Document Type : Original Research Paper


1 Ph.D., Department of Earth Sciences, Tehran Energy Consultants (TEC), Tehran, Iran

2 MSc., Department of Earth Sciences, Kish Petroleum Engineering (KPE) , Tehran, Iran

3 Assistant Professor, Department of Geology, University of Damghan, Damghan, Iran

4 MSc., Department of Earth Sciences, Tehran Energy Consultants (TEC), Tehran, Iran


The Lower Cretaceous Fahliyan Formation is one of the main oil reservoirs in the Persian Gulf. In this study, for investigating facies characteristics, depositional environment, diagenetic features, sequence stratigraphy and describing factors controlling reservoir quality, the integration of the results from core description, petrographic studies, and petrophysical data was utilized. Nine main facies were recognized and grouped in four facies belts of lagoon, shoal, patch reef and shallow open marine, indicating deposition of the formation in a carbonate ramp platform. Various diagenetic processes that influenced facies, occurred in marine, meteoric, and burial diagenetic realms. Four main pore types have been identified in the reservoir that include interparticle, moldic, vuggy, and microporosity. From the sequence stratigraphy point of view, three third-order sequences which are correlatable within the Fahliyan Formation were identified. The development of grainstone and algal rudstone/floatstone in shoal/ patch reef sub-environment played an important role in developing the high reservoir. In view of their controls on reservoir quality and pore system, diagenetic features can be categorized into two classes: (1) diagenetic processes enhancing reservoir quality that include dissolution and fracturing, and (2) diagenetic processes reducing reservoir quality that include cementation and compaction.


