t o t h e b e d d i n gi n t h e h u m i n i t e m a t r i x . E x s u d a t i n i t e i s a s e c o n d a r ym a c e r a l w h i c h r e p r e s e n t s b i t u m e n p r o d u c e d d u r i n gl a t e d i a g e n e s i s a n d e a r l y c a t a g e n e s i s T e i c h m i i l l e r ,1 98 2). I n s a m p l e M M - 3 e x s u d a t i n i t e c a n b e o b s e r v e de x u d i n g f r o m b o t h t h e r e s i n i t e a n d f l u o r i n i t e . I nP l a t e l b ) a n o i l b l o b c a n b e o b s e r v e d f o r m i n g f r o mt h e e x s u d a t i n i t e s u g g e s t i n g t h a t t h i s s a m p l e i s a t t h ei n i t i a l s t a g e s o f h y d r o c a r b o n g e n e r a t i o n .

T h e K A S - 3 s a m p l e f r o m t h e K a s s a n d r a w e l l h a sv e r y d i f f e re n t o r g a n i c p e t r o l o g i c a l c h a r a c t e r i st i c s f r o mt h e o t h e r t w o s a m p l e s . I t s h o w s d i s t i n c t m i c r o s t r a t i -f i c a ti o n m i c r o b a n d i n g ) a n d v i r t u a l l y n o i n e r t i n i te[ P l a t e l c , d ) ]. T h i s i n d i c a t e s t h a t t h e l i g n i t e w a sd e p o s i t e d i n a c a l m - w a t e r d e p o s i t i o n a l e n v i r o n m e n tw h e r e t h e o r g a n i c m a t t e r w a s n o t e x p o s e d t o t h ea t m o s p h e r e G o o d a r z i a n d G e n t z i s , 1 98 7). S a m p l eK A S - 3 c o n s is t s m a i n l y o f h u m i n i t e h u m o t e l i n i te a n dh u m o c o l l i n i t e , T a b l e 4 ) . T h e h u m o t e l i n i t e o c c u r s a st h i c k b a n d s w i t h o u t a n y l i p t in i t e i n c l u si o n s , w h il e t h eb u l k o f t h e l i p t i n i te m a c e r a l s o c c u r i n t h e h u m o -c o l l i n i t e m a t r i x [ P l a t e l c ) ] . A l s o p r e s e n t i s b r o w n i s h -f l u o r e s c i n g o v a l p h l o b a p h i n i t e [ P l a t e 1 d ) ] w i t h i n t h eh u m o t e l i n i t e , c a r b o n a t e c l a s t s , s m a l l a m o u n t s o f p y r i t e

a n d s o m e a l g i n it e . T h e m o s t s t r ik i n g c h a r a c t e r i st i c o ft h i s s a m p l e i s th e i n t e n s e f l u o r e s c e n c e o f t h e h u m i n i t eg r o u p m a c e r a l s . T h e v i t r i n i te o f a c o a l o f t h i s m a t u r i t ys h o u l d b e s h o w i n g a m i n i m u m o f f lu o r e sc e n c e in t e n -s i t y T e i c h m i i U e r a n d D u r a n d , 1 9 83 ; L i n a n d D a v i s ,1 9 8 8 ) . T h e p e r h y d r o u s n a t u r e o f t h e h u m i n i t e i n t h i sc o a l is p r o b a b l y d u e t o t h e i n c o r p o r a t i o n o f l ip o i d a im o s t l y r e s i n it e ) su b s t a n c e s , w i t h t h o s e o f t h e h u m i n i t e

p r e c u r s o r s, d u r i n g e a r l y d i ag e n e s i s r a t h e r t h a n t h eg e n e r a t i o n o f b i t u m i n o u s s u b s t an c e s f r o m o t h e rm a c e r a l s a n d t h e i r a b s o r p t i o n b y t h e h u m i n i t e sT e i c h m t i l le r a n d T e i c h m i i ll e r , 1 9 8 2 ). P e r h y d r o u s c o a l s

a r e u s u a l l y d e p o s i t e d i n b r a c k i s h - w a t e r e n v i r o n m e n t sa n d h a v e a h i g h b a c t e r i a l i n p u t .

EXTRACTION OF COALST e n l i g n it e s w e r e e x t r a c t e d b y a n a z e o t r o p i c m i x t u r e

o f c h l o r o f o r m a n d m e t h a n o l f o r 2 4 h . O n l y t h e r e s u lt so f t h o s e c o a l s t h a t w e r e s e l e c te d fo r t h e h y d r o u sp y r o l y s i s e x p e r i m e n t s w i ll b e d i s c u s s e d i n a n y d e t a i lhe r e .

S a m p l e M M - 3 g i v e s m u c h t h e l o w e s t y i e ld s o ft o t a l e x t r a c t a n d h y d r o c a r b o n s o f t h e t h r e e s a m p l e sT a b l e 3 ) . T h i s s a m p l e a l s o s h o w s t h e l e a s t a m o u n t

o f c h a n g e i n i t s R o c k - E v a l r e s ul t s b e f o r e a n d a f t e re x t r a c t i o n . T h e r e i s o n l y a s m a l l d e c r e a s e in t h e c o m -b i n e d S I + 2 a m o u n t . T h e l o w e r i n g o f H I a p p e a r st o b e b e c a u s e s o m e m a t e r i a l t h a t w a s m e a s u r e d a s S 2i s m e a s u r e d a s S l a f t e r e x t r a c t i o n . T h e i n c r e a s e i n


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816 MARTING. FOWLER t al.1 c o u l d a l s o b e d u e t o r e t e n t i o n o f s o m e s o l v e n f

pr io r t o t he an a lys i s o f the ex t rac t ed sample . Th i s i scons ide re d un l ike ly a s t he ex t rac t ed sam ples were l e ftu n d e r p a r t i a l v a c u u m i n a d e s ic c a t o r f o r 1 w e e k t oremo ve s o lven t p r io r t o ana lys i s . The Tm~x show s aninc rease o f 2C. The v i t r in i t e r e f l ec tance i nc reased by0 . 1 - 0 . 4 5 % R 0 w h i c h i s th e v a l u e o b t a i n e d f o r t h eo t h e r t w o c o a l s e a m s a t M o s c h o p o t a m o s w h i c h a r eno t a s r i ch i n l i p t i n i t e s . Hence , t he o r ig ina l v i t r i n i t ere f l ec t ance o f t h i s sample was sup pressed b y theex t rac t ed ma te r i a l .

F r o m t h e R o c k - E v a l a n a ly s i s o f t h e o r ig i n a l co a l s ,s a m p l e 6 O G - 5 m i g h t h a v e b e e n p r e d i c t e d t o h a v eg i v e n t h e g r e a te s t a m o u n t o f e x t r a c t b e c a u s e o f i tsh i g h 1 v a l u e. A l t h o u g h i t g a v e s u b s t a n t ia l l y m o r ee x t r a c t t h a n M M - 3 , i t w a s m u c h l es s t h a n t h e K A S - 3samp le (Tab le 3 ) . The dec rease i n t he S~ + 2 t o t a lis a p p r o x i m a t e l y e q u a l t o t h a t o f t h e S ] v al u e o f t h eo r i g i n a l 6 O G - 5 s a m p l e ( T a b l e 2 ) . H o w e v e r , t h eex t rac t ed samp le s ti ll show s a subs t an t i a l S~ peakw h i c h m a y h a v e c o m e f r o m t h e 2 o r b e r es i d u al S ~o r a m i x t u r e o f b o t h . T h e H I d e c r ea s e s b e c a u s e th e

2 i s l ower . T he Tm~x of t he ex t rac t ed samp le i st he same a s t ha t o f t he o r ig ina l sample sugges t i ng i ts t il l con ta in s resini te . This re te nt io n o f resini te af tere x t r a c t i o n w a s c o n f i r m e d o p t i c a l l y . T h e o n l y c h a n g ei n t h e a p p e a r a n c e o f t h e s a m p l e w a s a n i n c re a s e i nf luore scence i n t ens i t y and a s l i gh t i nc rease i n t here f l ec t ance o f t he humin i t e (Tab le 2 ) .

