The Genesis of Hydrocarbons

& the Origins ofPetroleum

J. F. KenneyRussian Academy of Sciences - Joint Institute of Physics of the EarthGas Resources Corporation

The Evolution of Multicomponent Systems at High Pressures: VI. The Thermodynamic Stability of the Hydrogen-Carbon System: The Genesis of Hydrocarbons and the Origin of Petroleum. 

J. F. Kenney, (JFK@alum.MIT.edu)Vladimir A. KutcherovNikolai A. Bendeliani, Vladimir A. Alekseev

Proc. Natl. Acad. Sci. U.S.A. 99(17):10976-10981.

http://www.GasResources.net

Dedication:

In the first instance, this article is dedicated to the memory of Nikolai Alexandrovich Kudryavtsev, who first enunciated, in 1951(1), what has become the modern Russian-Ukrainian theory of abyssal, abiotic petroleum origins. After Kudryavtsev, all the rest followed.

This article is dedicated generally to the many geologists, geochemists, geophysicists, and petroleum engineers of the former U.S.S.R. who, during the past half century, developed modern petroleum science. By doing so, they raised their country from being, in 1946, a relatively petroleum-poor one, to the greatest petroleum producing and exporting nation in the world.

This article is dedicated specifically to the late Academician Emmanuil Bogdanovich Chekaliuk, the greatest statistical thermodynamicist ever to have turned his formidable intellect to the problem of petroleum genesis. In the Summer of 1976, during the depths of the cold war and at immeasurable hazard, Academician Chekaliuk chose to respond, across a gulf of political hostility, to an unsolicited letter from an unknown American chief executive officer of a petroleum company headquartered in Houston, Texas. Thenafter and for almost fifteen years, Academician Chekaliuk was my teacher, my collaborator, and my friend. [JFK]

0. Overview:1. No more amnesia,-connected with the constraints of thermo-dynamics and “fossil” fuels.2. No more reticence,-

when confronting same, (refer to article).

I. The constraints of the 2nd law:

, ,

, ,, ,

0c r

i ii

dQ A d

A

, ,

, ,, ,

0c r

i ii

dQ A d

A

0

0

i kk

k

i k kk

dS dXF

dt dt

dS F J

II. The thermodynamic energy spectrum of the H-C system, and the H-C-O system.

The chemical potentials of the elemental compo-nents of the H-C system, at STP:

Carbon - graphite & diamond

Hydrogen - gas, H2.

1-1.0

-0.5

0.0

0.5

1.0

Graphite = 0.00 kcal

Diamond = 0.685 kcal

Chemical potentialsof elemental carbon

graphite diamond

Che

mic

al p

oten

tial,

i ,

kca

l/mol

e

Carbon number

The chemical potentials of the n-alkane series of the H-C system at STP, from CH4, methane, through C20H42, dodecane.

Graphite

Diamond

Chemical potentialsof n-Alkanes @ STP

0 2 4 6 8 10 12 14 16 18 20

-10

0

10

20

30

Met

hane Eth

ane

Pro

pane

But

ane

Pen

tane

Hex

ane

Hep

tane

Oct

ane

Non

ane

Dec

ane

C11

H24

C12

H26

C13

H28

C14

H30

C15

H32

C16

H34

C17

H36

C18

H38

C19

H40

Dod

ecan

e

n-alkanes diamond graphite

Che

mic

al p

oten

tial, i,

(kc

al/m

ole)

Carbon number

The chemical potentials of all the straight-chain hydrocarbon components of the H-C system at STP: n-alkanes, n-alkenes, and

n-alkynes.

Straight-chainHydrocarbons

0 2 4 6 8 10 12 14 16 18 20

0

20

40

60

80

Met

hane

-C

H4

Eth

ane

-C2H

6P

ropa

neB

utan

eP

enta

neH

exan

eH

epta

neO

ctan

eN

onan

eD

ecan

eC

11H

24C

12H

26C

13H

28C

14H

30C

15H

32C

16H

34C

17H

36C

18H

38C

19H

40D

odec

ane

Eth

yne

- C

2H2

Pro

pyne

But

yne

Pen

tyne

Hex

yne

Hep

tyne

Oct

yne

Non

yne

Dec

yne

C11

H20

C12

H22

C13

H24

C14

H26

C15

H28

C16

H30

C17

H32

C18

H34

C19

H36

Dod

ecyn

e

Eth

ene-

C2H

4P

rope

neB

uten

eP

ente

neH

exen

eH

epte

neO

cten

eN

onen

eD

ecen

eC

11H

21C

12H

23C

13H

25C

14H

27C

15H

29C

16H

C17

H33

C18

H35

C19

H37

Dod

ecen

e

alkynes alkenes alkanes

che

mic

al p

ote

ntia

l,

,

Kca

l / m

ole

Carbon number

The chemical potentials of the straight-chain and cyclic hydro-carbons:

