Relationship Between Igneous Rocks and Hydrocarbon Accumulation

Igneous rocks are widely distributed in the world and have a big impact on oil and gas exploration. In order to discover the relationship between igneous rocks and oil and gas accumulation, starting from the whole process of oil and gas accumulation, the effect of igneous rocks on basin evolution, oil and gas generation, reservoir development, seal conditions, trap formation, oil and gas migration, and oil and gas reservoir preservation were analyzed, and the patterns were summarized. The study results show that igneous rocks are rich in minerals, which provide material conditions for the reproduction of hydrocarbon-generating rocks, increases the geothermal gradient and accelerates the hydrocarbon-generating procession, the metal elements carried can improve the hydrocarbon-generating transformation efficiency of the source rocks. Igneous rocks have positive and negative effects on the reservoir. It has a constructive role as reservoir, transforming reservoir and changing paleo morphology, which is beneficial to carbonate rock deposition. It has destructive effect of baking the reservoir to make it dense and occupying the reservoir space. Tight igneous rocks can act as effective seals and fluid segmentation layers. During the spilling and eruption of magma along the volcanic channel, various types of structures can be formed, which enriches the types of traps. The thermodynamic effect on surrounding rock during the igneous eruption process produces a large number of faults and fractures, which are conducive to the migration of oil and gas. The igneous rocks developed in the early stage or at the same time with hydrocarbon generation have constructive effects on oil and gas accumulation, and the igneous rocks in the later stage have destructive effects on early oil and gas reservoirs. The formation and evolution of oil and gas in igneous rock-bearing basins were closely related to that of igneous rocks. We should dialectically recognize its positive and negative effects in oil and gas exploration, which requiring targeted theoretical innovations and methodological improvements.