The Bikaner-Nagaur and Barmer Basins(Rajasthan)are the most important petroliferous sedimentary basins in India.For over a decade,the exploration and extraction of hydrocarbons in these basins.Paleocene-Eocene age roc...The Bikaner-Nagaur and Barmer Basins(Rajasthan)are the most important petroliferous sedimentary basins in India.For over a decade,the exploration and extraction of hydrocarbons in these basins.Paleocene-Eocene age rocks bear organic-rich sediments in these basins,including lignite and carbonaceous shale deposits.The present research investigates the source rock properties,petroleum potential and thermal maturity of the carbonaceous shale partings from the lignite mines of Gurha(Bikaner-Nagaur Basin)and Kapurdi(Barmer Basin)using petrographical and geochemical tools.The carbonaceous shales have high organic matter(OM),with considerable total organic carbon(TOC)contents ranging from 13%to 39%.Furthermore,they contain hydrogen-rich kerogen,including types II and II/III,as evidenced by the Rock-Eval and elemental analysis results.The existence of these kerogen types indicates the abundance of reactive(vitrinite and liptinite)macerals.However,the carbonaceous shales from the Bikaner–Nagaur Basin have oil generation potentials,with a high hydrogen index(up to 516 mg HC/g TOC)and a H/C ratio(up to 1.5)along with a significant presence of oil-prone liptinitic macerals.Apart from the geochemical and petrological results,the studied shales have low huminite reflectance(0.31%–0.48%),maximum temperature(S_(2) peak;Tmax)between 419℃ and 429℃,and low production index values(PI:0.01–0.03).These results indicate that these carbonaceous shales contain immature OM,and thereby,they cannot yet release commercial amount of oil.This immaturity level in the studied outcrop section is due to the shallow burial depth.Geochemical proxies further indicate the presence of both oil and gas-prone source rocks.展开更多
At 20:08,on September 18,2024,an M4.7 earthquake occurred along the Tanlu fault zone in the Feidong County of Hefei,Anhui Province.This earthquake is the largest event in the modern history of Hefei,which caused subst...At 20:08,on September 18,2024,an M4.7 earthquake occurred along the Tanlu fault zone in the Feidong County of Hefei,Anhui Province.This earthquake is the largest event in the modern history of Hefei,which caused substantial social impact.To reveal the seismogenic structure of the M4.7 Feidong earthquake sequence and assess seismic risks,we use data from both the permanent seismic network and a temporary dense nodal array deployed in the epicentral region prior to the mainshock for:(1)accurate location of the earthquake sequence and determination of the focal mechanisms;(2)obtaining the spatiotemporal distribution,b-value,and half-day occurrence frequency of the earthquake sequence.The Sentinel-1 satellite data are used to analyze the coseismic displacement.Additionally,velocity models from regional tomography and local high-resolution 2D active-and passive-source surveys across the Tanlu fault zone in the epicentral area are also used to reveal the detailed geometry of the seismogenic fault.The results indicate:(1)the M4.7 Feidong earthquake sequence is concentrated around 10.5 km in depth along a NW-dipping,subvertical fault which trends NE and is approximately 5 km in length;the focal mechanism solution also reveals that the fault hosting the mainshock is a subvertical strike-slip fault,driven by the regional compressional stress in ENE-WSW;the coseismic horizontal displacement on the surface caused by the M4.7 mainshock has a maximum value close to 1 mm;(2)the regional velocity model shows significant lateral variation in v_(S) in the source region,with the mainshock occurring in the area with higher velocity;high-resolution P-wave velocity structures obtained by full waveform inversion from active sources,and S-wave velocity structures from passive-source ambient noise tomography indicate that the mainshock occurred along the boundary between high-and low-velocity bodies,and the seismogenic fault dips NW;the deep seismic reflection profiling shows that the mainshock occurred within the Jurassic strata;(3)based on these results,we suggest the seismogenic fault for the M4.7 Feidong earthquake is either the Zhuding-Shimenshan fault,one of the major faults in the Tanlu fault zone,or a hidden fault to the east;the intersection of the NE-trending Tanlu fault zone and the WNW-trending Feizhong fault,along with significant velocity variations,likely create local stress concentrations which could have triggered the M4.7 Feidong earthquake sequence;(4)the strong aftershocks following the M4.7 Feidong mainshock did not further extend the fault rupture zone;the active period of the Zhuding-Shimenshan fault was the late Early Pleistocene to Middle Pleistocene,and the imaging results indicate that this fault does not cut through the shallow Feidong depression.In conjunction with the small coseismic rupture area,it is inferred that the probability of surface-rupturing earthquakes in the future is relatively low.展开更多
