Document Type : Original Research Paper

Authors

1 Department of Geology, Faculty of Science, Bu-Ali Sina University, Hamedan, Iran.

2 Exploration and Production Office, National Iranian Oil Company, Tehran, Iran.

Abstract

Carbonate – evaporates intervals of Dashtak formation is an important cap rocks in Zagros basin. Sequence stratigraphic analysis of Dashtak Formation in two wells (Aghar#1; West Aghar#1) was investigated in sequence stratigraphic framework. Data obtained from petrographic examinations of thin sections prepared from cuttings, in addition, a full suite of gamma ray and sonic logs were interpreted. Dashtak Formation comprises eight facies belts that are: (i) detrital clastics, (ii) supratidal, (iii) tidal flat, (iv) lagoon, (v) shoal, (vi) restricted marine, (vii) open marine, (viii) mid ramp. Dashtak Formation consists of four sequences with four transgressive, regressive and maximum flooding surfaces. Two sequence boundaries type I and three sequence boundaries type II were recognized in the Dashtak Formation. As far the depositional environment of the formation is interpreted as a homocline ramp with mild lateral changes in depositional environment, hence negligible lateral changes of stratigraphic sequences are expected in the study area.

Keywords

References
Alavi, M., 1994- Tectonics of the Zagros orogenic belt of Iran: new data and interpretations: Tectonophysics, v. 229, p. 211–238.
Alavi, M., 2004- Regional Stratigraphy of the Zagros Fold-Thrust Belt of Iran and Its Proforeland Evolution. American Journal of Science, v. 304, p. 1–20.
Berberian, M., 1995- Master “blind” thrust faults hidden under the Zagros folds, active basement tectonics and surface morphotectonics: Tectonophysics, v. 241, p. 193-224.
Burchette, T. P. & Wright, V. P., 1992- Carbonate ramp depositional systems. Sedimentary Geology, N0. 79, p. 3-57.
Dunham, R. J., 1962- Classification of carbonate rocks according to depositional texture. AAPG Bull, Memoir# 1, p. 108-121.
Embry, A. F. & Klovan, J., E., 1971- A late Devonian reef tract on northeastem Banks Island, NorthweastTerritories. Bull, Can. Petrol. Geol, v. 19, p. 730-781.
Emery, M. & Myers, K., 1996- Sequence Stratigraphy, Blackwell Science, 279 pp.
Evans, G., Schmidt, V., Bush, P. & Nelson, H., 1969- Stratigraphy and geologic history of the sabkha, Abu Dhabi, Persian Gulf, Sedimentology, v.12, p. 145-149. 
Falcon, N. L., 1961- Major earth-flexuring in the Zagros Mountain of southwest Iran, Geological Society of London, v.117, p. 367–376.
Flügel, E., 2004- Microfacies of Carbonate Rocks. Springer Verlag. 915 pp.
Haq, B. U. & Al-Qahtani, A. M., 2005- Cambrian-Triassic Arabian Platform Cycle Chart Phanerozoic Cycles of Sea-Level Change on the Arabian Platform, Geo Arabia, v. 10, No. 2.
Haq, B. U., Hardenbol, J. & Vail, P. R., 1988- Mesozoic and Cenozoic chronostratigraphy and eustatic cycles, SEPM, Special Publication 42, p. 71-108.
Hurford, A. J., Grunau, H. R. & Stocklin, J., 1984- Fission track dating of an apatite crystal from Hormoz Island, Iran: Journal of Petroleum Geology, v. 7, p. 365-380.
James, G. A. & Wynd, J. G., 1965- Stratigraphical nomenclature of Iranian Oil Consortium Agreement Area: AAPG BULL, v. 49, p. 2182–2245.
Kashfi, M. S., 1992- Geology of the Permian “Super-Giant” gas reservoirs in the Greater Persian Gulf area Journal of Petroleum Geology, v. 15, p. 465-480.
Kashfi, M. S., 2000- Greater Persian Gulf Permian-Triassic stratigraphic nomenclature requires study, Oil and Gas Journal. Tulsa 6, p. 36-44.
Khoshnoodkia, M., Mohseni, H., Hajian, M. & Rafiyee, B., 2008a- Depositional environment and Microfacies of carbonate-evaporite of Dashtak Formation at Aghar#1 on Subcostal Fars in Iran. GEO 2008, 8th Middle East Geosciences Conference and Exhibition of Petroleum Middle East, 2-5 March, Manamah. Bahrain.
