Based on one by one anatomical and statistical analysis of 1021 giant oil and gas fields all over the world, this paper analyzes their discovery age, oil and gas properties and geographical location, reservoir geological age, lithology, depth, trap type, scale of reserves, and basin type, sums up their major distribution characteristics, puts forward the concept of petroleum domain, and expounds their distribution in eight petroleum domains all over the world. The study shows that there are 609 giant oilfields all over the world and they concentrate in the Middle East. There are 412 giant gas fields and they concentrate in Eastern Europe, Middle Asia and Russia. Giant oil and gas fields are mostly distributed in Asia, Oceania and Middle East, followed by Europe. The discovery of global giant oil and gas fields peaked from 1960 to 1990, and there are also many giant ones found in following two decades. They mainly occurred in Mesozoic strata, and next is Cenozoic. Oil and gas are rich in sandstone and secondly in carbonate, but the reserves are higher in carbonate reservoirs. Giant oil and gas fields mainly concentrate at a depth within three kilometers, and the trap type is mainly structural. From the analysis of ultimate recoverable reserves, it is concluded that oil and gas resources are rich in the Middle East, and there are huge reserves of oil and gas found in Venezuela’s Orinoco Belt. The main types of basins in which giant oil and gas fields lie are Class Ⅱ and Ⅰbasins in accordance with the Bally Basin classification mode, ClassⅡ basins in accordance with the Klemme Basin classification mode, and ClassⅡ and Ⅰ basins in accordance with theMann Basin classification mode. Tethyan petroliferous domain has the richest oil and gas. According to the distribution of giant oil and gas fields, emphasis should be laid on the exploration in Arctic petroliferous domains, heavy oil belt, deep water area, and lithologic traps in the future, and there would be a great breakthrough.

Based on the data of 54 giant gas fields discovered in the Persian Gulf Basin, this paper applies the concept and analytic method of petroleum system, dissects giant gas fields one by one, and probes into their formation and distribution in the Basin. Study shows that the source rocks of giant gas fields are Silurian Gahkum Formation, Qusaiba Shale Member, and Cretaceous Kazhdumi Formation. The reservoirs are mainly in Permian, Jurassic and Cretaceous strata. Giant gas fields are controlled by the tight limestone regional cap rocks in Lower Triassic Sudair Formation, the anhydrite seal in Upper Jurassic Tithonian Hith Formation, and the evaporite rock seal in Lower Miocene Fars Formation (Gachasaran Formation). The main trap is structural. In this region giant gas fields are mainly distributed in two regions: foreland area and passive continental margin, and gas is rich in different layers and formations in different regions. Gas distribution is mainly controlled by four factors: organic material type and gradation of thermal evolution of source rocks, accumulation conditions favorable for reservoirs, high-quality regional and local cap rocks, and structural elements like lateral compression, salt flow, and basement rift. They determine the distribution region and the accumulation zone of gas. It is predicted that there are three favorable exploration areas: the first is the “areas that have been explored and developed” and the exploration targets in these areas are structural; the second is the “areas that have been explored and developed” and the exploration targets here are nonstructural; the third is the “areas that have not been explored and developed”

West Siberian Basin is the largest petroliferous basin of Russian Federation, which is one of the largest petroleum basins in the world newly developed since 1970s, with largest area, most hydrocarbon reserves and highest production. By the end of 2007, the ultimate recoverable reserves of natural gas ofWest Siberian petroleum basin is 16.1 × 1012m3, in which the reserves of undeveloped oil & gas fields occupy 9.96 × 1012m3 and the undiscovered resources account for 31.6 × 1012m3. Based on the data of 57 large gas fields, combined with the tectono-depositional evolution process of the basin, applying the research idea and method of petroleum system, and through analyzing the reservoir-formation elements of generation, reservoir and cap rock, it is considered that Bazhenov Formation of Upper Jurassic and the equivalent ones are the most significant gas-generation rock of northern West Siberian Basin, in which the organic carbon content occupies more than 7%. Cenomanian rock located at the top of Cretaceous Formation is the reservoir of most large gas fields (80% natural gas), with 800m in average thickness. Avast number of complex structural-stratigraphic traps are generated in the basin and large gas fields that have been found concentrate in the uplift area of the northern margin of the basin including Nurmin and Medvezh, etc. In the future, the exploration target of increasing natural gas reserves will still be the oil-bearing provinces of Kara- Yamal and Nadym-Taz.

