تعیین درجه پختگی مواد آلی سازند سرچاهان با استفاده از انعکاس گراپتولیت

نوع مقاله : مقاله پژوهشی

چکیده

به منظور تعیین درجه پختگی (بلوغ) مواد آلی سازند سرچاهان در منطقه تنگ زاکین در شمال بندرعباس، نمونه‌های سطح‌الارضی انتخاب و مورد ارزیابی "راک اِول" و با تهیه قرص مقطع ضخیم، مورد مطالعه میکروسکوپی قرار گرفتند. نمونه‌ها غالباً حاوی گراپتولیت بودند که با بررسی میکروسکوپی و شناسایی گراپتولیت‌ها انعکاس آنها اندازه‌گیری شد. همچنین اسلایدهای تهیه شده از کروژن در نور گذرا مورد بررسی قرار گرفتند. از کروژن استخراج شده نیز تجزیه عنصری به عمل آمد. انعکاس گراپتولیت، رنگ کروژن، فلورسانس‌زایی مواد آلی لیپتینیتی و نتیجه آنالیز عنصری کروژن، همگی نشان دهنده پختگی مواد آلی رسوبات سازند مذکور در منطقه تنگ زاکین در مراحل پایانی نفت‌زایی و اوایل گاززایی می‌باشند
 

کلیدواژه‌ها

عنوان مقاله [English]

Thermal Maturity Determination of Sarchahan Formation (NE Bandar Abbas, South Iran) Using Graptolite Reflectance (GRo%)

چکیده [English]

In order to determine the maturity of the organic matter of Sarchahan Formation in northern Bandar Abbas, 15 outcrop samples were collected from Tang-e-Zakin, North Syahoo village, 70 km. from the city of Bandar Abbas. The Reflectance of Graptolites (%GRo) were measured by a reflected light microscope (MPV-SP) and histograms were plotted. The Mean Random Reflectance of these samples were 1.11% which indicate the catagenetic stage of maturity. These samples were also subjected to Rock- Eval Pyrolysis. The average Tmax for these samples is 455
◦C that indicates the end of oil generation window and early stage of gas generation. The Gahkum Formation (Silurian shales) as a whole was reported as overmature and its organic matter considered to have graphitic stage of maturity. Nevertheless Gahkum Fm. was divided into Syahoo Fm. (Ordovician) and Sarchahan Fm. (lower Silurian) on the basis of their biozones. On the other hand, this study geochemically investigated Sarchahan Formation separately with the help of Rock-Eval data, TAI, elemental analysis of kerogen and measurements of graptolite reflectance (Gro%), and concluded that it is in the catagenetic stage of maturity and emphasis on the Silurian strata for future hydrocarbon exploration in Iran.

کلیدواژه‌ها [English]

  • Gahkum Formatiom
  • Sarchahan Formation
  • Graptolite Reflectance
  • GRo%
  • Elemental Analysis

مراجع

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