ریزرخساره‌ها، محیط رسوبی و پالئواکولوژی سازند آسماری در میدان نفتی کرنج، شمال فروافتادگی دزفول، جنوب غرب ایران

نوع مقاله : علمی -پژوهشی

نویسندگان

1 گروه پژوهشی ساختمانی و معدنی، پژوهشکده فناوری و مهندسی، پژوهشگاه استاندارد، کرج، ایران

2 گروه زمین‌شناسی، دانشکده علوم پایه، دانشگاه آزاد اسلامی، واحد لاهیجان، لاهیجان، ایران

3 گروه زمین‌شناسی نفت، دانشکده علوم پایه، دانشگاه آزاد اسلامی، واحد علوم و تحقیقات تهران، تهران، ایران

چکیده

در این پژوهش ریزرخساره­ها، محیط رسوبی و پالئواکولوژی سازند آسماری با تکیه بر مطالعه 105 مقطع نازک (شامل مغزه­های حفاری) تهیه شده از 132 متر توالی­های برش تحت­الارضی یکی ازچاه­های میدان نفتی کرنج انجام شده است. 12 ریزرخساره شناسایی و تفسیر شد که شامل: 1) انیدریت، 2) مادستون-دولومادستون، 3) باندستون استروماتولیتی، 4) ماستون کوارتزدار، 5) بیوکلاستیک بنتیک فرامینیفرا (بدون منفذ) پکستون-گرین استون، 6) بنتیک فرامینیفرا (منفذ دار و بدون منفذ) وکستون-پکستون-گرین استون، 7) بایوکلاست گرینستون، 8) اُاُیید گرینستون، 9) کورالیناسه آ کورال فلوتستون، 10) لپیدوسیکلینا کورالیناسه آ نئوروتالیا پکستون-گرین استون، 11) لپیدوسیکلینا نومولیتیده پکستون-وکستون، 12) پلاژیک فرامینیفرا وکستون هستند، که می­توان به 5 محیط رسوبی شامل: پهنه جذر و مدی، لاگون محصور، لاگون نیمه محصور، دریای باز تقسیم کرد. به­طور کلی این رسوبات تحت 3 نوع متفاوت از شوری در دریایی باز(psu 40-34)، لاگون نیمه محصور (psu 50-45) و لاگون محصور (بیش از (psu 50 با زون نوری افوتیک، الیگوفوتیک، مزوفوتیک تا یوفوتیک و تحت 4 نوع رژیم غذایی: الیگوتروفی، مزوتروفی، یوتروفی و هایپرتروفی در یک پلاتفرم کربناته از نوع رمپ هموکلینال در زمان چاتین تا بوردیگالین رسوب­گذاری نموده است.

کلیدواژه‌ها


عنوان مقاله [English]

Microfacies, depositional environment and paleoecology of the Asmari Formation in the Karanj oil field, norhtern Dezful embayment, SW Iran

نویسندگان [English]

  • Behzad Saeedi Razavi 1
  • Alierza Ganji 2
  • Sepehr Zarrabi 3
1 Department of Construction and Mineral Engineering, Technology and Engineering Research Center, Standard Research Institute (SRI), Karaj, Iran
2 Department of Geology, Faculty of Basic Sciences, Islamic Azad University, Lahijan, Iran
3 Department of Petroleum Geology, Faculty of Basic Sciences, Islamic Azad University, Tehran University of Science and Research, Tehran, Iran
چکیده [English]

