Taking member one of Yingcheng Formation of Cretaceous in Xudong area, Xushen Gas Field of Songliao Basin for an example and aimed at the diachronous problem generally existed in vol- canic reservoir division, firstly...Taking member one of Yingcheng Formation of Cretaceous in Xudong area, Xushen Gas Field of Songliao Basin for an example and aimed at the diachronous problem generally existed in vol- canic reservoir division, firstly advanced the method of two steps and two unites in the researches of volcanic reservoir finely division that guided by the method that sources controlled and founded the stratigraphic trellis. In this process, volcanic edifices and bodies were identified and traced. The results indicated that aimed strata in study areas could be carved up to six layers of YCII1, YCII2, YCII-II, YCIIlI, YCIII2 and YCIIII from the top to the bottom. Analyzing causes and firmly united of well data and seismic data could achieve fine stratigraphic division of volcanic reservoir. Surfaces of layers and volcanic bodies were basically unanimous in side direction. Stratum inclination gradually reduced with the distances increased from craters. The results of volcanic reservoir division had preferable con- sistency with lithologies and volcanic lithofacies and dynamic development data. The researches offered a useful method to stratigraphic division of volcanic reservoir and it had very important significance to effective development of volcanic reservoir in practice.展开更多
The multivariate statistical techniques, principal component analysis, Q-modefactor analysis, correspondence analysis and fuzzy C-means clustering were applied to analyzing thedatasets of minor element concentrations ...The multivariate statistical techniques, principal component analysis, Q-modefactor analysis, correspondence analysis and fuzzy C-means clustering were applied to analyzing thedatasets of minor element concentrations in sediment samples of a core collected from the outershelf of the East China Sea. According to the analysis results, the sediment core Q43 can be dividedinto three strata with different features in minor elements. The first stratum (unit Ⅰ) ischaracterized by higher concentrations of Ⅴ, Cr, Cd and Sc, which are active and inactive elements.The second stratum (unit Ⅱ) is controlled by ultrastable elements Ⅴ, Ti, Cr, Th, Sc, Pb, etc. Thethird stratum (unit Ⅲ) is dominated by Ni, Co, Ba, Rb and Mn, which are authigenic andvolcanogenic elements. The geochemical features of the core Q43 show environmental changes in thedepositional process from the Late Pleistocene to Holocene.展开更多
1 Introduction Stratigraphic correlation is the most important basic work in oil and gas exploration and development,Scientific and reasonable stratigraphic correlation is the premise of developing fine reservoir desc...1 Introduction Stratigraphic correlation is the most important basic work in oil and gas exploration and development,Scientific and reasonable stratigraphic correlation is the premise of developing fine reservoir description,and it is展开更多
The ultra-deep Cambrian System in the Tarim Basin is an important field for petroleum exploration,while fine division of the Cambrian strata remains controversial.In recent years,carbon isotope stratigraphy of the Cam...The ultra-deep Cambrian System in the Tarim Basin is an important field for petroleum exploration,while fine division of the Cambrian strata remains controversial.In recent years,carbon isotope stratigraphy of the Cambrian System has been established and widely used.Here,we report an integrated profile of carbonate and organic carbon isotopic values(δ^(13)C_(carb)andδ^(13)C_(org))from cuttings of the Tadong2 Well in the eastern Tarim Basin.Three carbon isotope anomalies of BACE,ROECE and SPICE were recognized on theδ^(13)C_(carb)profile.Three apogees and a nadir on theδ^(13)C_(org)profile and the onset of ROECE on theδ^(13)C_(carb)profile were suggested as boundaries of the present four series of the Cambrian System.Suggested boundaries are easily identifiable on the gamma logging profile and is consistent with the previous division scheme,based on biostratigraphic evidence in outcrop sections.Abnormal carbon cycle perturbations and organic carbon burials during the BACE and SPICE events might be related to the reduction and expansion of a huge dissolved organic carbon reservoir in the deep ocean of the ancient Tarim Basin.展开更多