在系统介绍洞穴石笋高精度ICP-M S铀系年代学原理与方法的基础上,对贵州荔波县衙门洞Y 1石笋进行了ICP-M S 2 30 T h测年研究。综合分析认为精确时标的建立对于利用石笋进行古气候重建具有重要的实际意义;采用ICP-M S2 3 0 T h测年方法...在系统介绍洞穴石笋高精度ICP-M S铀系年代学原理与方法的基础上,对贵州荔波县衙门洞Y 1石笋进行了ICP-M S 2 30 T h测年研究。综合分析认为精确时标的建立对于利用石笋进行古气候重建具有重要的实际意义;采用ICP-M S2 3 0 T h测年方法进行石笋样品定年准确可靠,并且比T IM S方法具有更高的效率,所需样品更微量。通过生长速率变化分析表明,石笋生长速率记录了过去冷暖突变事件,因此可以用它作为一个有意义的环境记录替代指标来研究古降水及古气候变化。展开更多
Seismic attributes, such as P- and S-wave velocity, Poisson＇s ratio, and acoustic impedances, all generally can be used for distinguishing different rock types. The nonuniqueness can be largely reduced using Lame imp...Seismic attributes, such as P- and S-wave velocity, Poisson＇s ratio, and acoustic impedances, all generally can be used for distinguishing different rock types. The nonuniqueness can be largely reduced using Lame impedances instead of acoustic impedances as additional constraints. We have followed this method to constitute a petrologic composition model of the upper crust in the Bohai Bay basin, China. We briefly review the seismic parameters used for discrimination of rock types and focus our attention on the sensitivity of different combinations of parameters to determine the composition of materials. Corrections for pressure and temperature are performed in order to compare elastic wave velocities and densities measured at room temperature and surface pressure in laboratory with those for representative rock parameters. In a second step, we find the rock classes in the tested area by contrasting known data to laboratory measurements on a variety of rock samples extracted in the area. The basic field data are P-wave velocity values collected along a seismic profile conducted in the Bozhong Depression. The different rock types belonging to a particular rock class are finally constrained by the seismic velocities, Poisson＇s ratio, density, acoustic impedance, and Lame imoedance related to the topmost 10 km of the Bohai Bav crust.展开更多
The Early Cretaceous Jehol biota of northeastern China contains a diverse group of notostracans, including two genera, Chenops and Jeholops, described here. Chenops is characterized by a combination of an ovate carapa...The Early Cretaceous Jehol biota of northeastern China contains a diverse group of notostracans, including two genera, Chenops and Jeholops, described here. Chenops is characterized by a combination of an ovate carapace, narrow anal plate, equant distal endites and endopod on the anterior thoracic limbs. In addition to the new species, Chenops yixianensis, the genus also provisionally includes Prolepidurus oblongus Oleynikov, 1968. Jeholops, however, is monotypic, represented by the new species Jeholops hongi. It is characterized by a combination of kazacharthran and notostracan features unique to this taxon. Both new genera are provisionally placed in the taxon Notostraca. More detailed work exploring the morphology of exceptionally-preserved branchiopod crustaceans is needed. The difficulties in placing fossil notostracans into a phylogenetie framework are discussed.展开更多
Bryozoan nodules, coralline algae, scleractinian corals and oysters form an important organic buildup, 1.2-4.5 m thick in the Langhian-Serravaliann sediments of Egypt. Based on type, shape and size of the substrate, b...Bryozoan nodules, coralline algae, scleractinian corals and oysters form an important organic buildup, 1.2-4.5 m thick in the Langhian-Serravaliann sediments of Egypt. Based on type, shape and size of the substrate, bryozoan nodules take tree-like and globular morphologies. Tree-like speci- mens reach 10 cm in maximum height and 3 cm in diameter, while Globular ones attain 9 cm in maxi- mum diameter. Most tree-like nodules are perforated with wide or narrow pores, few are non-perforated. Globulars and few tree-like forms are with mamelon-like structures. Perforations on the outer surfaces may indicate a symbiotic relationship between bryozoans and a live plant substrate. Nod- ules from Homiera and Gharra areas of the Cairo-Suez District with wider perforations may indicate growth in slightly lighter or turbid areas of the continental shelf than those of North Western Desert of narrower perforations. Non-perforated nodules may assume an incrustation on ephemeral substrate .展开更多