IntroductionThe Asmari Formation (Oligo-Miocene) is spread in the Zagros region. The Formation was first identified in Tang-Gel-Torsh, located on Mount Asmari. In a sample type section, the thickness of this formation is 314 meters. Kranj oil field is one of the most important oil fields in the North of the restricted embayment of Dezful. The Karanj anticline structure, one of the most important oil fields in Iran, is located in the southwest of the Zagros sedimentary basin and in the southern part of the north of restricted Dezful embayment adjacent to the Persian fields.Material and methodsThe study section is located 115 km east of Ahvaz. In this study, 105 thin sections of core drilling, belonging to Asmari Formation wells, were prepared in Karanj oil field. They were prepared with the help of a microscope equipped with a camera and carefully examined in lithology and fossiles studies. In the study of microfacies, the naming of limestones was done by Dunham and Amberi and Calvan methods and the identification of microfacies was based on the Flogel model. Asmari Formation is 132 meters thick in this well.Resultes and DiscussionIn this study, microfacies, depositional environment and paleoecology of Asmari Formation have been performed based on the study of 105 thin sections (including Core drilling) prepared from 132 m of subsurface cutting sequences from one of the wells of Karanj oil field.12 microfacies related to the environments, tidal flat, lagoon, shoal and open marine were identified and interpreted, including: 1) Anhydrite, 2) Mudstone-Dolomudstone, 3) Stromatolitic boundstone, 4) Quartz mudstone, 5) Bioclastic benthic foraminifera (perforate and imperforate) packstone-grainstone, 6) Benthic foraminifera (perforate) wackestone-packstone-grainstone, 7) Bioclastic grainstone, 8) Ooid grainstone, 9) Corallinacean coral floatstone, 10) Lepidocyclina corallinacean Neorotalia packstone-grainstone, 11) Lepidocyclina Nummulitids wackestone-packstone, 12) planktonic foraminifera wackestone, which can be grouped into five depositional environments: tidal flat, restricted lagoon, open lagoon, shoal and open marine.Investigating the important factors in the distribution of large benthic Foraminifera in this wellThe following factors play a role in the distribution of large benthic Foraminifera in the study period: 1- Salinity, 2- Distribution of food, 3- Temperature, 4- Water mobility, 5- Water depth, 5- Light.ConclusionIn deposits of Asmari Formation in this well in Karanj oil field, aging from chattian to Burdigalin, with 132 meters in thickness, 12 microfacies were identified. The microfacies identified in this section belong to four ancient environments, including the tidal flat, lagoon, shoal, and open marine. Based on these microfacies and how to expand them, a hemoclinical ramp is recommended for sedimentation of this Formation. .Based on the presence of benthic and other components of sediments and how they are distributed in the carbonate platform, these sediments were formed with normal salinity in aphoic, oligophic and oligophic to mesophotic zones and under low nutritional (oligotrophy) and medium (mesotrophy) food conditions in chatian age. In Aquitanian-Burdigalian age, in the study section, high salinity conditions in the uphotic zone with high (uphotic) feeding conditions were present. Within the studied profile, the Asmari Formation was deposited during the Chattian period in the open marine with normal salinity (Psu 40-34) in the aphotic, oligophic to mesophotic light zone, and under the oligotrophic to mesotrophic nutrient.  At the time of Aquitanian to Burdigalian, it was deposited in a restricted lagoon environment with a psu 50-45 salinity and in an open lagoon with a salinity of more than 50 psu, in the uphotic light zone, under a uphoty nutrient.

کلیدواژه‌ها [English]

