Konferenz Klima im System Erde Berlin 2. - 3. November 2009

Organic Petrography Determination of organofacies and thermal maturity

Hans-Martin Schulz

3.2 Organic Geochemistry

Microscope LEICA DM 4 P-Mikroskop,

equipped with the programmes Hilgers FOSSIL and FOSSIL MOT

Konferenz Klima im System Erde Berlin 2. - 3. November 2009

Macerals are organic particles in sediments.

They are composed of three classes:

Huminite/Vitrinite: woody tissue

Inertinte: aromatized particles

Liptinite: pollen, spores, cuticules, algae

Their analysis enables:

Facies analysis

Background

Liptinite (Cuticule)

Inertinite

(Fusinite)

Vitrinite

Vitrinite

Inertinite

(Semifusinite)

(Reflected white light)

Source: coalandcarbonatlas.siu.edu

Konferenz Klima im System Erde Berlin 2. - 3. November 2009

Liptinite appears black under reflected white light.

It can be made visible by UV light illumination.

At the end of the oil window liptinite becomes vitrinite.

Why to use reflected white light and UV light?

Alginite

(UV light illumination) (Reflected white light)

Konferenz Klima im System Erde Berlin 2. - 3. November 2009

The physicochemical properties of

vitrinite and liptinite change during

burial:

Huminite/Vitrinite get aromatized and thus

can better reflect the light. This is used as

a maturity parameter, and is measured as

„vitrinite reflectance (%), calibrated against

known reflectance standards.

Vitrinite reflectance data enable to

reconstruct:

Thermal history of a sediment

Maturation of organic matter

Source: coalandcarbonatlas.siu.edu

Konferenz Klima im System Erde Berlin 2. - 3. November 2009

Macroalga species

Chara in Tibetian lakes

Aichner, B., Herzschuh, U., Wilkes, H., Schulz, H.-M., Wang, Y., Plessen, B., Mischke, S., Diekmann, B.,

and Zhang, C. (2012): Ecological development of Lake Donggi Cona, north-eastern Tibetan Plateau, since

the late glacial on basis of organic geochemical proxies and non-pollen palynomorphs. - Palaeogeography

Palaeoclimatology Palaeoecology, 313-314, p. 140-149.

Case study: Palaeoclimate

Fluorescing algae (UV light illumination)

Fluorescing algae (UV light illumination)

Konferenz Klima im System Erde Berlin 2. - 3. November 2009

100 µm

Graptolites in Ordovician Dictyoname Shale: Reconstruction of palaeo upwelling zones

Case study: Palaeofacies

(UV light illumination) (Reflected white light)

Graptolite Graptolite

Konferenz Klima im System Erde Berlin 2. - 3. November 2009

Hartwig, A., Schulz, H.-M. (2010): Applying classical shale gas evaluation concepts to Germany—Part I: The

basin and slope deposits of the Stassfurt Carbonate (Ca2, Zechstein, Upper Permian) in Brandenburg. - Chemie

der Erde - Geochemistry, 70, Suppl. 3, p. 77-91.

Thermal maturity and organofacies

of Ca2 black shales in the Brandenburg

Case study: Oil and gas potential

Onset of oil generation at 2300 m

Gas generation below 3500 m

Well Schadewalde 2/75 was

tectonically uplifted by 1500 m

Semifusinite

Botryococcus-shaped alginite

Basin and lower slope facies

Lower slope facies

Konferenz Klima im System Erde Berlin 2. - 3. November 2009

20 µm

Schulz et al. (2015): From shale oil to biogenic shale gas: Retracing organic–inorganic interactions in the

Alum Shale (Furongian–Lower Ordovician) in southern Sweden. - AAPG Bulletin, 99, 5, p. 927-956.

Biogenic shale gas in the Alum Shale (c/o)

Fluorescing microbal mats (UV light illumination)

Case study: Unconventionals