Analysis of the orderly distribution of oil and gas fields in China based on the theory of co-control of source and heat

Taking a hydrocarbon zone or a basin group as a unit, this paper analyzed the vertical hydrocarbon generation regularity of onshore and offshore oil and gas fields in China, based on the theory of co-control of source and heat. The results demonstrated that the hydrocarbon generation modes of oil and gas fields in China are orderly. First, the hydrocarbon zones in southeastern China offshore area, including the East and South China Sea basins, are dominated by single hydrocarbon generation mode, which displays as either single oil generation in the near shore or single gas generation in the offshore controlled by both source and heat. Second, the eastern hydrocarbon zones, including the Bohai Bay, Songliao and Jianghan basins and the North and South Yellow Sea basins, are dominated by a two-layer hydrocarbon generation mode, which performs as “upper oil and lower gas”. Third, the central hydrocarbon zones, including the Ordos, Sichuan and Chuxiong basins, are also dominated by the “upper oil and lower gas” two-layer hydrocarbon generation mode. In the Ordos Basin, gas is mainly generated in the Triassic, and oil is predominantly generated in the Paleozoic. In the Sichuan Basin, oil was discovered in the Jurassic, and gas was mostly discovered in the Sinian and Triassic. Fourth, the western hydrocarbon zones are dominated by a “sandwich” multi-layer mode, such as the Junggar, Tarim, Qaidam basins. In summary, the theory of co-control of source and heat will be widely applied to oil and gas exploration all over China. Oil targets should be focused on the near shore areas in the southeastern China sea, the upper strata in the eastern and middle hydrocarbon zones, and the Ordovician, Permian and Paleogene strata in the western hydrocarbon zone, while gas targets should be focused on the off-shore areas in the southeastern China sea, the Cambrian, Carboniferous, Jurassic, and Quaternary strata in the western hydrocarbon zone. A pattern of exploring gas fields under or outside oil fields and oil fields under or outside gas fields is presented. Therefore, there is still a great prospect for oil and gas exploration in China.