n-alkanes, n-al-kenes, n-al-kynes, cyclo-hexanes, cyclo-pentanes, and alkylbenzenes, at STP.

alkynes alkylbenzenes alkenes cyclopentanes cyclohexanes alkanes

0 2 4 6 8 10 12 14 16 18 20

0

20

40

60

80

Straight-chain & cyclicHydrocarbons

cycloHexanes

cyclopentanes

n-Alkynes

n-Alkenes

n-Alkanes

alkylbenzines

che

mic

al p

ote

ntia

l, ,

(Kca

l / m

ole

)

Carbon number

The chemical potentials of the naturally oc-curring compo-nents of the H-C system at STP: n-alkanes, n-alkenes, cyclohexanes, cyclopentanes, and alkyl-benzenes.

Naturally occurringstraight-chain & cyclic

hydrocarbons

alkylbenzenes alkenes cyclopentanes cyclohexanes alkanes

0 2 4 6 8 10 12 14 16 18 20

0

20

40

60

cycloHexanes

cyclopentanes

n-Alkenes

n-Alkanes

alkylbenzines

che

mic

al p

ote

ntia

l, ,

(Kca

l / m

ole

)

Carbon number

Chemical potentials of the H-C system, at STP, together with represen-tative com-pounds invol-ving single and multiple states of oxidation, (OH): alcohols and carbohy-drates.

Straight-chain & cyclichydrocarbons, alcohols& carbohydrates

-400

-350

-300

-250

-200

-150

-100

-50

0

500 2 4 6 8 10 12 14 16 18 20

Carbon number

Carbohydrates

cycloHexanescycloPentanesn-Alkenes

n-Alkanes

alkylbenzines

alkylbenzenes n-alkenes cyclopentanes cyclohexanes n-alkanes alcohols carbohydrates

chem

ical

pot

entia

l, ,

(Kca

l / m

ole

)

n-Alcohols

(1.) The H-C system which constitutes natural petroleum is a metastable one. At low pressures, all heavier hydrocarbon molecules are unstable with respect to methane and the stoichiometric quantity of hydrogen. All heavier hydrocarbon molecules are only kinetically stable against decomposition into methane and hydrogen, - similarly as is diamond into graphite.

(2.) Methane, or natural gas, does not polymerize into heavy hydrocarbon molecules at low pressures, at any temperature. Contrarily, increasing temperature at low pressures must increase the rate of decomposition of heavier hydrocarbons.

(3.) Because the chemical potentials of all biotic molecules lie far below that of methane, no hydrocarbon molecule heavier than methane will evolve spontaneously from any biotic molecule, or combination of such.

An additional complication:No benefit is gained from the predictions of the Le Chatelier - Braun rules:

4 6 14 2

1 5CH C H H

6 6

Increasing pressure does not drive methane to transform into n-hexane and hydrogen.

Increasing temperature, at low pressures, will increase the decomposition of hexane into methane and carbon.

A further complication:The relative covolumes inhibit hydrocarbon genesis:

SPHCT 34

SPHCT3

6 14 2

CH 17.292 cm

1 5C H H 20.790 cm

6 6

V

V

Both the pressure and Gibbs potential depend upon a third-order singularity in the reduced density: ~ 1/(1-V*/V)3.

III. Determination of the chemical potentials.

ii V T n

F

nj i

FHG

IKJ

, ,o t

The theoretical formalism:Q = QrefQvdW

The formalism uses a factored partition function with a reference system.

The reference system used is Scaled Particle Theory [SPT] for mixtures of arbitrary convex, hard-body fluids fluids, which represents an exact statistical mechanical solution.

The mean-field formalism developed for the Simplified Perturbed Hard Chain Theory [SPHCT] formalism is used to account for the attractive, van der Waals component of the inter-particle potential.

