Research on the Differences of Oil and Gas Migration Systems in Hydrocarbon Source Rocks and Sandstone Reservoirs

The migration system, serving as the direct carrier that connects hydrocarbon source rocks and traps, is an important aspect of the research on oil and gas migration, accumulation, and reservoir formation. This paper mainly relies on the relevant sample data collected from the Upper Paleozoic in the Ordos Basin. By measuring the permeability, porosity values, and ratios of mudstone (coal) samples and sandstone samples under different conditions, it explores the migration and conduction mechanism of oil and gas in different lithological strata. The results indicate that the permeability and porosity of mudstone (coal) and sandstone samples in the direction parallel to the bedding plane are higher than those in the direction perpendicular to the bedding plane, and the permeability and porosity of sandstone are higher than those of mudstone (coal). In the presence of fractures, the permeability and porosity of fractured mudstone (coal) and sandstone samples are significantly higher than those without fractures. Based on this, the following conclusions can be drawn: When there is no fracture development, the permeability and porosity of hydrocarbon source rocks and sandstone in the direction parallel to the bedding plane are better than those in the direction perpendicular to the bedding plane, and the permeability and porosity of sandstone are better than those of hydrocarbon source rocks (mudstone and coal rock). When fractures are developed, the permeability and porosity in the fracture direction are the best, followed by sandstone, and hydrocarbon source rocks are the worst. The research conclusions lay a foundation for further improving the relevant theoretical research on the oil and gas migration system and also play an important guiding role in the exploration and development of oil and gas reservoirs.