Base-level is a kind of surface which controls sedimentation and erosion. So, it can be concluded that it is base-level change that controls the formation and internal structure of a sequence. A single cycle of base-l...Base-level is a kind of surface which controls sedimentation and erosion. So, it can be concluded that it is base-level change that controls the formation and internal structure of a sequence. A single cycle of base-level change can generate four sets of different stacking patterns. They are two sets of aggradation, one progradation and one retrogradation, which affects the features of the internal structure of a sequence. Lishu fault subsidence of Songliao basin is a typical half-graben lacustrine basin. Comprehensive base-level change analysis indicates that six base-level cycles and their related six sequences can be recognized between T 4 and T 5 seismic reflection surface. The contemporaneous fault is the main controlling factor of the fault lacustrine basin. There are obvious differences exist in the composition of sedimentary systems and all systems tracts between its steep slope (the side that basin control fault existed) and flat slope. Except highstand systems tract is composed of fan delta-lacustrine system, lowstand systems tract, transgressive systems tract and regressive systems tract are all made up of fan delta-underwater fan-lacustrine sedimentary systems in the side of steep slope.展开更多
The advantage of high-resolution sequence stratigraphy, which takes base-levels as reference, is that it can be applied to continental depositional basins controlled by multiple factors and can effectively improve the...The advantage of high-resolution sequence stratigraphy, which takes base-levels as reference, is that it can be applied to continental depositional basins controlled by multiple factors and can effectively improve the accuracy and resolution of sequential stratigraphic analysis. Moreover, the principles of base-level cycles are also suitable for analyzing sequential stratigraphy in continental coal-bearing basins because of their accuracy in forecasting distribution of coal measures. By taking the Dongsheng coalfield in the Ordos basin as an example, the extensive application of base-level cycles in exploration and exploitation of coal is analyzed. The result shows that the Yan’an formation in the Dongsheng area is a long-term base-level cycle which is bordered by nonconformities and made up of five mid-term cycles and 13 short-term cycles. The long-term cycle and the mid-term cycles are obvious in comparison with a transverse profile. The episodic coal accumulation in the Mesozoic Ordos basin means that the deposition of primary matter (peat bogs) of coalification is discontinuous, periodical and cyclical in the evolution of the basin. The episodic accumulation of coal measures in the Yan’an stage is controlled by ascending-descending changes of a long-term cycle and middle-term cycles. Coal measures formed during the early and late periods of the long-term cycle are characterized by multiple layers, big cumulative thickness and poor continuity. Coal measures formed in the mid-term of the long cycle are dominated by good continuity, fewer layers and a small additive thickness, which is favorable for the accumulation of thick and continuous coal measures in the transition stage of mid term base-level cycles.展开更多
The identification of sequence boundaries is the key point for sequence stratigraphicclassification.Both the higher-order sequences and the units within the sequencesare bounded with the key sediments or isochronous s...The identification of sequence boundaries is the key point for sequence stratigraphicclassification.Both the higher-order sequences and the units within the sequencesare bounded with the key sediments or isochronous surfaces.Eight sequences can be dividedin the whole Permo-Carboniferous strata (the Shiqianfeng Formation is not included)which is from the Benxi Formation,Taiyuan Formation,Shanxi Formation,Xiashihezi Formation,Wanshan Section,and Kuishan Section to the Xiaofuhe Section.Also,differentsystem tracts (lowstand system tract,transgression system tract and highstand systemtract) and some parasequences can be recognized in each sequence.Parasequenceanalysis was on the basis of the division of the base-level cycle.The base-level cycle wasmainly identified according to the change of the water area,which was reflected by thedepositional sequence.The physical characteristic of the strata was reflected by the welllog.It was supplied by the test of the minerals and rocks and the analysis of the microelementin the lab.The paleogeographic characteristic of the lowstand system tract in thesequence Ⅵ is that the east-north part takes the river system as its feature;the south partis the lake system,the river channel spreads from north to south,and the area of theflooding plain is great.The paleogeographic characteristic of the water-transgressive systemtract is that the range of the lake in the south extended distinctively,the range of theriver channel in the east reduced.The coastal shallow lake deposit is the main characteristicin the water-transgressive system tract.The paleogeographic characteristic of thehighstand system tract is similar to the one of the lowstand system tract.展开更多
The authors discussed the method of wavelet neural network(WNN) for correlation of base-level cycle.A new vectored method of well log data was proposed.Through the training with the known data set,the WNN can remenber...The authors discussed the method of wavelet neural network(WNN) for correlation of base-level cycle.A new vectored method of well log data was proposed.Through the training with the known data set,the WNN can remenber the cycle pattern characteristic of the well log curves.By the trained WNN to identify the cycle pattern in the vectored log data,the ocrrelation process among the well cycles was completed.The application indicates that it is highly efficient and reliable in base-level cycle correlation.展开更多
文摘Base-level is a kind of surface which controls sedimentation and erosion. So, it can be concluded that it is base-level change that controls the formation and internal structure of a sequence. A single cycle of base-level change can generate four sets of different stacking patterns. They are two sets of aggradation, one progradation and one retrogradation, which affects the features of the internal structure of a sequence. Lishu fault subsidence of Songliao basin is a typical half-graben lacustrine basin. Comprehensive base-level change analysis indicates that six base-level cycles and their related six sequences can be recognized between T 4 and T 5 seismic reflection surface. The contemporaneous fault is the main controlling factor of the fault lacustrine basin. There are obvious differences exist in the composition of sedimentary systems and all systems tracts between its steep slope (the side that basin control fault existed) and flat slope. Except highstand systems tract is composed of fan delta-lacustrine system, lowstand systems tract, transgressive systems tract and regressive systems tract are all made up of fan delta-underwater fan-lacustrine sedimentary systems in the side of steep slope.