  • Paleoecology
  • Microfacies
  • Asmari Formation
  • Depositional environment
  • Karanj oil field
-مطیعی، ه.، 1372. زمین‌شناسی ایران، چینه-شناسی زاگرس، انتشارات سازمان زمین‌شناسی کشور، 536 ص.
-Allahkarampour, M., Seyrafian A. and Vaziri-Moghaddam, H., 2010. The Asmari Formation, north of the Gachsaran (Dill anticline), southwest Iran: facies analysis, depositional environments and sequence stratigraphy: Carbonates and Evaporites, v. 25, p. 45-160.
-Baratollo, F., Bassi, D. and Romero, R., 2007. Upper Eocene larger foraminiferal-coralline algal facies from Klokova Mountain (south continental Greece): Facies, v. 53, p. 361-375.
-Beavington-Penney, S.J. and Racey, A., 2004. Ecology of extant nummulitids and other larger benthic foraminifera, applications in Paleoenvironmental analysis: Earth Science Review, v. 67, p. 219-265.
-Brandano, M., Frezza, V., Tomassetti, L. and Pedley, M., 2009. Facies analysis and paleoenvironmental interpretation of the Late Oligocene Attard Member (Lower Coralline Limestone Formation), Malta: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 274, p. 54-63.
-Brasier, M.D., 1975c. Morphology and habitat of living benthonic foraminiferids from Caribbean carbonate environments, In Beavington- Penney, S. J. and A. Racey (Eds.), Ecology of extant Nummulitids and other larger benthic foraminifera: Applications in palaeoenvironmental analysis Earth Science, v. 67, p. 219-265.
-Burchette, T.P. and Wright, V.P., 1992. Carbonate ramp depositional systems: Sediment Geology, v. 79, p. 3-57.
-Corda, L. and Brandano, M., 2003. Aphotic zone carbonate production on a Miocene ramp, Central Apennines, Italy: Sedimentary Geology, v. 161(1–2), p. 55-70.
-Cosovic, V., Drobne, K. and Moro, A., 2004. Paleoenvironmental model for Eocene foraminiferal limestones of the Adriatic carbonate platform (Istrian Peninsula): Facies, v. 50, p. 61-75.
-Dunham, R.J., 1962. Classification of carbonate rocks according to depositional texture: American Association of Petroleum Geologists Bulletin, v. 1, p. 108-121.
-Ehrenberg, S.N., Pickard, N.A.H., Laursen, G.V., Monibi, S., Mossadegh, Z.K., Svana, T.A., Aqrawi, A.A.M., McArthur, J.M. and Thirlwall, M.F., 2007. Strontium isotope stratigraphy of the Asmari Formation (Oligocene-Lower Miocene), SW Iran: Journal of Petroleum Geology, v. 30, p. 107-128.
-Emery, D. and Myers, K.J., 1996. Sequence stratigraphy: Blackwell, Sci., Oxford, 297 p.
-Flügel, E., 2004. Microfacies analysis of carbonate rocks: Interpretation and application: Springer-Verlag, Berlin, 976 p.
-Flügel, E., 2010. Microfacies analysis of limestone: interpretation and application: Springer-Verlag, Berlin, 976 p.
-Geel, T., 2000. Recognition of stratigraphic sequence in carbonate platform and slope, empirical models based on microfacies analysis of Paleogene deposits in southeastern Spain: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 155(3), p. 211-238.
-Greensmith, J.T., 1988. Petrology of the Sedimentrary Rocks: 6th edition, George Allen & Unuin, London, 241 p.
-Hallock, P. and Glenn, E.C., 1986. Larger foraminifera, a tool for paleoenvironmental analysis of Cenozoic carbonate facies: Palaios, v. 1, p. 55-64.
-HallocK, P., 1988. The role of nutrient availability in bioerosion, Consequences to carbonate buildups: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 63, p. 275-291.
-Hallock, P., Muller, T., Karger, F.E. and Halas, J.C., 1993. Coral reef decline - anthropogenic nutrients and the degradation of western Atlantic and Caribbean coral reefs: Research and Exploration, v. 9, p. 358-378.
-Hallock, P., 2001. Coral reefs in the 21st century: is the past the key to the future? In: Proceedings of the 10th Symposium on the Geology of the Bahamas and Other Carbonate Regions (Eds B.J. Greenstein and C.K. Carney): Gerace Research Center, San Salvador, Bahamas, p. 8-13.
-Heydari, E., Hassanzadeh, J., Wade, W.J. and Ghazi, A.M., 2003. Permian– Triassic boundary interval in the Abadeh section of Iran with implications for mass extinction, Part 1-Sedimentology: Paleogeography, Paleoclimatology, Paleoecology, v. 193, p. 405-423.
-Hottinger, L., 1983. Processes determining the distribution of larger foraminifera in space and time, In: Meulenkamp, J.E. Eds., Reconstruction of marine paleoenvironments: Utrecht Micropaleontological Bulletin, v. 30, p. 239-253.
-Hottinger, L., 1997. Shallow benthic foraminiferal assemblages as signals for depth of their deposition and their limitations: Bulletin de la Societe Geologique de France, v. 168(4), p. 491-505.
-James, G.A. and Wynd, J.G., 1965. Stratigraphic nomenclature of Iranian oil consortium agreememt Area: American Association of Petroleum Geologists Bulletin, v. 49, p. 2182- 2245.
-Lee, J.J., 1990. Fine structure of the rhodophycean Porphyridium purpureum in situ in Peneroplis pertusus (Forskal) and P. acicularis (Batsch) and in axenic culture: Journal of Foraminiferal Research, v. 20, p. 162-169.
-Mossadegh, Z.K., Haig, D.W., Allan, T., Adabi, M.H. and Sadeghi, A., 2009. Salinity changes during Late Oligocene to Early Miocene Asmari Formation deposition, Zagros Mountains, Iran: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 272, p. 17-36.
