In order to determine the planar and volume distribution of sand bodies of the Jurassic Badaowan formation in Block T13 of Junggar basin,we used analysis of field outcrop and 3D seismic data,which play an essential ro...In order to determine the planar and volume distribution of sand bodies of the Jurassic Badaowan formation in Block T13 of Junggar basin,we used analysis of field outcrop and 3D seismic data,which play an essential role in areas of sparse well coverage.We describe sedimentary facies characteristics,sand body planforms,width and connectivity patterns of sand bodies,and vertical associations and successions by acoustic impedance inversion technology and sedimentological theory.Results of our study show braided fluvial strata deposits in the Jurassic Badaowan formation.Each sand body is approximately lenticular in shape.The width of each sand body falls in the range 100～800 m,with most between 200 and 400 m.The sand bodies vary in thickness from 4 to 13 m,with most below 9 m.The width/thickness ratios lie in the range 20～55.The connectivity of braided fluvial channel sand bodies is controlled by changes of accommodation space.One fining-upward sedimentary cycle of base-level rise is recognized in Badaowan formation,representing an upward rise of base level.The connectivity of sand bodies was found to be greatest in the early stage of base-level rise,becoming progressively worse with increasing base-level rise.展开更多
Based on the field survey of Lower Jurassic Badaowan Formation(Fm.)in Changji area of Xinjiang,China,the authors studied the sedimentary environment and provenance characteristics using the analyses of stratigraphic p...Based on the field survey of Lower Jurassic Badaowan Formation(Fm.)in Changji area of Xinjiang,China,the authors studied the sedimentary environment and provenance characteristics using the analyses of stratigraphic profiles,sedimentary structures,petrography,zircon U-Pb chronology and geochemistry.The results show that Badaowan Fm.deposited in fluvial to swamp shallow-deeplacustrine sedimentary facies deposition.Contents of Sr and ratios of Sr/Cu,Sr/Ba,Th/U,SiO_(2)/Al_(2)O_(3),V/(V+Ni),V/Cr,and Cu/Zn together indicate that Badaowan Fm.was deposited in an oxygen-poor transitional freshwater environment,under humid climatic conditions.Geochemical characteristics and Q–F–L,Qm–E–Lt,Th–Co–Zr/10,La–Th–Sc,and Th–Sc–Zr/10 discrimination diagrams indicate that the tectonic setting of the source area was a continental island arc environment.Lithological composition,Th/U ratios,and Co/Th–La/Sc,La/Th–Hf,and La/Yb–REE discrimination diagrams show that the source rocks of Badaowan Fm.were upper-crust felsic volcanic rocks.U-Pb dating of detrital zircons yields ages of 1542.3±15.0 to 232.9±3.3 Ma and mostly in the ranges of 470–410 and 370–280 Ma.A comparison of these ages with the age data from different blocks of crystalline rock in Tianshan Mountains area reveals that the sedimentary rocks in the Badaowan Fm.were sourced predominantly from the central and subordinately from the southern Tianshan Mountains during Early Jurassic.展开更多
The Jurassic Badaowan Formation on the southern slope of the Mahu Sag has a shallow burial depth and abundant oil and gas resources.On the basis of clarifying the basic characteristics of the reservoir,an in-depth ana...The Jurassic Badaowan Formation on the southern slope of the Mahu Sag has a shallow burial depth and abundant oil and gas resources.On the basis of clarifying the basic characteristics of the reservoir,an in-depth analysis is conducted on the control of sedimentation and diagenesis on the reservoir genesis.The reservoir is mainly composed of lithic sandstone and feldspathic lithic sandstone;the types of reservoir space are mainly intergranular pores and intragranular pores,belonging to a low-porosity and ultra-low-permeability reservoir.The sedimentary environment is the underwater distributary channel of the delta front subfacies,and the distribution of sedimentary facies determines the distribution of sand bodies.Compaction is the main factor destroying primary pores.The changes in reservoir physical properties are mainly controlled by sedimentation and diagenesis.Sedimentation lays the material foundation for reservoir formation,while diagenesis plays a role in later transformation of the reservoir.The research results can provide ideas and directions for the next exploration and development of the Mahu Sag.展开更多
