Marine Chemistry in the Coastal Environment

14

Downloaded by KTH ROYAL INST OF TECHNOLOGY on September 12, 2015 | http://pubs.acs.org Publication Date: June 1, 1975 | doi: 10.1021/bk-1975-0018.ch014

Genesis and Degradation of Petroleum Hydrocarbons in Marine Environments T. F. YEN Departments of Chemical Engineering, Medicine (Biochemistry) and Program of Environmental Engineering, University of Southern California, Los Angeles, Calif. 90007

Petroleum and i t s r e l a t e d organic matter comprise the following e n t i t i e s : (a) gas, a gaseous mixture of methane to butane; (b) petroleum, a l i q u i d mixture of mainly hydrocarbons; (c) a s p h a l t , a semi-solid mixture of complex nonhydrocarbons and (a) kerogen, a s o l i d , c r o s s - l i n k e d , insoluble multipolymer. Gas, petroleum, and asphalt can be found i n r e s e r v o i r s , but kerogen i s located only i n source r o c k s . U s u a l l y , gas, asphalt and kerogen are associated with petroleum production. The elemental d i s t r i b u t i o n and composition of a t y p i c a l o i l , asphalt, and kerogen are i l l u s t r a t e d i n Table 1. In going from gas (alkanes), to o i l (petroleum), asphalt and kerogen, there i s a decrease i n the r a t i o of hydrogen to carbon i n the m a t e r i a l . Table I Chemical Composition o £ G&s, O u , Asphalt âflâ Keroeen Gas Carbon Hydrogen Sulphur Nitrogen Oxygen

76 23 0.2 0.2 0.3

Oil

Asphalt

84 13 2 0.5 0.5

Kerogen

83 10 4 1 2

79 6 5 2 8

Composition of a t y p i c a l crude o i l consists of 30% gasoline (C4-C10), 10% kerosene (C11-C15), 15% gas o i l (C lube o i l (020-^40) and'25% asphaltic bitumen ( C40). In terms of molecular types, an o i l contains 30% p a r a f f i n s , 50% naphthenics, 15% aromatics and 5% a s p h a l t i c s . The r e l a t i o n s h i p of d i f f e r e n t petroleum products together with the b o i l i n g ranges of representative hydrocarbons are i l l u s t r a t e d i n Figure 1 · 231

In Marine Chemistry in the Coastal Environment; Church, T.; ACS Symposium Series; American Chemical Society: Washington, DC, 1975.

232

MARINE CHEMISTRY

%Wt.


PFM

CARBON NUMBER Figure 1. (Right) Composition and boiling points of major petroleum fractions. (Left) Summary of the boiling points of pure hydrocarbons (based on Ref. 34).



14.

YEN

233

Petroleum Hydrocarbons in Marine Environments

Asphalts are derived e i t h e r from s t r a i g h t run residues of d i s t i l l e d crude, or from the bottom of the pot with the "visbreaker" thermal cracking process· They can a l s o be formed by oxidation of crude residues by the "blown" a i r oxidation process. T y p i c a l asphalt i s a composite material c o n s i s t i n g of asphaltene, wax, and r e s i n s . Asphaltene i s responsible f o r many properties of the asphalt system. Furthermore, asphalts a l s o may be converted to a s p h a l t i t e s or asphaltoids by weathering and metamorphism ( 1 ) . One of the properties of the a s p h a l t i c bitumen or " r e s i d " f r a c t i o n i s i t s concentration of metals such as vanadium and n i c k e l ( 2 ) , as indicated by Figure 1. Kerogen i s a s o l i d , i n s o l u b l e , organic material derived through b i o l o g i c a l o r i g i n and l a i d down with the sediments. S t r u c t u r a l l y , i t i s a c r o s s - l i n k e d multipolymer (3) composed of subunits s i m i l a r to a s p h a l t i c bitumens. Kerogen i s the major organic component i n source rock and shale. In terms of carbon d i s t r i b u t i o n on earth, kerogen i n shales and sandstone constitutes at least 1000 times more than the biomass of l i v i n g organisms (Table I I ) (4)· Table II

Carbon on Earth Carbon g/cn£*

Carbonates Shales and Sandstones Ocean (HCO3-I+CO3- ) Coal and Petroleum L i v i n g matter and dissolved Organic Carbon Atmosphere 2

2340 633 7.5 1·1 0·6 0·!

*Gram per square centimeter earth surface based on Skirrow (Ref. 8 ) . A c t u a l l y , kerogen i s the most abundant organic m a t e r i a l i n the ecosystem; surveys i n d i c a t e (5) the d i l u t e reserves are 3200 t r i l l i o n metric tons. This amount i s at least 5000 times the volume of known petroleum reserves ( F i g . 2 ) . Gas (C1-C4) usually admixes with petroleum i n producing r e s e r v o i r s to a small extent. I t i s evolved from source rock through the terminal maturation sequence as shown i n Figure 3, as w e l l as product of metamorphism of a l l f o s s i l f u e l s during diagenesis. The amount i n subsurface water i s considerable.