T h e K A S - 3 s a m p l e h a d a l o w P r o d u c t i o n I n d e xb o t h b e f o r e a n d a f t e r e x tr a c t i o n ( T a b l e 2 ). H o w e v e r ,e x t r a c t io n c a u s e s a la r g e r e d u c t i o n in th e 2 a n dth i s sample p rov ided the g rea t e s t y i e ld o f ex t rac t andhyd roca rbon s (Tab le 3 ). Asso c i a t ed wi th these changeswas an i nc rease o f 8C in t he Tmax . Ex t ra c t i on causesa subs t an t i a l r edu c t ion o f t he f l uore scence i n t ens i t yo f t h e h u m i n i t e w h i c h n o w h a s a g r e e n i s h - b r o w n l o win t ens i t y f l uore scence [P l a t e l ( e ) ] , t hus making thehumin i t e ce l l s t ruc tu re more v i s ib l e . The re f l ec t anceo f t h e h u m i n i t e i n c r ea s e s f r o m 0 . 4 4 t o 0 . 4 8 % R os u g g e s t i n g t h a t t h e m a t e r i a l t h a t w a s c a u s i n g t h ehumin i t e t o f l uore sce cou ld a l so be re spons ib l e fo rsuppres sing the or iginal ref lec tance . Y el low f luorescingt iny b lobs o f exsuda t in i t e can be obse rved f i l l i ngcav i t i e s i n t he ph lobaph in i t e a f t e r ex t rac t i on . Whi l s te x t r a c t i o n c a u s e d a l a r g e d e c r e a s e i n H I , i n c o m m o nw i t h t h e o t h e r t w o s a m p l e s , t h e a to m i c H / C r a t i o d i dn o t c h a n g e .G a s c h r o m a t o g r a m s o f o ri g i na l c o a l e x t r a c t s

T h e p r o p o r t i o n o f h y d r o c a r b o n s i n t he e x t ra c tso f a ll t h ree samples i s low an d th a t o f the sa tu ra t ehyd roca rbo ns even low er (Tab le 3 ) . How ever , t he C ,5+s a t u r a t e f r a c t i o n g a s c h r o m a t o g r a m s ( s f g c ) ( F i g . 5 )i l l us t ra t e some ve ry i n t e re s t i ng d i f fe rences be tweenthe t h ree samples .

T h e s f g c o f t h e K A S - 3 s a m p l e i s d o m i n a t e d b ya m o s t l y u n r e s o l v e d h u m p o f t e r p a n e s a r o u n d C 30[Fig. 5 (a)] . Th ere ar e smal ler am ou nts o f sesquiter-panes , d i t e rpanes , i sopreno ids (e spec i a l l y p r i s t ane ) ,

67L:5-

5 0 2 0 ~1 3 7 4 t -

5 0 1 8

7 7 2 9

5 0 3 1

r i t e r p a n a s

L J 1 .1 ~ 1 Ut O 151 L:o i L:.31 30 351 401 451 501 55 1D t t e r p a n e s

101 t 201 251 301 351 401 451 501 551 60T ~ l e ~ $ n )

Fig. 5. Saturate fraction gas chromatograms of ligniteextracts; (a) KAS-3, (b) 6OG-5 and (c) MM-3.

a n d n - a l k a n e s . T h e s e l a t t e r c o m p o u n d s a r e d o m i -n a t e d b y C 2 3- C3 1 m e m b e r s w i t h a p r o n o u n c e d o d dc a r b o n n u m b e r p r e f e r e n c e . N o a t t e m p t h a s y e t b e e nmade to i den t i fy i nd iv idua l componen t s o f t he t r i t e r -p a n e h u m p , b u t c o m p o u n d s o t h e r t h a n h o p a n e sp r e d o m i n a t e . T h e a r o m a t i c g a s c h r o m a t o g r a m i sd o m i n a t e d b y a h u m p o f c o m p o u n d s w h i c h a reprobab ly C30-de r ived a roma t i c t r i t e rpeno id com-p o u n d s . T h e a b u n d a n c e o f t r i te r p e n o i d s s u g g e s t s t h a ta n g i o s p e r m s w e r e th e m a j o r c o n t r i b u t o r s t o t h is c o a l .T h e s f g c o f t h e 6 O G - 5 s a m p l e i s d o m i n a t e d b yd i t e r p a n e s [ F i g . 5 ( b ) ] . T h e r e a r e m i n o r a m o u n t s o fs e s q u i te r p a n e s a n d n - a lk a n e s . T h e g a s c h r o m a t o g r a mo f a r o m a t i c h y d r o c a r b o n s i s d o m i n a t e d b y a r o m a t i cd i te r p e n o id c o m p o u n d s a n d c o m p o u n d s w i th s i m il are l u t io n t i m e s t o t h e c o m p o u n d s o f t r i te r p e n o i d o r i g int h a t p r e d o m i n a t e i n t h e K A S - 3 a r o m a t i c g a s c h r o -m a t o g r a m . H e n c e , m o s t o f t h e m a t e ri a l e x t ra c t ed f r o mth i s coa l has been de r ived f rom d i t e rpeno id re s in i t ewi th some t r i t e rpeno id con t r i bu t ion . As t he re a re s t i l lrou nde d bod ie s o f r e s in i t e p re sen t i n t he coa l a f t e rex t rac t ion , a nd the hum in i t e f l uorescence i n t ens it y hasgrea t l y dec reased , i t i s p rob ab le t ha t r e s in it e d i spe r sedt h r o u g h o u t t h e h u m i n i t e i s w h a t h a s b e e n e x t r a c t e d .The humin i t e f l uore sence i n t ens i t y i nc reases becausea t t h e v e r y l o w m a t u r i t y o f 6 O G - 5 , t h e p r i m a r yf luore sence o f t he hum in i t e i s g rea t e r t han tha t o f t here s in i t e (Te ichmi i l le r and D ura nd , 1983) and i s conse -quen t ly suppressed . The l a rge r p i eces o f r es in it e t ha tw e r e o b s e r v e d p a r a l l e l t o t h e b e d d i n g m a y a l s o b e


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Petroleum potential of Tertiary lignites 817e x t r a c ta b l e b u t b e c a u s e o f th e i r m a s s t h i s m a y t a k el o n g e r t h a n t h e 2 4 h u s e d i n t h i s w o r k .

