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Площадь: 298800.5 км²
Gulf of Mexico
Deepwater exploration literally started in the Gulf of Mexico with huge oil/gas discoveries in deepwater clastic turbidite, pre-salt, and ultra-deep water formations (Fig. 1). Accordingly, the Gulf of Mexico is currently one of the most important deepwater oil/gas zones in the world.
Fig.1. Distribution of basin and deepwater oil and gas fields in the Gulf of Mexico (according to Refs)
Formation and evolution of the Gulf of Mexico Basin can be divided into 3 stages: rifting (Triassic–Mid-Jurassic), transition (Late Jurassic) and passive continental margin (Early Cretaceous–Neogene), forming two structural layers, pre-salt and post-salt (Fig. 2). These basins contain 4 packages of hydrocarbon source rocks: Upper Jurassic Oxfordian–Tithonian, Lower Cretaceous Barremian, Upper Cretaceous Turonian, and Paleogene. Among them, the Upper Jurassic Tithonian marine shale and marlite are key hydrocarbon source rocks. Deepwater reservoir formations include Paleogene–Neogene sandstone and Cretaceous carbonate. The Paleogene–Neogene sandstone formations are key reservoirs. Furthermore, Jurassic sandstone reservoirs were also discovered in deepwater areas in the eastern part of the basin. Regional seals include Mid-Jurassic Louann salt rocks, and Paleogene–Neogene marine shale. Majority of traps are structural traps formed by faults and salt structures with migration of hydrocarbon along faults to form reservoirs.
Fig. 2. Geological section of the deepwater basin in the Gulf of Mexico (according to Ref.).
With a history of more than 100 years, a large portion of oil/gas exploration operations in the Gulf of Mexico Basin were carried out in the United States. In the 1940s, exploration operations in the Gulf of Mexico Basin penetrated offshore areas. Discovery of the world's first deepwater oil field—Cognac Oil Field (with a water depth of 313 m) in 1975 ushered in a new stage with deepwater oil and gas exploration in the Gulf of Mexico and even all around the world. Up until the end of 2000, productivities in deepwater areas of the Gulf of Mexico have exceeded those in shallow-water zones. In the 21st century, explorations in deepwater areas of the Gulf of Mexico entered the fast track with discoveries of a series of major deepwater oil fields (Fig.1, Table 1). Up until the end of 2009, 149 deepwater oil fields (Water depth >305 m) with proven reserves up to 707 × 106 toe, or 73.7% of the total reserves had been found in the Gulf of Mexico, according to data of the US Bureau of Ocean Energy Management for 2013. Moreover, ultra-deep oil and gas exploration operations were active in the Gulf of Mexico. Up to 2012, 75 discoveries had been made in ultra-deep waters over 1500 m. Deepwater oil and gas exploration operations in the Gulf of Mexico were conducted in different zones. Currently, the majority of deepwater oil and gas exploration operations and discovered reserves were distributed in three zones: Pliocene, Miocene and Paleogene Wilcox. In the past few years, breakthroughs were also made in deepwater Cretaceous formations, ultra-deep water salt rocks and deepwater Jurassic formations in the eastern part. These three exploration zones may provide sustainable reserves for deepwater oil and gas exploration in the Gulf of Mexico in the future.
Table 1. Reserves of the top 20 deepwater oil and gas fields in the Gulf of Mexico.
Data source: Giant discoveries of oil and gas fields in global deepwaters in the past 40 years and the prospect of exploration.
Gongcheng Zhang, Hongjun Qu, Guojun Chen, Chong Zhao, Fenglian Zhang, Haizhang Yang, Zhao Zhao, Ming Ma. 2019
Следующий Бассейн: Magiscatzin