234

MARINE CHEMISTRY

ORGANIC SEDIMENTS DILUTED

CONCENTRATED I Downloaded by KTH ROYAL INST OF TECHNOLOGY on September 12, 2015 | http://pubs.acs.org Publication Date: June 1, 1975 | doi: 10.1021/bk-1975-0018.ch014

PETROLEUM

ASPHALTS

1

I

COALS

HYDROCARBONS

(LIGNITE) (PEAT) 0,3

0.6

I

KEROGEN

BITUMEN

NON-HYDROCARBON (EXTRACTABLE) (NON-EXTRACTABLE) 60

7.0

3,200

100

(NUMBERS IN TRILLION TONS) Figure 2.

Classification of organic sediments. The abundance of various fossil fuels in the ecosphere is presented in trillion tons.

KEROGEN

< M m o )«p

/

/

LIGHT1 Γ OIL GA'S

METHANE

Figure 3.

E A

u

'

M N

\ HEAVY OIL pyfcc PYROBITUMEN

\

GRAPHITE

Schematic of the origin of petroleum (including the maturation process)


14.

YEN


235


Biogenesis At the 8th World Petroleum Congress f o r the Panel Discussion on '"Recent Advances i n Understanding the O r i g i n , Migration and Accumulation of O i l and Gas and the Resulting Methods of Evaluating E x i s t i n g Petroleum Prospects" i n 1971, s c i e n t i s t s working i n t h i s f i e l d have agreed to r u l e out any theories on inorganic o r i g i n . The general acceptance of a biotic o r i g i n i s due to the overwhelming evidence of biogenic o r i g i n s supplied by recent research. However, even r e c e n t l y , a few people s t i l l advocate the F i s c h e r Tropsch formation from the "Petroleum Rain" ( 6 ) . I t i s not the i n t e n t i o n of the present paper t o t r a c e the biogenesis of a l l the components i n petroleum since the required lengthy d i s c u s s i o n i s out of the scope of t h i s presentation, and an excellent review has been compiled by Hodgson ( 7 ) . Rather, the emphasis here i s to point out the important evidence f o r organic o r i g i n . The general s i m i l a r i t y of petroleum composition and the nature of i t s constituents to the basic s t r u c t u r a l subunits of components occurring i n organisms i s a major reason f o r b e l i e v i n g the b i o t i c o r i g i n of petroleum. For example, i n l i v i n g matter, both b a c t e r i a and spores contain major concentrations of l i p i d s , as shown i n Table I I I , and simple decarboxylation of those l i p i d s w i l l y i e l d hydrocarbons. Long-chain hydrocarbons derived from organisms do form portions of petroleum, but the amount i s less than 10%. The bulk of the petroleum constituents are derived from the f o s s i l i z e d biomass through b a c t e r i a l and chemical a c t i o n . As indicated i n Figure 3, kerogen i s the c o n t r o l l i n g f a c t o r f o r such b i o stratinomy and taphonomy processes. Table I I I

Composition of L i v i n g Matter Weight % of Mftjojr Consequents

Substance Green plants Humus Phytoplankton Zooplankton B a c t e r i a (veg.) Spores

Lipids

Proteins

Carbohydrates

2 6 11 15 20 50

7 10 15 53 60 8

75 77 66 5 20 42


MARINE


236

CHEMISTRY

As i n d i c a t e d i n T a b l e IV, l o n g - c h a i n h y d r o c a r b o n s a r e d e r i v e d f r o m m i c r o o r g a n i s m s s u c h as a l g a e and f u n g i . These i n c l u d e n- and i s o - a l k a n e s , a l k e n e s , a l k a d i e n e s and i s o p r e n o i d s ( 9 ) . T h e r e i s no need f o r t h e more advanced o r g a n i s m t o y i e l d s t e r o i d s and t e r p e n o i d s s i n c e s t e r o i d s have been found i n p r o k a r y o t i c organisms. Furthermore, the algae are r e s p o n s i b l e f o r most C j 7 h y d r o c a r b o n s ( T a b l e V ) . The same **-C]7 h y d r o c a r b o n has been found i n 2.5 b i l l i o n - y e a r Sudan Shale. Non-photosynthetic b a c t e r i a y i e l d hydrocarbons i n the g e n e r a l range of 0 ^ 5 - 0 2 5 · For the photos y n t h e t i c b a c t e r i a , the c o n t r i b u t i o n i s s h i f t e d t o the h i g h e r m o l e c u l a r weight r a n g e o f c y c l i c s and uns a t u r a t e s ( T a b l e V I ) (10). The h y d r o c a r b o n d i s t r i b u t i o n i n C 2 5 - C 3 3 ^ n g e i s mostly d e r i v e d from p l a n t and i n s e c t m a t e r i a l ( F i g . 4 ) . I n most a n a e r o b i c and a e r o b i c b a c t e r i a , t h e r e a r e u n s a t u r a t e d l o n g - c h a i n c a r b o x y l i c a c i d s . These uns a t u r a t e d a c i d s c o n t a i n m u l t i p l e unconjugated o l e f i n i c d o u b l e bonds ( T a b l e V I I ) (11). U s u a l l y , these i s o l a t e d d o u b l e bond s i t e s may cros"sTink to f o r m high m o l e c u l a r weight kerogen analogs o r p r e c u r s o r s . One of t h e d i r e c t e v i d e n c e s of b i o t i c o r i g i n o f p e t r o l e u m i s t h e r e m a i n s and d e b r i s found i n kerogens through peleobiology. These a r e s p o r e s and even specimens o f B o t r v o c o c u s b r a n n i i i n s h a l e samples. The k e r o g e n may o r i g i n a t e from lacustrine basins, s h a l l o w s e a s , c o n t i n e n t a l p l a t f o r m s and s h e l v e s , o r i n s m a l l l a k e s , bogs, lagoons a s s o c i a t e d w i t h c o a l f o r m i n g swamps. The t y p e s o f m i c r o o r g a n i s m s i n e a c h s e t o f g e o l o g i c a l environments a r e d i f f e r e n t . A c t i v e enzymes have been i s o l a t e d f r o m k e r o g e n bearing shales or rocks. T y p i c a l a n a l y s e s by Bergmeyer s method f o r some s h a l e s and l i g n i t e s a r e summarized i n T a b l e V I I I (12). r

