بررسی رخساره‌های رسوبی و پارامترهای ژئوشیمیایی سازند آسماری (الیگوسن - میوسن) در میدان نفتی شادگان، فروافتادگی دزفول، جنوب غرب ایران

نوع مقاله : مقاله پژوهشی

نویسندگان

1 شرکت ملی مناطق نفت‌خیز جنوب، اهواز، ایران

2 گروه حوضه‌های رسوبی و نفت، دانشکده علوم زمین، دانشگاه شهید بهشتی، تهران، ایران

چکیده

در این پژوهش، محیط رسوبی و مطالعات ژئوشیمیایی سازند آسماری با ضخامت 9/363 متر در چاه شماره 11 از میدان نفتی شادگان در فروافتادگی دزفول، حوضه زاگرس بررسی شد. سازند آسماری در میدان نفتی شادگان عمدتا از سنگ آهک و دولوستون­های متخلخل در تناوب با ماسه سنگ­ها و شیل­ها تشکیل شده است. در چاه شماره 11، سازند آسماری با سن الیگوسن (شاتین) و میوسن زیرین (آکی­تانین - بوردیگالین) با ناپیوستگی هم شیب رسوبات مارلی و شیلی سازند پابده را می­پوشاند و توسط رسوبات تبخیری سازند گچساران پوشیده می­شود. در این توالی 26 ریزرخساره کربناته - تبخیری شناسایی گردید که در چهار محیط اصلی رمپ داخلی، رمپ میانی، رمپ بیرونی و حوضه نهشته شده­اند. محیط رسوبی سازند آسماری یک رمپ هموکلینال معرفی شده است. مطالعات ژئوشیمیایی و پتروگرافی کربنات­های سازند آسماری نشان می­دهد که آراگونیت، ترکیب کانی­شناسی اولیه این سازند بوده است. دامنه تغییرات ایزوتوپ اکسیژن در سنگ آهک­های آسماری بین ‰PDB 85/0- تا ‰PDB 96/8- (میانگین‰PDB 99/2-) و مقادیر ایزوتوپ کربن بین‰PDB 86/5- تا‰PDB 56/1 (میانگین‰PDB 74/0-) متغیر است. نتایج این مطالعه نشان می­دهد که ترکیب ایزوتوپی سنگ آهک­های سازند آسماری نسبتا اولیه بوده و عمدتا در تعادل ایزتوپی با آب دریای پالئوژن - نئوژن بوده است. اگرچه برخی از نمونه­ها توسط فرآیندهای دیاژنتیکی در طول تدفین در سیستم دیاژنتیکی نیمه بسته تا بسته بعدی تحت­تاثیر قرار گرفته­اند. مقادیر نسبتاً بالای Sr/Mn نیز حاکی از سیستم دیاژنتیکی بسته تا نیمه بسته (Closed to semi-closed diagenetic system) با نسبت پایین تبادل آب به سنگ (Water/rock interaction) برای کربنات‌های سازند آسماری است. سبک­ترین ایزوتوپ اکسیژن (‰96/8-) دمایی معادل 8/68 درجه سانتی گراد را نشان می­دهد که بدیهی است باید دمای محیط دیاژنز تدفینی باشد و سنگین ترین میزان ایزوتوپ اکسیژن (‰85/0-)، حداقل دمای رسوبگذاری معادل 23 درجه سانتی گراد را نشان می­دهد.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Investigation of sedimentary facies and geochemical parameters of the Asmari Formation (Oligocene-Miocene) in the Shadegan Oil Field, Dezful Embayment, SW Iran

نویسندگان [English]

  • Armin Omidpour 1
  • Roghayeh Fallah-Bagtash 2
1 National Iranian South Oil Company, Ahvaz, Iran
2 Department of Petroleum and Sedimentary Basins, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Iran
چکیده [English]

