Inversion structure and its application in petroleum exploration in Santos Basin, Brazil

To reveal the hydrocarbon accumulation characteristics of inversion structures, the types, styles, and formation mechanism of inversion structures are summarized, and exploration examples of the Santos Basin, Brazil, were analyzed. Results show that positive-inversion structures are important hydrocarbon-bearing traps. Their development and evolution are related to compressive stress intensity. In slight or intermediate inversion stage, they mainly develop flexural fold inversion structures. In strong or full inversion stages, they mainly show strong thrusting and develop fault-related inversion structures. Inversion structures are the response of regional tectonic events. Thermal regime change and regional tectonic regime change are two main tectonic counter-rotational force mechanisms. Positive inversion structures are characterized by near-source hydrocarbon supply, development of migration channels such as faults and fractures, and reliable and large-scale traps. In addition, positive inversion structures provide a good condition in which hydrocarbon generation, migration, and accumulation are well-matched in space and time, forming an important reservoir type.