1

B i o l o g i c a l Markers I n E g l i n t o n ' s d e f i n i t i o n (13)» a b i o l o g i c a l marker i s "a compound, t h e s t r u c t u r e o f which can be i n t e r p r e t e d i n terms o f p r e v i o u s b i o l o g i c a l origin"· I t i s e s s e n t i a l t h a t t h i s p a r t i c u l a r compound i s a s t a b l e one t h a t can s u r v i v e t h r o u g h a number o f e n v i r o n m e n t a l s t i m u l i (14). H i t c h o n (15) has d i s c u s s e d d e t a i l e d c l a s s e s of b i o l o g i c a l markers. T h i s review i s only limited to c e r t a i n basic principles of t h e i r nature. The b e s t example i s p o r p h y r i n . Petroporphvrin i s widespread i n a l l petroleum and r e l a t e d substances (16). These porphyrins c h e l a t e e i t h e r w i t h vanadium o r n i c k e l ; other


14. Y E N



Table IV

237

Lone-Chain Hydrocarbons Produced by. Mjcroorgap^sms

Hydrocarbons

Range and predominant carbon no.

n-Alkanes

^^5-033,017

Type of Micro-

Anacystis cyanea Chroococcus &jr£idus Lvnebva a e s t u a r i i (A.)* C13-C19 Sclerotinia C - C 29> 29 sclerotiorum (£)** 2 5 » 2 7 > 2 9 » 3 1 Sphacelothlca r e i l i a n a 27» 29» 31 C

25

i-Alkanes

c

c

c

c

c

c

4-Me C

Alkenes

ChloTPfilosa f r i t s c h i i

1 7

7-M C 8-M C j n - C j - or e

c

I*9?tPÇ fftfsçgryffi Anacvstis cvanea (A.) C h l o r e l l a pvrenoidosa

1 7 7

7

Anacygtis niduleps n

c

e

n

c

" 23" » " 25*

Scendesmus auadricauda

(Δ)

n

Alkadiene

~ 26" » ~ 29" Anaçreti? wntftfffl (4) c

a

n

c

û

n-C -«,n-C2 n-027-Δ 1,18 n-C -Al,20 25

7

2 9

η

_0

3 1

a

ÇhPgeUa

yulfifflls (A)

Botrvococcus b r a u n i i

- Δ 1,22

botryococcene isobotryococcene (A,) (tetra-M acyclic triterpene) squalene MethVlPgoCCW? e

Isoprenoids

capsulatflg *Algae (4). **Fungi ( £ ) .

hopene-22 |29J Methvlococcus capsulatas hopene-17 [21J BaçiJ-Î-W? acidocaldarius



15

17

17

16

n-C n-C A-C n-C 7- and 8-methyl heptadecane 4-methylheptadecane n-C 18

16.10

0.41

0.15

82.75

Anacystis nidulans (blue-green)

4.00

96.00

—

Phormidium luridum (blue-green)

12.20 0.09

0.09

87.30

___ 0.26

n

Chorogloea fritschii (blue-green)

0.055

0.13 0.073 81.5 18.5 n

Chlorella pyrenoidosa (green aleae)

Hydrocarbons front Algae (percent only of t o t a l listed)

20.60 ο .ςη 2.50 2.95 73.75

0.35 0.35

ff

Nostoc muscorum (blue- een)

Table V



15

2

2?

