| Author's Name: FAN Guozhang, SHI Buqing, YANG Liu, WANG Chaofeng,
SHAO Dali, WANG Hongping, ZUO Guoping |
| Institution: |
| Abstract: |
| The Santos Basin is the richest hydrocarbon continental marginal basins in the world so far. This paper studied
the discovery history and discussed the characteristics and distribution of the pre-salt oil-gas fields in the basin.
According to the exploration strategy, the discovery history could be divided into three stages. The first stage is concerned
with the exploration at the core of outer high (2005-2009) while the second stage at the surrounding of outer high (2009-
2013). The third stage is characterized by the commercial mode of PSC given its increasing exploration risks. The
hydrocarbon mainly lies under the thick salt in the deep water ocean. The discoveries are primarily oil reservoir with few
gas reservoir and condensate oil reservoir. The oil reservoirs are characterized by medium-high density, high gas/oil ratio,
existence of CO2 and normal / super-high pressure. The reservoir type is mainly structural reservoir whose source
(lacustrine shale) - reservoir (lacustrine carbonate) - cap (continuous salt rock) developed in the rift and sag stage. The
super-giant oilfields are located in the structural traps of Lula-Sugar Loaf uplift and Aram-Uirapuru uplift. The large and
medium-small oilfields are located in the structural traps of secondary uplifts in western depression and central
depression. From the viewpoint of basin evolution and hydrocarbon accumulation, the formation and distribution of
hydrocarbon reservoirs are decided by the tectonic framework of rift stage. The hydrocarbon accumulation directions and
favorable enrichment belts are decided by the tectonic activity of passive continental margin stage. There are five
geological factors controlling the pre-salt hydrocarbon enrichment. The paleo-structure controls the reservoir type and
quality. The current structure controls the accumulation direction. The salt rock controls the accumulation efficiency. The
source kitchen controls the oil enrichment belt. The CO2 charging influences the fluid property. The study shared a
comprehensive understanding about the exploration of Santos Basin and may provide some references of the exploration
for other deep-water passive margin basins. |
| Keywords: pre-salt; tectonic framework; hydrocarbon distribution; accumulation rule; Santos Basin |
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投稿时间：
2023-02-06 |
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