Introduction
Carbonates of the Asmari Formation form the youngest reservoir rock of the Zagros Basin (Ghazban, 2007). Various studies have shown that sedimentary geochemistry can be used to evaluate palaeotemperature and palaeoclimate by reconstructing the chemical and isotopic content of the ancient seawater and/or diagenetic fluids (Winefield et al, 1996; Adabi, 2004; Adabi and Mehmandosti 2008; Crowe et al, 2013; Swart, 2015; Fallah-Bagtash et al, 2020; Omidpour et al, 2021). The present study is based on a combination of different data such as core analysis, thin-section petrography, trace-element and stable-isotope analysis of Asmari carbonates to recognize the original carbonate mineralogy and diagenetic environment. 
Materials and methods
In this study, 524 thin sections prepared from core samples of well-11 were used to achieve the desired goals. All thin sections were stained with potassium ferricyanide and Alizarin Red-S to dolomite and calcite minerals identification (Dickson, 1965). The nomenclature for carbonate rocks used in this work is a combination of the terminology introduced by Dunham (1962) and Embry and Klovan (1971), which is based on textural aspects. Facies analysis and interpretation of the depositional environment was performed using by Burchette and Wright (1992) and Flügel (2010) schemes. Based on the detailed petrographic results, forty-five limestones and thirty-two dolomites from well-11 were carefully selected for trace elemental analysis. Elemental analysis carried out using atomic absorption spectrometry (AAS) in the geochemistry laboratory in the Ferdowsi University of Mashhad for the major and trace element determinations. Forty-five powdered of the limestone samples, that were previously used for the major and trace elements, were analyzed with a VG STRA Series II for oxygen and carbon isotopes at the G.G. Hatch Stable Isotope Laboratory, University of Ottawa.
Results and discussion
The detailed thin-sections analysis of the carbonate samples resulted in the distinction of 26 microfacies types in a subsurface section of the Shadegan Oil Field along that have been deposited along a homoclinal ramp-type platform and is divisible into an inner ramp, mid ramp, outer ramp and basinal settings.
The bulk-rock oxygen and carbon isotopic analyses of the Asmari limestones are compared with similar analyses of the Asmari Formation in the Dezful Embayment (Aqrawi et al, 2006) and of other Palaeogene-Neogene carbonates (Veizer et al, 1999). It can be deduced from Figure 10 that the δ18O and δ13C values correlate well with those found by Aqrawi et al. (2006) for the Asmari Formation, but show slightly lower δ18O and δ13C values than those mentioned by Veizer et al. (1999) for the Palaeogene-Neogene carbonates. The geochemical and isotopic data allow, in combination with the petrographic data obtained from thin-section analysis, recognition of the primary aragonite mineralogy and the evolution of the rock fabric, as well as a reconstruction of the diagenetic evolution, temperature, the nature of the percolating fluids, and the water/rock ratio or diagenetic system.  The input of the δ18O-enriched samples (-0.85‰) within the Anderson and Arthur (1983) formula gives a syn-sedimentary temperature of only 23 °C. Based on textural and geochemical features four types of dolomite (D1 to D4) were identified in the sedimentary succession of the Asmari Formation. D3 (with high values of iron and manganese) is more affected by diagenetic alteration than the D1. Due to oxidizing conditions, iron and manganese values in D1 (near-surface) are lower than the burial dolomites (D3), which formed under a more reducing state at the greater depth of burial (Tucker and Wright 1990; Hou et al, 2016).

کلیدواژه‌ها [English]

  • Shadegan Oil Field
  • Oxygen and carbon isotopes
  • Oligocene-Miocene
  • Asmari Formation
  • Diagenetic system

مراجع

-آدابی، م.ح.، 1390. ژئوشیمی رسوبی، انتشارات آرین زمین، چاپ 2، 503 ص.
 
