As one of the most important reservoirs in submarine fan, submarine lobes are hot fields for the deep-water oil-gas exploration in the world. Although a large amount of researches have been carried out on the architec...As one of the most important reservoirs in submarine fan, submarine lobes are hot fields for the deep-water oil-gas exploration in the world. Although a large amount of researches have been carried out on the architecture model of submarine lobes throughout the world, some controversies still exist on aspects such as the differential distribution of composite patterns and the quantitative relationships among different sedimentary settings. This paper, which took an oilfietd in the Niger Delta Basin offshore West Afnca as an example and utilized abundant core, welt-logging and seismic data comprehensively, established the semi- quantitative to quantitative architecture model for individual lobe and lobe complex. Results show that （1） A lobe complex was composed of multiple individual lobes as the compensational stacking pattern. According to the stacked relationship among individual lobes, four types of compensational stacking pattern were classified as the inordered type, the lateral migration type, the retrograding type and the prograding type. Influenced by the laterally confined degree of palaeotopography, the basin floor fan lobe complex was easily superimposed as inordered type, showing relatively large lateral width but relatively small thickness; the slope fan lobe complex was easily superimposed as lateral migration, retrograding and pro- grading types, showing relatively small lateral width but relatively large thickness. （2） Influenced by the laterally confined degree of palaeotopography, the basin floor fan individual lobes showed relatively large planar distribution area but relatively small thickness, while the slope fan individual lobes showed relatively small planar distribution area but relatively large thickness. An individual lobe was composed of multiple lobe stories by the way of aggradation-progradation pattern. From proximal to middle and distal part of individual lobes, the bottom mass-transport-deposits and the top branch channels disappeared gradually, and the amalgamated degree of the middle tabular sandbodies weakened as well with gradually developing of muddy interlayers. The formation of an individual lobe generally includes three stages as ＂rapid accumulation-progradation-aggradation＂.展开更多
When we look back the contributions on submarine fans during the past 65 years （1950 -2015）, the empirical data on 21 modern submarine fans and I0 ancient deep-water sys- tems, published by the results of the First ...When we look back the contributions on submarine fans during the past 65 years （1950 -2015）, the empirical data on 21 modern submarine fans and I0 ancient deep-water sys- tems, published by the results of the First COMFAN （Committee on FANs） Meeting （Bouma eta｜., 1985a）, have remained the single most significant compilation of data on submarine fans. The 1970s were the ＂heyday＂ of submarine fan models. In the 21st century, the general focus has shifted from submarine fans to submarine mass movements, internal waves and tides, and contourites. The purpose of this review is to illustrate the complexity of issues surrounding the origin and classification of submarine fans. The principal ele- ments of submarine fans, composed of canyons, channels, and lobes, are discussed using nine modern case studies from the Mediterranean Sea, the Equatorial Atlantic, the Gulf of Mexico, the North Pacific, the NE Indian Ocean （Bay of Bengal）, and the East Sea （Korea）. The Annot Sandstone （Eocene-Oligocene）, exposed at Peira-Cava area, SE France, which served as the type locality for the ＂Bouma Sequence＂, was reexamined. The field details are documented in questioning the validity of the model, which was the basis for the turbidite- fan link. The 29 fan-related models that are of conceptual significance, developed during the period 1970-2015, are discussed using modem and ancient systems. They are： （I） the classic submarine fan model with attached lobes, （2） the detached-lobe model, （3） the channel-levee complex without lobes, （4） the delta-fed ramp model, （5） the gully-lobe model, （6） the suprafan lobe model, （7） the depositional lobe model, （8） the fan lobe model, （9） the ponded lobe model, （I0） the nine models based on grain size and sediment source, （11） the four fan models based on tectonic settings, （12） the Jackfork debrite model, （13） the basin-floor fan model, （14） supercritical and subcritical fans, and （15） the three types of fan reservoirs. Each model is unique, and the long-standing belief that submarine fans are composed of turbidites, in particular, of gravelly and sandy high-density turbi- dites, is a myth. This is because there are no empirical data to validate the existence of gravelly and sandy high-density turbidity currents in the modern marine environments. Also, there are no experimental documentation of true turbidity currents that can trans- port gravels and coarse sands in turbulent suspension. Mass-transport processes, which include slides, slumps, and debris flows （but not turbidity currenrs）, are the most viable mechanisms for transporting gravels and sands into the deep sea. The prevailing notion that submarine fans develop during periods of sea-level lowstands is also a myth. The geologic reality is that frequent short-term events that last for only a few minutes to several hours or days （e.g., earthquakes, meteorite impacts, tsunamis, tropical cyclones, etc.） are more important in controlling deposition of deep-water sands than sporadic long- term events that last for thousands to millions of years （e.g., lowstand systems tract）. Submarine fans are still in a stage of muddled turbidite paradigm because the concept of high-density turbidity currents is incommensurable.展开更多
