An integrated benthic foraminiferal and organic matter analysis of samples obtained from sedimentary sections exposed in the Mangoule-Bonepoupa area, revealed a very shallow marine paleo-depositional environment for t...An integrated benthic foraminiferal and organic matter analysis of samples obtained from sedimentary sections exposed in the Mangoule-Bonepoupa area, revealed a very shallow marine paleo-depositional environment for the sediments studied, with considerable influx of continental organic matter that were accumulated during the Cenomanian-Turonian age. With reference to the lithostratigraphic profile of the Douala/Kribi-Campo Basin, the age obtained reveals that the sedimentary sections studied belong particularly to the lower section of the Logbadjeck/Mungo River Formation, based on the following benthic foraminifera assemblage: Ammobaculites jessensis, Ammobaculites benuensis, Ammobaculites coprolithiformis, Ammotium cf nkalagum, Ammotium nwalum, Haplophragmoides cf beuchensis, Trochamina taylorana. A particularly very poor palynomorph assemblage was recovered and included no age diagnostic species: Acrostichum aureum, Lycopodiumsporites sp., Fungal spore, Lavigatosporites discordatus, Longapertites sp., Verrucosisporites sp. An organic petrographic analysis performed on these samples revealed Kerogen Type-II and Type-III. The entire data sets obtained from this area is remarkably poor and we suspect poor preservation as the cause viewing the extent of weathering. The paleo-depositional environment of these sediments was suggested both from the foraminifera and palynomorphs present and confirmed from the organic matter types and macrofossil contents. The studied sections are composed generally of dark to dark-gray shale beds. As one of the petroleum producing basins within the Gulf of Guinea in which exploration/exploitation activities are on-going, the current research is aim at providing more data useful in the continuous search for more potential source rocks in this basin.展开更多
Through analysis of the connotation of unconventional hydrocarbons,the source-reservoir assemblages of unconventional hydrocarbons are divided into three types,i.e.,source-reservoir neighboring type,source-reservoir i...Through analysis of the connotation of unconventional hydrocarbons,the source-reservoir assemblages of unconventional hydrocarbons are divided into three types,i.e.,source-reservoir neighboring type,source-reservoir integration type,and source-reservoir separation type.The source-reservoir neighboring type resources mainly include tight oil and tight gas with the following formation conditions and characteristics:(1)efficient near-source accumulation close to high-quality source rocks with the pressure difference between source and reservoir as the dynamic force;(2)large-area tight reservoirs with certain porosity,dominated by micro-nanopores of inorganic origin;(3)distributed in depressions and slopes with large hydrocarbon-bearing area and great resource quantity,low abundance and local development of“sweet spots”;(4)weak tectonism.The source-reservoir integration type resources mainly include coalbed methane,shale gas,shale oil and oil shale.The formation conditions and characteristics are:(1)high abundance of organic matter,different types of organic matter and thermal evolution grades leading to formation of different resources types;(2)organic-rich sections are distributed continuously in the reservoiring space which is dominated by nanometer organic pores,interparticle pores and microfissures;(3)hydrocarbons mainly occur in free or adsorbed state,varying much with resource type;(4)the resources are self-conserved,and enriched in depressions and slopes,the conservation conditions are controlled by tectonics,temperature and pressure;(5)the production per well can be enhanced by volume fracturing,which increases the permeability of the reservoirs.The source-reservoir separation type resources are more special,mainly including(1)transformed conventional resources such as oil sand and heavy oil;(2)unsteady resources formed under special conditions of temperature and pressure,among which natural gas hydrate is a representative.These three types of resources in China are different in both development prospect and current situation:(1)the source-reservoir neighboring type is most practical and will develop fast in the next 5 years;(2)the source-reservoir integration type needs continuous exploration and technical breakthrough,and is expected to develop rapidly in the coming decade;(3)in the source-reservoir separation type resources,natural gas hydrates have the greatest development potential,on which technical tests are being conducted.展开更多
文摘An integrated benthic foraminiferal and organic matter analysis of samples obtained from sedimentary sections exposed in the Mangoule-Bonepoupa area, revealed a very shallow marine paleo-depositional environment for the sediments studied, with considerable influx of continental organic matter that were accumulated during the Cenomanian-Turonian age. With reference to the lithostratigraphic profile of the Douala/Kribi-Campo Basin, the age obtained reveals that the sedimentary sections studied belong particularly to the lower section of the Logbadjeck/Mungo River Formation, based on the following benthic foraminifera assemblage: Ammobaculites jessensis, Ammobaculites benuensis, Ammobaculites coprolithiformis, Ammotium cf nkalagum, Ammotium nwalum, Haplophragmoides cf beuchensis, Trochamina taylorana. A particularly very poor palynomorph assemblage was recovered and included no age diagnostic species: Acrostichum aureum, Lycopodiumsporites sp., Fungal spore, Lavigatosporites discordatus, Longapertites sp., Verrucosisporites sp. An organic petrographic analysis performed on these samples revealed Kerogen Type-II and Type-III. The entire data sets obtained from this area is remarkably poor and we suspect poor preservation as the cause viewing the extent of weathering. The paleo-depositional environment of these sediments was suggested both from the foraminifera and palynomorphs present and confirmed from the organic matter types and macrofossil contents. The studied sections are composed generally of dark to dark-gray shale beds. As one of the petroleum producing basins within the Gulf of Guinea in which exploration/exploitation activities are on-going, the current research is aim at providing more data useful in the continuous search for more potential source rocks in this basin.
基金This work was funded by National Science and Technology Major Project of China(Grant No.2011ZX05043)Major Science and Technology Special Project of China National Petroleum Corporation(Grant No:2013E-0502)。
文摘Through analysis of the connotation of unconventional hydrocarbons,the source-reservoir assemblages of unconventional hydrocarbons are divided into three types,i.e.,source-reservoir neighboring type,source-reservoir integration type,and source-reservoir separation type.The source-reservoir neighboring type resources mainly include tight oil and tight gas with the following formation conditions and characteristics:(1)efficient near-source accumulation close to high-quality source rocks with the pressure difference between source and reservoir as the dynamic force;(2)large-area tight reservoirs with certain porosity,dominated by micro-nanopores of inorganic origin;(3)distributed in depressions and slopes with large hydrocarbon-bearing area and great resource quantity,low abundance and local development of“sweet spots”;(4)weak tectonism.The source-reservoir integration type resources mainly include coalbed methane,shale gas,shale oil and oil shale.The formation conditions and characteristics are:(1)high abundance of organic matter,different types of organic matter and thermal evolution grades leading to formation of different resources types;(2)organic-rich sections are distributed continuously in the reservoiring space which is dominated by nanometer organic pores,interparticle pores and microfissures;(3)hydrocarbons mainly occur in free or adsorbed state,varying much with resource type;(4)the resources are self-conserved,and enriched in depressions and slopes,the conservation conditions are controlled by tectonics,temperature and pressure;(5)the production per well can be enhanced by volume fracturing,which increases the permeability of the reservoirs.The source-reservoir separation type resources are more special,mainly including(1)transformed conventional resources such as oil sand and heavy oil;(2)unsteady resources formed under special conditions of temperature and pressure,among which natural gas hydrate is a representative.These three types of resources in China are different in both development prospect and current situation:(1)the source-reservoir neighboring type is most practical and will develop fast in the next 5 years;(2)the source-reservoir integration type needs continuous exploration and technical breakthrough,and is expected to develop rapidly in the coming decade;(3)in the source-reservoir separation type resources,natural gas hydrates have the greatest development potential,on which technical tests are being conducted.
