Organic geochemistry and petroleum potential of Early Cretaceous Garau Formation in central part of Lurestan zone,northwest of Zagros,Iran |
| |
| Institution: | 1. School of Resources and Geosciences, China University of Mining and Technology, Xuzhou 221116, China;2. Mendocino County Museum, 400 East Commercial Street, Willits, CA 95490, USA;3. Noyo Hill House, 28953 Highway 20, Fort Bragg, CA 95437, USA .;4. Instituto de Ciências da Terra (ICT), Pólo da Faculdade de Ciências da Universidade do Porto, Departamento de Geociências, Ambiente e Ordenamento do Território, Faculdade de Ciências, Universidade do Porto, Porto, Portugal;5. Department of Earth and Space Sciences, 404-A Lappin Hall, Morehead State University, Morehead, KY 40351, USA;6. Federal Institute for Geosciences and Natural Resources, Department Geochemistry of Petroleum and Coal, Stilleweg 2, D-30655 Hannover, Germany;7. Indiana University, Indiana Geological Survey, 611 N. Walnut Grove Ave., Bloomington, IN 47405-2208, USA;8. University of Kentucky, Center for Applied Energy Research, 2540 Research Park Drive, Lexington, KY 40511, USA;9. State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology (Beijing), Beijing 100083, China;1. Department of Applied Geosciences and Geophysics, Montanuniversitaet, Leoben A-8700, Austria;2. Northeast Petroleum University, Institute of Unconventional Oil and Gas, Daqing, China;3. GEOS4 GmbH, Michendorf D-14552, Germany;4. GFZ German Research Centre for Geosciences, Potsdam D-14473, Germany;5. Department of Materials Science, Montanuniversitaet Leoben, A-8700, Austria |
| |
| Abstract: | Deposition of organic rich black shales and dark gray limestones in the Berriasian-Turonian interval has been documented in many parts of the world. The Early Cretaceous Garau Formation is well exposed in Lurestan zone in Iran and is composed of organic-rich shales and argillaceous limestones. The present study focuses on organic matter characterization and source rock potential of the Garau Formations in central part of Lurestan zone. A total of 81 core samples from 12 exploratory wells were subjected to detailed geochemical analyses. These samples have been investigated to determine the type and origin of the organic matter as well as their petroleum-generation potential by using Rock-Eval/TOC pyrolysis, GC and GCMS techniques. The results showed that TOC content ranges from 0.5 to 4.95 percent, PI and Tmax values are in the range of 0.2 and 0.6, and 437 and 502 °C. Most organic matter is marine in origin with sub ordinary amounts of terrestrial input suggesting kerogen types II-III and III. Measured vitrinite reflectance (Rrandom%) values varying between 0.78 and 1.21% indicating that the Garau sediments are thermally mature and represent peak to late stage of hydrocarbon generation window. Hydrocarbon potentiality of this formation is assessed fair to very good capable of generating chiefly gas and some oil. Biomarker characteristics are used to provide information about source and maturity of organic matter input and depositional environment. The relevant data include normal alkane and acyclic isoprenoids, distribution of the terpane and sterane aliphatic biomarkers. The Garau Formation is characterized by low Pr/Ph ratio (<1.0), high concentrations of C27 regular steranes and the presence of tricyclic terpanes. These data indicated a carbonate/shale source rock containing a mixture of aquatic (algal and bacterial) organic matter with a minor terrigenous organic matter contribution that was deposited in a marine environment under reducing conditions. The results obtained from biomarker characteristics also suggest that the Garau Formation is thermally mature which is in agreement with the results of Rock-Eval pyrolysis. |
| |
| Keywords: | Hydrocarbon potential Organic geochemistry Garau Formation Zagros Lurestan zone |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