T h e l a r g e s t p e a k s i n t h e s a t u r a t e f r a c t i o n g a sc h r o m a t o g r a m o f M M - 3 a r e o d d n u m b e r ed C 2 3 C 3 1n - a l k a n e s . T h e s e a r e p o s s i b l y d e r i v e d f r o m c u t i n o u sma te r i a l s such a s t he cu t in i te t ha t w as mic roscop ica l l yo b s e r v e d i n t h i s s a m p l e . T h e r e i s a l s o a h u m p o ft ri te r p a n es a n d a s e c o n d h u m p o f c o m p o u n d s t h a te lu t e a ro un d n C22 , poss ib ly C24 t e rpanes de r ived f romsester terpenoids (cf . W an g and S imonei t , 1990) . Di ter-p a n e s a r e n o t p r e s e n t i n l a r g e a m o u n t s i n d i c a ti n g t h a tt he re s in i t e i s d i f fe ren t f rom the F lo r ina sample . Th i si s a l s o s u g g e s t e d b y t h e a r o m a t i c g a s c h r o m a t o g r a mw h i c h s h ow s a p r e d o m i n a n c e o f c o m p o u n d s t h a te l u t e e a r l i e r t h a n t h e t r i t e r p e n o i d c o m p o u n d s a n dl a te r t h a n d i t e rp e n o i d s . T h e s e c o u l d b e d e r i v e d f r o mses t e r t e rpeno ids .

H Y R O U S P Y R O L Y S I S E X PE R I M E N T S

K A S - 3 s a m p l eFigure 6 shows the e ffec ts o f hy dro us pyro lys i s

o n s a m p l e K A S - 3 a s in d i c a t e d b y R o c k - E v a l a n al y s e so f t h e o r i g in a l c o a l , t h e e x t r a c te d c o a l a n d t h e p y r o -lysis residues. Heat ing the or iginal coal ( i .e . coalno t ex t rac t ed) a t 300C causes a l a rge dec rease i n t heHI (Tab le 2 ) and p roduces t he l a rges t ex t rac t y i e ld(Tab le 3 ) . As d i scussed above , ex t rac t i on removesmu ch o f t he $2 peak in t he o r ig ina l K AS -3 l ign it e.The re fo re , t he h igh ex t rac t y i e lds and l a rge d rop in $2a f t er p y r o l y s i s o f t h e o r i g i n a l s a m p l e a t 3 0 0 C c o u l dbe mi s l ead ing s ince we ex t rac t ed t he whole samplea f t e r each o f t he sma l l - sca l e pyro lys i s expe r iment s .The Rock-Eva l r e su l t s f rom bo th t he o r ig ina l and p re -ex t rac t ed 300C re s idues a re ve ry s imi l a r (Tab le 2 ) . I t

6 II

O X Y G E N I N E X

Fig . 6 . HI vs OI p lo t o f KAS-3 and i ts pyro lys is re s idues .0 Orig ina l l ign i te ; O ex trac ted l ign i te ; A the 300Cresidues; and I I 330C residues.

is f u r t h e r s u p p o r t e d b y t h e a m o u n t o f e x tr a c t o b t a in e df rom the 300C expe r im ent on t he o r ig ina l coa l (202 .4m g / g o r g C ) b e i n g s im i l a r to t h e s u m o f th e a m o u n t sof ex t rac t s ob t a in ed f r om the o r ig ina l coa l (116 .2mg /g o rg C) and the p re -ex t rac t ed sample a f t e r hea t inga t 300C (101 .63 mg/g o rg C) . However , t he op t i ca lev idence d i scussed be low sugges t s t ha t t he o r ig ina lcoa l does reac t i n a d i ffe ren t wa y to t he p re -ex t rac t eds a m p l e d u r i n g p y r o l y si s .

T h e a m o u n t o f e x t r a c t o b t a i n e d a f t e r t h e 3 3 0 Cexpe r iment s was l e ss fo r t he o r ig ina l coa l sample ,bu t s l i gh t ly g rea t e r fo r t he p re -ex t rac t ed sample ,compared to t he i r 300C equ iva l en t s (Tab le 3 ) . Theh y d r o c a r b o n y ie ld s, a n d p r o p o r t i o n o f h y d r o c a r b o n sin t he ex t rac t , a re h ighe r t han f rom the 300C expe r -i m e n t s f o r b o t h s a m p le s . T h e d e c r e a s e in t h e a m o u n to f e x t r a c t o b t a i n e d f r o m t h e o r i g in a l c o a l a t 3 3 0 C ,c o m p a r e d t o t h e e q u i v a l e n t s a m p l e a t 3 0 0 C , is p r o b -a b l y d u e t o t h e p r o d u c t i o n o f a g r e a t e r p r o p o r t i o no f l ig h t e r p r o d u c t s t h a t w e r e n o t m e a s u r e d i n t h e s eexpe r iment s . In a l l ex t rac t s t he re i s a p redominanceo f a r o m a t i c s o v e r s a t u r at e s .Ne i the r o f t he 300C re s idues show f luore scencew h e n e x a m i n e d u n d e r u . v. l ig h t. T h e y d o s h o w s o m eimp or t a n t d i f fe rences und e r r e f l ect ed li gh t. The 300Cres idue o f t he o r ig ina l coa l i s composed o f v i t r i n i t e -l i k e f r a g m e n t s t h a t a r e r o u n d e d t o s u b - a n g u l a r a n dc o n t a i n l a r g e ( u p t o 1 0 0 m i n d i a ) d e v o l a t i z a t i o nvacuo le s [P l a t e 2 (a )] . The p re sence o f t he vacuo le ssugges t s t he coa l was ex t reme ly reac t i ve dur ing pyro-lys is and p ro duc ed l a rge amo unt s o f vo la t il e s . There s idue o f t he p re -ex t rac t ed l ign i t e cons i s t s o f angu la rto we l l - rounded v i t rop l a s t s (Dav i s et a l . 1976; Steller,1981) which have fused toge the r t o fo rm cha insb u t w h i c h d o n o t s h o w a n y d e v o l a t i z a t i o n v a c u o l e s[Pl a t e 2 (b ) ] . Hence , i t appea rs t ha t ex t rac t i on g rea t l yreduces t he reac t i v i t y o f KAS-3 a s sugges t ed by theRo ck-E va l r e su l t s. T he re f l ec t ance o f t he v i t r in i t e -l i kema te r i a l i n bo th 300C re s idues i s abou t t he same(Table 2) .

Bo th o f t he 330C re s idues have a s imi l a r appea r -ance when examined mic roscop ica l l y [P l a t e 2 (c ) ] .T h e y s h o w t h e d e v e l o p m e n t o f s u b a n g u l ar t o r o u n d e dv i t r i n i t e - l i ke f ragment s and devo la t i l i z a t i on vacuo le s .The l a t t e r a re l a rge r i n t he re s idue o f t he o r ig ina ll i gn i t e t han the p re -ex t rac t ed sample sugges t i ngaga in t ha t ex t rac t i on reduces t he reac t i v i ty o f KAS -3 .The re f l ect ance o f t he v i t r in i t e -l i ke m a te r i a l d i f feredbe tween the two samples wi th t he re s idue o f thepre -ex t rac t ed l i gn i t e showing a somewha t h ighe rre f lec t ance . T he Cl s+ s fgc o f t he pyro lysa t e s (F ig . 7 ) ,un l ike t he o r ig ina l ex t rac t [F ig . 5 (a ) ] , a re domina t edb y n - a lk a n e s . I n t h e c h r o m a t o g r a m o f t h e p y r o l y s a t ef r o m t h e 3 0 0 C o r i g i n a l c o a l , t h e m o s t a b u n d a n tt e r p a n es e l u t e a r o u n d nC17 a n d a r o u n d n C ~ 4 w i t h t h et r i t e rpeno id hump be ing re l a t i ve ly sma l l . The l owermolecu la r we igh t t e rpanes m ay be de r ived by c rack ingo f t r it e r p e n o i d c o m p o u n d s o b s e r v e d i n t h e o r ig i n a lcoa l ex trac t. C yc l ic com pou nds a re i n ve ry l ow abun-dance , r e l a ti ve t o t he n -a lk anes and C15-C20 acyc l i c


14/22

818 MARTING. FOWLER t a l7 0 2 t -

oll8 2 2 t -

oii O

Pr

1 5 m 2 0 2 5 1 ~ I

2 7

+

3 5 ~ 4 0 1 4 5 1I,

5 0 5 5 : (%(

1 0 1 1 5 1 2 0 1

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2 5 1

2 7

3 0 1 3 5 1 4 0 1 5 0 1 5 5 1 6 (. j J j . j1 14 5 ~5 7 0 9 -ooi~ mO l 1 5 2 0 1

T2 O

2 5 1

: 7

3 0 1 3 5 1 4 0 1 4 5 5 0 1 5 8 1] .