 
 
-Adabi, M.H. and Mehmandosti, E.A., 2008. Microfacies and geochemistry of the Ilam Formation in the Tang-E Rashid area, Izeh, SW Iran: Journal of Asian Earth Sciences, v. 33(3-4), p. 267-277.
-Adabi, M.H. and Rao, C.P., 1991. Petrographic and geochemical evidence for original aragonitic mineralogy of the Upper Jurassic carbonates (Mozduran Formation), Sarakhs area, Iran: Sedimentary Geology, v. 72, p. 253-267.
-Adabi, M.H., Salehi, M.A. and Ghobeishavi, A., 2010. Depositional environment, sequence stratigraphy and geochemistry of Lower Cretaceous carbonates (Fahliyan Formation), South-west Iran: Journal of Asian Earth Sciences, v. 39, p. 148-160.
-Adabi, M.H., Kakemem, U. and Sadeghi, A., 2016. Sedimentary facies, depositional environment and sequence stratigraphy of Oligocene-Miocene shallow water carbonate from the Rig Mountain, Zagros Basin (SW Iran): Carbonates and Evaporites, v. 31, p. 69-85.
-Adabi, M.H., 1996. Sedimentology and geochemistry of carbonates from Iran and Tasmania (Doctoral dissertation, PhD. thesis (unpublished). University of Tasmania, Australia).
-Adabi, M.H., 2004. A re-evaluation of aragonite versus calcite seas: Carbonates and Evaporites, v. 19, p. 133-141.
-Adabi, M.H., 2009. Multistage dolomitization of the Upper Jurassic Mozduran Formation, Kopeh dagh Basin, NE Iran: Carbonates and Evaporites, v. 24, p. 16-32.
-Adams, T.D. and Bourgeois, F., 1967. Asmari Biostratigraphy: Iranian Oil Operation Companies, Geological and Exploration Division, Report No. 1074, p. 6-11.
-Ahmad, A.H.M., Bhat, G.M. and Azim Khan, M.H., 2006. Depositional environments and diagenesis of the Kuldhar and Keera Dome carbonates (Late Bathonain-Early Callovian) of Western India: Journal Asian Earth Sciences, v. 27, p. 765-778.
-Anderson, T.F. and Arthur, M.A., 1983. Stable isotopes of oxygen and carbon and their application to sedimentologic and paleoenvironmental problems: SEPM Short Course, v. 10, p. 1-1.
-Aqrawi, A.A.M., Keramati, M., Ehrenberg, S.N., Pickard, N., Moallemi, A., Svana, T., Darke, G., Dickson, J.A.D. and Oxtoby, N.H., 2006. The origin of dolomite in the Asmari Formation (Oligocene – Lower Miocene), Dezful Embayment, SW Iran: Journal of Petroleum Geology, v. 29(4), p. 381-402.
-Avarjani, S., Mahboubi, A., Moussavi-Harami, R., Amiri-Bakhtiar, H. and Brenner, R.L., 2015. Facies, depositional sequences, and biostratigraphy of the Oligo-Miocene Asmari Formation in Marun Oil Field, North Dezful Embayment, Zagros Basin, SW Iran: Palaeoworld, v. 24(3), p. 336-358.
-Azomani, E., Azmy, K., Blamey, N., Brand, U. and Al-Aasm, I., 2013. Origin of Lower Ordovician dolomites in eastern Laurentia: controls on porosity and implications from geochemistry: Marine and Petroleum Geology, v. 40, p. 99-114.
-Bathurst, R.G.C., 1975. Carbonate Sediments and their Diagenesis: Developments in Sedimentology: Elsevier, Amsterdam, 658 p.
-Bordenave, M.L. and Hegre, J.A., 2010. Current distribution of oil and gas fields in the Zagros Fold Belt of Iran and contiguous offshore as the result of the petroleum systems: Geological Society Special Publication, v. 330, p. 291-353.
-Brand, U. and Veizer, J., 1980. Chemical diagenesis of multicomponent carbonate system, II: stable isotopes: Journal of Sedimentary Petrology, v. 51, p. 987-997.