-Mutti, M. and Hallok, P., 2003. Carbonate system along nutrient and temperature gradient: Some sedimentological and geochemical constraits: Earth-Science, v. 92, p. 465-475.
-Nebelsick, J.H., Stingl, V. and Rasser, M., 2001. Autochthonous facies and allochthonous debris compared: early Oligocene carbonate facies patterns of the Lower Inn Valley (Tyrol, Austria): Facies, v. 44, p. 31-46.
-Pomar, L., 2001. Ecological control of sedimentary accomodation: Evolution from a carbonate ramp to rimmed shelf, Upper Miocene, Balearic Island: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 175, p. 249-272.
-Rahmani, Z., Vaziri-Moghaddam, H. and Taheri, A., 2010. Facies distribution and palaeoecology of the Guri member of the Mishan Formation in Lar area Fars Province SW Iran: Iranian Journal of Science and Technology. Transaction A. 34(A3).
-Rasser, M.W., Scheibner, C. and Mutti, M., 2005. A paleoenvironmental standard section for Early Ilerdian tropical carbonate factories (Corbieres, France; Pyrenees, Spain): Facies, v. 51, p. 217-232.
-Read, J.F., 1985. Carbonate platform facies models: American Association of Petroleum Geologists Bulletin, v. 69, p. 1-21.
-Reading, H.G., 1996. Sedimentary environments and facies: Blackwell Scientific Publication, 425 p.
-Renema, W., 2006. Large benthic foraminifera from the deep photic zone of a mixed siliciclastic-carbonate shelf off East Kalimantan, Indonesia: Marine Micropaleontology, v. 58, p. 73-82
-Richardsons, R.K., 1924. The geology and oil measures of southwest Persia: Journal of the Institute of Petroleum Technology, v. 10, p. 256-283.
-Sadeghi, R., Vaziri-Moghaddam, H. and Taheri, A., 2010. Microfacies and sedimentary environment of the Oligocene sequence (Asmari Formation) in Fars sub-basin, Zagros Mountains, southwest Iran: Facies, v. 57, p. 431-446.
-Seyrafian, A. and Hamedani, A., 1998. Microfacies and depositional environment of the Upper Asmari Formation (Burdigalian), north-central Zagros Basin, Iran: Neues Jahrbuch fur Geologie und Palaontologie - Abhandlungen, v. 210, p. 129-141.
-Seyrafian, A., 2000. Microfacies and depositional environment of the Asmari Formation at Dehdez area: Carbonates and Evaporites, v. 15, p. 121-130.
-Seyrafian, A. and Hamedani, A., 2003. Microfacies and paleoenvironmental interpretations of the Lower Asmari Formation (Oligocene), north-central Zagros Basin, Iran: Neues Jahrbuch für Geologie und Paläontologie Monatshefte, v. 3, p. 164-174.
-Seyrafian, A., Vaziri-Moghaddam, H., Arzani N. and Taheri, A., 2011. Facies analysis of the Asmari Formation in central and north-central Zagros basin, southwest Iran: Biostratigr, Paleoecol Diagenes, v. 28, p. 439-458.
-Shabafrooz, R., Mahboubi, A., Vaziri Moghaddam, H., Ghabeishavi, A. and Moussavi Harami, R., 2015. Depositional architecture and sequence stratigraphy of the Oligo-Miocene Asmari platform; Southeastern Izeh Zone, Zagros Basin, Iran: Facies, v. 61, p. 1-32.
-Sherkati, S., Letouzey, J. and Frizon De Lamotte, D., 2006. The central Zagros fold-thrust belt (Iran): New insights from seismic data, field observation and sandbox modeling: Tectonics, v. 25, p. 1-27.
-Sooltanian, N., Seyrafian, A. and Vaziri-Moghaddam, H., 2011. Biostratigraphy and paleo-ecological implications in microfacies of the Asmari Formation (Oligocene), Naura anticline (Interior Fars of the Zagros Basin), Iran: Carbonates and Evaporites, v. 26, p. 167-180.
-Sherkati, S., Letouzey, J., Frizon, D.E. and Lamotte, D., 2004. The central Zagros fold-thrust belt (Iran): New insights from seismic data, field observation and sandbox modeling. Tectonics, v. 25, p. 1-27.
-Tucker, M.E., 1990. Geological background to carbonate sedimentation. In: Carbonate Sedimentology (Ed. by M.E. Tucker & V.P. Wright): Blackwell Scientifc Publications, Oxford, 482 p.
-Van Buchem, F.S.P., Allan, T.L., Laursen, G.V., Lotfpour, M., Moallemi, A., Monibi, S., Motiei, H., Pichard, N.A.H., Tahmasbi, A.R., Vedrenne, V. and Vincent, B., 2010. Regional stratigraphic architecture and reservoir types of the Oligo-Miocene deposites in the Dezful Embayment (Asmari and Pabdeh formations), SW Iran. Geological Society, London, special publications, v. 329, p. 219-263.
-Vaziri-Moghaddam, H., Kimiagari, M. and Taheri, A., 2006. Depositional environment and sequence stratigraphy of the Oligo-Miocene Asmari Formation is SW Iran: Facies, v. 52, p. 41-51.
-Vaziri-Moghaddam, H., Seyrafian, A. and Taheri, A., 2010. Oligocene-Miocene ramp system (Asmari Formation) in the NW of the Zagros basin, Iran: microfacies, paleoenvironment and depositional sequence. Revista Mexicana de Ciencias Geologicas, v. 27, p. 56-71.
-Vaziri-Moghaddam, H., Kalanat, B. and Taheri, A., 2011. Sequence stratigraphy and depositional environment of the Oligocene deposits at Firozabad section, southwest of Iran based on microfacies analysis: Geopersia, v. 1, p. 71-82.
-Wilson, J.L., 1975. Carbonate facies in geologic history: New York, Springer-Verlag. 471 p.
-Wynd, J.G., 1965. Biofacies of the Iranian oil consortium agreement area: Report 1082, unpublished.