Dynamic continuous hydrocarbon accumulation (DCHA): Existing theories and a new unified accumulation model.

Replacing coal with cleaner hydrocarbon resources is a viable solution to reach carbon neutrality goals over time, especially given the current lack of growth in green energy resources (e.g., hydro, solar, wind, geothermal) globally. Hydrocarbon resources offer a low-carbon, low-waste, large-scale, rapid solution. Dynamic continuous hydrocarbon accumulation (DCHA) exists widely in sandstone and shale reservoirs and has enormous resource potential. However, understanding the accumulation mechanisms and models of DCHAs in different structural locations is highly challenging. In this study, we first extensively review hydrocarbon resources derived from hydrocarbon accumulation and identify key scientific issues and theories. We then take the well-known typical DCHA in the Bohai Bay Basin in eastern China as a case, and combine multiple analytical methods, such as biomarker analysis, petroleum and aqueous inclusion analysis, quantitative fluorescence analysis, microscopic thin section observations, and basin modeling, to investigate petroleum sources, charging times, and charging forces. The results of our study show that the DCHA is a superimposed accumulation of multiple petroleum reservoir types with multiple petroleum sources, charging times, charging forces, and modes. Petroleum reservoirs at high structural locations are conventional trap reservoirs accumulated by buoyancy in the early stage, with long migration distances. Petroleum reservoirs at the sag location are deep unconventional petroleum reservoirs accumulated by the petroleum generation pressurization force in the middle stage, with short migration distances. Petroleum reservoirs at the slope location are superpositions of conventional traps and deep unconventional petroleum reservoirs in the middle and late stages, with moderate migration distances. [ABSTRACT FROM AUTHOR]