Structural interpretation of the Strait of Hormuz by using seismic lines and well data

Document Type : Research Article

Authors

Abstract

The main purpose of this study is to analyze structural features in the Strait of Hormuz by using subsurface geophysical data. One of the main tasks is, therefore, to interpret 75 lines of the PC2000 seismic lines acquired by the Dutch and Norwegian Statoil company in the waters of the Persian Gulf and Oman Sea in 2000. In addition to interpreting the horizon, these data are used to understand the evolution of stratigraphic–structural history of this region. Situated in 55°–56° E longitude and 25°30'–27° N latitude, the study area is located in the south of Iran in the Strait of Hormuz which is known as Block E for the National Iranian Oil Company. The size of the Hormuz study area is in the order of 10000 km2. Within the area, there is one large island, Qeshm Island, and several smaller ones. Because the study area is a submarine, there is no possibility of direct examination of existing structures; therefore 2D seismic reflection data and submarine drilling data (8 wells) are used for modeling the subsurface structures and structural analysis in this area by Petrel software. Eight offshore wells were tied to the seismic data, providing the basis for the definition of horizons that varied in age from Early Cretaceous to Pliocene. The seismic data have been loaded to Petrel software in SEG-Y tape format. The SEG-Y format is generally accepted as a common format for both marine and land seismic data. The results have shown that in parts of the area, salt diapirism began after sedimentation of the Hormuz salt by downbuilding mechanism, and in other parts it has been affected by Mesozoic and Cenozoic reactivated basement faults coupled with buoyancy force. Two growth stages, active and passive, are known for diapiric structures. Also, the salt dome structures are related to some basement faults trending NE–SW, which provided a path for upward movement of salt. Most of these faults are concentrated in the eastern Hormuz Province where structural complexity is justified due to the effect of Oman and Zagros orogenies. The structuring as seen today is mainly the result of the Upper Cretaceous to Early Tertiary Oman Orogeny and the Late Miocene to Recent arrival of the southward advancing Zagros Orogeny. Most faults below the Intra-Mishan unconformity are thrust and reverse faults. The radial normal faults are predominant on top of the all diapirs. Radius of influence of individual diapirs is about twice of their diameter. Furthermore, folds are shorter and wider as compared to those in the north-western part of the Zagros, such that the wavelength is about 23 times of amplitude. The measurements carried out on the 39 interlimb angle folds reveals that 2/56 percent are open fold and 97/43 percent are gentle folds (50 percent have 140-160 interlimb angle, 34/21 percent have 160-180 interlimb angle and 15/78 percent have 120-140 interlimb angle).

Keywords


السوقی، م.، 1387، تحلیل و تفسیر ساختارهای پیچیده تنگه هرمز با استفاده از داده های لرزه نگاری بازتابی سه بعدی: رساله دکتری، دانشکده مهندسی معدن، متالورژی و نفت، دانشگاه صنعتی امیرکبیر.
پاژنگ، س.، 1392، تحلیل و تکامل گنبدهای نمکی و ساخت‌های مرتبط با آن با استفاده از داده‌های لرزه‌ای در تنگه هرمز: پایان‌نامه کارشناسی ارشد، زمین‌شناسی (تکتونیک)، دانشکده علوم طبیعی، دانشگاه تبریز.
قلاوند، ه.، پولادزاده، م.، ارزانی، ع.، و مهدی‌پور، ض.، 1388، کاربرد لرزه‌نگاری در توسعه مخازن هیدروکربوری: مجله اکتشاف و تولید، 59، 20-23.
مطیعی، ه.، 1372، زمین‌شناسی ایران چینه‌شناسی زاگرس: سازمان زمین‌شناسی کشور، 536ص.
عبدالملکی، ن.، و بحرودی، ع.، 1389، ارزیابی توانمندی روش تداخل‌سنجی راداری جهت بررسی فعالیت نمک های خروجی منطقه شمال غربی قم: نشریه تخصصی روش تداخل‌سنجی راداری و اطلاعات مکانی، 1 (3).

