Advanced Applied Geology

Advanced Applied Geology

Morphology and microthermometry of petroleum inclusions in one of the oil fields in south Iran

Authors
Nadia Azizi 1
Mohsen Rezaei 2
Alireza Zarasvandi 3
Bahram Alizadeh 4
Akbar Heydari 5
1 Department of Geology, Faculty of Earth Sciences, Shahid Chamran University, Ahvaz
2 Department of Geology, Faculty of Earth Sciences, Shahid Chamran University of Ahvaz, Ahvaz, Iran Center for International Scientific Studies & Collaborations (CISSC), Ministry of Science Research and Technology of Iran
3 Department of Geology, Faculty of Earth Sciences, Shahid Chamran University of Ahvaz, Ahvaz, Iran
4 Department of Petroleum Geology, Faculty of Earth Sciences, Shahid Chamran University of Ahvaz, IRAN.
5 Department of Petroleum Geology and Sedimentary Basins, Faculty of Earth Sciences, Shahid Chamran Ahvaz University, Ahvaz, Iran
10.22055/aag.2025.48420.2487
Abstract
Fluid inclusions provide valuable data regarding the physicochemical conditions at the time of mineral formation. They could be used in determining the burial history, maturity, diagenesis environment, and the degree of cementation of the reservoir. In this study, a total of 239 double-polished thin sections were prepared from 105 wells of Asmari reservoir in the North Azadegan oil field. Amongst fifty-four fluid inclusions were selected for the microthermometry analysis using a Linkam THMSG 600 heating-freezing stage mounted on an Olympus microscope. Based on the fluid inclusion phases at room temperature, they are classified as single-phase gas, single-phase liquid, and two-phase oil-rich inclusions, occurring mostly as primary and/or pseudo-secondary inclusions. Based on microthermometry data, the homogenization temperatures (Th) vary from 62 °C to 178°C in the Sarvak and Kazhdumi samples, respectively. In the studied samples, final ice-melting temperatures (Tm (Ice)) vary between -1 and 16 °C, corresponding to salinities of 1 to 9 wt. % NaCl equivalent. Assessment of fluorescence emission under UV light for 239 fluid inclusion samples indicates that the majority of samples (over 75 %) have green color emission equivalent to API gravity of 30-40º degrees. Also, 20% of samples represent blue color emission, indicating the API gravity of 40-50º degrees. Yellow color emissions were seen only in 5% of samples. They imply for the API gravity of 20-30º degrees. Based on the available phases at room temperature and physicochemical attributes of fluid inclusions, it is concluded that the Asmari reservoir were charged in two stages as confirmed before by two sources of oil in this reservoir.
Keywords
Petroleum inclusion
Microthermometry
Petrography
API gravity
Subjects
Abdollahie Fard, I., Braathen, A., Mokhtari, M., Alavi, SA., 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 12, 347-362.
Bourdet, J., Eadington, P., Volk, H., George, SC., Pironon, J., Kempton, R., 2012. Chemical changes of fluid inclusion oil trapped during the evolution of an oil reservoir: Jabiru-1A case study (Timor Sea, Australia). Marine and Petroleum Geology 36(1), 118-139.
Brown, SR., 1989. Transport of fluid and electric current through a single fracture. Journal of Geophysical Research: Solid Earth 94 (B7), 9429-9438.
Du, Y., Chen, J., Cui, Y., Xin, J., Wang, J., Li, YZ. and Fu, X., 2016. Genetic mechanism and development of the unsteady Sarvak play of the Azadegan oil field, southwest of Iran. Petroleum Science 13, 34-51.
George, SC., Ruble, TE., Dutkiewicz, A., Eadington, PJ., 2001. Assessing the maturity of oil trapped in fluid inclusions using molecular geochemistry data and visually-determined fluorescence colours. Applied Geochemistry 16(4), 451-473.
Goldstein, R., Reynolds, J., 1994. Systematics of fluid inclusions. SEPM short course notes 31, 188.
Goldstein, RH., 2001. Fluid inclusions in sedimentary and diagenetic systems. Lithos 55(1-4), 159-193.
Hurai, V., Huraiova, M., Slobodnik, M., Thomas, R., 2016. Geofluids: Developments in microthermometry, spectroscopy, thermodynamics and stable isotopes. Economic Geology 111(4), 1041-1041.
Jayanthi, JL., Nandakumar, V., 2021. Fluid inclusion studies to determine the paleotemperature and hydrocarbon quality in petroliferous basins. Journal of Petroleum Science and Engineering 197, 108082.
Karim, A., Hanley, JJ., Pe-Piper, G., Piper, DJ., 2012. Paleohydrogeological and thermal events recorded by fluid inclusions and stable isotopes of diagenetic minerals in Lower Cretaceous sandstones, offshore Nova Scotia, Canada. AAPG bulletin 96(6), 1147-1169.
Lu, X., Yu, Z., Liu, K., Zhao, M., Fan, J., Guo, X., Zhuo, Q. and Gui, L., 2022. Transformation of a Large Ancient Oil Reservoir to a Dry Gas Reservoir: A Case Study of the Kela‐2 Gas Field in the Kuqa Foreland Basin, NW China. Geofluids 2022(1), 6615336.
McLimans, RK., 1987. The application of fluid inclusions to migration of oil and diagenesis in petroleum reservoirs. Applied Geochemistry 2(5-6), 585-603.
Munz, IA., 2001. Petroleum inclusions in sedimentary basins: systematics, analytical methods and applications. Lithos 55(1-4), 195-212.
Shariatinia, Z., Haghighi, M., Shafiei, A., Feiznia, S. and Zendehboudi, S., 2015. PVTX characteristics of oil inclusions from Asmari formation in Kuh-e-Mond heavy oil field in Iran. International Journal of Earth Sciences 104, 603-623.
Testa, SM., 1995. Chemical aspects of cold‐mix asphalt incorporating contaminated soil. Soil and Sediment Contamination, 4(2), 191-207.
Volk, H., George, SC., 2019. Using petroleum inclusions to trace petroleum systems A review. Organic Geochemistry 129, 99-123.
Wang, H., Liu, J., 2023. Emulsification and corrosivity study of bio-oil and vacuum gas oil mixtures with a novel surfactant system. Fuel 333, 126460.
Zarasvandi, A., Liaghat, S., Lentz, D. and Hossaini, M., 2013. Characteristics of Mineralizing Fluids of the Darreh‐Zerreshk and Ali‐Abad Porphyry Copper Deposits, Central I ran, Determined by Fluid Inclusion Microthermometry. Resource Geology 63(2), 188-209.
Advanced Applied Geology
Volume 15, Issue 1
Winter 2025
Pages 189-202