Stratigraphic division and correlation are crucial for the identification of sweet spots and drilling design of shale gas.In this study,a stratigraphic division and correlation was carried out for the Wufeng-Longmaxi ...Stratigraphic division and correlation are crucial for the identification of sweet spots and drilling design of shale gas.In this study,a stratigraphic division and correlation was carried out for the Wufeng-Longmaxi Formations in southern China from the prospective of lithostratigraphy,sea level changes,and biostratigraphy using data from seismic investigation,wells,and outcrops.The Wufeng and Longmaxi Formations were respectively divided into four members,Wu 1 and Wu2 for the former and Long 1 and Long 2 for the latter.Of the members,Long 1 was subdivided and its first subdivision(Long 11)was further divided into 4 layers(Long 1^(1)_(1),Long 1^(2)_(1),Long 1^(3)_(1),and Long 1^(4)_(1)).Three eustatic cycles were recognized in the Wufeng-Longmaxi Formations.Cycle I corresponds to the Wufeng Formation with the maximum flooding surface at the top ofWu 1.Cycle II corresponds to Long 1,with the maximum flooding surface at the top of Long 1^(3)_(1).CycleⅢⅢcorresponds to Long 2.Furthermore,4 graptolite biozones(WF1 to WF4)were identified in the Wufeng Formation and 9 graptolite biozones(LM1 to LM9)in the Longmaxi Formation.WF1-2 and WF3-4 correspond to Wu 1 and Wu 2,respectively;and LM1,LM2-4,LM5,LM6,and LM7-9 correspond to Long 1^(1)_(1),Long 1^(2)_(1),Long 1^(3)_(1),Long 1^(4)_(1),and Long 12 and Long 2,respectively.Highquality shales mainly occur in the Wufeng Formation and Long 11.The major intervals that should be investigated with regards to shale gas production include LM1eLM5(10m thick)in the Weiyuan Block and WF1eLM5(20e35m thick)in the Changning Block.Long 1^(1)_(1)is believed to be an optimal target for drilling due to its high TOC content,siliceous content,porosity,microfracture density,and horizontal/vertical permeability ratio.展开更多
Correspondence analysis and fuzzy C-means cluster methods were used to divide the stratigraphy of heavy mineral assemblages, and the sediment sources and depositional dynamics of the environment reconstructed. The ass...Correspondence analysis and fuzzy C-means cluster methods were used to divide the stratigraphy of heavy mineral assemblages, and the sediment sources and depositional dynamics of the environment reconstructed. The assemblages were taken from marine sediments from the late Pleistocene to the Holocene in Core Q43 situated on the outer shelf of the East China Sea. Based on the variable boundaries of the mineral assemblage at 63 and 228 cmbsf （cm below sea floor）, the core might have previously been divided into three sediment strata marked with units Ⅰ, Ⅱ and Ⅲ, which would be consistent with the divided sediment stratum of the core using minor element geochemistry. The downcore distribution of heavy minerals divided the sedimentary sequence into three major units, which were further subdivided into four subunits. The interval between 0 and 63 cmbsf of the core （unit Ⅰ）, which spans the Holocene and the uppermost late Pleistocene, is characterized by a hornblende-epidote-pyroxene assemblage, and contains relatively a smaller amount of schistic mineral and authigenic pyrite. In comparison, the interval between 63 and 228 cmbsf （unit Ⅱ）, is representative of the Last Glacial Maximum （LGM）, and features a hornblende-epidote-magnetite-ilmenite assemblage containing the highest concentrations of heavy minerals and opaque minerals. However, the interval between 228 and 309 cmbsf （unit Ⅲ）, which spans the subinterglacial period, is characterized by a hornblende-authigenic-pyrite-mica assemblage. Relative ratios of some heavy minerals can be used as tracers of clastic sediment sources. The lower part of the sediment core shows the highest magnetite/ilmenite ratio and relatively high hornblende/augite and hornblende/epidote ratios. The middle core shows the highest hornblende/augite and hornblende/epidote ratios, and the lowest magnetite/ilmenite ratio. The upper part exhibits a slightly higher magnetite/ilmenite ratio, and also the lowest hornblende/augite and hornblende/epidote ratios. The distribution of the mineral ratio is consistent with stratigraphic division in heavy mineral data using correspondence analysis and fuzzy C-means clustering. Variations in heavy mineral association and mineral ratio in core Q43 revealed changes in provenance and depositional environment of the southern outer shelf of the East China Sea since the late Pleistocene, well corresponding to interglacial and glacial cycles.展开更多
This paper takes Chang 6 and Chang 7 of Yanchang Formation in Heshui area of China as the research object. This study first divides the strata of Chang 6 and Chang 7. According to the review data, significant geologic...This paper takes Chang 6 and Chang 7 of Yanchang Formation in Heshui area of China as the research object. This study first divides the strata of Chang 6 and Chang 7. According to the review data, significant geological activities have caused a large settlement of the strata in this area. During the Chang 6 period, a lacustrine basin sedimentary system developed, reaching its peak in the Chang 7 period. The Chang 6 and Chang 7 members primarily feature deep-water gravity flow sedimentary systems, which can be categorized into three subfacies: outer fan, middle fan, and inner fan. These systems also exhibit turbidite fan sedimentary patterns, ranging from deep lake to semi-deep lake facies. By examining these sedimentary models, we can identify different types of turbidite deposits. Understanding the process of gravity flow deposition and the evolution of ancient lakes is crucial for guiding oil and gas exploration and conducting paleogeographic research.展开更多
