Petroleum Generation

Istvan CsatoUniversity of South CarolinaDepartment of Geological Sciences

Petroleum Geology Class 745Spring 2002

I. Organic MatterI. Organic Matter

II. Petroleum GenerationII. Petroleum Generation

III. Source Rock EvaluationIII. Source Rock Evaluation

IV. Thermal Maturation ModelsIV. Thermal Maturation Models

Sequence Stratigraphy

Controls on total organic matter

• Productivity• Grain size• Sedimentation rate• Oxidation/Reduction

Preservation of Organic Matter

Demaison and Moore, 1980

Conversion of Organic Matter

Barker, 1996

• biopolymers• bitumen• biomarkers

I. Organic MatterI. Organic Matter

II. Petroleum GenerationII. Petroleum Generation

III. Source Rock EvaluationIII. Source Rock Evaluation

IV. Thermal Maturation ModelsIV. Thermal Maturation Models

Conversion of Kerogen

Barker, 1996

Organic matter: 1%

• Kerogen 90%• Bitumen 10%

Kerogen Evolution Paths

Tissot et al., 1974

Variation of the HC/TOC, Los Angeles and Ventura Basins

Philippi, 1965

Depths and Temperatures for Onset of Oil Generation

Tissot et al., 1975

General Scheme for Hydrocarbon Formation

Tissot et al., 1974

I. Organic MatterI. Organic Matter

II. Petroleum GenerationII. Petroleum Generation

III. Source Rock EvaluationIII. Source Rock Evaluation

IV. Thermal Maturation ModelsIV. Thermal Maturation Models

1. Does the the rock have sufficient organic matter?2. Is the organic matter capable of generating?3. Has this organic matter generated petroleum?4. Has the generated petroleum migrated out?5. Is the rock oil-prone or gas-prone?

Questions for exploration geologist:

Quantity of Organic Matter:TOC must be greater than 0.5%

Type of Organic Matter:

Thermal Alteration Index, Paris Basin

Correia, 1971

Maturity

Kerogen Maturation Profile, Louisiana Gulf Coast

Barker, 1996

Vitrinite: woody, Type III kerogen

Maturity

Vitrinite Reflectance Data

Dow and O’Connor, 1982

Maturity

Vitrinite Reflectance Profile, Elmsworth Field, Canada

Welte et al., 1984

Maturity

Disturbing of Vitrinite Reflectance

Barker, 1996

Elemental Data For Kerogen

Peters, 1986

Increase of S1 with Depth

Barker, 1996

Pyrolysis

Tmax

S1

S2

Yield of Hydrocarbons with Increasing Temperature

Barker, 1974

Pyrolysis

Tmax

S2/TOC = HIS3/TOC = OI

S1

S2

S1 S2

Changes in TR and Tmax

Espitalie et al., 1977

HI versus OI

Peters, 1986

Evaluation of Geochemical Parameters

Peters, 1986

I. Organic MatterI. Organic Matter

II. Petroleum GenerationII. Petroleum Generation

III. Source Rock EvaluationIII. Source Rock Evaluation

IV. Thermal Maturation ModelsIV. Thermal Maturation Models

KER = BIT + RESIDUE

At t=0KER= Vo, BIT=0

At t>0KER=Vo-Vt, BIT=Vt

dV/dt= k(Vo-Vt)

k=A*e[-E/RT]

Kinetics of Chemical Reactions

Arrhenius equation

R =Gas constant (0.008314 KJ/mol0K)T=absolute temperatureE=activation energyA=frequency factor

Activation Energy

Barker, 1996

Bond Energies

March, 1985

Increasing Reaction Rate with Temperature

Barker, 1996

Bitumen Release Curves with Different Activation Energies

Barker, 1996

Bitumen Release Curves with Different Frequency Factors

Barker, 1996

Increase in Reaction Rate

Barker, 1996

Bitumen Release Curves for 8 Parallel Reactions

Juntgen and Klein, 1975

Distribution of Activation Energies, Paris Basin

Tissot et al., 1987

Temperature Factors used by Lopatin

Barker, 1996

maturity = (ti)(rni) TTI (Time-Temperature Index)

Burial History Plot

Barker, 1996

Calculated TTI

Barker, 1996

Calibration of TTI

Waples, 1980

Time-Temperature Reconstruction, Big Horn Basin, Montana

Hagen and Surdam, 1984

Kinetic Model of Tissot and Espitalie, 1975

Tissot and Espitalie, 1975

Kinetic Model of Sweeney et al., 1987

Sweeney et al., 1987