Sandy debris flow is a new genetic type of sand bodies,which has gained much attention in recent years and its corresponding theory is proved to be a significant improvement and even partial denial to the 'Bouma S...Sandy debris flow is a new genetic type of sand bodies,which has gained much attention in recent years and its corresponding theory is proved to be a significant improvement and even partial denial to the 'Bouma Sequence' and 'turbidite fan' deep-water sedimentary theories to some point. Oil exploration researchers are highly concerned with sandy debris flows for its key role in controlling oil and gas accumulation processes.In this article,by applying sandy debris flows theory and combining a lot work of core,outcrop observation and analysis plus seismic profile interpretation,we recognized three types of sedimentary gravity flows that are sandy debris flows,classic turbidites and slumping rocks in chang-6 member of Yanchang Formation in the deep-water area of central Ordos Basin.Among the three types,the sandy debris flows are the most prominent and possesses the best oil bearing conditions.On the contrary,the classic turbidites formed by turbidity currents are limited in distribution;therefore,previous Yanchang Formation deep-water sedimentary studies have exaggerated the importance of turbidite currents deposition.Further study showed that the area distribution of deep water gravity flow sand bodies in Yanchang Formation were controlled by the slope of the deep-water deposits and the flows had vast distribution,huge depth and prevalent advantages for oil forming,which make it one of the most favorable new areas for Ordos Basin prospecting.展开更多
Recently, more attention has been paid on the high gamma sandstone reservoirs of the Yanchang Formation in the Ordos Basin, China. These high gamma sandstones have logging characteristics different from conventional s...Recently, more attention has been paid on the high gamma sandstone reservoirs of the Yanchang Formation in the Ordos Basin, China. These high gamma sandstones have logging characteristics different from conventional sandstones, which influences the identification of sandstone reservoirs. Zhang et al （2010） proposed that the high gamma sandstones of the Yanchang Formation might be the result of re-deposition of homochronous sedimentary tufts or previous tufts as a part of the sandstone. However, we present a different viewpoint： 1） few tufts or tuff debris have been found in the high gamma sandstones of the Yanchang Formation; 2） high gamma （or high Th content） sandstones of Yanchang Formation are not related to either clay minerals or feldspar; 3） the heavy minerals in the sandstone reservoirs of the Yanchang Formation are dominated by zircon, which is characterized by abnormally high Th and U contents, up to 2,163 ppm and 1,362 ppm, respectively. This is sufficient to explain the high gamma anomaly. The conclusion is that the high gamma value of the Yanchang Formation sandstones might be caused by zircon with high Th and U contents in sandstones rather than from the tuff components.展开更多
It is important to determine the properties of the tectonics in Cambrian period for the sake of prospecting deep hydrocarbon in the near future in the southern Ordos Kratogen of North China. Authors chose the marginal...It is important to determine the properties of the tectonics in Cambrian period for the sake of prospecting deep hydrocarbon in the near future in the southern Ordos Kratogen of North China. Authors chose the marginal areas of the southern Ordos basin as the object of research, avoided the effects of both the Qinling Orogenic Belts （QOB） and Weihe River Graben （WRG） whose geological structures are too complicated. By surveying typical Cambrian outcrops and profdes in the basin edges and based on the cores of 57 wells which penetrated the Cambrian in the basin, combined with the seismic profiles, the field gammaray measuement results and the carbon isotope analysis, Authors conclude that the southern margin of the Ordos Kratogen during Cambrian was a passive continental margin which resulted from sea-floor spreading of the Ancient Qinling Ocean. Epicontinental sea carbonate sediments formed in the south Ordos continental margin during Cambrian, and were predominant as tidal flat and o61itic shoal. Both transgression-regression process and the change in palaeostructure have the obvious cyclicity. Using the junction between the late Nangao age of Qiandong epoch and the early Duyun age of Qiandong epoch as a boundary, each had a full transgression cycle at the upper and lower stages. The early cycle is characterized by high energy clastic littoral facies while the late cycle is characterized by carbonate ramp on which clear water and muddy water developed alternately changing to carbonate platform last. During the early stages, An aulacogen was formed in the middle section of the southern margin. The southern Ordos margin was uplifted and denudated by the Huaiyuan Movement which occurred from the late Furongian age to the middle Flolan age and the history of the passive continental margin ended and entering into a new tectonic cycle. The unconformity surface caused by the Huaiyuan Movement, along with its neighborhood areas where dissolved pores and cavities are developed, may be another important district for good hydrocarbon reservoirs （excluding the unconformity surface on the top of the Ordovician in the Ordos basin）.展开更多
针对主动配电网的日前-日内两阶段优化调度问题,首先构建了配电管理系统总揽全局、区域调控终端负责分区的调控框架。采用经济性与安全性协调统一的两阶段调度策略:日前执行经济调度,降低主动配电网(active distribution network,ADN)...针对主动配电网的日前-日内两阶段优化调度问题,首先构建了配电管理系统总揽全局、区域调控终端负责分区的调控框架。采用经济性与安全性协调统一的两阶段调度策略:日前执行经济调度,降低主动配电网(active distribution network,ADN)运行成本;日内阶段正常时各子区域跟踪日前计划进行分区局部修正,存在电压越限时DMS执行系统全局调整以消除越限。建立了日前经济调度、日内分区局部功率修正与系统全局电压调整的数学优化模型,并采用和声搜索算法来求解调度模型。最后通过算例分析,验证了所提调度方法能够适用于日前-日内两个阶段,保障ADN经济安全运行。展开更多
文摘Sandy debris flow is a new genetic type of sand bodies,which has gained much attention in recent years and its corresponding theory is proved to be a significant improvement and even partial denial to the 'Bouma Sequence' and 'turbidite fan' deep-water sedimentary theories to some point. Oil exploration researchers are highly concerned with sandy debris flows for its key role in controlling oil and gas accumulation processes.In this article,by applying sandy debris flows theory and combining a lot work of core,outcrop observation and analysis plus seismic profile interpretation,we recognized three types of sedimentary gravity flows that are sandy debris flows,classic turbidites and slumping rocks in chang-6 member of Yanchang Formation in the deep-water area of central Ordos Basin.Among the three types,the sandy debris flows are the most prominent and possesses the best oil bearing conditions.On the contrary,the classic turbidites formed by turbidity currents are limited in distribution;therefore,previous Yanchang Formation deep-water sedimentary studies have exaggerated the importance of turbidite currents deposition.Further study showed that the area distribution of deep water gravity flow sand bodies in Yanchang Formation were controlled by the slope of the deep-water deposits and the flows had vast distribution,huge depth and prevalent advantages for oil forming,which make it one of the most favorable new areas for Ordos Basin prospecting.
