Microfacies, sedimentary environment and diagenesis of the Ilam Formation in an Oilfield of the Abadan plain

Document Type : Research Paper



The Ilam Formation with Coniacian- Santonian ages is one of the petroleum reservoir in the Zagros basin and wide area of Khozastan plain, which mainly composed of carbonate rocks. In this study, the Ilam Formation in 3 subsurface sections with total thickness of 274 m was studied in one of the southwest Iranian oilfields. The lithology of this formation in studied wells is limestone with interbedded shale and clayey limestone. Sedimentological studies and facies analysis of 230 thinsections of drilling cutting lead to recognition of 11 microfacies and one shale petrofacies in 3 facies belts. These microfacies were deposited in lagoon, shoal and open marine facies belts. According to recognised microfacies and comparing them with same carbonate deposits in other places, absent of reef structures, sliding and slumping facies, the sedimentary envirnment of this carbonate sequence was recognised as a homocline ramp which consist outer, middle and inner ramps. The main diagenetic features of the Ilam Formation in studied oilfield are bioturbation, micritization, cementation, dissolution and porosity, dolomitization, stylolitization, pyritization and fractures. Main cement types in this formation are equant, drusy, blocky, syntaxial and vein filling cements which formed in marine, meteoric and burial diagenetic environments.


خانجانی، م.، موسوی­حرمی، ر.، رحیم­پور بناب، ح،.  کمالی، م. و چهرازی، ع (1392) محیط رسوبی، دیاژنز و چینه­نگاری سکانسی سازند ایلام در میدان نفتی سیری الوند. علوم زمین، سال بیست و چهارم شماره 95، صفحه 253 تا 262.
سپیانی، ه.، محبوبی، ا.، موسوی­حرمی، ر.، محمودی قرایی، م، ح. و غفرانی، ا) 1389) فرآیندهای دیاژنز و تأثیر آن بر کیفیت مخزنی سازند ایلام، میدان نفتی ماله کوه، شمال باختری اندیمشک. پژوهش و نفت سال بیستم شماره 62.
صفاری، ب (1391) بررسى رخساره­ها و تفسیر محیط رسوبى سازند ایلام در یکى از میادین ناحیه دشت آبادان. ماهنامه اکتشاف و تولید، شماره 90.
عبدالملکی، س (1395) محیط رسوبی، ریزرخساره و ژئوشیمی رسوبی سازند ایلام در چاه­هایC، B، A یکی از میادین جنوب غرب ایران. پایان­نامه کارشناسی­ارشد، دانشگاه خوارزمی، 300 صفحه.
غبیشاوی، ع (1387) چینه­شناسی سازند سروک و ایلام در تاقدیس بنگستان و میدان پارسی. رساله دکتری، دانشکده علوم، دانشگاه اصفهان، 204 صفحه.
 قلاوند، ه (1386) لیتواستراتیگرافی و بیواستراتیگرافی سازند ایلام و سروک در بخش شمال شرقی فروافتادگی دزفول و مقایسه آن­ها با مقاطع زیرسطحی مجاور. رساله دکتری، دانشکده علوم زمین، دانشگاه شهید بهشتی، 484 صفحه.
مرادپور، م. و آدابی، م) ١٣٨4( پتروگرافی و ژئوشیمی دولومیت­ها در نهشته­های کرتاسه زیرین شرق اصفهان. مجله علوم دانشگاه تهران، جلد 33، شماره 1.
مطیعی، ه) 1372( زمین­شناسی ایران، چینه­شناسی زاگرس. انتشارات سازمان زمین­شناسی کشور، 536 صفحه.
Abdollahie Fard, I., Braathen, A., Mokhtari, M., & Alavi, A) 2006( Interaction of the Zagros Fold-Thrust Belt and the Arabiantype, deep-seated folds in the Abadan Plain and the Dezful Embayment, SW Iran. Petroleum Geoscience, v. 12, p. 347-362.
Adabi, M.H. & Asadi Mehmandosti, E) 2008( Microfacies and geochemistry of the Ilam Formation in the Tang-E Rashid area, Izeh, S.W. Iran. Journal of Asian Earth Sciences. v. 33, p. 267-277.
Adabi, M.H) 2009( Multistage dolomitization of Upper Jurassic Mozduran Formation, Kopet-Dagh, N.E. Iran. Carbonates and Evaporites, v. 24, p. 16-32.
Ahmad, A.H.M., Bhat, G.M., & Haris AzimKhan, M (2006) Depositional environments and diagenesis of the kuldhar and keera dome carbonates (Late Bathonian-Early Callovian) of Western India. Journale of Asian Earth Sciences., v. 27, p. 765-778.
Ahr, W.M (2008) Geology of carbonate reservoirs. Wiley publication, p. 277.
