Paleozoic-Mesozoic Stratigraphy of Oman

-181 Middle East Geology -Geol 501-142

Paleozoic-Mesozoic Subsurface Stratigraphy and Petroleum System of Oman

by

Abdullah [email protected]

KFUPMEarth Science Department

May 10, 2015


Outline• Introduction.• Geological and Tectonic Settings of Oman.• Paleozoic Stratigraphy of Oman.• Paleozoic Petroleum System of Oman.• Mesozoic Stratigraphy of Oman.• Mesozoic Petroleum System of Oman.• Conclusion.


Introduction

(Forbes, et al., 2010)

North

Central

South


Objectives

• To summarize the geologic and tectonic settings of Oman.• To demonstrate the Paleozoic-Mesozoic subsurface stratigraphy and

Petroleum System of Oman.


Summary of the tectonic history of Oman

• Oman was situated in a passive margin after final amalgamation of Gondwana with collision of East and West Gondwana, transpressional in character, which led to the development of extensive salt basins.

• During ‘Hercynian’ event, the collision of Gondwana and Laurasia, uplifts and erosions were happened on the eastern flank of Oman and spread to the north during the Devonian– Carboniferous, resulting in a major stratigraphic unconformity.

• By the Late Carboniferous, Oman was affected by the 3rd glacial phase of AP.

• From mid-Permian to ‘mid’-Cretaceous times, a passive margin was developed with an extensive carbonate deposition.

• The opening of the Atlantic Ocean during the Late Cretaceous led to the closure of the Neo-Tethys Ocean, obduction of Semail Ophiolite, and finally to southward thrust stacking in the Oman Mountains.


Main Structu

ral Elemen

ts

(For

bes,

et a

l., 2

010)


Surface Geolog

ic setting

s

(Forbes, et al., 2010)

-188 Middle East Geology -Geol 501-142(Forbes, et al., 2010)

Cross Section A-A’

Surf

ace

Geo

logi

c se

tting

s

-189 Middle East Geology -Geol 501-142 (Forbes, et al., 2010)

Surf

ace

Geo

logi

c se

tting

s


Cross Section B-B’

Surf

ace

Geo

logi

c se

tting

s


Pale

ozoi

c Su

bsur

face

St

ratig

raph

yDepositional

Environment

-Shallow-marine

-Muddy, Playa

-Continental

-subtidal , fluvial to shallow marine, braided delta

-Trans.-Regres. cycles open-marine

Siliciclastic, glacially-influenced

-Shallow-marine

-Braided

- Marginal marine to fluvial


Mes

ozoi

c Su

bsur

face

St

ratig

raph

yDepositional

Environment

- marginal-marine to tidal-flat

-From lower clastic succession into a shallow-marine.

- from deep to shallow marine. -Clastics in south

-Shallow marine

-Shallow-marine

- estuarine and fluvial


Pale

ozoi

c eq

uiva

lent

fo

rmati

ons

(PGS, 2003)

-1814 Middle East Geology -Geol 501-142(PGS, 2003)

Mes

ozoi

c eq

uiva

lent

fo

rmati

ons


(Al-Barwani & McClay,2008)

Subs

urfa

ce

Chro

nost

ratig

raph

yReservoir


Conclusion• Oman is distinguished by the appearing of Precambrian salt basins, and Late

Cretaceous Semail Ophiolite.

• Stratigraphers divided the whole sedimentary successions of Oman into 16 groups and 48 formations.

• Misfar Group which is the only group having no classified formations due to the lack of information.

• Omani sedimentary successions, from the infracambrian successions to the Cenozoic successions, are important in terms of petroleum system.

• The source rocks recognized in Ara Group, Sahmah formation, Shuaiba and Natih formations.

• The major hydrocarbon-bearing units in the whole Omani successions include: Ara Group, Mahatta Humaid Formation, Gharif and Al Khalata formations; Shu’aiba Formation, and Natih Formation.



References• Al-Barwani, B., & McClay, K. (2008). Salt tectonics in the Thumrait area, in the southern part of

the South Oman Salt Basin: implications for mini-basin evolution. GeoArabia, 13(4), 77-108.• Clarke, M. W. H. (1988). Stratigraphy and rock unit nomenclature in the oil-producing area of

interior oman. Journal of Petroleum Geology, 11(1), 5-60.• Forbes, G. A., Jansen, H. S., & Schreurs, J. (2010). Lexicon of Oman: Subsurface Stratigraphy:

Reference Guide to the Stratigraphy of Oman's Hydrocarbon Basins. Gulf PetroLink.• Nairn, A. E. M., & Alsharhan, A. S. (1997). Sedimentary basins and petroleum geology of the

Middle East. Elsevier.• Sharland, P. R., Archer, R., Casey, D. M., Davies, R. B., Hall, S. H., Heward, A. P., ... & Simmons,

M. D. (2001). Arabian Plate sequence stratigraphy. GeoArabia, Journal of the Middle East Petroleum Geosciences, 18(4).

Education

Paleozoic-Mesozoic Stratigraphy of Oman