Acta Sedimentologica Sinica

A major breakthrough of thick bedded sandstone oil and gas exploration is in China's western Xinjiang region of Jurassic and Cretaceous. Large areas of thick layer of sand body and red mudstone layer deposition formation mechanism have been a research focus by attention for a long time. Combined with much more information including southern margin of Junggar Basin sedimentary system of seasonal rivers,sand body distribution characteristics of analysis,and analysis of the lithofacies assemblages and rock color,sedimentary structure and formation mechanism of sandstone and mudstone of the Haojiagou-Toutun River section and Manasi River section of Toutun River formation of Middle Jurassic in upper part of Middle Jurassic Qigu and Kalazha Formation in the southern margin of the Junggar Basin,We think arid climate background ephemeral streams are the main sediment types of the period. An ephemeral streams sand body configuration and the genetic model have been established,and further understanding of ancient ephemeral streams sedimentary will provide the beneficial reference in China.

Gao Zhi

Chenji xuebao

Distribution of a Large Area of Sand Body Formation Mechanism:Ephemeral Streams in Arid Climate

大面积砂体形成机制的分布：干旱气候下的暂时性河流

Mixed sedimentary rock is referred to the rock composed of terrigenous clastics and carbonate components under mixed sedimentation.In a broad sense,it also includes the spatially alternating layers or intercalations of terrigenious clastic and carbonate components.On the basis of the research on a lot of materials and study on the lower Cretaceous mixed sedimentary reservoir in Qingxi depression of Jiuquan Basin,using methods such as thin-section observation,field-emission scanning electron microscope observation,bulk minerals and clay minerals analysis,mercury injection test and nano-CT,analysis on lithologic associations and reservoir characteristics has been carried out on the mixed sedimentary reservoir.Macroscopically,the mixed sedimentary rock is lithologically complex,composed of dolomitic mudstone,argillaceous dolomite,lime mudstone,lime dolomite and dolomitic limestone,and so on,and presenting three types of vertical profile associations as great suites of thick layers,thick layers intercalated with thin layers and interbedded layers of similar thickness.Microscopically,clay minerals,carbonate minerals and organic matters present laminated or massive distribution form.The mixed sedimentary reservoir develops micro-nanometer scale interparticle pores,intraparticle pores and microfractures.The composition and content of minerals are one of the main factors affecting reservoir space types.Most mixed sedimentary reservoir has low permeability and low porosity,being regarded as tight reservoir.

Li Ting

Characteristics of Mixed Sedimentary Reservoir:Taking the Lower Cretaceous mixed sedimentary rock of Qingxi depression in Jiuquan Basin as an example

混积型储层特征：以酒泉盆地青西凹陷下白垩统混积岩为例

Saturated hydrocarbons in source rock from member 8 of Yanchang Formation( Upper Triassic) in Ordos Basin were analyzed by GC-MS. Different isomers of monomethylalkanes( MMAs)( carbon number ranging from 12 to31) have been measured on a rock sample from Well Wu 56 located in Wuqi area. MMAs,with different substituted methyl ranging from the second carbon to the middle carbon,have shorter retention time than the corresponding n-alkanes with identical carbon number. 2-methylalkanes and 3-methylalkanes are the most abundant compounds among MMAs,while 4-methylalkanes and other MMAs are relatively low. The positions of the substituted methyl in the MMAs can be identified through typical fragment ions,recombination pattern for chemical bonds,and retention time by mass spectrometry. For example,it has been found that the substituted methyl positions of C22-MMAs are C2-C11.The mass spectrometry is similar to the n-alkane with the same carbon number,m / z57 or m / z 71 is their base peak.They also show a predominant M+peak and( M-15)+peak,suggesting a branched methyl. Moreover,the relative abundance decreases as the total carbon increases. When the methyl position is exceeding the fifth carbon,in comparison with n-alkanes,their major characteristic fragment ions are such m / z126,140,154,as even CnH2 n,which are important to identify MMAs. Generally,a table about the characteristic fragment ions of MMAs are concluded. As well as gas chromatographic unseparated monomethylalkane isomers were resoluted by mass spectrometric deconvolution.Finally,by using of the Kovats index and the homomorphy factors for precise retention prediction and identification of the monomethylalkanes.