6 8 4 t -

5 0 2 7 -1 0 1 @.51 2 1 L:~i 3 1 35J 5 1 ~ l

T t m e m l n )4 1 451

Fig. 7 . Saturate fraction gas chrom atogram s of KA S-3 pyrolysates: a) original lignite 300C; b) originallignite 330C; c) pre-extracted lignite 300C; d) pre-extracted lignite 330C. Num bers refer to n-alkanesand pr is pristane.

i s o p r e n o i d s i n t h e 3 3 0 C s a m p l e . I n t h e g a s c h r o -m a t o g r a m s o f t h e p r e - e x t r a c t e d c o a l p y r o l y s a t e s , t h et e r p a n e h u m p s a r e c o n s i d e r a b l y s m a l l e r c o m p a r e dt o n - a l k a n e p e a k s t h a n t h e y a r e i n t h e o r i g i n a l c o a lp y r o l y s a t e s . T h i s s u g g e s t s t h a t m o s t o f t h e t r i t e r -p e n o i d s p r e s e n t i n t h e o r g i n a l li g n i te w e r e r e m o v e d b ye x t r a c t i o n . T h e p y r o l y s a t e s o f th e o r i g i n a l sa m p l ec o n t a i n n - a l k a n e s f r o m C 23 t o C 3~ t h a t s h o w a n o d d

c a r b o n n u m b e r p r e f e r e n c e a n d a h i g h r a t i o o f p r is -t a n e t o p h y t a n e . T h e r e i s n o s i g n if i c an t o d d n - a l k a n ec a r b o n n u m b e r p r e f e r e n c e i n e it h e r o f t h e p y r o l y s a t e sf r o m t h e p r e - e x t r a c t e d l i g n i t e b u t t h e y d o s h o w h i g hp r /p h ra t io s .

T h e g a s c h r o m a t o g r a m s o f t h e a r o m a t i c h y d r o -c a r b o n s a r e d o m i n a t e d b y l o w e r m o l e c u l a r w e i g h tc o m p o u n d s . O n l y t h e p y r o ly s a t e s o f t h e u n e x tr a c t ed


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a

Petroleum potential o f Tertiary lignitesO

819

^ . / t . . ~ ~ _

T m [ 2 9

d T m 1 2 9 M3 0

Fig. 8. m z 191 m ass fragmentograms of 330 C lignite pyrolysates: (a) K AS-3 original l ignite; (b)KAS-3 pre-extracted lignite; (c) 6OG-5 original lignite; (d) MM-3 original lignite. 29, 30 and 31 areC29-C31 17~t(H),21fl(H)-hopanes, Tm is 1 7:t(H)-trisnorhop ane, M is 17fl(H),21ct(H)-m oretane and O isoleanane.

s a m p l e s h o w t h e p r e s e n c e o f t h e h i g h e r m o l e c u l a rw e i g h t c o m p o u n d s o b s e r v e d i n t h e o r i g i n a l e x t r a c tand t he se a re i n l ow concen t ra t i ons ( e spec i a l l y i n t he330C pyro lysa t e ) .

T h e p r o p o r t i o n o f h y d r o c a r b o n s i n t h e e x p e ll e d oi lf r ac t ion , ob t a ined f ro m the l a rge - sca l e expe r imen t

u s i n g u n e x t r a c t e d p i e c es o f K A S - 3 , i s m u c h h i g h e rthan t ha t ex t r ac t ed f rom the sma l l - sca l e expe r imen t s ,up t o 46 .7 a f t e r hea t i ng a t 330C. The ga s ch ro -m a t o g r a m s o f t h e e x p e ll e d s a tu r a t e h y d r o c a r b o n s a r es i m il a r t o t h o s e o f t h e p y r o l y s a t e s o b t a i n e d a f t e r t h esma l l - sca l e expe r imen t s wi th t he o r ig ina l coa l .


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820 MARTIN G FOWLER t a l

T h e m/z 1 91 m a s s f r a g m e n t o g r a m s o f t h e K A S - 33 3 0 C p y r o l y s a t e s f r o m t h e s m a l l - s c a l e e x p e r i m e n t sa r e s h o w n i n F i g . 8 . T h e p y r o l y s a t e o f th e u n e x t r a c t e dsamp le is dom ina t e d b y C30 t e rpanes . Iden t i f i c a t i ono f 1 8 ct H ) - o l e a n a n e a n d 1 7 ~ ( H ) - h o p a n e w a s m a d ea s f o r t h e E p a n o m i o i l. T h e p y r o l y s a t e o f t h e p re oex t rac t ed sample shows a ve ry d i f f e ren t d i s t r i bu t i onw i t h t h e r e s in - d er iv e d c o m p o u n d s i n l o w e r a b u n d a n c ea n d a h i g h e r c o n c e n t r a t i o n o f h o p a n e s . 1 8 ct (H ) -o l eanane shows a s imi l a r abundance t o 17~t - (H) -h o p a n e i n b o t h p y r o l y s a t e s s u g g e s ti n g i ts p r e c u r s o r sw e r e n o t e x t r a c t e d w i t h t h e r e s i n - d er i v e d c o m p o u n d s .6 O G - 5

As ind i ca t ed by F ig . 9 and Tab le 2 , t he r e su l t so b t a i n e d b y R o c k - E v a l a n a l y s i s o f t h e r es i du e s , a f t e rh e a t i n g s a m p l e 6 O G - 5 a t 3 0 0 a n d 3 3 0 C , w e re s i m il a rfo r bo th t he o r ig ina l and t he p re -ex t rac t ed sample .The y i e lds o f ex t r ac t ob t a ined f ro m the expe r imen t swi th t he p re -ex t rac t ed sample a re ex t r eme ly l ow( T a b l e 3 ), ev e n i f t h e a m o u n t o f e x t ra c t r e m o v e d f r o mthe o r ig ina l l i gn i t e i s t aken i n to accoun t . As t he re i sa subs t an t i a l dec rea se i n HI d ur ing t he se expe r imen t s ,s o m e c o m p o u n d s m u s t h a v e b e e n g e n e r a t e d . T h e s ea r e p r e s u m a b l y l i g h t c o m p o u n d s t h a t w e r e n o tmeasured i n t he se expe r imen t s . Hence , t he ex t r ac t i onof t he d i t e rpen o id r e s in it e seems to have enab l ed ag r e a te r a m o u n t o f c r a c k i n g t o h a v e o c c u r r e d e i th e rd u r i n g o r a f t e r g e n e r a t io n o f h y d r o c a r b o n s f r o m t h i ssample .