When topography and low velocity zone differences vary greatly, conventional vertical static time shifts will cause wavefield distortion and influence wave equation seismic imaging for seismic data acquired on a compl...When topography and low velocity zone differences vary greatly, conventional vertical static time shifts will cause wavefield distortion and influence wave equation seismic imaging for seismic data acquired on a complex near surface. In this paper, we propose an approach to datum correction that combines a joint tomography inversion with wavefield continuation to solve the static problem for seismic data on rugged acquisition topography. First, the near surface model is obtained by refracted wave tomography inversion. Second, the wavefield of sources and receivers are continued downward and upward to accomplish datum correction starting from a flat surface and locating the datum above topography. Based on the reciprocal theorem, Huygens＇ and Fresnel principles, the location of sources and receivers, and regarding the recorded data on the surface as a secondary emission, the sources and receivers are upward-continued to the datum above topography respectively. Thus, the datum correction using joint tomography inversion and wavefield continuation with the condition of a complex near surface is accomplished.展开更多
The Gulf of Suez region is one of the most interesting geothermal areas in Egypt because of the high temperatures of its springs.The eastern and western shores of the Gulf of Suez are characterized by superficial ther...The Gulf of Suez region is one of the most interesting geothermal areas in Egypt because of the high temperatures of its springs.The eastern and western shores of the Gulf of Suez are characterized by superficial thermal manifestations including a cluster of hot springs with varied temperatures.Variations of deuterium and oxygen-18 concentrations in thermal waters have been used to aid in describing the source of recharge in the Gulf of Suez hot springs.Isotope and geochemical data for the Gulf of Suez thermal waters suggest that recharge to the hot springs may not be entirely from the Gulf of Suez water,but possibly from the meteoric water that comes from areas of higher altitude surrounding the hot springs.展开更多
A 3-D chemical transport model (OSLO CTM2) is used to investigate the influences of the increasing anthropogenic emission in India. The model is capable of reproducing the observational results of the INDOEX experimen...A 3-D chemical transport model (OSLO CTM2) is used to investigate the influences of the increasing anthropogenic emission in India. The model is capable of reproducing the observational results of the INDOEX experiment and the measurements in summer over India well. The model results show that when NOx and CO emissions in India are doubled, ozone concentration increases, and global average OH decreases a little. Under the effects of the Indian summer monsoon, NOx and CO in India are efficiently transported into the middle and upper troposphere by the upward current and the convective activities so that the NOX, CO, and ozone in the middle and upper troposphere significantly increase with the increasing NOx and CO emissions. These increases extensively influence a part of Asia, Africa, and Europe, and persist from June to September.展开更多
The Middle Jurassic Shaximiao Formation encompasses tens of meters of thick lowstand meandering valley （LMV） strata in the western Sichuan foreland basin. Ancient LMVs newly discovered in this area were further stud...The Middle Jurassic Shaximiao Formation encompasses tens of meters of thick lowstand meandering valley （LMV） strata in the western Sichuan foreland basin. Ancient LMVs newly discovered in this area were further studied based on sequence stratigraphy and seismic sedimentology. The aim of the present study was to investigate the sedimentary characteristics, sequence architecture, and the controls on LMV deposition in this tectonically active basin using field survey data, seismic sections, seismic amplitude imaging, core description, and comprehensive application of drilling data. The results