Al-Sharhan, A.S., & Whittle, G.L (1995) Carbonate – Evaporite Sequences of the Late Jurassic, Southern and Southwestern Arabian Gulf. AAPG Bull, v.79, No.11, p.1608-1630.
Aurell, M., Ba´denas, B., Bosence, D.W.J., & Waltham, D.A (1998) Carbonate production and offshore transport on a Late Jurassic carbonate ramp (Kimmeridgian, Iberian basin,NE Spain): evidence from outcrops and computer model-ling. In:Carbonate Ramps (ed.), V.P. Wright and T.P. Bur-chette). Geological Society Special Publication, v. 149, p. 137-161.
Berberian, M (1995) Master Blind Thrust faults hidden under the Zagros folds. Active basement tectonics and surface morphotectonics. Tectonophysics, v. 241, p. 193-224.
Brandano, M., Frezza, V., Tomassetti, L., & Pedley, M (2008) Facies analysis and paleoenvironmental interpretation of the Late Oligocene Attard Member (Lower Coralline Limstone Formation),  Maltese Sedimentology, v. 56, p. 1138-1158.
Choquette P.W., & Pray, L.C (1970) Geologic nomenclature and classification of porosity in sedimentary carbonate. AAPG Bulletin, v. 54, No. 2, p. 207-250.
Dias-Brito, D (2000) Global Stratigraphy, paleobiogeography and paleoecology of Albian – Maastrichtian pithonellid calcispheres, impact on Tethys configuration. Cretaceous Research, v. 21, p. 315-349.
Dunhum, R.J (1962) Classification of carbonate rocks according to depositional texture. In: Ham, W.E. (ed.), Classification of carb.
Flugel, E (2010) Microfacies of Carbonate Rocks, analysis, interpretation and application. Springer, Berlin Heidelberg, New York, p. 984.
Garcia-Pichel, F (2006) Plausible mechanisms for the boring on carbonates by microbial prototrophs. Sedimentary Geology, v. 105, p. 29-50.
Geel, T (2000) Recognition of stratigraphic sequences in carbonate platform and slope deposits, empirical models based on microfacies analysis of Palaeogene deposits in southeastern Spain. Palaeogeography, Palaeoclimatology, Palaeoecology, v. 155, p. 211-238.
Ghabeishavi, A., Vaziri-Moghadam, H., Taheri, A., & Taati, F (2010) Microfacies and depositional environment of the Cenomanian of the Bangestan anticline, SW Iran. Journal of Asian Earth Sciences, v. 37, p. 275-285.
Goldhaber, M.B (2004) Sulfur-rich sediments, In: Mackenzie F.T. (ed.), Sediments, Diagenesis and Sedimentary Rocks.Treatise on Geochemistry, Elsevier, Amsterdam, p. 257-288.
Greeg J.M., & Shelton K. L (1990) Dolomitization and dolomite neomorphism in the back reef facies of the Bonnetrre and Davis formation (Cambrian), southern Missouri. Journal of Sedimentary Petrology, v. 60, p. 549-562.
Zhang, H., Ding, L., Wang, X., Wang, L., Wang, Q., & Xia, G (2006) Carbonate Diagenesis Controlled by Glacioeustatic Sea-Level Changes, A Case Study from the Carboniferous-Permian Boundary Section at Xikou, China. Journal of China University of Geosciences, v. 17, No. 2, p. 103-114.
Hardwood, G. M (1988) Principles of sedimentary petrography. In: Tucker, M.E. (ed.), Technique in Sedimentology, Blackwell Oxford, p. 108 -174.
Hood, S.D., Nelson, C.S., & Kamp, P.J.J (2004) Burial dolomitisation in a non tropical carbonate petroleum reservoir, the Oligocene Tikorangi Formation, Taranaki Basin, New Zealand. Sedimentary Geology, v. 172, p. 117-138.
Huber, H (1977) Geological map of Iran with explanatory note. Tehran, National Iranian Oil Company, Tectonic map of Iran, 1: 2500, 000: NIOC, Exploration and Production Affairs.
Jahani, S., Callot, J. P., Letouzey, J., & Frizon de Lamotte, D (2009) The eastern termination of the Zagros Fold-and-Thrust Belt, Iran. Structures, evolution, and relationships between salt plugs, folding, and faulting. Tectonics  v. 28, TC6004.
James, G.A., & Wynd, J.G (1965) Stratigraphic nomenclature of Iranian oil consortium agreement area. American Association of Petroleum Geologists Bulletin, v. 49, p. 2182-2245.
Kastner, S., DeSimone, K., Konen, C.S., Szczepanski, S. M., Weiner, K. S., & Schneider, K. A (2007) Topographic maps in human frontal cortex revealed in memory-guided saccade and spatial working-memory tasks. Journal of Neurophysiol, v. 97, p. 3494-3507.