基金supported by the National Science and Technology Major Subject(No.2008ZX05044 2-8-2)"Large scale oil and gas field and coal bed methane development"
文摘Recently, more attention has been paid on the high gamma sandstone reservoirs of the Yanchang Formation in the Ordos Basin, China. These high gamma sandstones have logging characteristics different from conventional sandstones, which influences the identification of sandstone reservoirs. Zhang et al （2010） proposed that the high gamma sandstones of the Yanchang Formation might be the result of re-deposition of homochronous sedimentary tufts or previous tufts as a part of the sandstone. However, we present a different viewpoint： 1） few tufts or tuff debris have been found in the high gamma sandstones of the Yanchang Formation; 2） high gamma （or high Th content） sandstones of Yanchang Formation are not related to either clay minerals or feldspar; 3） the heavy minerals in the sandstone reservoirs of the Yanchang Formation are dominated by zircon, which is characterized by abnormally high Th and U contents, up to 2,163 ppm and 1,362 ppm, respectively. This is sufficient to explain the high gamma anomaly. The conclusion is that the high gamma value of the Yanchang Formation sandstones might be caused by zircon with high Th and U contents in sandstones rather than from the tuff components.
基金supported by a grant from the special research project-Key Technologies of Exploration and Development in Marine Carbonatite for Major Oil-Gas Fields in China (Code: 2008E-0700)sponsored by the State funding and PetroChina
文摘It is important to determine the properties of the tectonics in Cambrian period for the sake of prospecting deep hydrocarbon in the near future in the southern Ordos Kratogen of North China. Authors chose the marginal areas of the southern Ordos basin as the object of research, avoided the effects of both the Qinling Orogenic Belts （QOB） and Weihe River Graben （WRG） whose geological structures are too complicated. By surveying typical Cambrian outcrops and profdes in the basin edges and based on the cores of 57 wells which penetrated the Cambrian in the basin, combined with the seismic profiles, the field gammaray measuement results and the carbon isotope analysis, Authors conclude that the southern margin of the Ordos Kratogen during Cambrian was a passive continental margin which resulted from sea-floor spreading of the Ancient Qinling Ocean. Epicontinental sea carbonate sediments formed in the south Ordos continental margin during Cambrian, and were predominant as tidal flat and o61itic shoal. Both transgression-regression process and the change in palaeostructure have the obvious cyclicity. Using the junction between the late Nangao age of Qiandong epoch and the early Duyun age of Qiandong epoch as a boundary, each had a full transgression cycle at the upper and lower stages. The early cycle is characterized by high energy clastic littoral facies while the late cycle is characterized by carbonate ramp on which clear water and muddy water developed alternately changing to carbonate platform last. During the early stages, An aulacogen was formed in the middle section of the southern margin. The southern Ordos margin was uplifted and denudated by the Huaiyuan Movement which occurred from the late Furongian age to the middle Flolan age and the history of the passive continental margin ended and entering into a new tectonic cycle. The unconformity surface caused by the Huaiyuan Movement, along with its neighborhood areas where dissolved pores and cavities are developed, may be another important district for good hydrocarbon reservoirs （excluding the unconformity surface on the top of the Ordovician in the Ordos basin）.
文摘针对主动配电网的日前-日内两阶段优化调度问题,首先构建了配电管理系统总揽全局、区域调控终端负责分区的调控框架。采用经济性与安全性协调统一的两阶段调度策略:日前执行经济调度,降低主动配电网(active distribution network,ADN)运行成本;日内阶段正常时各子区域跟踪日前计划进行分区局部修正,存在电压越限时DMS执行系统全局调整以消除越限。建立了日前经济调度、日内分区局部功率修正与系统全局电压调整的数学优化模型,并采用和声搜索算法来求解调度模型。最后通过算例分析,验证了所提调度方法能够适用于日前-日内两个阶段,保障ADN经济安全运行。