show the following： （1） Three regional sequence boundaries and two flooding surfaces were recognized, and the Shaximiao For- mation was divided into two-third-order sequences and four systems tracts. （2） Three sedimentary facies associations were identified： incised valley-fill, tributary channel, and overbank facies. Incised valleys are 5-17 km wide, 20-60 m deep and traceable for 120 km along their axes. （3） In the downstream segment, the role of tectonism gradually diminishes, and periodic base-level changes control the form and evolution of the incised valleys. Three types of LMVs--AI, A2, and A3--developed with changes in base level （lake level）; of these types, the base level of the A3 LMV was likely the lowest.展开更多
A collection of data obtained from analytical methods in geochemistry along with the reservoir engineering and geologic data were used to investigate the reservoir continuity in the Cretaceous Fahliyan, Gadavan, Kazhd...A collection of data obtained from analytical methods in geochemistry along with the reservoir engineering and geologic data were used to investigate the reservoir continuity in the Cretaceous Fahliyan, Gadavan, Kazhdumi and Sarvak reservoirs of the super-giant Azadegan oilfield, SW Iran. The geochemical data indicate that the oil samples, with medium to high level of thermal maturity, have been generated from the anoxic marine marl/carbonate source rock(s). The Sargelu(Jurassic) and Garau(Cretaceous) formations are introduced as the main source rocks for the studied oils. The dendrogram obtained from the cluster analysis of high-resolution gas chromatography data introduces two main oil groups including Fahliyan reservoir, and Kazhdumi along with Sarvak/Gadvan reservoirs. This is confirmed by C7 Halpern star diagram, indicating that, the light oil fraction from Fahliyan reservoir is distinct from the others. Also, different pressure gradient of the Fahliyan Formation(over-pressured) relative to other reservoirs(normally-pressured) show the presence of compartments. The relation between toluene/n-heptane and n-heptane/methylcyclohexane represents the compartmentalization due to maturation/evaporative fractionation for Fahliyan and water washing for other studied reservoirs. Also, the impermeable upper part of the Fahliyan Formation and thin interbedded shaly layers in the Kazhdumi, Sarvak and Gadvan formations have controlled reservoir compartmentalization.展开更多
基金The University of Malaya's postdoctoral fellowship program has been acknowledged by the first author and is associated with grant number IF064-2019the Department of Science and Technology (Project No. SB/S4/ES-681/2013), Government of India, for their supportthe Researchers Supporting Project number (RSPD2024R546) at King Saud University in Riyadh, Saudi Arabia
文摘The Bikaner-Nagaur and Barmer Basins(Rajasthan)are the most important petroliferous sedimentary basins in India.For over a decade,the exploration and extraction of hydrocarbons in these basins.Paleocene-Eocene age rocks bear organic-rich sediments in these basins,including lignite and carbonaceous shale deposits.The present research investigates the source rock properties,petroleum potential and thermal maturity of the carbonaceous shale partings from the lignite mines of Gurha(Bikaner-Nagaur Basin)and Kapurdi(Barmer Basin)using petrographical and geochemical tools.The carbonaceous shales have high organic matter(OM),with considerable total organic carbon(TOC)contents ranging from 13%to 39%.Furthermore,they contain hydrogen-rich kerogen,including types II and II/III,as evidenced by the Rock-Eval and elemental analysis results.The existence of these kerogen types indicates the abundance of reactive(vitrinite and liptinite)macerals.However,the carbonaceous shales from the Bikaner–Nagaur Basin have oil generation potentials,with a high hydrogen index(up to 516 mg HC/g TOC)and a H/C ratio(up to 1.5)along with a significant presence of oil-prone liptinitic macerals.Apart from the geochemical and petrological results,the studied shales have low huminite reflectance(0.31%–0.48%),maximum temperature(S_(2) peak;Tmax)between 419℃ and 429℃,and low production index values(PI:0.01–0.03).These results indicate that these carbonaceous shales contain immature OM,and thereby,they cannot yet release commercial amount of oil.This immaturity level in the studied outcrop section is due to the shallow burial depth.Geochemical proxies further indicate the presence of both oil and gas-prone source rocks.