T h e H I a n d H / C v a l u e s o f t h e 3 0 0 C re s id u e s a r elower t han t hose ob t a ined f rom the 330C expe r imen t su s i n g t h e o t h e r t w o c o a l s s u g g e s ti n g t h a t 6 O G - 5 m a ybe mo re r eac t i ve a t l ower t em pe ra tu re s . Tmax and

v i t r i n i t e r e f l e c tance r esu l t s o f t he 300C re sidues ,

zHz

x

/m

oo

Ao

~ ~ IllOXY EN INDEX

Fig. 9. HI vs OI plot of 6OG-5 and i ts pyrolysis residues.Annotation as for Fig. 6.

e spec i a ll y o f t he p re -ex t rac t ed sample , a l so i nd i ca t et h a t t h e r e s id u e s o f 6 O G - 5 a r e m o r e m a t u r e t h a nt h o s e o f t h e o t h e r c o a l s . I t s h o u l d b e e m p h a s i z e d t h a tt he se expe r imen t s we re run a t t he same t ime and u nde rexac t ly t he s ame cond i t i ons a s t he KA S-3 exper imen ts .I t i s possible tha t d i te rpenoid resini te genera tes hydro-c a r b o n s a t l o w e r t e m p e r a t u r e s t h a n o t h e r m a c e r a l s(Sn ow don a nd Powe l l , 1982) . The ve ry l ow Tmaxva lueob ta ined fo r t h i s sample , and t he o the r l i gn i t e s f romthe F lo r ina Bas in , sugges t s t ha t t he ac t i va t i on ene rgyn e e d e d t o g e n e r a t e h y d r o c a r b o n s f r o m d i t e r p e n o i dre s in i t e ma y be s i gn i f ic an t l y l ower t han t ha t fo r o the rtypes o f o rgan i c ma t t e r . A l t e rna t ive ly , t he g rea t e rreac t i v i ty o f 6OG -5 m ay be r e l a t ed t o t he l ow er i n it ia lm a t u r i t y o f t h is s a m p l e a n d t h e g r e a t e r a m o u n t s o fo t h e r p r o d u c t s g e n e r a t e d s u c h a s c a r b o n d i o x i d e .

No f luoresc ing mater ia l was observed in the residuesf rom the 300C expe r imen t s . U nd e r r e f l e c ted l igh t t heo r g a n i c m a t t e r s h o w s a m o r p h o l o g y t y p i ca l o f v it -f i n it e ( te li n it e) . Rem nan t m orph o log y o f t he o r ig ina lrounded re s in i t e /ph lobaph in i t e bod i e s c an s t i l l beobserved wi thin the te l in i te ce l l cavi t ies [Pla te 2(d)] .T h e o n l y m o r p h o l o g y p r e s e n t i n t h e 3 3 0 C r e si d u esi s subangu la r hom ogen eous f r agment s o f v it ri ni te -l ikema te r i a l . Th i s m a te r i a l show s on ly a s l i gh t inc rea se i nre f l e c t ance f rom the 300C re s idues .

T h e C ~ 5+ s a t u r a t e f r a c t i o n g a s c h r o m a t o g r a m s o fthe pyro lysa t e s (F ig . 10 ) a re dom ina t ed by n -a lkanes .In a ll t he py ro lysa t e s , excep t t ha t f rom the 300C p re -e x t r a c t e d s a m p l e , t h e n - a l k a n e s s h o w a n o d d c a r b o nn u m b e r p r e fe r e nc e . T h e 3 0 0 C p y r o l y s a t e o f t h ep r e - e x tr a c t e d s a m p l e s h o w s a s i m il a r c a r b o n n u m b e rd i s t r i b u t i o n b u t w i t h a n e v e n c a r b o n n u m b e r p r e f e r -ence ove r t he C22-C26 range . T h i s i s t ho ug h t t o ber e la t e d t o t h e e x t r e m e l y s m a ll a m o u n t o f e x tr a c t t h a twas ob t a ined f rom th i s expe r imen t . I t i s ev iden t t ha td i t e rpanes a re s ti ll impor t an t com pone n t s o f t he pyro -lysa te s o f t he unex t rac t ed sample . Th e re a re a l so o the rt e r p a n e p e a k s a r o u n d nCl and nC~7, especia l ly in the3 0 0 C c h r o m a t o g r a m . T e r p a n e s a r e p r e s e n t i n m u c hl o w e r a m o u n t s i n t h e p y r o l y s a te s o f t h e p r e - e x t r ac t e ds a m p l e p r e s u m a b l y b e c a u s e o f t h e r e m o v a l o f s o m eof t he i r p recur so r s by ex t r ac t i on . A cyc l i c i sopreno ids ,e spec i a l l y p r i s t ane have a l so been gene ra t ed and a l lt he pyro lysa t e s show h igh p r /ph r a t i os .

T h e m/z 1 91 m a s s f r a g m e n t o g r a m s o f t h e p y r o -l y s a t e s o f 6 O G - 5 a r e d o m i n a t e d b y h o p a n e s [ e . g .F ig . 8 (c ) ] . Othe r t r i t e rpanes we re no t de t ec t ed . Thes t e ra n e s s h o w a n e x t r e m e p r e d o m i n a n c e o f C29m e m b e r s .MM 3

H y d r o u s p y r o l y s i s a t 3 0 0 C d i d n o t r e d u c e t h e H Iv a lu e s o f t h e M M - 3 s a m p l e s i g n if i ca n t ly a l t h o u g hthe re was a l a rge r educ t ion i n t he OI va lue (F ig . 11 ,T a b l e 2 ) . H o w e v e r , c o n s i d e r a b l y h i g h e r e x t r a c t a n dh y d r o c a r b o n y i e l d s a r e o b t a i n e d a f t e r t h e 3 0 0 Cexpe r imen t s t han f rom the o r ig ina l sample ex t r ac t i on .H e a t i n g a t 3 3 0 C i n c r ea s e d t h e y i e l d o f e x t ra c t o b -t a in e d a n d c a u s e d t h e H I a n d H / C v a l ue s t o d e cr e a s e


17/22

Petroleum potential of Tertiary lignites 8217 3 5 0 -

5 0 2 6 -7 6 8 4 -

5 0 2 5 51

aP r

l o t 1 5 1 2 0 1

20.

J I2 5 3 0 1

2 5

3 5 1 4 0 : 4 5 1 5 0 i 5 5

1 i . | 01 i51 201 2 6

2 5

2 0

3 0 3 5 40 451 5 0 : 5 5 1 8 0 ~5 9 4 7 -

5 0 2 t -6 4 2 t -

5 0 2 1 -

i O 5 1 2 0 :

P P

I

I

2

2 5 I

I

3 : 3 5 i 4 0 :i I . .