The Changjiang fault zone,also known as the Mufushan-Jiaoshan fault,is a famous fault located at the southern bank of the Changjiang River,near the Nanjing downtown area.Based on multidisciplinary data from shallow ar...The Changjiang fault zone,also known as the Mufushan-Jiaoshan fault,is a famous fault located at the southern bank of the Changjiang River,near the Nanjing downtown area.Based on multidisciplinary data from shallow artificial seismic explorations in the target detecting area(Nanjing city and the nearby areas),trenching and drilling explorations,classification of Quaternary strata and chronology dating data,this paper provides the most up-to-date results regarding activities of the Changjiang fault zone,including the most recent active time,activity nature,related active parameters,and their relation to seismic activity.展开更多
The research object of this paper is Neoproterozoic strata in Liaodong and Jiaobei. Through collecting data, sorting out data, making maps, analyzing maps, comparative research, summarizing and so on, the comparative ...The research object of this paper is Neoproterozoic strata in Liaodong and Jiaobei. Through collecting data, sorting out data, making maps, analyzing maps, comparative research, summarizing and so on, the comparative study of Neoproterozoic strata characteristics in the two areas is completed. Based on the knowledge of petrology and stratigraphy, as well as the stratigraphic histogram drawn by the collected stratigraphic lithology of the two areas, through the comparative analysis of the lithologic characteristics of the two areas, it is concluded that the Baoshankou formation, Fuziguang formation, Nanzhuang formation and Xiangkuang formation in Jiaobei correspond to Nanfen formation, Qiaotou formation, Changlingzi formation and Nanguanling formation in Liaodong.展开更多
The formal recognition of Quaternary as a Period/System was approved by IUGS in June 2009,in accordance with a proposal originated by INQUA.There are reasons to believe that this will have destabilizing consequences f...The formal recognition of Quaternary as a Period/System was approved by IUGS in June 2009,in accordance with a proposal originated by INQUA.There are reasons to believe that this will have destabilizing consequences for the geological time scale.Until now,the primary divisions of the stratigraphic record,at the Period level and above,have been based on the progressive change of Earth’s biota.The Quaternary,on the other hand,is a paleoclimatic concept based on glacial-interglacial variability,expressed in lithological change.The IUGS vote holds that this paradigm now supersedes the biochronological identity of the Neogene Period/System.展开更多
基金sponsored by the Magnitude Project of Ministry of Science and Technology of China (No. 2008ZX05016-001)the China Postdoctoral Science Foundation (No. 20100480344)Youth Innovation Fund of Research Institute of Petroleum Exploration and Development of PetroChina (No. 2009-B-10-03)
文摘Taking member one of Yingcheng Formation of Cretaceous in Xudong area, Xushen Gas Field of Songliao Basin for an example and aimed at the diachronous problem generally existed in vol- canic reservoir division, firstly advanced the method of two steps and two unites in the researches of volcanic reservoir finely division that guided by the method that sources controlled and founded the stratigraphic trellis. In this process, volcanic edifices and bodies were identified and traced. The results indicated that aimed strata in study areas could be carved up to six layers of YCII1, YCII2, YCII-II, YCIIlI, YCIII2 and YCIIII from the top to the bottom. Analyzing causes and firmly united of well data and seismic data could achieve fine stratigraphic division of volcanic reservoir. Surfaces of layers and volcanic bodies were basically unanimous in side direction. Stratum inclination gradually reduced with the distances increased from craters. The results of volcanic reservoir division had preferable con- sistency with lithologies and volcanic lithofacies and dynamic development data. The researches offered a useful method to stratigraphic division of volcanic reservoir and it had very important significance to effective development of volcanic reservoir in practice.
基金funded by the National Natural Science Foundation(Nos.40176014 and 40067013).
文摘The multivariate statistical techniques, principal component analysis, Q-modefactor analysis, correspondence analysis and fuzzy C-means clustering were applied to analyzing thedatasets of minor element concentrations in sediment samples of a core collected from the outershelf of the East China Sea. According to the analysis results, the sediment core Q43 can be dividedinto three strata with different features in minor elements. The first stratum (unit Ⅰ) ischaracterized by higher concentrations of Ⅴ, Cr, Cd and Sc, which are active and inactive elements.The second stratum (unit Ⅱ) is controlled by ultrastable elements Ⅴ, Ti, Cr, Th, Sc, Pb, etc. Thethird stratum (unit Ⅲ) is dominated by Ni, Co, Ba, Rb and Mn, which are authigenic andvolcanogenic elements. The geochemical features of the core Q43 show environmental changes in thedepositional process from the Late Pleistocene to Holocene.