2

2

24

21

2

19

18

---

—

2.1 2.6 46.5 13.3 1.0 3.6 3.8 3.8 4.2 4.1 3.1 1.5 1.0 0.5 0.5

0.5 1.7

5.5 Phytane 27.6 n-C 12.0 n-C 10.0 n-C Q 5.5 n-C 6.0 n-C£2 8.3 n-C23 7.4 n-C 6.0 n-C 5 3.3 n-C 6 n-C 3.3 0.5 n-C Q Squalene £ high MW cyclics

16

n n -"Cc Pristane

P. shermanii (anaerobic)

—

- - -

1.0 14.4 2.1 50.0 1.3 4.5 4.9 3.1 1.9 1.7 1.0 1.0 0.7 0.5

Clostridium acidiurici

94.7

. . .

. . .

. . .

. . .

. . .

0.35 0.45 0.32 0.24

3.50

0.01 0.06 0.10

Rhodospirilium rubrum

50.0 0.5 1.3 1,3 1.0 1.5 3.0 4.1 6.9 10.8 13.1 2.1

. . .

1.5 0.75 0.5

Chlorobrium (sulf urbacteria)

Hydrocarbons from Photosynthetic and Nonphotosynthetic Bacteria (percent only o f t o t a l listed)

Ε· c o l i (aerobic)

Table VI



C l o s t r i d i u m butvricum C l o s t r i d i u m pasteurianum

L a c t o b a c i l l u s arabinosus Pseudomonas fluoréscens Rhodopseudomonas spheroides anaerobic c u l t u r e ( l i g h t ) aerobic c u l t u r e (dark)

Anaerobic b a c t e r i a :

Mycobacterium p h l e i Corvnebacterium ovis

Aerobic b a c t e r i a :

B a c t e r i a l species

(0.3%) (1%)

(6%) (3%)

(8%) (3%)

(3%) (3%)

(4%) (31%)

(3%) (14%)

11 11

11 11

11 11

(2%) (2%)

(69%) (78%)

(35%) (12%)

9 (7%) 9 (6%)

JJL

Number of carbon atoms i n the acids

Table VII Has. Nature ££ Unsaturated Acids Found i n Some Species of. Bacteria (Mainly from Scheuerbrandt & Bloch)


14.

YEN


241


types o f metals are r a r e l y found ( 2 ) .

The predominant types of petroporphyrin, both the DPEP (Desoxyphilloerythroetioporphyrin) and the e t i o (Etioporphyrin), are unsymmetrically s u b s t i t u t e d . They are quite d i f f e r e n t from the non- or symmetrically substituted porphins synthesized from e l e c t r i c d i s charge or chemical condensation of pyrroles and aldehydes. Further the sequential evolution scheme of the porphyrin structure can only be explained and traced stepwise by biodiagenesis. F o s s i l porphyrins from c h l o r o p h y l l a, t o DPEP, t o E t i o and formally t o a r y l porphyrin can be i l l u s t r a t e d by Figure 5. A d e t a i l e d account of the b i o l o g i c a l diagenesis of petroporphyrin has been reviewed by Yen ( 2 ) . The predominance of pEytane and pristane i n petroleum i s a l s o c l o s e l y r e l a t e d t o c h l o r o p h y l l pigments. The sequence can be depicted i n Figure 6. In recent marine sediments, b i o l o g i c a l markers such as pheophorbides and c h l o r i n s are detected. The s i m i l a r i t y of the composition i n organisms and i n recent sediments has enhanced g r e a t l y the b i o t i c o r i g i n claim (see Figure 4) ( 1 7 ) . Carbon isotope r a t i o studies i n d i c a t e that organic compounds of petroleum and of the associated shales have s i m i l a r i t i e s . Silverman (18) has i n d i c a t e d the d i f f e r e n c e between marine and nonmarine l i p i d s and t h e i r r e l a t i o n s h i p t o crude o i l ( F i g . 7 ) . Silverman ( 1 9 ) has analyzed narrow petroleum d i s t i l l a t i o n f r a c t i o n s and revealed that there i s minimum i n the 425-450OC range ( F i g . 8 ) . Since f r a c t i o n a t i o n w i l l r e s u l t i n higher i s o t o p i c ratios by s p l i t t i n g of the lowi s o t o p i c r a t i o methane molecule, compounds located i n minimum must be unaltered, n a t u r a l l y occurring molec u l e s . A c t u a l l y , i t was found that the 425-450°C f r a c t i o n consisted of steriods and t r i terpenoids. Furthermore, there i s a maximum i n o p t i c a l a c t i v i t y corresponding to the minimum i s o t o p i c p o s i t i o n s . For a R i o Z u l i a crude o i l , there i s more than one minimum ( F i g . 9 ) . The minimum at 150°C i n d i c a t e s isoprenoids of C J Q type which are present i n petroleum i n considerable amounts (Table I X ) . Geological Fence C l a s s i c a l Cox's "posts" theory (20) i s s t i l l u s e f u l f o r the l i m i t i n g f a c t o r s under which organic m a t e r i a l could transform i n t o petroleum. Some of the "posts" are as follows: Temperature not exceeding 200°C, pressure not exceeding 500 p s i , and at least


242

MARINE CHEMISTRY


40Γ

CARBON NUMBER Figure 4.