Ala, M., 1974, Salt diapirism in southern Iran: Am. Ass. Petrol. Geol. Bull., 58, 1758–1770.
Barton, D., 1933, Mechanics of formation of salt domes with special reference to Gulf Coast salt domes of Texas and Louisiana: Am. Ass. Petrol. Geol. Bull., 17, 1025–1083.
Callot, J., Jahani, S., and Letouzey, J., 2007, The Role of Pre-Existing Diapirs in Fold and Thrust Belt Development: Springer, 309–325.
Falcon, N., 1967, Southern Iran, Zagros Mountains: In Spencer, A., (Editor), Mesozoic–Cenozoic orogenic belts: Geol. Soc. London, 4, 199–211.
Fletcher, R., Hudec, M., and Waston, I., 1995, Salt glacier and composite sediment-salt glacier models for the emplacement and early burial of allochthonous salt sheet. Salt tectonics: A global perspective: AAPG Memoir, 65, 77–108.
Glennie, K., 2000, Cretaceous tectonic evolution of Arabia’s eastern plate margin: a tale of two oceans: Society for sedimentary Geology, 69, 9–20.
Haffer, J., Benyamin, N., and Zardosht, H., 1977, The regional geology of the strait of Hormoz, southern iran and northern Oman: Hormoz Petrolum Company.
Harrison, J., 1930, The Geologhy of some salt plugs in Laristan (Southern Persia): Quart. J. Geological Soc., 86, 463–522.
Jackson, M., and Vendeville, B., 1994, Regional extension as a geologic trigger for diapirism: GSA Bulletin, 106, 57–73.
Jackson, M., and Talbot, C., 1994, Advances in salt tectonics: Pergamon Press, 159–179.
Jahani, S., Callot, J.-P., Lamotte, D., Letouzey, J., and Leturmy, P., 2007, The Salt Diapirs of the Eastern Fars Province (Zagros, Iran): A Brief Outline of their Past and Present: Springer, 287–306.
Jahani, S., Callot, J.-P., Letouzey, J., and Lamotte, D., 2009, The eastern termination of the Zagros Fold-and-Thrust Belt, Iran: Structures, evolution, and relationships between salt plugs, folding, and faulting: Tectonics, 28, 1–22.
Kent, P., 1958, Recent studies of south Persian salt plugs: Am. Ass. Petrol. Geol. Bull., 42, 2951–2979.
Kent, P., 1979, The emergent Hormoz salt plugs of southern Iran: J. Petroleum Geology, 2(2), 117–144.
Letouzey, J., and Sherkati, S., 2004, Salt Movement, Tectonic Events, and Structural Style in the Central Zagros Fold and Thrust Belt (Iran): In Salt sediments interactions and hydrocarbon prospectivity: 24th Ann. GCSSEP Foundation, Bob F. Perkins Research Conf.
Nettleton, L., 1934, Fluid mechanics of salt domes: AAPG Bulletin, 18, 1175–1204.
Player, R., 1969, The Hormuz Salt Plugs of southern Iran: Iranian Oil Operating Companies, Geological and Exploration Division Report NO. 1146, (unpublished).
Richardson, F., Lees, G., and De Bockh, H., 1929, The Structure of Asia: Edited by Gregory, J. W., Methuen London, 125–159.
Talbot, C., and Alavi, J., 1996, The past of a future syntaxis across the Zagros: Salt Tectonics, 100, 89-110.
Vendeville, B., and Jackson, M., 1992, The rise of diapirs during thin-skinned extension: Marine and Petroleum Geology, 9(4), 331–353.
Windelstad, J., Hilde, E., Skarpnes, O., Scotchmer, J., Fjelland, M., and Svånå, T., 2003, NIOC-Statoil Joint Exploration Study Hormuz: Statoil INT GEX Iran, Report NO. 2042, (unpublished).