基金supported by the Anhui Province Science and Technology Breakthrough Plan Project(Key Project,No.202423l10050030)the National Natural Science Foundation of China(Fundamental Science Center Category B,No.4248830017)+4 种基金the Joint Funds of National Natural Science Foundation of China(No.U2139204)the National Natural Science Foundation of China Project(No.42104063)the Hefei Government Key Construction Project(No.2024BFFFD02048)the Earthquake Science and Technology Spark Program of the China Earthquake Administration(Nos.XH23020YA,XH24020B)the Anhui Mengcheng National Geophysical Observatory Joint Open Fund(No.MENGO-202307).
文摘At 20:08,on September 18,2024,an M4.7 earthquake occurred along the Tanlu fault zone in the Feidong County of Hefei,Anhui Province.This earthquake is the largest event in the modern history of Hefei,which caused substantial social impact.To reveal the seismogenic structure of the M4.7 Feidong earthquake sequence and assess seismic risks,we use data from both the permanent seismic network and a temporary dense nodal array deployed in the epicentral region prior to the mainshock for:(1)accurate location of the earthquake sequence and determination of the focal mechanisms;(2)obtaining the spatiotemporal distribution,b-value,and half-day occurrence frequency of the earthquake sequence.The Sentinel-1 satellite data are used to analyze the coseismic displacement.Additionally,velocity models from regional tomography and local high-resolution 2D active-and passive-source surveys across the Tanlu fault zone in the epicentral area are also used to reveal the detailed geometry of the seismogenic fault.The results indicate:(1)the M4.7 Feidong earthquake sequence is concentrated around 10.5 km in depth along a NW-dipping,subvertical fault which trends NE and is approximately 5 km in length;the focal mechanism solution also reveals that the fault hosting the mainshock is a subvertical strike-slip fault,driven by the regional compressional stress in ENE-WSW;the coseismic horizontal displacement on the surface caused by the M4.7 mainshock has a maximum value close to 1 mm;(2)the regional velocity model shows significant lateral variation in v_(S) in the source region,with the mainshock occurring in the area with higher velocity;high-resolution P-wave velocity structures obtained by full waveform inversion from active sources,and S-wave velocity structures from passive-source ambient noise tomography indicate that the mainshock occurred along the boundary between high-and low-velocity bodies,and the seismogenic fault dips NW;the deep seismic reflection profiling shows that the mainshock occurred within the Jurassic strata;(3)based on these results,we suggest the seismogenic fault for the M4.7 Feidong earthquake is either the Zhuding-Shimenshan fault,one of the major faults in the Tanlu fault zone,or a hidden fault to the east;the intersection of the NE-trending Tanlu fault zone and the WNW-trending Feizhong fault,along with significant velocity variations,likely create local stress concentrations which could have triggered the M4.7 Feidong earthquake sequence;(4)the strong aftershocks following the M4.7 Feidong mainshock did not further extend the fault rupture zone;the active period of the Zhuding-Shimenshan fault was the late Early Pleistocene to Middle Pleistocene,and the imaging results indicate that this fault does not cut through the shallow Feidong depression.In conjunction with the small coseismic rupture area,it is inferred that the probability of surface-rupturing earthquakes in the future is relatively low.
文摘在系统介绍洞穴石笋高精度ICP-M S铀系年代学原理与方法的基础上,对贵州荔波县衙门洞Y 1石笋进行了ICP-M S 2 30 T h测年研究。综合分析认为精确时标的建立对于利用石笋进行古气候重建具有重要的实际意义;采用ICP-M S2 3 0 T h测年方法进行石笋样品定年准确可靠,并且比T IM S方法具有更高的效率,所需样品更微量。通过生长速率变化分析表明,石笋生长速率记录了过去冷暖突变事件,因此可以用它作为一个有意义的环境记录替代指标来研究古降水及古气候变化。
基金supported by the National Natural Science Foundation of China (Grant 20930140)the Chinese Academy of Sciences and the sponsors of the Centre for Reservoir Geophysics of the Imperial College
文摘Seismic attributes, such as P- and S-wave velocity, Poisson＇s ratio, and acoustic impedances, all generally can be used for distinguishing different rock types. The nonuniqueness can be largely reduced using Lame impedances instead of acoustic impedances as additional constraints. We have followed this method to constitute a petrologic composition model of the upper crust in the Bohai Bay basin, China. We briefly review the seismic parameters used for discrimination of rock types and focus our attention on the sensitivity of different combinations of parameters to determine the composition of materials. Corrections for pressure and temperature are performed in order to compare elastic wave velocities and densities measured at room temperature and surface pressure in laboratory with those for representative rock parameters. In a second step, we find the rock classes in the tested area by contrasting known data to laboratory measurements on a variety of rock samples extracted in the area. The basic field data are P-wave velocity values collected along a seismic profile conducted in the Bozhong Depression. The different rock types belonging to a particular rock class are finally constrained by the seismic velocities, Poisson＇s ratio, density, acoustic impedance, and Lame imoedance related to the topmost 10 km of the Bohai Bav crust.