4 5 : 501 556 61

2 0I

1 0 1 1 5 1 2 0 1 2 5 1

2 5

3 0 i 5 8T il e (11111)

I l l _4 0 1 4 5 1 5 0 i 5 5 1 6

Fig. 10. Saturate fraction gas chromatog rams of 6OG -5 pyrolysates: a) original lignite 300C ; b) originallignite 330C ; c) pre-extracted lignite 300C; d) pre-extracted lignite 330C . Nu mbe rs refer to n-alkanesand pr is pristane.

t o a b o u t t h e s a m e a s t h o s e f r o m t h e K A S - 3 s a m p l ea f t e r i t had been hea t ed t o 330C. Gene ra l l y , t he re a refewer d i f f e rences be tween re su l t s o f t he expe r imen t sus ing t he p re -ex t rac t ed coa l wi th t hose us ing t heor ig ina l coa l t han fo r t he o the r two sample s . Th i s i sno t su rp r i s i ng because ex t r ac t i on a f fec t ed MM-3 l e ssthan t he o the r coa l s . Th i s is a lso ev iden t f ro m the s fgc

Fig . 12 ) wh ich fo r e ach t empe ra tu re a re s im i l a r fo rb o t h t h e o r i g i n a l a n d p r e - e x t r a c t e d s a m p l e s . T h e s ec h r o m a t o g r a m s d i f f e r f r o m t h e o r i g i n a l e x t r a c t i ns h o w i n g a b r o a d e r r a n g e o f n - a l k a n e s a n d a n i n -c rea sed abu nd anc e o f i sopreno ids , e spec ia l l y p r i s t ane .B o t h t h e u n e x t r a c t ed a n d t h e p r e - e x t ra c t e d 3 0 0 C g a sc h r o m a t o g r a m s s h o w a h u m p o f c o m p o u n d s e lu t in g

O G 1 7 / ~ - J


18/22


xu.Irt

Zt~J0nC3

/

oo

OXYGEN IN EXFig. 11. HI v s OI plot of M M-3 and its pyrolysis residues.Annotation as for Fig. 6.

a r o u n d t h e nCl7 p e a k . T h e s e c o m p o u n d s a r e g r e a t l yd i m i n i s h e d i n t h e 3 3 0 C c h r o m a t o g r a m s w h e r e t h eC l ~ C 2 0 a c y c li c i s o p r e n o i d s d o m i n a t e t h e b r a n c h e d /cyc l i c f r ac t i on . The m / z 1 9 1 m a s s f r a g m e n t o g r a m s[e.g. F ig . 8 (d ) ] o f p re -ex t rac t ed and unex t rac t eds a m p l e s a r e d o m i n a t e d b y h o p a n e s w i t h o t h e rc o m p o u n d s s u c h a s t h e t r ic y c li c t e r p a n e s i n v e r y lo wa b u n d a n c e . T h e C 29 s t e ra n e s p r e d o m i n a t e o v e r t h eC 7 and C2s steranes.T h e d o m i n a n t m a t e r i a l i n t h e r e s i d u e s i s a n g u l a r

vi t r ini te- l ike mater ia l [Pla te 2(e)]. N o devola t iza t ionv a c u o l e s s u c h a s t h o s e i n t h e K A S - 3 r e s i d u e w e r eobse rved sugges t i ng t ha t t h i s sample d id no t r eac t i nt h e s a m e w a y .

DISCUSSIONK A S - 3 i s i n d i c a t e d b y R o c k - E v a l a n a l y s i s t o h a v e

t h e b e s t h y d r o c a r b o n p o t e n t i a l , b u t c o m p a r e d t on o r m a l s o u r c e ro c k s th e q u a l i t y o f t h e o r g a n i cm a t t e r a s m e a s u r e d b y t h e H y d r o g e n I n d e x i s n o tpa r t i cu l a r ly good . However , a l l t h ree samples do havea b e t t e r p o t e n t i a l t o s o u r c e h y d r o c a r b o n s t h a n i sg e n e r a ll y a s s u m e d f o r c o a l s. T h i s i s s u p p o r t e d b y t h ea m o u n t o f f l u o re s c i n g m a t e r i a l t h a t c a n b e o b s e r v e dunde r u .v . l igh t. T he p ro por t i o n o f l ip t in it es com paredto v i t r i n i t e s and ine r t i n i t e s e s t ima ted f rom po in t -c o u n t i n g u n d e r b o t h w h i t e l ig h t a n d u .v . l ig h t , o n am i n e r a l - fr e e b a si s , i s 3 0 % f o r M M - 3 , 2 4 % f o r 6 O G - 5a n d 1 6 % f o r K A S - 3 . T h i s a p p a r e n t l y s u g g e s t s t h a tM M - 3 h a s b e t te r h y d r o c a r b o n p o t en t ia l t h a n K A S - 3i n c o n t r a s t t o t h e g e o c h e m i c a l d a t a . H o w e v e r , a sd e s c r i b e d b e l o w a m o r e d e t a i l e d v i s u a l e x a m i n a t i o no f K A S - 3 , a n d t h e g e o c h e m i c a l re s u lt s , s u g g e st t h a tm u c h o f t h e h y d r o g e n - r i c h m a t er i al i n K A S - 3 i s w i th i n

the f l uore sc ing humin i t e . Addi t i ona l ly , t h i s sampleconta ins a signi ficant ( 4% ) am ou nt o f a lgini te . H ence,q u a n t i t a ti v e m a c e r a l a n a l y s is o f c o a ls c o n t a i n i n gpe rhydrous v i t r i n i t e does no t t ru ly i nd i ca t e t he i r t rueh y d r o c a r b o n p o t e n t i a l . T h i s i s i n a g r e e m e n t w i t hK h a v a r i - K h o r a s a n i ( 1 9 8 7 ) w h o f o u n d t h a t t h e o i l -p r o n e n e s s o f W a l l o o n C o a l s f r o m t h e S u r a t B a s i nwas gove rned no t on ly by the d i f fe ren t l i p t i n i t em a c e r a l s b u t a l s o b y t h e p e r h y d r o u s n a t u r e o f t h ev i t r in i t e and the l ack o f ine r t i n i te m ace ra l s . B e r t rand(1989) came to s imi l a r conc lus ions i n a s t udy o fN o r t h S e a J u r a s s i c c o a l s .

T h e u n u s u a l l y h i g h f l u o r e s c e n c e d i s p l a y e d b yhumin i t e i n t he K AS -3 sample , fo r i t s level o f ma tur i t y ,c a n b e e x p l a in e d u s i n g t h e f l u o r o g e o c h e m i c a l m o d e lo f L i n a n d D a v i s ( 1 98 8 ). A c c o r d i n g t o t h e s e a u t h o r s ,a s coa l if i ca ti on p roceeds up to t he su bb i tumino us s t agethe p r im ary f l uore scence o f hum in i t e i s l os t because aninc rease in a rom a t i c i t y causes a g rea t e r de loca l i za t i onof t he u -e l ec t rons . Dev e lopm ent o f t he mobi l e phase ,dur ing t he b i t um inous s t age o f coa l i f i ca ti on , r e su l ts i nsecon da ry f l uore scence o f v it r in i t e , a l t ho ugh the v i t -f i n it e ne tw ork i t sel f i s t oo c ond ense d to f l uore sce . There s inous ma te r i a l i n t he KAS-3 sample , be ing ea s i l ye x t r ac t e d , i s o b v i o u s l y n o t s t r o n g l y b o u n d w i t h in t h ehumin i t e s t ruc tu re . I t t he re fo re may be ac t i ng i n as i m i l a r f a s h i o n t o t h e m o b i l e p h a s e i n b i t u m i n o u scoa l s by con ta in in g f l uorop hores w i th le ss de loca l isede l ec t rons t han the humin i t e . Once t he humin i t e i sex t rac t ed and the re s inous ma te r i a l r emoved , i t sf l uore scence i n t ens i t y dec reases t o t he l ow in t ens i t yexpec t ed f o r i ts l evel o f ma tur i t y .Al l t h ree coa l s g ive mu ch h ighe r ex t rac t y i e lds t hanexpec t ed f rom the i r Rock-Eva l S~ va lues . The l ack o fcor re l a t i on be tween ex t rac t y i e lds and S~ va lues hasb e e n c o m m e n t e d u p o n b y s e v e r a l w o r k e r s ( e . g .Clemen tz , 1979; Sno wd on , 1984; Esp i t a li 6 e t a l .1985; Pe t e r s , 1986) and occurs because t he so lven te x t r a c t in c l ud e s h e a v y c o m p o u n d s s u c h a s r es in s a n daspha l t enes t ha t a re c racked in t he $2 t empera tu rerange and , t he re fo re , n o t i nc luded in t he S l peak .S a m p l e K A S - 3 d if fe rs f r o m t h e o t h e r t w o s a m p l e s b ys h o w i n g a m u c h l a r g e r d r o p i n $ 2 w i t h e x t r a c t i o n .M o r e o v e r , t h e a m o u n t o f h y d r o c a r b o n s a l o n e ( 9. 41m g / g r o c k ) e x t r a c t e d f r o m K A S - 3 i s h i g h e r t h a nwo uld be exp ec t ed f ro m i t s S~ va lue (6 .38 m g/g rock) .G a s c h r o m a t o g r a p h y o f t h e s a tu r a te a n d a r o m a t i ch y d r o c a r b o n f r a c t i o n s o f t h is s a m p l e a r e d o m i n a t e db y t r i t e r p e n o i d c o m p o u n d s . T a r a f a e t a l . (1983)r e p o r t e d t h a t c o m p o u n d s u p t o n C 3 2 w e r e v o la t il ee n o u g h t o b e m e a s u r e d a s p a r t o f t h e S~ p e a k .Henc e , i t i s p rob ab le t ha t no t a ll o f t he t r i te rpeno idc o m p o u n d s i n K A S - 3 a r e b e i n g m e a s u r e d i n t h e S ~peak . Th i s , e spec i a l ly , migh t be t he ca se fo r a rom a t i c swhich a re u sua l ly l ess vo l a ti l e t han n -a lkan es o f thes a m e c a r b o n n u m b e r .