Khoshnoodkia, M., Mohseni, H., Hajian, M. & Rafiyee, B., 2008b- Identification maximum flooding surface of Dashtak Formation and accordance with sea level change and eustasy in Aghar#1, West Aghar#1 and Naura#1 Subcostal Fars in Iran, Conference / Meeting European Geosciences Union General Assembly, 12- 14 April, Vienna , Austria.
Koop, W. & Stoneley, R., 1982- Subsidence history of the Middle East Zagros basin, Permian to Recent: Philosophical Transactions of Royal Society of London, A 305, p. 149–168.
Koop, W. J., 1977- Time-stratigraphic table, OSCO Unpub. Report No. 32602.
Koopman, A., Mercadier, M., Mohammadi, M., Richard, P., Beintema, K. & Rawnsely, K., 2005- Fractured Carbonates reservoir of the Zagros Fold Belt, Shell Carbonate Workshop-Shiraz Southwest Iran, 190 pp.
Lopatin, N. V., 1971- Temperature and geologic time as factors in coalification, Akademiya Nauk SSSr Izvestiga, Seriya geologicheskeya, No.3, p.95-106.
Loutit, T. S., Hardenbol, J., Vail, P. R. & Baum, G., 1988- Condensed Sections: The Key to age determination and correlation of Continental Margin Sequences, Sea-Level Changes—an Integrated Approach, SEPM, Special Publication 42, p. 183-213.
Mina, P., Razaghnia, M. T. & Paran, Y., 1967- Geological and geophysical studies and exploratory drilling of the Iranian continental shelf–Persian Gulf: Mexico, Seventh World Petroleum Congress Proceedings, v. 2, p. 771–903.
Mohseni, H., Khoshnoodkia, M., Hajian, M. & Rafiyee, B., 2008a- Depositional environment and Microfacies of carbonate-evaporite of Dashtak Formation in Aghar#1, West Aghar#1 and Naura#1 on Subcostal Fars in Iran, 33 IGC, Oslo Norway.
Mohseni, H., Khoshnoodkia, M., Hajian, M. & Rafiyee, B., 2008b- Sequence Stratigraphy of Dashtak Formation in Aghar#1, West Aghar#1 and Naura#1 on Subcostal Fars in Iran, 33 IGC, Oslo Norway.
Murris, R. J., 1980- The Middle East: stratigraphic evolution and oil habitat: AAPG Bull, v. 64, p. 597–618.
Purser, B. H. & Evans, G., 1973- The Persian Gulf: Regional sedimentation along the TrucialCoast, SE Persian Gulf, In: The Persian Gulf (Ed. By B. H. Purser), Springer-Verlag, p. 211-232.
Sadooni, F. N. & Alsharhan, A. S, 2004- Stratigraphy, lithofacies distribution and petroleum potential of the Triassic strata of the northern Arabian plate. AAPG Bull, v. 88, No. 4, p. 515-538.
Sarg, J. F., 2001- The Sequence Stratigraphy, Sedimentology and economic importance of evaporite- carbonate transitions: a Review, Sedimentary Geology, V.140, p. 9-42
Sharland, P. R., Archer, R., Casey, D. M., Davies, R. B., Hall, S. H., Heward, A. P., Horbury, A. D. & Simmons, M. D., 2001- Arabian Plate Sequence Stratigraphy. Gulf petrolink, Bahrain, Special Publication 2, 371 pp.
Sharland, P. R., Casey, D. M., Davies, R. B., Simmons, M. D., Satcliffe, O. E., 2004- Arabian Plate Sequence Stratigraphy. Geo Arabia, V.9, p. 199-214.
Sloss, L. L., 1963- Sequence in cratonic interior of North America, G.S.A. Bull. v. 74, p. 93-114.
Szabo, F. & Kheradpir, A., 1978- Permian and Triassic stratigraphy, Zagros basin, southwest Iran: Journal of Petroleum Geology, v. 1, p. 57–82.
Szabo, F., 1977- Permian-Triassic stratigraphy Zagros basin, south west Iran. NIOC unpub. Rep. No. 1261.
Tucker, M. E., 1993- Carbonate Diagenesis and sequence stratigraphy, In: V. P. Wright (Ed) Sedimentology Review, Blackwell, p. 5 1-72.
Van Wagoner, J. C., Posamentier, H. W., Mitchum, R. M., Vail, P. R., Sarg, J. F., Loutit, T. S & Hardenbol, J., 1988- An overview of the fundamentals of sequence stratigraphy and key definitions, Sea level changes: an integrated approach. Tulsa, Oklahoma, SEPM, Special Publication 42, p. 37-45.
Warren, J., 1989- Evaporite Sedimentology: Importance in Hydrocarbon Accumulation. Prentice-Hall, 285 pp.
Ziegler, M., 2001- Late Permian to Holocene Paleofacies Evolution of the Arabian Plate and its Hydrocarbon Occurrences, Geo Arabia, v.6, No,3. p. 445-504.