基金the National Natural Science Foundation of China(Grant No. 41172106) for financial support of this work
文摘1 Introduction Stratigraphic correlation is the most important basic work in oil and gas exploration and development,Scientific and reasonable stratigraphic correlation is the premise of developing fine reservoir description,and it is
基金financially supported by the National Key Research and Development Program of China(2017YFC0603101)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA14010101)the National Natural Science Foundation of China(41872125,42102146,42002158)。
文摘The ultra-deep Cambrian System in the Tarim Basin is an important field for petroleum exploration,while fine division of the Cambrian strata remains controversial.In recent years,carbon isotope stratigraphy of the Cambrian System has been established and widely used.Here,we report an integrated profile of carbonate and organic carbon isotopic values(δ^(13)C_(carb)andδ^(13)C_(org))from cuttings of the Tadong2 Well in the eastern Tarim Basin.Three carbon isotope anomalies of BACE,ROECE and SPICE were recognized on theδ^(13)C_(carb)profile.Three apogees and a nadir on theδ^(13)C_(org)profile and the onset of ROECE on theδ^(13)C_(carb)profile were suggested as boundaries of the present four series of the Cambrian System.Suggested boundaries are easily identifiable on the gamma logging profile and is consistent with the previous division scheme,based on biostratigraphic evidence in outcrop sections.Abnormal carbon cycle perturbations and organic carbon burials during the BACE and SPICE events might be related to the reduction and expansion of a huge dissolved organic carbon reservoir in the deep ocean of the ancient Tarim Basin.
基金Preparation of this manuscript was supported by the National Natural Science Foundation of China(No.41572079)National Major Science and Technology Project(No.2017ZX05035).
文摘Stratigraphic division and correlation are crucial for the identification of sweet spots and drilling design of shale gas.In this study,a stratigraphic division and correlation was carried out for the Wufeng-Longmaxi Formations in southern China from the prospective of lithostratigraphy,sea level changes,and biostratigraphy using data from seismic investigation,wells,and outcrops.The Wufeng and Longmaxi Formations were respectively divided into four members,Wu 1 and Wu2 for the former and Long 1 and Long 2 for the latter.Of the members,Long 1 was subdivided and its first subdivision(Long 11)was further divided into 4 layers(Long 1^(1)_(1),Long 1^(2)_(1),Long 1^(3)_(1),and Long 1^(4)_(1)).Three eustatic cycles were recognized in the Wufeng-Longmaxi Formations.Cycle I corresponds to the Wufeng Formation with the maximum flooding surface at the top ofWu 1.Cycle II corresponds to Long 1,with the maximum flooding surface at the top of Long 1^(3)_(1).CycleⅢⅢcorresponds to Long 2.Furthermore,4 graptolite biozones(WF1 to WF4)were identified in the Wufeng Formation and 9 graptolite biozones(LM1 to LM9)in the Longmaxi Formation.WF1-2 and WF3-4 correspond to Wu 1 and Wu 2,respectively;and LM1,LM2-4,LM5,LM6,and LM7-9 correspond to Long 1^(1)_(1),Long 1^(2)_(1),Long 1^(3)_(1),Long 1^(4)_(1),and Long 12 and Long 2,respectively.Highquality shales mainly occur in the Wufeng Formation and Long 11.The major intervals that should be investigated with regards to shale gas production include LM1eLM5(10m thick)in the Weiyuan Block and WF1eLM5(20e35m thick)in the Changning Block.Long 1^(1)_(1)is believed to be an optimal target for drilling due to its high TOC content,siliceous content,porosity,microfracture density,and horizontal/vertical permeability ratio.
