关键词: 海相碳酸盐岩, 油气成藏理论, 成储过程, 成藏过程, 万米深层, 超深层资源潜力

Abstract: Marine carbonate rocks are an important part of onshore oil-gas exploration in China. A series of exploration breakthroughs have been made in recent years, which play an important role in ensuring energy security. Based on the recent achievements of petroleum exploration in the three craton basins of China, this paper systematically reviews the latest advances in the theory and technology of marine petroleum accumulation in China, and forms the following understandings and advances. (1)Significant achievements have been made in marine oil and gas exploration in three major cratons. For example, two ultra-deep fault-controlled giant oil-gas fields with 1 billion tons of geological reserves have been discovered in in Fuman and Shunbei areas of Tarim Basin, the trillion cubic meters of large gas field has been initially established in the northern slope of central Sichuan Basin, and several new exploration zones have been discovered in the dolomites from the Ordovician pre-salt submember 6 of Member 5 of Majiagou Formation to Member 4 of Majiagou Formation in Ordos Basin. (2)A series of important advances have been made in reservoir prediction and reservoir tracing. For example, the study of Mg isotope tracing dolomitization process has promoted the development of genetic mechanism analysis of dolomite. By analyzing the spatial characteristics and retention mechanism of carbonate reservoirs such as deep fault solution, it is clear that the lower limit of exploration depth of carbonate cavern reservoir is far beyond the drilling depth. Advances in fault solution characterization, reef bank characterization, reservoir transparency and constant volume characterization have promoted efficient exploration and significantly improved drilling success. (3)Remarkable progress has been made in hydrocarbon accumulation process and fluid tracing. For example, technological innovations such as light hydrocarbons, isotopes and biomarkers have been used to improve the effectiveness of hydrocarbon source correlation. Important progress has been made in the dating techniques of accumulation with various methods, which can effectively guide the determination of favorable accumulation areas. With the development of hydrocarbon reservoir evolution and reconstruction technology, the marine carbonate reservoir formation process under complex tectonic background has been transformed from qualitative analysis to quantitative study. (4)By systematically analyzeing the accumulation law and main controlling factors of marine carbonate oil and gas in China, it is clear that marine oil and gas reservoirs in China are characterized by large area distribution, large amplitude of oil and gas column, high production well controlled by source rock and large-scale reservoir, oil and gas richment controlled by strike-slip fault, and ultra-long life of hydrocarbon reservoirs. (5)The deep and ultra-deep resource potential of marine basins in China is huge, with the potential development of 5 trillion cubic meter gas fields and 1 billion-ton oilfield. The development of marine oil and gas theory enriches the accumulation theory of small craton basins, promotes the progress of petroleum geology theory, and plays an important role in the practice of oil and gas exploration.

Key words: marine carbonates, hydrocarbon accumulation theory, reservoir forming process, accumulation process, deep strata buried at a depth of about 10 000 meters, resource potential in ultra-deep fields