PHiOPORPHYfUN 4

Figure 5.

r

η-Paraffin distribution in plant and insect waxes and recent sediments (based on Ref. 17)

PHYUOEAYTHRIN

T>EOXOPHYU.O£J\rTHRlN

Diagenesis of petroporphyrins from chlorophyll a (I) to DPEP (VII)


14.

YEN


243

CHLOROPHYLL I HYDROLYSIS

i C-G-C^-Ç- G3-C-C3-G * " "


C

c

c

è

C

0 H

c

PHYTOL OXIDATION - Ο Ο β ^ ^ ^ Ε Ο ϋ Ο Τ Ι Ο Ν -ΗβΟ

\

/ c

è

c

c

c

c

c

c

PRISTANE PHYTANE Figure 6. Fate of pristane and phytane in petroleum

and Etio (VIII). The end-product of MS-a-naphthyl-porphyrin (XII) is also shoum.


244

MARINE CHEMISTRY

INCREASING C, 1 I

I MARINE

^


CRUDE OIL

1

ι PLANTS

^

LIPIDS ^

'

1

I

1

1 PLANTS

1LIPIDS 1 1 1

CRUDE OIL

ι

I

-30

COAL 1

-25

NONMARINE I 1

-20

1

-15

1

-10

C /C p«rmll RELATIVE TO PREEDEE BEL EM ΝI TE after Silverman l3

,E

Figure 7.

Carbon isotope range of natural materials (based on Ref. 19)

+ 10 WHOLE + 5

CRUDE

S 0

ο o-

5

-10 200

100

0

100 200 300 400 500

_1_

600

DISTILLATION TEMPERATURE

Figure 8. Generalized curve relating carbon isotope ratios and boiling temperature of petroleum distillation fractions (based on Ref. IB)


14.

YEN


Table V I I I

245

Enzvmes Isolated from

State? â£à M f i P t W


i y (B^rfi^yey's Method) Aldolase ot-Amylase Creatine phosphokinase Glutamate dehydrogenase Glutamic-oxalacetic transaminase Glucos e-6-phosphate

3.2-25.3 111 .5-701.4 0.0-10.2 40.3-150.3 130.1-800.2

dehydrogenase

14.3-96.3

7.6-30.4

I s o c i t r a t e dehydrogenase

Malate dehydrogenase

14.2-66.2

Leucine aminopeptidase Trypsin

60.4-260.5 43.5-240.3

Table IX CiQ-Isoprenoid Fraction Com Ponca C i t v Crude O i l Compos

B.P. (QQ)

2,6 Dimethyloctane 160.4 2-Methyl, 3-ethylheptane 160.9 A l l other isomers (49 possible) 155-165

Cone, ( v o l . 0.50 0.64

0.44


Ρ

246

MABINE CHEMISTRY

+ 4Γ

C /C , 3

1 2

RATIOS

OPTICAL ROTATIONS

RESIDUUM 4-08 >635 C -VJ4-0.7 +0.6 +0.5 +0.4 i-t-OJ


e

+02 +αι l-o 0.1 02

50

_l

100

L

150

I

I

I

I

I

AVERAGE DISTILLATION TEMPERATURE Figure 9.

I

I

I

I

I

L

200 250 300 350 400 450 500 550

600

CO

•

Relation between C /C ratio and optical rotation in Rio Zulia crude oil distillation fractions (based on Ref. 19) J3

i2

σ Έ P.

400 600 Number of Taxa

800

I

1000 0

ι

I

ι

I

ι

I

20 40 60 % Reserves

Figure 11. Reaction of variation in number of taxa of total plants and animals over geological time. The right band rotation is percent reserves of total free world (based on Ref. 21 ).


Petroleum Hydrocarbons in Manne Environments


14. Y E N

Figure 10. Redox potential vs. pH for different types of deposits


247

MARINE


248

CHEMISTRY

one m i l l i o n years to allow the transformation» Refinement of these g e o l o g i c a l constraints has included the e l e v a t i o n of temperature and pressure and the r e duction of maturating time, since Pleistocene o i l has been discovered. In order to preserve the organics, a reducing environment i s much favored. Under marine conditions, a s i t u a t i o n of high production of organics and a r a p i d sedimentation i s o f t e n r e q u i r e d . Petroleum deposits tAiich behave as any other mineral ore concentrate are formed at a given set of pHHEh boundary regions ( F i g . 10)· Again, the c o n d i t i o n of preservation i s enhanced e i t h e r i n the absence of b a c t e r i a or i n the presence of fine-grained sediments such as s i l t s or c l a y s , and carbonate r e e f s . In studies of the habitat of o i l through g e o l o g i c a l age, the amount of reserves i s p r o p o r t i o n a l to the extant taxa ( F i g . 11) (21). The c o n d i t i o n of petroleum production i s w e l l exemplified i n the hinge-be It of major downwarps, f o r example, the east-west Tethyan Belt of Eurasia and the eastern Circum-Pacific Belt ( F i g . 12). These temperate zones have the conditions favorable to the overproduction of food. The major o i l f i e l d s of the world are included i n those two major b e l t s . Major kerogen deposits are l i m i t e d by the con d i t i o n s l i s t e d i n Table X. In t h i s case, the micro organisms source m a t e r i a l i s d i f f e r e n t f o r d i f f e r e n t set of g e o l o g i c a l c o n d i t i o n s . 1