基金supported by the National Planned Major Science and Technology Projects of China(No. 2011ZX05030-005-02)
文摘As one of the most important reservoirs in submarine fan, submarine lobes are hot fields for the deep-water oil-gas exploration in the world. Although a large amount of researches have been carried out on the architecture model of submarine lobes throughout the world, some controversies still exist on aspects such as the differential distribution of composite patterns and the quantitative relationships among different sedimentary settings. This paper, which took an oilfietd in the Niger Delta Basin offshore West Afnca as an example and utilized abundant core, welt-logging and seismic data comprehensively, established the semi- quantitative to quantitative architecture model for individual lobe and lobe complex. Results show that （1） A lobe complex was composed of multiple individual lobes as the compensational stacking pattern. According to the stacked relationship among individual lobes, four types of compensational stacking pattern were classified as the inordered type, the lateral migration type, the retrograding type and the prograding type. Influenced by the laterally confined degree of palaeotopography, the basin floor fan lobe complex was easily superimposed as inordered type, showing relatively large lateral width but relatively small thickness; the slope fan lobe complex was easily superimposed as lateral migration, retrograding and pro- grading types, showing relatively small lateral width but relatively large thickness. （2） Influenced by the laterally confined degree of palaeotopography, the basin floor fan individual lobes showed relatively large planar distribution area but relatively small thickness, while the slope fan individual lobes showed relatively small planar distribution area but relatively large thickness. An individual lobe was composed of multiple lobe stories by the way of aggradation-progradation pattern. From proximal to middle and distal part of individual lobes, the bottom mass-transport-deposits and the top branch channels disappeared gradually, and the amalgamated degree of the middle tabular sandbodies weakened as well with gradually developing of muddy interlayers. The formation of an individual lobe generally includes three stages as ＂rapid accumulation-progradation-aggradation＂.
文摘When we look back the contributions on submarine fans during the past 65 years （1950 -2015）, the empirical data on 21 modern submarine fans and I0 ancient deep-water sys- tems, published by the results of the First COMFAN （Committee on FANs） Meeting （Bouma eta｜., 1985a）, have remained the single most significant compilation of data on submarine fans. The 1970s were the ＂heyday＂ of submarine fan models. In the 21st century, the general focus has shifted from submarine fans to submarine mass movements, internal waves and tides, and contourites. The purpose of this review is to illustrate the complexity of issues surrounding the origin and classification of submarine fans. The principal ele- ments of submarine fans, composed of canyons, channels, and lobes, are discussed using nine modern case studies from the Mediterranean Sea, the Equatorial Atlantic, the Gulf of Mexico, the North Pacific, the NE Indian Ocean （Bay of Bengal）, and the East Sea （Korea）. The Annot Sandstone （Eocene-Oligocene）, exposed at Peira-Cava area, SE France, which served as the type locality for the ＂Bouma Sequence＂, was reexamined. The field details are documented in questioning the validity of the model, which was the basis for the turbidite- fan link. The 29 fan-related models that are of conceptual significance, developed during the period 1970-2015, are discussed using modem and ancient systems. They are： （I） the classic submarine fan model with attached lobes, （2） the detached-lobe model, （3） the channel-levee complex without lobes, （4） the delta-fed ramp model, （5） the gully-lobe model, （6） the suprafan lobe model, （7） the depositional lobe model, （8） the fan lobe model, （9） the ponded lobe model, （I0） the nine models based on grain size and sediment source, （11） the four fan models based on tectonic settings, （12） the Jackfork debrite model, （13） the basin-floor fan model, （14） supercritical and subcritical fans, and （15） the three types of fan reservoirs. Each model is unique, and the long-standing belief that submarine fans are composed of turbidites, in particular, of gravelly and sandy high-density turbi- dites, is a myth. This is because there are no empirical data to validate the existence of gravelly and sandy high-density turbidity currents in the modern marine environments. Also, there are no experimental documentation of true turbidity currents that can trans- port gravels and coarse sands in turbulent suspension. Mass-transport processes, which include slides, slumps, and debris flows （but not turbidity currenrs）, are the most viable mechanisms for transporting gravels and sands into the deep sea. The prevailing notion that submarine fans develop during periods of sea-level lowstands is also a myth. The geologic reality is that frequent short-term events that last for only a few minutes to several hours or days （e.g., earthquakes, meteorite impacts, tsunamis, tropical cyclones, etc.） are more important in controlling deposition of deep-water sands than sporadic long- term events that last for thousands to millions of years （e.g., lowstand systems tract）. Submarine fans are still in a stage of muddled turbidite paradigm because the concept of high-density turbidity currents is incommensurable.