基金supported by the National Natural Science Foundation of China(no.40872022)the Nature Science Foundation of Beijing(no.5082002)+1 种基金Scientific Research Key Program and PHR Project of Beijing Municipal Commission of Educationfunded by a Crustacean Society Denton Belk Fellowship and the Yale Peabody Museum
文摘The Early Cretaceous Jehol biota of northeastern China contains a diverse group of notostracans, including two genera, Chenops and Jeholops, described here. Chenops is characterized by a combination of an ovate carapace, narrow anal plate, equant distal endites and endopod on the anterior thoracic limbs. In addition to the new species, Chenops yixianensis, the genus also provisionally includes Prolepidurus oblongus Oleynikov, 1968. Jeholops, however, is monotypic, represented by the new species Jeholops hongi. It is characterized by a combination of kazacharthran and notostracan features unique to this taxon. Both new genera are provisionally placed in the taxon Notostraca. More detailed work exploring the morphology of exceptionally-preserved branchiopod crustaceans is needed. The difficulties in placing fossil notostracans into a phylogenetie framework are discussed.
基金supported by King Saud University, Deanship of Scientific ResearchCollege of Science Research Center
文摘Bryozoan nodules, coralline algae, scleractinian corals and oysters form an important organic buildup, 1.2-4.5 m thick in the Langhian-Serravaliann sediments of Egypt. Based on type, shape and size of the substrate, bryozoan nodules take tree-like and globular morphologies. Tree-like speci- mens reach 10 cm in maximum height and 3 cm in diameter, while Globular ones attain 9 cm in maxi- mum diameter. Most tree-like nodules are perforated with wide or narrow pores, few are non-perforated. Globulars and few tree-like forms are with mamelon-like structures. Perforations on the outer surfaces may indicate a symbiotic relationship between bryozoans and a live plant substrate. Nod- ules from Homiera and Gharra areas of the Cairo-Suez District with wider perforations may indicate growth in slightly lighter or turbid areas of the continental shelf than those of North Western Desert of narrower perforations. Non-perforated nodules may assume an incrustation on ephemeral substrate .
基金the National Development and Innovation Committee Program (2005) 2372the National High-tech R&D Program (863 Program) 2006AA06Z241 of ChinaYouth Innovation Fund of CNPC’ Prestack Imaging Integral Study for Complex near Surface.
文摘When topography and low velocity zone differences vary greatly, conventional vertical static time shifts will cause wavefield distortion and influence wave equation seismic imaging for seismic data acquired on a complex near surface. In this paper, we propose an approach to datum correction that combines a joint tomography inversion with wavefield continuation to solve the static problem for seismic data on rugged acquisition topography. First, the near surface model is obtained by refracted wave tomography inversion. Second, the wavefield of sources and receivers are continued downward and upward to accomplish datum correction starting from a flat surface and locating the datum above topography. Based on the reciprocal theorem, Huygens＇ and Fresnel principles, the location of sources and receivers, and regarding the recorded data on the surface as a secondary emission, the sources and receivers are upward-continued to the datum above topography respectively. Thus, the datum correction using joint tomography inversion and wavefield continuation with the condition of a complex near surface is accomplished.
