Sedimentary characteristics,model and hydrocarbon accumulation of deep water pre-salt carbonate rocks in South Atlantic
Author(s): QIN Yanqun, WEN Zhixin, WANG Zhaoming, FENG Dong, KE Weili, ZHANG Xinshun, Research Institute of Petroleum Exploration and Development, PetroChina, School of Energy Resources, China University of Geosciences
Pages: 127-133
Year: 2014 Issue: 3
Journal: Earth Science Frontiers
Keyword: South Atlantic; deep water; pre-salt; carbonate rocks; sedimentary characteristics;
Abstract: Recently,there have been great discoveries in the deep water pre-salt carbonate rocks in South Atlantic.According to the characteristics of discovered deep water oil and gas fields,regional geological and geophysical data,the South Atlantic deep water pre-salt carbonate formation,which mainly locates in the high structural areas and slope zones,belongs to limited lake sedimentation under the barrier conditions during the period of the South American and African plate cracking,and is characterized by main limestone and algal limestone.The carbonate develops in the local highlands and slope areas due to the shallow water which is the result of the cracking of different plates and the resistance of volcanic ridge in Walvis.When the evaporation of the ancient salt basin is larger than the amount of water provided by the ocean,the salt rocks begin to precipitate and the development of the ancient salt basin continues.The carbonate reservoirs are mainly controlled by the salt rocks and sourced by the bottom lacustrine mudstone formed during the rift stage.The oil and gas migrate through the faults and the short distance unconformities to accumulate as effective reservoirs in the high structural areas and the developmental zones of salt rocks.These reservoirs covered by the overlying formation are characterized by structural and stratigraphic traps.
Pages: 127-133
Year: 2014 Issue: 3
Journal: Earth Science Frontiers
Keyword: South Atlantic; deep water; pre-salt; carbonate rocks; sedimentary characteristics;
Abstract: Recently,there have been great discoveries in the deep water pre-salt carbonate rocks in South Atlantic.According to the characteristics of discovered deep water oil and gas fields,regional geological and geophysical data,the South Atlantic deep water pre-salt carbonate formation,which mainly locates in the high structural areas and slope zones,belongs to limited lake sedimentation under the barrier conditions during the period of the South American and African plate cracking,and is characterized by main limestone and algal limestone.The carbonate develops in the local highlands and slope areas due to the shallow water which is the result of the cracking of different plates and the resistance of volcanic ridge in Walvis.When the evaporation of the ancient salt basin is larger than the amount of water provided by the ocean,the salt rocks begin to precipitate and the development of the ancient salt basin continues.The carbonate reservoirs are mainly controlled by the salt rocks and sourced by the bottom lacustrine mudstone formed during the rift stage.The oil and gas migrate through the faults and the short distance unconformities to accumulate as effective reservoirs in the high structural areas and the developmental zones of salt rocks.These reservoirs covered by the overlying formation are characterized by structural and stratigraphic traps.
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