Characteristics and main controlling factors of post-salt hydrocarbon accumulation in Espirito Santo Basin, Brazil

The Campos Basin in Brazil is well-known of deep-water sedimentary exploration in the world. However, no systematic study has been carried out on the post-salt hydrocarbon accumulation in the Espirito Santo Basin （ESB） in the northern part of the Campos Basin. To advance the post-salt oil and gas exploration, the characteristics of oil-gas accumulation and the main controlling factors in the ESB were scrutinized using drilling, logging, and seismic profiling. Results bring up the following 4 conclusions: ① Two sets of source rocks including pre-salt lacustrine and post-salt marine source rocks are developed. The reservoir is mainly composed of the Upper Cretaceous to Tertiary deepwater channel sandstone in the north of the basin. ② According to the detachment deformation of salt rock, post-salt formation can be divided into detachment zone, diapir zone, and nappe zone. ③ The hydrocarbon accumulation model of salt detachment zone shows that the hydrocarbon generated by pre-salt and post-salt source rocks migrate through salt windows and salt related faults, respectively, and finally form reservoirs in rolling anticlines and other traps formed by salt detachment. ④ The hydrocarbon accumulation model of salt diapir zone is that hydrocarbon generated by post-salt source rocks migrate through salt-related faults, and finally accumulated in anticlines related with salt diapers and other traps blocked by salt flank. ⑤ Reservoir- and salt-related listric faults, and activities of salt-bearing rocks are the main controlling factors of hydrocarbon accumulation in the ESB.