Qian Y

Analysis and Identification of Monomethylalkanes in Source Rocks

源岩中单甲基烷烃的分析与鉴定

The sandy hill sand and loess deposits constitute the regional sand-loess system,which are widely distributed in the middle reach of Yangtze River especially in the Poyang Lake area since the last interglacial. A transect named D-D transect was set from north to south along with the winter monsoon direction. The 20 mm grains extracted from bulk sample on the basis of wet-sieve methods were used to measure major and trace element abundances by XRF.Our results reveal that:( 1) The content of major element has a systemic change from north to south. The changes are most pronounced within the range of 5 to 20 km away from the Yangtze River,and then level off. Sr O,Na2 O,Ca O,K2 O,Mn O,Ca O are of negative logarithmic function changes,Si O2,Zr O2,Al2O3,Ti O2 and CIA are of positive logarithmic function changes; The profiles of D-D transect seem to have a similar source displayed by the scatter diagrams of Zr O2/ Al2O3 vs. Zr O2/ Ti O2,Ti O2/ Al2O3 vs. Ti O2/ Zr O2,K2 O / Al2O3 vs. Zr O2/ Ti O2,K2 O / Ti O2 vs. Zr O2/ Al2O3,Sr O / Ti O2 vs. Sr O / Al2O3,Base /Zr O2 vs. Base / Ti O2,ect. These characteristics further reveals that all of the profiles in D-D transect belong to the same aeolian deposits system.( 2) The stable elemental compositions of the D-D transect are similar to the WN loess,Xiashu loess,and sediment of flood land of the Yangtze River,these results reveal that aeolian deposits and the Yangtze River sediment have a rich source and over-commixing. Therefore,it is suggested that the factors on chemical composition of clastic sediment should be fully studied when geochemistry methods are used to analyze the province and depositional setting,and multiple methods can be synthetically used and the study on regional geology should be paid more attention.

Long Ji

Geochemical Characteristics of Loess from Northeast of Poyang Lake since Last Glacial and Its Provenance Implications

鄱阳湖东北部末次冰期以来黄土地球化学特征及其物源意义

According to a large number of previous studies,we summarized the research progress of tight sandstone gas reservoir formation process and mechanism. Under its genetic classification,it was divided into conventional tight sandstone reservoir,deep basin tight sandstone reservoir and composite tight sandstone reservoir by its genetic classification. Their accumulation process was hydrocarbon generation → accumulation → densified → structure improved,densified → gas charge → accumulation and conventional reservoir→ densified →deep basin tight sandstone reservoir→ accumulation compounded,respectively. Currently the conventional tight sandstone reservoir accumulation mechanism had been studied deeply. But the deep basin accumulation mechanism was studied at all the time. As we have known,it contained the following six general mechanism,water block,lack of buoyancy,fault block,straitigraphicdiagenetic,driving pressure differential and dynamic balance. Although among them the dynamic balance was widespread accepted,it all had deficiencies. So,considering the practical situation of geology is very important. And then we can understand and research different areas of tight sandstone gas reservoirs clearly to provide theoretical guidance for its exploration and development.

Sun Li

A Review of the Accumulation Process and Formation Mechanism about Different Genetic Types of Tight-Gas Sandstone Reservoir