以Vail and Wornardt(1990)层序地层学作为理论指导,收集整理大量钻探、测井等地质资料,以和什托洛盖盆地下侏罗统八道湾组为目标层位,开展层序地层、沉积、聚煤规律研究,将八道湾组划分为3个层序,煤层主要发育于高位体系域,具北厚南薄...以Vail and Wornardt(1990)层序地层学作为理论指导,收集整理大量钻探、测井等地质资料,以和什托洛盖盆地下侏罗统八道湾组为目标层位,开展层序地层、沉积、聚煤规律研究,将八道湾组划分为3个层序,煤层主要发育于高位体系域,具北厚南薄特征。富煤中心位于图拉东一带,含煤12~18层,可采煤层总厚度10~14 m。聚煤的主要控制因素为基底沉降和湖平面特征变化。展开更多
基金Financial support for this work,provided by the National Basic Research Program of China(No.2006 CB202300),
文摘In order to determine the planar and volume distribution of sand bodies of the Jurassic Badaowan formation in Block T13 of Junggar basin,we used analysis of field outcrop and 3D seismic data,which play an essential role in areas of sparse well coverage.We describe sedimentary facies characteristics,sand body planforms,width and connectivity patterns of sand bodies,and vertical associations and successions by acoustic impedance inversion technology and sedimentological theory.Results of our study show braided fluvial strata deposits in the Jurassic Badaowan formation.Each sand body is approximately lenticular in shape.The width of each sand body falls in the range 100～800 m,with most between 200 and 400 m.The sand bodies vary in thickness from 4 to 13 m,with most below 9 m.The width/thickness ratios lie in the range 20～55.The connectivity of braided fluvial channel sand bodies is controlled by changes of accommodation space.One fining-upward sedimentary cycle of base-level rise is recognized in Badaowan formation,representing an upward rise of base level.The connectivity of sand bodies was found to be greatest in the early stage of base-level rise,becoming progressively worse with increasing base-level rise.
基金Supported by Geological Survey Project of China(No.K45E001012,2019–002).
文摘Based on the field survey of Lower Jurassic Badaowan Formation(Fm.)in Changji area of Xinjiang,China,the authors studied the sedimentary environment and provenance characteristics using the analyses of stratigraphic profiles,sedimentary structures,petrography,zircon U-Pb chronology and geochemistry.The results show that Badaowan Fm.deposited in fluvial to swamp shallow-deeplacustrine sedimentary facies deposition.Contents of Sr and ratios of Sr/Cu,Sr/Ba,Th/U,SiO_(2)/Al_(2)O_(3),V/(V+Ni),V/Cr,and Cu/Zn together indicate that Badaowan Fm.was deposited in an oxygen-poor transitional freshwater environment,under humid climatic conditions.Geochemical characteristics and Q–F–L,Qm–E–Lt,Th–Co–Zr/10,La–Th–Sc,and Th–Sc–Zr/10 discrimination diagrams indicate that the tectonic setting of the source area was a continental island arc environment.Lithological composition,Th/U ratios,and Co/Th–La/Sc,La/Th–Hf,and La/Yb–REE discrimination diagrams show that the source rocks of Badaowan Fm.were upper-crust felsic volcanic rocks.U-Pb dating of detrital zircons yields ages of 1542.3±15.0 to 232.9±3.3 Ma and mostly in the ranges of 470–410 and 370–280 Ma.A comparison of these ages with the age data from different blocks of crystalline rock in Tianshan Mountains area reveals that the sedimentary rocks in the Badaowan Fm.were sourced predominantly from the central and subordinately from the southern Tianshan Mountains during Early Jurassic.
文摘The Jurassic Badaowan Formation on the southern slope of the Mahu Sag has a shallow burial depth and abundant oil and gas resources.On the basis of clarifying the basic characteristics of the reservoir,an in-depth analysis is conducted on the control of sedimentation and diagenesis on the reservoir genesis.The reservoir is mainly composed of lithic sandstone and feldspathic lithic sandstone;the types of reservoir space are mainly intergranular pores and intragranular pores,belonging to a low-porosity and ultra-low-permeability reservoir.The sedimentary environment is the underwater distributary channel of the delta front subfacies,and the distribution of sedimentary facies determines the distribution of sand bodies.Compaction is the main factor destroying primary pores.The changes in reservoir physical properties are mainly controlled by sedimentation and diagenesis.Sedimentation lays the material foundation for reservoir formation,while diagenesis plays a role in later transformation of the reservoir.The research results can provide ideas and directions for the next exploration and development of the Mahu Sag.
文摘以Vail and Wornardt(1990)层序地层学作为理论指导,收集整理大量钻探、测井等地质资料,以和什托洛盖盆地下侏罗统八道湾组为目标层位,开展层序地层、沉积、聚煤规律研究,将八道湾组划分为3个层序,煤层主要发育于高位体系域,具北厚南薄特征。富煤中心位于图拉东一带,含煤12~18层,可采煤层总厚度10~14 m。聚煤的主要控制因素为基底沉降和湖平面特征变化。