基金Supported by the National Natural Science Foundation of China (Nos. 40176014,40067013)
文摘Correspondence analysis and fuzzy C-means cluster methods were used to divide the stratigraphy of heavy mineral assemblages, and the sediment sources and depositional dynamics of the environment reconstructed. The assemblages were taken from marine sediments from the late Pleistocene to the Holocene in Core Q43 situated on the outer shelf of the East China Sea. Based on the variable boundaries of the mineral assemblage at 63 and 228 cmbsf （cm below sea floor）, the core might have previously been divided into three sediment strata marked with units Ⅰ, Ⅱ and Ⅲ, which would be consistent with the divided sediment stratum of the core using minor element geochemistry. The downcore distribution of heavy minerals divided the sedimentary sequence into three major units, which were further subdivided into four subunits. The interval between 0 and 63 cmbsf of the core （unit Ⅰ）, which spans the Holocene and the uppermost late Pleistocene, is characterized by a hornblende-epidote-pyroxene assemblage, and contains relatively a smaller amount of schistic mineral and authigenic pyrite. In comparison, the interval between 63 and 228 cmbsf （unit Ⅱ）, is representative of the Last Glacial Maximum （LGM）, and features a hornblende-epidote-magnetite-ilmenite assemblage containing the highest concentrations of heavy minerals and opaque minerals. However, the interval between 228 and 309 cmbsf （unit Ⅲ）, which spans the subinterglacial period, is characterized by a hornblende-authigenic-pyrite-mica assemblage. Relative ratios of some heavy minerals can be used as tracers of clastic sediment sources. The lower part of the sediment core shows the highest magnetite/ilmenite ratio and relatively high hornblende/augite and hornblende/epidote ratios. The middle core shows the highest hornblende/augite and hornblende/epidote ratios, and the lowest magnetite/ilmenite ratio. The upper part exhibits a slightly higher magnetite/ilmenite ratio, and also the lowest hornblende/augite and hornblende/epidote ratios. The distribution of the mineral ratio is consistent with stratigraphic division in heavy mineral data using correspondence analysis and fuzzy C-means clustering. Variations in heavy mineral association and mineral ratio in core Q43 revealed changes in provenance and depositional environment of the southern outer shelf of the East China Sea since the late Pleistocene, well corresponding to interglacial and glacial cycles.
文摘This paper takes Chang 6 and Chang 7 of Yanchang Formation in Heshui area of China as the research object. This study first divides the strata of Chang 6 and Chang 7. According to the review data, significant geological activities have caused a large settlement of the strata in this area. During the Chang 6 period, a lacustrine basin sedimentary system developed, reaching its peak in the Chang 7 period. The Chang 6 and Chang 7 members primarily feature deep-water gravity flow sedimentary systems, which can be categorized into three subfacies: outer fan, middle fan, and inner fan. These systems also exhibit turbidite fan sedimentary patterns, ranging from deep lake to semi-deep lake facies. By examining these sedimentary models, we can identify different types of turbidite deposits. Understanding the process of gravity flow deposition and the evolution of ancient lakes is crucial for guiding oil and gas exploration and conducting paleogeographic research.
基金sponsored by the Key Construction Programof the National Tenth"Five-year Plan"the Sub-project forthe Earthquake Active Fault Detecting Technology System(1-4-10)the Active Fault Detecting and Earthquake Risk Evaluation of Nanjing City
文摘The Changjiang fault zone,also known as the Mufushan-Jiaoshan fault,is a famous fault located at the southern bank of the Changjiang River,near the Nanjing downtown area.Based on multidisciplinary data from shallow artificial seismic explorations in the target detecting area(Nanjing city and the nearby areas),trenching and drilling explorations,classification of Quaternary strata and chronology dating data,this paper provides the most up-to-date results regarding activities of the Changjiang fault zone,including the most recent active time,activity nature,related active parameters,and their relation to seismic activity.
文摘The research object of this paper is Neoproterozoic strata in Liaodong and Jiaobei. Through collecting data, sorting out data, making maps, analyzing maps, comparative research, summarizing and so on, the comparative study of Neoproterozoic strata characteristics in the two areas is completed. Based on the knowledge of petrology and stratigraphy, as well as the stratigraphic histogram drawn by the collected stratigraphic lithology of the two areas, through the comparative analysis of the lithologic characteristics of the two areas, it is concluded that the Baoshankou formation, Fuziguang formation, Nanzhuang formation and Xiangkuang formation in Jiaobei correspond to Nanfen formation, Qiaotou formation, Changlingzi formation and Nanguanling formation in Liaodong.
文摘The formal recognition of Quaternary as a Period/System was approved by IUGS in June 2009,in accordance with a proposal originated by INQUA.There are reasons to believe that this will have destabilizing consequences for the geological time scale.Until now,the primary divisions of the stratigraphic record,at the Period level and above,have been based on the progressive change of Earth’s biota.The Quaternary,on the other hand,is a paleoclimatic concept based on glacial-interglacial variability,expressed in lithological change.The IUGS vote holds that this paradigm now supersedes the biochronological identity of the Neogene Period/System.