Res inous ma te r i a l s e i t he r occur r ing a s d i sce rn ib l ere s in i t e bod ie s ( a s i n MM-3 and 6OG-5) o r d i spe r sedwi th in t he humin i t e ma t r ix (a s in KA S-3) a re t he mosti m p o r t a n t c o n t r i b u t o r s t o t h e h y d r o c a r b o n p o t e n t i a l


19/22

Petroleum pote ntial of Tertia ry lignites 82375s4 ~

5 0 3 1 -

a

I O w 1 5 1 ;2 ~ 2 5 1 3 0 1 3 5 : 4 0 1 4 5 1 5 o 5 5 ~ 6 0

' 1 b

5 0 4 0 - 1 0 1 t 5 I8 3 1 4 - C

~27 ~ . 0 1 5

.k2 0

F ) r

2 5 1 3 0 1 3 5 ~ 4 0 1 4 5 1 5 0 1 5 5

= r

251 . , 0 1 3 5 1 4 0 1 4 5 1 5 0 1 5 5 1

2 7

7 3 5 9 -

5 0 2 3 -

d2 0

~r,

. t ~ t151 2 j

2 7

: : _ _ L J J J A . , , , .1 0 1 2 5 * 3 0 1 3 5 1 5 0 1 5 5

T i m e ( m l n ) ] l l4 1 4 5 1Fig. 12. Satu rate fraction gas chrom atogra ms of MM-3 pyrolysates: a) origina l lignite 300C; b) origin allignite 330C; c) pre-extracted lignite 300C; d) pre-extracted lignite 330C. Nu mb er refer to n-alk ane sand pr is pristane.o f t h e c o a l s . W h i l e t h e a l g i n i t e o b s e r v e d i n K A S - 3w o u l d a l s o b e e x p e c t e d t o c o n t r i b u t e t o t h e h y d r o -c a r b o n p o t e n t i a l o f t h i s s a m p l e , i t c a n n o t b e a m a j o rf a c t o r . T h i s i s b e c a u s e , a s d i s c u s s e d p r e v i o u s l y , a m a j o rp a r t o f t h e h y d r o c a r b o n p o t e n t i a l o f K A S - 3 c a n b er e m o v e d b y e x t r a c t i o n , w h i c h h a s n o a p p a r e n t e f fe c to n t h e a l g i n i t e .

Ga s c h rom at ogra p h i c ev i d en ce in d i cat es t h at d i ff er-i n g t y p e s o f p l a n t s c o n t r i b u t e d t h e r e s in s t o t h e c o a l s .T h e 6 O G - 5 s a m p l e i s d o m i n a t e d b y d i t e r p e n o i d -d e r i v e d c o m p o u n d s s u g g e s t i n g t h a t g y m n o s p e r m sw e r e t h e m a j o r c o n t r i b u t o r s t o t h i s i n t e r m o n t a n el ig n it e. T h e h y d r o c a r b o n s o f t h e l a g o o n a l l i g n i teK A S - 3 a r e d o m i n a t e d b y t r it e rp e n o id c o m p o u n d s


20/22


p r o b a b l y d e r i v e d f r o m a n g i o s p e r m s . A m o r e d i v e r s es e t o f c o m p o u n d s a r e p r e s e n t in t h e e x t r a c t o f th ed e l t a i c s a m p l e M M - 3 , w h i c h m a y b e a f u n c t i o n o ft h i s d e p o s i t i o n a l e n v i r o n m e n t , w i t h t h e p r e d o m i n a n tres in it e-der ived com po und s be ing d i ffe ren t t o t hose o fthe o the r two samples . The h igh p r op or t i o n o f re s in it e-d e r i v ed c y c l ic c o m p o u n d s i n t h e e x t r a c t s o f a ll t h r e esamples i nd i cat e s t ha t t he i r b iochemica l p recursors a ren o t s t r o n g l y b o u n d w i t h i n t h e c o a l m a t r i x ( L u a n dKaplan , 1990) . The d i f fe ren t ways i n which t he t h rees a m p l e s b e h a v e u p o n e x t r a c t i o n a n d h y d r o u s p y r o -lys i s i s because t hey con ta in d i f fe ren t r e s in i t e s wi thd i f fe ren t p rope r t i e s .