基金Project2003CB214603 supported by Development Plan of the State Key Fundamental Research, China
文摘The advantage of high-resolution sequence stratigraphy, which takes base-levels as reference, is that it can be applied to continental depositional basins controlled by multiple factors and can effectively improve the accuracy and resolution of sequential stratigraphic analysis. Moreover, the principles of base-level cycles are also suitable for analyzing sequential stratigraphy in continental coal-bearing basins because of their accuracy in forecasting distribution of coal measures. By taking the Dongsheng coalfield in the Ordos basin as an example, the extensive application of base-level cycles in exploration and exploitation of coal is analyzed. The result shows that the Yan’an formation in the Dongsheng area is a long-term base-level cycle which is bordered by nonconformities and made up of five mid-term cycles and 13 short-term cycles. The long-term cycle and the mid-term cycles are obvious in comparison with a transverse profile. The episodic coal accumulation in the Mesozoic Ordos basin means that the deposition of primary matter (peat bogs) of coalification is discontinuous, periodical and cyclical in the evolution of the basin. The episodic accumulation of coal measures in the Yan’an stage is controlled by ascending-descending changes of a long-term cycle and middle-term cycles. Coal measures formed during the early and late periods of the long-term cycle are characterized by multiple layers, big cumulative thickness and poor continuity. Coal measures formed in the mid-term of the long cycle are dominated by good continuity, fewer layers and a small additive thickness, which is favorable for the accumulation of thick and continuous coal measures in the transition stage of mid term base-level cycles.
基金Supported by the Nation's National Science Foundation of China(40742010)
文摘The identification of sequence boundaries is the key point for sequence stratigraphicclassification.Both the higher-order sequences and the units within the sequencesare bounded with the key sediments or isochronous surfaces.Eight sequences can be dividedin the whole Permo-Carboniferous strata (the Shiqianfeng Formation is not included)which is from the Benxi Formation,Taiyuan Formation,Shanxi Formation,Xiashihezi Formation,Wanshan Section,and Kuishan Section to the Xiaofuhe Section.Also,differentsystem tracts (lowstand system tract,transgression system tract and highstand systemtract) and some parasequences can be recognized in each sequence.Parasequenceanalysis was on the basis of the division of the base-level cycle.The base-level cycle wasmainly identified according to the change of the water area,which was reflected by thedepositional sequence.The physical characteristic of the strata was reflected by the welllog.It was supplied by the test of the minerals and rocks and the analysis of the microelementin the lab.The paleogeographic characteristic of the lowstand system tract in thesequence Ⅵ is that the east-north part takes the river system as its feature;the south partis the lake system,the river channel spreads from north to south,and the area of theflooding plain is great.The paleogeographic characteristic of the water-transgressive systemtract is that the range of the lake in the south extended distinctively,the range of theriver channel in the east reduced.The coastal shallow lake deposit is the main characteristicin the water-transgressive system tract.The paleogeographic characteristic of thehighstand system tract is similar to the one of the lowstand system tract.
基金Supported by Project of Dagang Branch of Petroleum Group Company Ltd,CNPC No TJDG-JZHT-2005-JSDW-0000-00339
文摘The authors discussed the method of wavelet neural network(WNN) for correlation of base-level cycle.A new vectored method of well log data was proposed.Through the training with the known data set,the WNN can remenber the cycle pattern characteristic of the well log curves.By the trained WNN to identify the cycle pattern in the vectored log data,the ocrrelation process among the well cycles was completed.The application indicates that it is highly efficient and reliable in base-level cycle correlation.