Molecular Diagenesis Major reactions under geochemical conditions are i n dynamic e q u i l i b r i u m . Major r e a c t i o n types can be exemplified by these types o u t l i n e d i n Figure 13. Decomposition ( s p a l l a t i o n ) and condensation (polymeri zation) s t i l l e x p l a i n many petroleum transformations. Using expressions i n Figure 13, Ρ i s a large complex molecule when complexed to a. Examples of t h i s could be the fragmentation of methane from p e n t a c y c l i c t r i t e r p e n o i d s , e.g., aromatization of b e t u l i n i c a c i d to 2,9-dimethylpicene ( F i g . 14). Condensation reactions can be i l l u s t r a t e d by the melanoidin f o r mation from the i n t e r a c t i o n of amino acids and simple sugars. This condensate can be f u r t h e r polymerized to melanoidin structure (22). The most frequent conversion f o r f o s s i l f u e l s i s dehydrogenation which i s i l l u s t r a t e d by the second type. Depicted by a triangular plot/ the end-product i s concentrated i n the shaded r e g i o n ( F i g . 15) from the s t a r t i n g m a t e r i a l such as c e l l u l o s e or carbon


YEN

249



14.

ο v. Ο δ* csj

ε



NSW T o r b a n i t e ( D e v o n i a n ? ) Fusan, M a n c h u r i a ( T e r t i a r y )

S m a l l l a k e s , bogs, lagoons, a s s o c i a t e d with coal-forming swamps

braunii3

Xanthophyceae Chlorophyceae (Botrvococcus

Unknown— probably red algae

A l a s k a n T a s m a n i t e , Brooks Range (Mississippian) Phosphoria Formation (Permian) Monterey F o r m a t i o n ( M i o c e n e ) I r a t i S h a l e , B r a z i l ( L a t e Permian)

S h a l l o w seas on continental platforms and s h e l v e s

Source

Green R i v e r F o r m a t i o n ( E o c e n e ) Cyanophyceae Stanleyville Basin—Congo ( T r i a s s i c ) A l b e r t S h a l e , New B r u n s w i c k ( M i s s i s s i p p i a n )

Type

Origin of Major Kerogen Environments of the World

Large lake basins

Location

Table X


14. Y E N


251

Decomposition ond Condensation a + P i aP Nophthenic- Aromatic interconversion Ν *A + H

2


Ν ΞΗΑ + ηΗ m>n

2

* A + mH

Tronsalkvlation

Figure 13. Major processes of petroleum diagenesis

RmAst RnA*

#RpA«*A m>n> >p

Figure 14. Dehydrogenation and the accompanying methane formation fromhetulinic acid to 2,9~dimethylpicene


2


100

K

C 02

GRAPHITE OXIDE

100

0

Figure 15. Ternary diagram relating gaseous components of prebiological environment to the formation of fuels. The shaded area indicates the region where the matured kerogen belongs.

Η

PQLYETrin

Δα

FUSFD MAPTHFMICS

PQLYPHENYLENE

PPIYACENE,

FUSED RING ,C [m,n Ca=50

CIOO GRAPHITE DIAMOND

1 ANTHRACITE 2 COKE 3 BITUMINOUS COAL 4 PITCH 5 LIGNITE 6 PETROLENE 7KER0GEN 8 TRONA ACID 9 LIGNIN 10 PEAT 11 BROWNING PRODUCT I2HUMIC ACID I3M0K0IA 14 WOOD I5HARIPURA I β CELLULOSE 17CARBOHYDRATE



14.

YEN


253

monoxide and water. Aromatization i s also i l l u s t r a t ed by the change of aromaticity f o r the more aged sample. In many cases, cracking of a l i p h a t i c s , or the opening of the strained naphthenics, with respect to aging are found. For petroporphyrins, the r a t i o of DPEP/Etio i s r e l a t e d to the depth of b u r i a l of petroleum ( F i g . 16) (23). The l a s t type of transformation, t r a n s a l k y l a t i o n i s the major c o n t r o l f o r maturation process. For example, the p a r t i a l mass spectrum of petroporphyrin i n o l d samples e x h i b i t wider d i s t r i b u t i o n of masses when paired with those of the recent sediments (14). This important p r i n c i p l e forms the basis of carbon preference indexes (CPI). For recent samples, there i s odd preference; as samples get o l d , t h i s sharp d i f f e r e n c e of odd and even carbon numbers of the hydrocarbons i n samples becomes almost equal. This CPI concept can be i l l u s t r a t e d i n Figure 17· Other miscellaneous changes w i l l involve weathering, or mild oxidation of petroleum components. A l l o m e r i z a t i o n may i l l u s t r a t e the above as one of such processes (25). A c t u a l l y , c h l o r i n and purpurin have been i s o l a t e d ( F i g . 18). A number of d e c a r b o x y l a t i o n , reduction and other reactions are occurr i n g . For a complete survey of other r e a c t i o n s , readers should consult the paper of Breger (26)· Microbial Modification Maturation s i g n i f i e s , i n a broad sense, the transformation from an uneven, d i s t o r t e d d i s t r i b u t i o n of homologs of compounds to an even, symmetrically Gaussian-type, bell-shaped d i s t r i b u t i o n . During the primary migration of petroleum from source to r e s e r v o i r and the secondary migration which involves the u p l i f t by buoying, s h i f t by f a u l t s or a l t e r n a t i v e paths by c a p i l l a r y a c t i v i t i e s , constant contact of subsurface water to petroleum i s r e q u i r e d . Types of water i n close contact are summarized i n Table XI. Table XI Subsurface Water During Petroleum I_ii£ra£ion No.