North Sea Basin is a typicalMesozoic rift basin, of which the formation and distribution of oil and gas has obvious characteristics. To understand the oil and gas formation and distribution could guide the exploration of other rift basins. Based on the relevant data provided by C&C and IHS, combined with the generation, reservoir, cap rock and trap features research, this paper analyzes the 57 giant oil and gas fields found in the North Sea Basin and adjacent areas, and concludes that the gas source rock of southern North Sea Basin is Westphalian coal of Upper Carboniferous, the main oil source rock of northern North Sea Basin is the shales of Kimmeridge Clay (Britain), Mandal, Draupne (Norway) and Farsund (Denmark) Formations from Upper Jurassic to Lower Cretaceous; the main reservoir of southern North Sea Basin is Rotliegendes sandstones, the Middle Jurassic Brent Group sandstones in Viking Graben and Upper Cretaceous chalk in Central Graben to the north; the regional cap rock of southern North Sea Basin is halite, and mud limestone to the north. It is also found that the critical factors that control the formation and distribution of giant oil and gas fields are: the distribution and maturity of effective source rock, the development of good reservoir rock and its distribution, the development of halite tectonic, fault block anticline and tilted fault block trap induced by halite and faulting movement during syn-rift period, the effective sealing by regional halite and mud limestone. Owing to these beneficial factors, the North Sea Basin is generally characterized by gas generation in the south and mainly oil generation in the north. Locally, because of the distribution of Brent group, and structural movement of regional halite in Central Graben, most giant oil and gas fields concentrate in northwestern Viking Graben and Norway area in middle of Central Graben.

North America has rich hydrocarbon resources, and about 1/5 global giant fields are distributed here. The regions of interest include American Craton circled by the fold thrust zones of Rocky Mountains, Marathon-Ouachita, Appalachian and the fold zone of Innuuite, and the passive continental margins of North Atlantic belong to North America, where can be called North America Petroliferous Domain. Based on characteristics of tectonic and sedimentary in North America, the distribution regularities of giant fields are studied by analyzing the play elements and processes of giant fields in this domain in depth. The study displays that the settings of tectonic and sedimentary evolution of the domain have three critical periods including Devonian, Permian, and Cretaceous, which are very important controlling effect to the distribution of giant oil and gas fields. The distribution of giant oil and gas fields in the domain can be divided into four belts, that is, the foreland of Rocky Mountains, the foreland of Marathon-Ouachita and Mid-Continent region, inner-Craton region, and passive continental margins of North Atlantic, where the forelands are the main region which giant fields distribute in. The source rocks, reservoirs and seals of giant fields mainly lie in Devonian System, Permian System and Cretaceous System. The patterns of traps chiefly are anticline, lithology or stratigraphy and reef. The producing pays of giant fields mainly distribute in over 3km in depth,where Devonian System mainly has giant oil fields, Cretaceous chiefly has giant gas fields, and Permian System has giant oil and gas fields.

The evolution of Atlantic passive continental margin of South Atlantic Ocean can be subdivided into pre-rifting, syn-rifting, transitional, and post-rifting phases, forming a series of the passive continental margin basins in Brazil (Campos, Santos, and Espirito Santo Basins) and West Africa (Niger Delta, Lower Congo, Gabon, and Kwanza Basins). Recently, several super giant oil and gas fields (including Tupi and Jupiter) have been discovered in the deep water area of Santos Basin. As a typical passive continental margin basin, Santos Basin could be good reference for other basins in terms of geological condition and hydrocarbon distribution. The primary source rocks in Santos Basin consist of Barremian-Aptian lacustrine shale and Cenomanian- Maastrichtian deep-marine shale. The subsalt synrifting lacustrine carbonate and postsalt marine turbidite sandstones are the predominant reservoirs. As a regional seal, the Aptian evaporate widely developed in South Atlantic Ocean, dominates the formation of traps and hydrocarbon migration. This paper summarizes the characteristics of hydrocarbon distribution and control factors in Santos Basin with analysis of the petroleum systems (Guaratiba- Guaratiba / Guaruja / Ilhabela and Itajai-Acu-Ilhabela / Marambaia) and plays (Guaratiba, Guaruja, Ilhabela et al.). In contrast to the geological conditions of basins in Brazil and West Africa, it is considered that the subsalt syn-rifting unit in deep water area of South Atlantic Ocean is the prolific strata, which could be the major target for exploration in the fut

Exploration for oil and gas in the Passive Continental Margin has been a hot spot of the whole world, and achieves a lot. The Northwest Shelf of Australia is a world-class gas province with minor oil, with 82% gas and only 18% condensate and oil, while other areas in the Margin are dominated by oil. Until 2009, 20 giant gas fields have been found in three basins in Northwest Shelf of Australia. Although the Northwest Shelf has rich hydrocarbon resources, its extent of exploration and exploitation is still low. Therefore, it is worthy of research and exploration. Based on the tectono-depositional evolution of Passive Continental Margin, combined with geological data of giant gas fields, this paper analyzes the features of main source rocks, reservoirs and seals in basins, studies the formation of giant gas fields, and thoroughly analyzes the factors controlling their distribution. It is believed that main source rock is humic and prone to generate gas, and the maturity is high, thereby the features of the source rock determine that the Northwest Shelf of is a gas province. Moreover, the main reservoirs are marine delta sandstone with excellent physical property, and they are widely developed in the syn-rift. After the Cretaceous Period, a set of excellent regional seals were deposited in the Northwest Shelf. Source rock, reservoirs, seals were vertically contacted and partially combined effectively, which is essential to the formation of giant gas fields. The geographic distribution of giant gas fields varies a lot. Most giant gas fields concentrate in Exmouth Platform and Rankin Platform. Besides, and most of them are buried deeply. The periods of reservoirs are chiefly Upper Triassic and Lower and Middle Jurassic, and all the giant gas fields are beneath the Cretaceous regional seals.