-Budd, D., 2002. The relative roles of compaction and early cementation in the destruction of permeability in carbonate grainstones: a case study from the Paleogene of west-central Florida: Journal of Sedimentary Research, v. 72, p. 116-128.
-Burchette, T.P. and Wright, V.P., 1992. Carbonate ramp depositional systems: Sedimentary Geology, v. 79, p. 3-57.
-Cantrell, D.L., 2006. Cortical fabrics of Upper Jurassic ooid, Arab Formation, Saudi Arabia: Implication for original carbonate mineralogy: Journal of Sedimentary Geology, v. 186, p. 157-170.
-Caron, V. and Nelson, C., 2009. Diversity of neomorphic fabrics in New Zealand Plio-Pleistocene cool-water limestones: insights into aragonite alteration pathways and controls: Journal of Sedimentary Research, v. 79, p. 226-246.
-Crowe, S.A., Døssing, L.N., Beukes, N.J., Bau, M., Kruger, S.J., Frei, R. and Canfield, D.E., 2013. Atmospheric oxygenation three billion years ago: Nature, v. 501, p. 535-538.
Dehghanzadeh, M. and Adabi, M.H., 2020. Petrography of carbonate rocks in the Asmari Formation, Zagros Basin, Dezful Embayment and Izeh Zone, SW Iran: Arabian Journal of Geosciences, v. 13(17), p. 1-15.
-Dickson, J., 1965. Carbonate identification and genesis as revealed by staining: Journal of Sedimentary Research, v. 36, p. 491-505.
-Dunham, R., 1962. Classification of carbonate rocks according to depositional texture. In: Classification of Carbonate Rocks: American Assocition Petroleum Geology, 121 p.
-Embry, A.F. and Klovan, J.E., 1971. A late Devonian reef tract on northeastern Banks Island, NWT: Bulletin of Canadian Petroleum Geology, v. 19(4), p. 730-781.
-Fallah-Bagtash, R., Adabi, M.H., Nabawy, B.S., Omidpour, A. and Sadeghi, A., 2022. Integrated petrophysical and microfacies analyses for a reservoir quality assessment of the Asmari Dolostone sequence in the Khesht Field, SW Iran: Journal of Asian Earth Sciences, v. 223, p. 104989.
-Fallah-Bagtash, R., Jafarian, A., Husinec, A. and Adabi, M.H., 2020. Diagenetic stabilization of the Upper Permian Dalan Formation, Persian Gulf Basin: Journal of Asian Earth Sciences, v. 189, p. 104144.
-Flügel, E., 2010. Microfacies Analysis of Limestones, Analysis Interpretationand Application. Springer-Verlag, 976 p.
-Ghazban, F., 2007. Petroleum Geology of the Persian Gulf: Tehran University and National Uranian Oil Company Publications, Tehran, 717 p.
-Herndon, E.M., Havig, J.R., Singer, D.M., McCormick, M.L. and Kump, L.R., 2018. Manganese and iron geochemistry in sediments underlying the redox-stratified Fayettvile Green Lake: Geochimica et Cosmochimica Acta, v. 231, p. 50-63.
-Heydari, E., 2008. Tectonics versus eustatic control on super sequences of the Zagros Mountains of Iran: Tectonophysics, v. 451, p. 56-70.
-Hood, A., Planavsky, N.J., Wallace, M.W. and Wang, X., 2018. The effects of diagenesis on geochemical paleoredox proxies in sedimentary carbonates: Geochimica et Cosmochimica Acta, v. 232, p. 265-287.
-Hou, Y., Azmy, K., Berra, F., Jadoul, F., Blamey, N.J., Gleeson, S.A. and Brand, U., 2016. Origin of the Breno and Esino dolomites in the western Southern Alps (Italy): Implications for a volcanic influence: Marine and Petroleum Geology, v. 69, p. 38-52.
-Huang, S.J., 2010. Carbonate Diagenesis: Geological Publishing, p. 29-44.