Horsf i e ld et a l . (1988) have ques t i oned the use o ft h e H I a s a p a r a m e t e r i n a s s e s s i n g t h e h y d r o c a r b o np o t e n t i a l o f a c o a l c o n t a i n i n g a h i g h a b u n d a n c e o fre s in i t e o r f l uore sc ing v i t r i n i t e . They found tha t t heH I o f T a l a n g A k a r c o a l s c o r r e l a te d p o s i t i v el y w i ththe am ou nt o f r e s in i t e and f l uore sc ing v i t r in i t e ye t theC~0 f rac t i on o f the Ar d jun a Bas in o i ls ( t hou gh t t o bes o u r c e d f r o m t h e c o a l s ) , b a s e d o n t h e r e s u l t s o fp y r o l y s i s - g a s c h r o m a t o g r a p h y , w a s p r e d o m i n a t e l yde r ived f rom ma t r ix l i p t i n it e . Horsf i e ld et a l . (1988)s u g g e s t e d t h i s b e c a u s e p y r o l y s i s - g a s c h r o m a t o g r a m sof re s in i t e and f l uore sc ing v i t r in i t e f rom the Ta l an gA k a r c o a l s w e r e d o m i n a t e d b y c y c l ic c o m p o u n d swhi l s t t he Ard juna Bas in o i l s , be l i eved to be sourcedf r o m t h e s e co a l s , a r e d o m i n a t e d b y n - a lk a n e s t h o u g h tto be de r ived p r inc ipa l ly f rom ma t r ix l i p ti n i t e(b i t umin i t e + l i p tode t ri n i t e ). These au th ors t ho ugh tt h a t r e s i n i t e - d e r i v e d c o m p o u n d s m a d e o n l y a m i n o rc o n t r i b u t i o n t o t h e o i l b u t w e r e i m p o r t a n t i n t h eexpu l s ion p rocess . L ip tode t r i n i t e does occur i n s ig -n i f ic a n t q u a n t i ti e s i n K A S - 3 ( a b o u t 7 % o f t h e o r g a n i cm a t t e r ) a n d c o u l d b e t h e m a j o r s o u r c e o f t h e h ig h e rm o l e c u l a r w e i g h t n - a l k a n e s , b u t u n l i k e t h e A r d j u n aBas in o i ls , t he C~0+ f rac t i on con s t i t u t e s on ly a min orpor t i o n , an d lon g cha in pa ra f f i ns even le ss, o f t heE p a n o m i o il . T h e l o w p r o p o r t i o n o f r e si n - d er i v edc o m p o u n d s i n t h e h y d r o c a r b o n f r a c t i o n s o f t h eK A S - 3 p y r o l y s a t e s is i n a g r e e m e n t w i t h t h e r e su l ts o fHorsf i e ld et a l . (1988) t ha t , when ma ture , r e s in i t ew o u l d n o t b e a m a j o r c o n t r i b u t o r t o t h e C ~ 0 +h y d r o c a r b o n s i n a n o i l . M a s s b a l a n c e c o n s i d e r a t i o n si n d i c at e t h a t m o s t o f t h e p y r o l y s i s p r o d u c t s w e r e n o tr e c o v e r e d b e c a u s e t h e y a r e o f l o w m o l e c u l a r w e i g h t.Di t e rpeno id re s in i t e ( such a s t ha t i n 6OG-5) b reaksd o w n t o f o r m m o s t l y l o w m o l e c u la r w e i g h t a r o m a t i cp r o d u c t s o n h y d r o u s p y r o l y s i s ( L e w a n a n d W i l l i a m s ,1 98 7 ; H w a n g a n d T e e r m a n , 1 9 8 8 ) . T h e t r it e r p e n o i dr e s i n i n K A S - 3 m a y a l s o g i v e s i m i l a r p r o d u c t s a l -t h o u g h a t h i g h e r te m p e r a t u re s t h a n t h o s e p r o p o s e d b ySn ow don and Pow e l l (1982) fo r d i t e rpeno id res in it e.T h e m u c h l o w e r c o n c e n t r a t i o n s o f tr i te r p e n o i d s c o m -pa red to l ow er molecu l a r we igh t te rpanes i n t he 300Cp y r o l y s a t e o f t h e o r i g i n a l co a l ( c o m p a r e d t o t h eo r i g in a l e x tr a c t ) s u g g es t s t h a t t h e f o r m e r c o m p o u n d sa re ea s i ly c racked . H ence , f r om the re su l t s o f t h i sw o r k , o n e m i g h t p r e d i c t t h a t a n o i l s o u r c e d f r o m t h eK A S - 3 c o a l w o u l d b e d o m i n a t e d b y l i g h t a r o m a t i c

c o m p o u n d s w i t h m i n o r a m o u n t s o f hi g h er m o l e c u la rw e i g h t n - a l k a n e s .

A l t h o u g h t h e m / z 1 91 m a s s f r a g r n e n t o g r a m s o f t h eE p a n o m i o i l [ F i g . 3 ( b ) ] a n d t h e K a s s a n d r a 3 3 0 Cunex t rac t ed pyro lysa t e [F ig . 8 (a ) ] a re no t i den t i ca lt hey do sho w imp or t a n t s imil ar it ie s , p r inc ipa l ly thepre sence o f t he re s in -de r ived t r i te rpanes i n conce n-t r a ti o n s g r e a t e r t h a n t h e h o p a n e s . B o t h s a m p l e s a l s ohave a p r edo min ance o f C29 ove r C27 and C28 s t e ranes .How ever , t h is cha rac te r i s ti c was sho wn by pyro lysa t e sof a ll t h ree l i gn i te samples . T he E pan om i o i l i s li gh tw i t h a p r e d o m i n a n c e o f a r o m a t i c s o v e r s a t u r at e s . F o rreasons d i scussed abov e th i s i s a l so cons i s t en t w i th i tbe ing sourced by a l i gn i t e s imi l a r t o KAS-3 . Hence ,i t i s poss ib l e t ha t t he Epanomi o i l ha s been sourcedf r o m a m o r e m a t u r e e q u i v a l e n t o f th e K a s s a n d r a c o a lo r c o a l t h a t c o n t a i n s a n g i o s p e r m - d e r i v e d o r g a n i cma t t e r . O the r exp lana t ions a re poss ib le . Fo r example ,t he o i l which i s f a i r ly l igh t , may have been sourced ina d e e p e r m o r e c o n v e n t i o n a l s o u r c e r o c k a n d p i c k e dup the ea s i l y ex t rac t ab l e r e s in C30 t r i t e rpanes dur ingm i g r a t i o n . B e c a u s e t h e b i o m a r k e r d i s t r i b u t i o n s o fthe o i l a re ma ture , t he l i gn i t e which t he o i l wouldh a v e t o c o m e i n t o c o n t a c t w i t h i n t h is s c e n a r i o w o u l dh a v e t o b e o f m u c h h i g h e r r a n k t h a n t h e K A S - 3sample . Fur the r geochemica l s t udy and e spec i a l l ya b e t t e r k n o w l e d g e o f th e s u b s u r f a c e g e o l o g y o f t h eT h e r m a i k o s G u l f a r e a i s n e e d e d t o r e s o l v e w h i c h o ft h e t w o a b o v e h y p o t h e s e s f o r t h e E p a n o m i o i l is t h emore p l aus ib l e .

CONCLUSIONS

T h e r e su l ts o f t h is s t u d y s u g g e s t t h a t s o m e T e r t i a r yl ign it es f rom nor the rn Greece have be t t e r hydroc a rbo npoten t i a l t han i s norma l ly a t t r i bu t ed t o coa l s . TheG r e e k l i g n i t e s t h a t s h o w t h e b e t t e r h y d r o c a r b o np o t e n t i a l a r e t h o s e t h a t c o n t a i n a g r e a t e r a m o u n tof r e s in i te -de r ived m a te r i a l, e i t he r a s d i sc re t e bod ie so r d i s p e rs e d w i t h in p e r h y d r o u s h u m i n it e . F o r s a m p l eKA S-3 , t he d i spe rsed re s in it e i s t he cause o f theintense humini te f luorescence . Al though not indica tedb y R o c k - E v a l a n a ly s i s [S l / S l + $2) is very low], i t isea s i l y ex t rac t ab l e i nd i ca t i ng t ha t i t i s no t s t rong lybound to t he humin i t e . Othe r l i p in i t e mace ra l s a l som a k e a l e s s e r c o n t r i b u t i o n t o t h e h y d r o c a r b o npoten t i a l o f t he se coa l s . Fr om a ve ry l imi t ed da t ase t, i t appea rs t ha t t he t ype o f r e s in i t e cor re l a t e sw i t h d e p o s i t i o n a l e n v i r o n m e n t . I n t e r m o n t a n e l i g n it es(e .g . 6OG-5) a re domina t ed by d i t e rpeno id re s in i t eand l i gn i t e s depos i t ed on a de l t a p l a in con ta in o the rtypes such a s t r i t e rpeno id re s in i t e i n t he ca se o fK A S - 3 .A s o u r c e o f th e E p a n o m i o i l f r o m a c o a l s i m il a r t ot h e K A S - 3 t h a t c o n t a i n s p r e d o m i n a t e l y a n g i o s p e r m -d e r i v e d o r g a n i c m a t t e r i s s u p p o r t e d b y

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