不同成因类型致密砂岩气藏的富集过程与成藏机理综述

The petrological and geochemical data of the Wufeng-Longmaxi Formations in the southern Sichuan Basin were recorded to restore the paleoenvironment and explore the mechanism of organic matter accumulation. The study shows that the Wufeng-Longmaxi Formations in the southern Sichuan Basin mainly developed siliceous shale,silty shale,argillaceous shale,and shell-bearing lime mudstone/muddy limestone. The average total organic carbon（TOC）of the Wufeng Formation is 3.36%,the TOC of the lower Longmaxi Formation is the highest,with an average of 3.99%,and the TOC of the middle and upper parts is low,with an average of 1.22%. Paleoproductivity proxies(Babio,Cu/Al,Ni/Al,and Siexcess)indicate that during most of the Ordovician-Silurian period（except for the Hirnantian period）,the surface water in the southern Sichuan Basin had a high primary productivity. The terrigenous influx proxies（Al,Zr,and Zr/Al）indicate that the terrigenous influx in the Wufeng period was moderate and varied greatly. The early Longmaxi period had a continuous low value,but it gradually increased in the middle and late periods.The correlation between redox-sensitive trace elements（Mo/Al,U/Al,and V/Al）and Mo-TOC shows that,during the Wufeng period,the ocean developed a strong restricted anoxic-euxinic environment. The water mass in the early stage of the Longmaxi maintained anoxic-euxinic conditions,the level of restriction was weakened,and the ocean evolved into an oxic environment in the middle and late periods. In the Late Ordovician,a favorable anoxic-euxinic environment and high productivity developed in the ocean,but the large amount of terrigenous influx weakened the organic matter accumulation. In the Early Silurian,sea level fluctuations caused multiple environmental parameters to coordinately change,which resulted in significant differences in the concentration of organic matter.

Huang ZiSang

Wang XingZhi

Yang XiYan

Zhu RuKai

Cui JingWei

LU YuanZheng

Li Yong

Gas Reservoir Geology

Exploitation

Constraints of Sedimentary Environment on Organic Matter Accumulation in Shale: A case study of the Wufeng-Longmaxi Formations in the southern Sichuan Basin

沉积环境对页岩有机质富集的制约——以四川盆地南部五峰组-龙马溪组为例

Zhang MingYu

Chang Xin

HU LiMin

BI NaiShuang

Wang HouJie

Liu XiTing

Source-to-Sink Process of Organic Carbon on the Inner Shelf of the East China Sea and its Sedimentary Records

东海内陆架有机碳的源汇过程及其沉积记录

沉积环境对页岩有机质富集的制约——以四川盆地南部五峰-龙马溪组为例

ISSN	1000-0550
h-index	16

Publication Information	Publisher: Science China Press，Publishing cycle: ，Journal Type: journal，Open Access Journals: Yes
Basic data	Year of publication: 2019，Proportion of original research papers: ，Self Citation Rate:， Gold OA Rate:
Journal Fees	$Details
Average review cycle	25 weeks

Acta Sedimentologica Sinica

Journal Citation Format

A journal article with 1 author

A journal article with 2 authors

A journal article with 3 authors

A journal article with 5 or more authors

Books Citation Format

Thesis Citation Format

Web sites Citation Format

Patent Citation Format

Staying up late manually editing references? ivySCI automatically matches journals and helps you generate references with a single click.

Share Submission Experience

Distribution of a Large Area of Sand Body Formation Mechanism:Ephemeral Streams in Arid Climate

Characteristics of Mixed Sedimentary Reservoir:Taking the Lower Cretaceous mixed sedimentary rock of Qingxi depression in Jiuquan Basin as an example

Analysis and Identification of Monomethylalkanes in Source Rocks

Geochemical Characteristics of Loess from Northeast of Poyang Lake since Last Glacial and Its Provenance Implications

A Review of the Accumulation Process and Formation Mechanism about Different Genetic Types of Tight-Gas Sandstone Reservoir

Constraints of Sedimentary Environment on Organic Matter Accumulation in Shale: A case study of the Wufeng-Longmaxi Formations in the southern Sichuan Basin

Source-to-Sink Process of Organic Carbon on the Inner Shelf of the East China Sea and its Sedimentary Records

Constraints of Sedimentary Environment on Organic Matter Accumulation in Shale: A case study of the Wufeng-Longmaxi Formations in the southern Sichuan Basin

Source-to-Sink Process of Organic Carbon on the Inner Shelf of the East China Sea and its Sedimentary Records

Constraints of Sedimentary Environment on Organic Matter Accumulation in Shale: A case study of the Wufeng-Longmaxi Formations in the southern Sichuan Basin