Longman, M.W (1980) Carbonate diagenetic textures from nearsurface diagenetic environments. American Association of Petroleum Geology Bulletin, v. 64, p. 461-487.
Mansurbeg, H., El-ghali, M.A.K., Morad, S., & Plink-Björklund, P (2007) The impact of meteoric water on the diagenetic alterations in deep-water, marine siliciclastic turbidites. Journal of Geochemical Exploration, v. 89, p. 254-258.
Mazzulo S. J (1992) Geochemical and neomorphic alteration of dolomite, a review. Carb. Evap.v.7, p. 21-37. Mchargue T.R., PRICE R.C. 1982: Dolomite from clay in argillaceous or shale associated marine carbonates. Journal of Sedimentary Petrology, v. 48, p. 799-814.
Mehrabi, H., Rahimpour­-­Bonab, H., Enayati­-­Bidgoli, A.H., & Navidtalab, A (2013) Depositional environment and sequence stratigraphy of the Upper Cretaceous Ilam Formation in central and southern parts of the Dezful Embayment, SW Iran. Carbonates Evaporites. v. 29, p. 263-278
Morad, S., Ketzer, J.M., & Ros, L.F (2000) Spatial and Temporal Distribution of Diagenetic Alterations in Siliciclastic Rocks: Implications for Mass Transfer in Sedimentary Basins. Sedimentology, v. 47, p. 95-120.
Murris, R.J (1980) Middle East: stratigraphic evolution and oil habitat. American Association of Petroleum Geologists Bulletin, v. 64, p. 597-618.
Qing H., & Mounjoy E.W (1989) Multistage Dolomitization in Rainbow buildups, Middle Devonian, Keg River Formation, Alberta, Canada. Journal of Sedimentary, v. 59, p. 114 -126.
Rahimpour-Bonab, H., Esrafili-Dizaji, B., & Tavakoli, V (2010) Dolomitization and anhydrite precipitation in Permo-Triassic carbonates at the South Pars gasfield, offshore Iran, Controls on reservoir quality. Jounal of Petroleum Geology, v. 33, No. 1, p. 43-66.
Sanders, D (2001) Burrow-mediated carbonate dissolution in rudist biostromes (Aurisina, Italy), implications for taphonomy in tropical, shallow subtidal arbonate environments. Palaeogeography, Palaeoclimatology, Palaeoecology, v. 168, p. 39-74.
Scholle, P.A., & Ulmer-Scholle., D.S (2003) A Color Guide to the Petrography of Carbonate Rocks: Grains, textures, porosity, diagenesis: Tulsa, OK, American Association of Petroleum Geologists Memoir v. 77, p. 474.
Sibley, D.F., & Greeg, J.M (1987) Classification of dolomite rock texture. Journal of Sedimentary Petrology, v. 57, p. 967-975. Spry A. 1969: Metamorphic textures. Oxford, Pergamon Press, p. 350.
Stoneley, R (1990) The Arabian continental margin in Iran during the late Cretaceous. in: A.H.F. Roberston, M.P. Searl, and A. Ries (ed.), The geology and tectonics of the Oman region. Geological Society London Special Publication, v. 49, p. 787-795.
Strasser, A., Hillgartner, H., Hag, W., & Pittet, B (2001) Third- order depositional sequences reflecting Milankovitch cyclicity. Terra Nova, v. 12, p. 303-311.
Tavakoli, V., Rahimpour-Bonab, H., & Esrafili-Dizaji, B (2011) Diagenetic controlled reservoir quality of South Pars gas field, an integrated approach. Comptes Rendus Geoscience, v. 343, p. 55-71.
Tucker, M.E (1991) Carbonate diagenesis and sequence stratigraphy. In: Wright VP (ed.), Sedimentology Review, Blackwells, Oxford, p. 51-72.
Tucker, M.E., & Wright, V. P (1990) Carbonate sedimentology. Blackwell Scientific, Oxford, p. 482.
Villan, J.M (1975) Les Calcisphaerulidae: (incertae sedis) du Cretaceous superieur du Limbourg (Pays-Bas), et dautre regions. Palaeontographica, v. 149, p. 193-242.
Wantland, K. F (1975) Distribution of Holocene benthic foraminifera on the Belize Shelf. In Wantland, K.F. and Pursey iii, W.C. (ed.), Belize Shelf, carbonate sediments, clastic sediments, and ecology. American Association of Petroleum Geologists Studies in Geology, No. 2, p. 233-399.
Wilson, J. L (1975) Carbonate facies in geologic history. Springer-Verlag, New York, p. 471.
Wynd, J.G (1965) Biofacies of the Iranian consortium-agreement area. Iranian Offshore Oil Company, Tehran, Report No. 1082.