-Kasting, J.F., Howard, M.T., Wallmann, K., Veizer, J., Shield, G. and Jaffrés, J., 2006. Paleoclimates, ocean depth, and the oxygen isotopic composition of seawater: Journal of Earth and Planetary Science Letters, v. 252(I-2), p. 82-93.
-Keith, M. and Weber, J., 1964. Carbon and oxygen isotope composition of selected limestone and fossils: Geochimica et Cosmochimica Acta, v. 28, p. 1787-1816.
-Knorich, A.C. and Mutti, M., 2006. Missing aragonitic biota and the diagenetic evolution of Heterozoan carbonates: a case study from the Oligo-Miocene of the central Mediterranean: Journal of Sedimentary Research, v. 76, p. 871-888.
-Madhavaraju, J., Kolosov, I., Buhlak, D., Armstrong-Altrin, J.S., Ramasamy, S. and Mohan, S.P., 2004. Carbon and oxygen isotopic signature in Albian – Danian limestones of Cauvery Basin, southeastern India: Gondwana Research, v. 7, p. 519-529.
-Mazzullo, S.J., 1992. Geochemical and neomorphic alteration of dolomite: a review: Carbonates and evaporates, v. 7(1), p. 21-45.
-Mazzullo, S.J., 2000. Organogenic dolomitizationl in peritidal to deep-sea sediments: Journal of Sedimentary Research, v. 70, p. 10-23.
-Milliman, J.D., 1974. Marine Carbonates Recent Sedimentary Carbonates, Part 1: Springer-Verlag, Berlin, 375 p.
-Morrison, J.O. and Brand, U., 1986. Geochemistry of Recent marine invertebrates: Geoscience Canada, v. 13, p. 237-254.
-Mouthereau, F., Lacombe, O. and Vergés, J., 2012. Building the Zagros collisional orogen: timing, strain distribution and the dynamics of Arabia/Eurasia plate convergence: Tectonophysics, v. 532, p. 27-60.
-Narayanan, V., Anirudhan, S. and Grottoli, A.G., 2007. Oxygen and carbon isotope analysis of the Miocene limestone of Kerala and its implications to palaeoclimate and its depositional setting: Current Science, v. 93, p. 1155-1159.
-Navabpour, P. and Barrier, E., 2012. Stress states in the Zagros fold-and-thrust belt from passive margin to collisional tectonic setting: Tectonophysics, v. 581, p. 76-83.
-Omidpour, A., Moussavi Harami, R., Tom Van Loon, A.J., Mahboubi, A. and Rahimpour-Bonab, H., 2021. Depositional environment, geochemistry and diagenetic control of the reservoir quality of the Oligo-Miocene Asmari Formation, a carbonate plat form in SW Iran: Geological quarterely, v. 65.
-Pingitore, N.E., 1978. The behavior of Zn2+ and Mn2+ during carbonate diagenesis: theory and applications: Journal of Sedimentary Research, v. 48(3), p. 799-814.
-Rao, C.P. and Adabi, M.H., 1992. Carbonate minerals, major and minor elements and oxygen and carbon isotopes and their variation with water depth in cool, temperate carbonates, western Tasmania, Australia: Marine Geology, v. 103, p. 249-272.
-Rao, C.P. and Amini, Z.Z., 1995. Faunal relationship to grain-size, mineralogy and geochemistry in recent temperate shelf carbonates, western Tasmania, Australia: Carbonates and Evaporites, v. 10, p. 114-123.
-Rao, C.P., 1990. Geochemical characteristics of cool-temperate carbonates, Tasmania, Australia: Carbonates and Evaporites, v. 5, p. 209-221.
-Rao, C.P., 1991. Geochemical differences between subtropical (Ordovician), temprate (Recent and Pleistocene) and subpolar (Permian) carbonates, Tasmania, Australia: Carbonates and Evaporites, v. 10, p. 114-123.