基金the stuff of National Research of Astronomy and Geophysics,Egypt for their continuous support and help
文摘The Gulf of Suez region is one of the most interesting geothermal areas in Egypt because of the high temperatures of its springs.The eastern and western shores of the Gulf of Suez are characterized by superficial thermal manifestations including a cluster of hot springs with varied temperatures.Variations of deuterium and oxygen-18 concentrations in thermal waters have been used to aid in describing the source of recharge in the Gulf of Suez hot springs.Isotope and geochemical data for the Gulf of Suez thermal waters suggest that recharge to the hot springs may not be entirely from the Gulf of Suez water,but possibly from the meteoric water that comes from areas of higher altitude surrounding the hot springs.
基金supported by the Young Grant of the Chinese Academy of Meteorological Sciencesthe Norwegian Research Council and the Natural Science Foundation of China.
文摘A 3-D chemical transport model (OSLO CTM2) is used to investigate the influences of the increasing anthropogenic emission in India. The model is capable of reproducing the observational results of the INDOEX experiment and the measurements in summer over India well. The model results show that when NOx and CO emissions in India are doubled, ozone concentration increases, and global average OH decreases a little. Under the effects of the Indian summer monsoon, NOx and CO in India are efficiently transported into the middle and upper troposphere by the upward current and the convective activities so that the NOX, CO, and ozone in the middle and upper troposphere significantly increase with the increasing NOx and CO emissions. These increases extensively influence a part of Asia, Africa, and Europe, and persist from June to September.
基金supported by the Natural Science Foundation of China(Grant No.41672098)the National Science and Technology Major Project(Grant No.2016ZX05002006)
文摘The Middle Jurassic Shaximiao Formation encompasses tens of meters of thick lowstand meandering valley （LMV） strata in the western Sichuan foreland basin. Ancient LMVs newly discovered in this area were further studied based on sequence stratigraphy and seismic sedimentology. The aim of the present study was to investigate the sedimentary characteristics, sequence architecture, and the controls on LMV deposition in this tectonically active basin using field survey data, seismic sections, seismic amplitude imaging, core description, and comprehensive application of drilling data. The results show the following： （1） Three regional sequence boundaries and two flooding surfaces were recognized, and the Shaximiao For- mation was divided into two-third-order sequences and four systems tracts. （2） Three sedimentary facies associations were identified： incised valley-fill, tributary channel, and overbank facies. Incised valleys are 5-17 km wide, 20-60 m deep and traceable for 120 km along their axes. （3） In the downstream segment, the role of tectonism gradually diminishes, and periodic base-level changes control the form and evolution of the incised valleys. Three types of LMVs--AI, A2, and A3--developed with changes in base level （lake level）; of these types, the base level of the A3 LMV was likely the lowest.
基金National Iranian Oil Company-Exploration Directorate(NIOC-EXP)the Petroleum Geology and Geochemistry Research Center(PGGRC)of Shahid Chamran University of Ahvaz.
文摘A collection of data obtained from analytical methods in geochemistry along with the reservoir engineering and geologic data were used to investigate the reservoir continuity in the Cretaceous Fahliyan, Gadavan, Kazhdumi and Sarvak reservoirs of the super-giant Azadegan oilfield, SW Iran. The geochemical data indicate that the oil samples, with medium to high level of thermal maturity, have been generated from the anoxic marine marl/carbonate source rock(s). The Sargelu(Jurassic) and Garau(Cretaceous) formations are introduced as the main source rocks for the studied oils. The dendrogram obtained from the cluster analysis of high-resolution gas chromatography data introduces two main oil groups including Fahliyan reservoir, and Kazhdumi along with Sarvak/Gadvan reservoirs. This is confirmed by C7 Halpern star diagram, indicating that, the light oil fraction from Fahliyan reservoir is distinct from the others. Also, different pressure gradient of the Fahliyan Formation(over-pressured) relative to other reservoirs(normally-pressured) show the presence of compartments. The relation between toluene/n-heptane and n-heptane/methylcyclohexane represents the compartmentalization due to maturation/evaporative fractionation for Fahliyan and water washing for other studied reservoirs. Also, the impermeable upper part of the Fahliyan Formation and thin interbedded shaly layers in the Kazhdumi, Sarvak and Gadvan formations have controlled reservoir compartmentalization.