Source

Type

1 2

Vadose Connate

surface meteoric trapped

3

Juvenile

magmatic

Nature sulfate alkaline carbonate chloride


254

MARINE CHEMISTRY

80


Q ROZEL PT.

G

SANTIAGO

Ο Ν. BELRIDGE

Q

ATHABASCA Ο

Ο MARA

2 i.O tu

BOSCAN

Ο AGHA JAR1

Ο WILMINGTON Ο BURGAN

BAXTERVILLE Q

01

i

0

1

1000

1

1

3000

ι

»

5000

»

»

7000

«

1

9000

DEPTH (FEET) Figure 16. A plot of the conversion of DPEP to Etio petroporphyrin vs. depth of burial in various petroleum



YEN


500-

I I I I I I I I I RECENT SEDIMENT (West Cortei Basin)

I I I I

400300-

r«3.8

200-

100

I 1 I II

Ο

PENNSYLVANIAN SHALE (Scurry Co., Texas)

< 400)ui > 300|

r-1.24

κ ι oof 300-

I I I I I 1 I I I I I I I +-HCRUDE OIL (Kelly Snyder Field) N^, r-107

200 100-

W W 2é' I tI

I I JI i I I. I J. I 30* A 4 36* 3*' To NUMBER OF CARBON-ATOMS PER n-PARAFFIN 1

1

1

Figure 17. η-Paraffin distributions for a recent sediment, an ancient sedi ment, and a crude oil (based on Ref. 35). The CPI numbers are indicated.



3

3

Figure 18.

chlorin acid

COOH

chlorin ester

COOH

Lo] O H -

pheophorbide a

O0H

COOCH3

0

A

0

purpurin 18

0

A

purpurin 7 trimethyl ester

COOCH3

0=0

OH

CH3OH

2

C H

3

g

COOH

chlorin p

COOH

chlorin e^

COOH

CH

Ύ Ύ

ο [-co,

iooH chlorin eg

CH,

Allomerization process and the formation of chlorin from pheophoride a

standing

standing

pheophor bin a^

:OOH


> 3


14.

YEN

257


Studies (27) f o r the m i c r o b i o l o g i c a l a l t e r n a t i v e of crude o i l ~ T n r e s e r v o i r s , have indicated the follow i n g : (a) the aerobic microbes w i l l s e l e c t i v e l y oxidize η-paraffins; (b) the a l t e r e d o i l s are usually located i n r e l a t i v e l y shallow r e s e r v o i r s which would be more e a s i l y reached by percolating surface waters with oxygen. The r e s u l t a n t crude o i l w i l l lose the p a r a f f i n wax f r a c t i o n and increase the naphthenic content. Laboratory conditions i n d i c a t e such modification i s completed i n one day or so by acclimated mixed culture of sewage-oxidizing b a c t e r i a ( F i g . 19) (28 ). Bacteria which w i l l attack petroleum hydrocarbons i n s a l i n e medium include CorypebftcteffAVPi, Arthrobacter and Achrobacter (29). Kuznetsov (30) advocates that i f the s t r a t a l water i s r i c h i n s u l f a t e , the subsurface water w i l l be a c t i v e with s u l f a t e reducers. In the presence of Desulfovibrio desulfuricans organics such as methane w i l l be consumed: Na2S(>4 + C H 4 — • Na2C0 + H2S 3

+

H2O

S u l f i d e w i l l be formed and, furthermore, deposits of secondary c a l c i t e w i l l be accumulated, i n many cases, even to s e a l the o i l deposits f o r further b a c t e r i a l decomposition. CaCl