-Rao, C.P., 1996. Modern Carbonates, Tropical, Temperate, Polar: Introduction to Sedimentology and Geochemistry: Hobart (Tasmania), 206 p.
-Read, J.F., Husinec, A., Cangialosi, M., Loehn, C.W. and Prtoljan, B., 2016. Climate controlled, fabric destructive, reflux dolomitization and stabilization via marine-and synorogenic mixed fluids: An example from a large Mesozoic, calcite-sea platform, Croatia: Palaeogeography, palaeoclimatology, palaeoecology, v. 449, p. 108-126.
-Rowlands, G., Purkis, S. and Bruckner, A., 2014. Diversity in the geomorphology of shallow-water carbonate depositional systems in the Saudi Arabian Red Sea: Geomorphology, v. 222, p. 3-13.
-Sandberg, P.A., 1985. Nonskeletal aragonite and pCO2 in the Phanerozoic and Proterozoic. The carbon cycle and atmospheric CO2: Natural variations Archean to present, v. 32, p. 585-594.
-Sharland, P.R., Casey, D.M., Davies, R.B., Simmons, M.D., Sutcliffe, O.E., 2004. Arabian plate sequence stratigraphy - revisions to SP2: GeoArabia, v. 9, p. 199-214.
-Sherkati, S. and Letouzey, J., 2004. Variation of structural style and basin evolution in the central Zagros (Izeh zone and Dezful Embayment), Iran: Marine and Petroleum Geology, v. 21, p. 35-55.
-Sibley, D.F. and Gregg, J.M., 1987. Classification of dolomite rock textures: Journal of Sedimentary Research, v. 57(6), p. 967-975.
-Swart, P.K., 2015. The geochemistry of carbonate diagenesis: The past, present and future: Sedimentology, v. 62, p. 1233-1304.
-Tucker, M.E. and Wright, V.P., 1990. Carbonate Sedimentology: Blackwell Scientific Publications, Oxford, 404 p.
-Urey, H.C., 1974. The thermodynamic properties of isotopic substance: Journal of Chemical Society p. 562-581.
-Van-Buchem, F.S.P., Allan, T.L., Laursen, G.V., Lotfpour, M., Moallemi, A., Monibi, M., Motiei, H., Pickard, N.A.H., Tahmasbi, A.R., Vedrenne, V. and Vincent, B., 2010. Regional stratigraphic architecture and reservoir types of the Oligo-Miocene deposits in the Dezful Embayment (Asmari and Pabdeh Formations) SW Iran. Journal of Geological Society, v. 329, p. 219-263.
-Veizer, J. and Hoefs, J., 1976. The nature of O18/O16 and C13/C12 secular trends in sedimentary carbonate rocks: Geochimica et Cosmochimoca Acta, v. 40, p. 1387-1395.
-Veizer, J., 1983. Trace elements and isotopes in sedimentary carbonates: Reviews in Mineralogy, v. 11, p. 265-300.
-Veizer, J., Ala, D., Azmy, K., Bruckschen, P., Buhl, D., Bruhn, F., Carden, G.A.F., Diener, A., Ebneth, S., Goddris, Y., Jasper, T., Korte, C., Pawellek, F., Podlaha, O.G. and Strauss, H., 1999. 87Sr/86Sr, δ18O and δ13C evolution of Phanerozoic seawater: Chemical Geology, v. 161, p. 59-88.
-Vincent, B., Rambeau, C., Emmanuel, L. and Loreau, J.P., 2006. Sedimentology and trace element geochemistry of shallow marine carbonates: an approach to paleoenvironment analysis along the Pagny-sur-Meuse Section (Upper Jurassic, France): Facies, v. 52, p. 69-84.
-Vincent, B., Van Buchem, F.S.P., Bulot, L.G., Immenhauser, A., Caron, M., Baghbani, D. and Huc, A.Y., 2010. Carbon isotope stratigraphy and organic matter distribution in the Aptian – Lower Albian successions of southwest Iran (Dariyan and Kazhdumi Formation): GeoArabia Special Publication, v. 4, p

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