Application of the formalism of the factored partition function:

refIG hc vdW

IG hc vdW

ref vdW

i i i i

p p p p

F F F

Statistical mechanical analysis:The exact SPT equation of state for a mixture of hard-body particles of Boublík is used for the reference system :

2ref

2 2

32

BoublikIG hc

2

1

1 1

1 2 5

3 1

in which

, , ,

,

i i i i i ii i i

i i i ii i

rs

p

qs rs

p p

r x R q x R s x S

xV xV

2

2

3

and

i i i ii i

i ii

i ii

i ii

x R x S

xV

x R

x R

The following compositional variables are defined:

The pressure and Gibbs free enthalpy of the reference system:

2 3ref 1 2 3

3

3 2ref

33

1 2 3

1 3

1 2 3

1 2

11

and

ln ln 11

in which

3 1, 3 1 2, 1 6 5

2 6 1 1

1 13 3 5 21 7 4

2 21

3 3 36

i i

ii

c c cp

n I J KG N x c

V

c c c

I c c

J c c c

K c c

3

13 1 1

2c

The van der Waals components of pressure and chemical po-tential, from SPHCT:pvdW, vdW

pN T

V

cZ

Y

TcZ YY

m

m

vdW B

vdWB

k

k

FHG

IKJ

UV||

W||

1

11

1

/

ln //

bgc hb g bgc h

At low pressures, me-thane and the H-C sys-tem are robustly stable against genesis of alkane compounds.At 10kbar, methane is

most stable against the genesis of heavier H-C compounds.At approximately

40kbar, the stability of the system inverts, and methane becomes unstable relative to alkanes and hydrogen.

CH4

1/nCnH2n+1 + (n-1)/nH2

G(1/10C10

H22

+ 9/10H2)

G(1/6C6H

14 + 5/6H

2)

G(1/4C4H

10 + 3/4H

2)

G(1/2C2H

6 + 1/2H

2)

G(CH4)

1 10 100 1000 10000 100000-200

-100

0

100

200

Gib

bs fr

ee e

ntha

lpy,

kJ

pressure, bar

Gibbs free enthalpy of methane & n-alkane + hydrogen at transition of genesis.

G(1/10C10

H22

+ 9/10H2)

G(1/6C6H

14 + 5/6H

2)

G(1/4C4H

10 + 3/4H

2)

G(1/2C2H

6 + 1/2H

2)

G(CH4)

25000 30000 35000 4000025

30

35

40

45

50

55

60

65

70

75

Gib

bs fr

ee e

ntha

lpy,

kJ

pressure, bar

IV. Experimentalinvestigations:

The spontaneous high-pressure genesis of hydro-carbons. Reagents:

FeO, CaCO3, H2O.

The reagents were placed into a high-pressure cell, brought to pressures up to 50 kbar, and 2000K. Pressure was maintained while temperature was reduced rapidly to ambient.

The volatile products present in the cell were analysed by gas chromatograph.

Experimental observation of high-pressure genesis of hydro-carbons:

C2H

6

C3H

8

C4H

10

C5H

12

C6H

14

600 800 1000 12000.0

2.0x103

4.0x103

6.0x103

8.0x103

1.0x104

p = 40 kbar

0.0

2.0x104

4.0x104

6.0x104

8.0x104

1.0x105

1.2x105

Cum

ulat

ive

n-al

kane

abu

ndan

ce

Temperature, C

CH4

IV. Significance of the theoretical & experimentalresults:

The pressures required for the spontaneous genesis of hydrocarbons determines the depth for such.

Average lapse rates of pressure and temperature with depth of the Earth.

pressure

0 100 200 300 400 500 600 7000

50

100

150

200

250pressure,

kbar

depth, km

0

500

1000

1500

2000

2500

3000

Tem

pera

ture

, K

temperature

“Every ten or fifteen years since the late 1800’s, ‘experts’ have predic-ted that oil reserves would last only ten more years. These experts have predicted nine out of the last zero oil-reserve exhaustions.”

C. Maurice and C. Smithson, Doomsday Mythology: 10,000 Years of Economic Crisis, Hoover Institution Press, Stanford, 1984.

“Five generations of imbecility are enough.”( ) Justice Oliver Wendell Holmes Jr.,Buck vs. Bell, (1927), 274 U.S., 200, 47 S. CT. 584. (writing for the majority).

“No more B.S.”J. F. Kenney