2

+ Na COj^CaC0 2

3

+ 2 KaCl

S u l f u r - o x i d i z i n g b a c t e r i a such as T h i o b a c i l l u s thiooarus were found to be in mixed waters and subsurface waters containing hydrogen s u l f i d e . In deep formation waters of the upper Paleozoic era i n the Volga region, various group of b a c t e r i a were found. These include p r o t e i n - u t i l i z i n g , methaneo x i d i z i n g , glucose-fermenting, d e n i t r i f y i n g , s u l f a t e reducing, methane-synthesizing and s u l f u r - o x i d i z i n g types (30). In general, i f the s u l f a t e i s absent and the water-transfer i s low, b a c t e r i a w i l l cause the an aerobic decomposition of o i l i n t o methane and nitrogen. In case the water-exchange i s enhanced, and, e s p e c i a l l y , during the e x p l o i t a t i o n of the o i l deposit, the oxygen-containing waters penetrate i n t o the stratum and the o i l i s a e r o b i c a l l y decomposed by hydrogen-oxidizing b a c t e r i a . In many cases, the o i l becomes heavy and subsequently, high s u l f u r , or high vanadium a s p h a l t i c fractions w i l l be formed. The p o s s i b i l i t y of c e l l material as a source f o r the vanadium and porphyrin during bituminization has been considered (31).


In Marine Chemistry in the Coastal Environment; Church, T.; ACS Symposium Series; American Chemical Society: Washington, DC, 1975. 2

Figure 19. Fermentation schemes representing the formation of methane and carbon dioxide

4

CH +C0

Oxidized Rrtroleum Product!


14. Y E N


259


Biochemical Degradation The mechanism of f a t t y acids degradation by hydrocarbon u t i l i z e r s i s well understood through bio-oxidation. For example, palmitic acid can be f i r s t , transformed into i t s coenzyme A ester through ATP, coenzyme A and thiokinas, then undergo dehydrogenation (which was catalyzed by f l a v o p r o t e i n ) , hydration (catalyzed by enoylhydrase; followed by oxidation (catalyzed by dehydrogenase) and f i n a l l y bond cleavage of a 2-carbon fragment r e s u l t i n g i n a Cj4 acid (catalyzed by t h i o l a s e ) . The alkanes can be degraded by both aerobic and anaerobic conditions. One of such routes can be expressed by the scheme shown i n Figure 20. The end-products are usually sample acids or alcohols. In the case of obligate anaerobic bacterium, e.g., Desulfovibrio desulfuricans « the oxidation of alkanes i s always favorable e n e r g e t i c a l l y (Table XII)· Table XII Free Energy of Alkane Oxidation H3J& Stflfgt:? â F H E c ΔF AF/S0 = (fcÇfrl) reduced (kcal) 4

HvflgpçarbQP Methane

CH4+SO4+2H — H2S+CO2+2H2O 2C3H8+5SO4+COH — • Propane 5H?S+6C02+2H20 η-Octane 4CQHI3+25SO4+5OH — I 25H2S+32C02+36H20 n-Undecane 2CJJH24+17S0 +30H 17H2S+22C02+24H20

-22.8

-22.8

-141 -744

-28.2 -29.8

-507

-29.8

4

Other microorganisms that dehydrogenate alkanes under aerobic conditions are as i n Table XIII (32). Table XIII

Anaerobic Dehvdrogenation o£ Alkgpe?

Organisms

Alkane

AçhgQW>b^ct^r sp.

r-Decane

Capdidfl rugosa

Pçç^rdi^ sp.

n-Decane n-Decane n-Hexadecane n-Decane

Pseudomonas aeroginosa

n-Heptane

£· t r o p i c u s D. desulfijriçfrps

Pffçdtfcys n-Decanol, decyl aldehyde, decanoic acid n-Decene, n-decanol n-Decane, n-decanol n-Hexadecane n-Heptene



ρ-Xylene Diphenyl methane Naphthalene

Toluene

Benzene

Acetylene Propane Butane Hexane Hexadecane Pristane (2,6,10,14-tetramethyIpentadecane)

Substrate

Mvcobacteri uni rhodochrous Pseudomonas aeruginose Micrococcus sphaeroides Pseudomonas putida Pseudomonas aeruginosa Achromobacter sp. Pseudomonas sp. Hvdrogenomonas sp. Pseudomonas sp.

AROMATIC HYDROCARBONS Succinic a c i d Succinic a c i d Phenol Catechol Benzoic a c i d Pyruvic acid p-Toluic a c i d Benzoic acid *-Hydroxy-muconic semialdehyde (proposed) Catechol S a l i c y c l i c acid

4,8,12 -trimethyltridecanoic a c i d

1

Hnrvnflh^rf ^-8 urn sp.

1

Product Acetadehyde Acetone 2-Butanone Hexanoic acid Hexadecanol

Organism

ALKANES

Degradation bv Microorganisms

Mycobacterium l a c t i c o l a Mycobacterium smegman s Mycobacterium smegman s Pseudomonas aeruginosa Arthrobacter sp.

Table XIV



Pseudomonas aeruginosa

Phenanthrene

A s p e r g i l l u s pîfiey A s p e r g i l l u s gi&SC A s p e r g i l l u s ni&çy Pseudomonas sp.

p-Cymene

TERPENE HYDROCARBONS

Pseudomonas flerMfiippsfl Flavobacterium sp. A s p e r g i l l u s nj&er

Marine Chemistry in the Coastal Environment

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