Main Subjects

Adabi, M. H., Salehi, M. A., and Ghabeishavi, A,. 2010- Depositional environment, sequence stratigraphy and geochemistry of Lower Cretaceous carbonates (Fahliyan Formation), south-west Iran. Journal of Asian Earth Sciences, 39(3), 148-160.
Ahr, W., 2008- Geology of carbonate reservoirs: the identification, description and characterization of hydrocarbon reservoirs in carbonate rocks. Wiley, New York, 296 p. DOI:10.1002/9780470370650.
Alavi, M. 2004- Regional stratigraphy of the Zagros fold-thrust belt of Iran and its proforeland evolution. American journal of Science, 304(1), 1-20. DOI:
Al-Husseini, M. I. 2007- Iran’s crude oil reserves and production. GeoArabia, 12(2), 69-94.
Assadi, A., Rahimpour-Bonab, H., and Kadkhodaie-Ilkhchi, R., 2018- Integrated rock typing of the grainstone facies in a sequence framework: a case from the Jurassic Arab formation in the Persian Gulf. Acta Geologica Sinica‐English Edition, 92(4), 1432-1450.
Borgomano, J., Lanteaume, C., Leonide, P., Fournier, F., Montaggioni, L. F., and Masse, J. P., 2020- Quantitative carbonate sequence stratigraphy: Insights from stratigraphic forward models. AAPG Bulletin, 104(5), 1115-1142.
Burchette, T. P., and Wright, V. P., 1992- Carbonate ramp depositional systems. Sedimentary geology, 79(1-4), 3-57.
Chehrazi, A., Rahimpour-Bonab, H., and Rezaee, M. R., 2013- Seismic data conditioning and neural network-based attribute selection for enhanced fault detection. Petroleum Geoscience, 19(2), 169-183.
Chehrazi, A., Rezaee, R., and Rahimpour, H., 2011- Pore-facies as a tool for incorporation of small-scale dynamic information in integrated reservoir studies. Journal of Geophysics and Engineering, 8(2), 202-224.
Dickson, J. A. D., 1965- A modified staining technique for carbonates in thin section. Nature, 205, 587-587.
Dunham, R.J., 1962- Classification of carbonate rocks according to depositional texture. In: Ham, W.E. (Ed.), Classification of Carbonate Rocks, vol. 1. AAPG Mem, pp. 108–121.https:// archives. /data/specpubs/carbona2/data/a038/a038/0001/0100/0108.htm
Ehrenberg, S. N., Nadeau, P. H., and Aqrawi, A. A. M., 2007- A comparison of Khuff and Arab reservoir potential throughout the Middle East. AAPG bulletin, 91(3), 275-286.
Esrafili-Dizaji, B., Hajikazemi, E., Dalvand, M., Nemati, M. H., and Swennen, R., 2020- Diagenesis and reservoir characteristics of the Lithocodium–Bacinella facies in a Lower Cretaceous reservoir, eastern Persian Gulf Basin. Facies, 66(4), 1-24.
Falahat, R., and Farrokhnia, F., 2020- Rock physics modelling of the carbonate reservoirs: A log-based algorithm to determine the pore aspect ratio. Journal of Applied Geophysics, 173, 103930.
Flügel, F., 2010- Microfacies of carbonate rocks, analysis interpretation and application (2nd edition). Springer, New York, 976 p.
Hosseini, S., Conrad, M. A., and Kindler, P., 2021- Sequence stratigraphy, depositional setting and evolution of the Fahliyan carbonate platform (Zagros fold-thrust belt, SW Iran) in the Early Cretaceous. Marine and Petroleum Geology, 128, 105062.
Hosseini, S., Conrad, M. A., Clavel, B., and Carras, N., 2016- Berriasian-Aptian shallow water carbonates in the Zagros fold-thrust belt, SW Iran: Integrated Sr-isotope dating and biostratigraphy. Cretaceous Research, 57, 257-288.
Jamalian, M., Adabi, M. H., Moussavi, M. R., Sadeghi, A., Baghbani, D., and Ariyafar, B., 2011- Facies characteristic and paleoenvironmental reconstruction of the Fahliyan Formation, Lower Cretaceous, in the Kuh-e Siah area, Zagros Basin, southern Iran. Facies, 57(1), 101-122.
Jamalian, M., and Adabi, M. H., 2015- Geochemistry, microfacies and diagenetic evidences for original aragonite mineralogy and open diagenetic system of Lower Cretaceous carbonates Fahliyan Formation (Kuh-e Siah area, Zagros Basin, South Iran). Carbonates and Evaporites, 30(1), 77-98.
James, G. A., and Wynd, J. G., 1965- Stratigraphic nomenclature of Iranian oil consortium agreement area. AAPG bulletin, 49(12), 2182-2245.
Lucia, F.J., 2007- Carbonate reservoir characterization: an integrated approach. Springer, Berlin, New York. 341 p.
Moore, C.H., and Wade, W.J., 2013- Carbonate reservoirs: porosity, evolution & diagenesis in a sequence stratigraphic framework: Porosity Evolution and Diagenesis in a Sequence Stratigraphic Framework, Elsevier 67, 369 p. carbonate -reservoirs-porosity-evolution-and-diagenesis-in-a-sequence-stratigraphic-framework/moore/978-0-444-50838-6.
Morad, S., Al-Aasm, I.S., Nader, F.H., Ceriani, A., Gasparrini, M., and Mansurbeg, H., 2012- Impact of diagenesis on the spatial and temporal distribution of reservoir quality in the Jurassic Arab D and C members, offshore Abu Dhabi oilfield, United Arab Emirates. Geo-Arabia 17:17-56.
Noori, H., Mehrabi, H., Rahimpour-Bonab, H., and Faghih, A., 2019- Tectono-sedimentary controls on Lower Cretaceous carbonate platforms of the central Zagros, Iran: An example of rift-basin carbonate systems. Marine and Petroleum Geology, 110, 91-111.
Pirouz, M., Avouac, J. P., Hassanzadeh, J., Kirschvink, J. L., and Bahroudi, A., 2017- Early Neogene foreland of the Zagros, implications for the initial closure of the Neo-Tethys and kinematics of crustal shortening. Earth and Planetary Science Letters, 477, 168-182.
Sadooni, F. N., 1993- Stratigraphie Sequence, Microfacies, and Petroleum Prospects of the Yamama Formation, Lower Cretaceous, Southern Iraq. AAPG bulletin, 77(11), 1971-1988.
Salifou, I. A. M., Zhang, H., Boukari, I. O., Harouna, M., and Cai, Z., 2021- New vuggy porosity models-based interpretation methodology for reliable pore system characterization, ordovician carbonate reservoirs in Tahe Oilfield, North Tarim Basin. Journal of Petroleum Science and Engineering, 196, 1077-1100.
Sepehr, M., and Cosgrove, J. W., 2004- Structural framework of the Zagros fold–thrust belt, Iran. Marine and Petroleum geology, 21(7), 829-843.
Setudehnia, A., 1978- The mesozoic sequence in south-west Iran and adjacent areas. Journal of Petroleum Geology, 1(1), 3-42.
Sharland, P.R., Archer, R., Casey, D.M., Davies, R.B., Hall, S.H., Heward, A.P., Horbury,
A.D., and Simmon, M.D., 2001- Arabian Plate Sequence Stratigraphy. GeoArabia Special
Publication 2, 371 p.
Skalinski, M., and Kenter, J. A., 2015- Carbonate petrophysical rock typing: integrating geological attributes and petrophysical properties while linking with dynamic behaviour. Geological Society, London, Special Publications, 406(1), 229-259.
Vail, P., 1991- The stratigraphic signatures of tectonics, eustasy andsedimentology: an overview. Springer, Berlin, pp 617–659.
van Buchem, F.S.P., Gaumet, F., Vedrenne, V., and Vincent, B., 2006- Middle East Cretaceous Sequence Stratigraphy Study, SW Iran. National Iranian Oil Company (NIOC) internal report, 167p.
Van Wagoner, J., Mitchum, R., Campion, K., Rahmanian, V., 1990- Siliciclastic sequence stratigraphy in well logs, cores, and outcrops: concepts for high-resolution correlation of time and facies. American Association of Petroleum Geologists Special series 7.
Wilson, J.L., 1975- Carbonate Facies in Geologic History. Springer-Verlag, New York, p. 471.