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Shu Jiang - One of the best experts on this subject based on the ideXlab platform.
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productivity or preservation the factors controlling the organic matter accumulation in the late katian through hirnantian wufeng organic Rich Shale south china
Marine and Petroleum Geology, 2019Co-Authors: Shu Jiang, Yi Shu, Yuxuan WangAbstract:Abstract The Wufeng organic-Rich Shale is widespread in the Upper Yangtze platform, and it is one of the most advantageous Shale gas producers in China. Its deposition commenced with the onset of the Boda warming event in the late Katian and terminated at the Hirnantian glacial maximum. The depositional mechanism of the Wufeng Formation was poorly understood owing to its relatively thin thickness, being interpreted as the result of organic matter (OM) accumulation in a shelf setting under anoxic conditions. This study integrated detailed geochemical analyses based on the core samples from three boreholes which are located in the outer-, middle- and inner-shelf of the Upper Yangtze platform, in order to investigate the depositional environments during the deposition of the Wufeng Formation. Geochemical redox proxies (Mo-EF, U-EF, and V/Cr) and productivity proxies (P, Baxs, Sixs) indicate that the deposition of the Wufeng Formation was associated with four intervals (WF1 to WF4), each characterized by its unique geochemical features related to sea-level fluctuations. Black siliceous mudstones deposited during WF1 and WF2 are relatively organic-lean due to low productivity, less favorable preservation conditions, and terrestrial dilution. Whereas black siliceous mudstone deposited during WF3 and WF4 is organic-Rich due to high paleoproductivity and conducive preservation conditions. The geochemical proxies (Cd/Mo, Co x Mn) associated with the modern upwelling settings were replicated in the Wufeng Formation, revealing that the outer-shelf of the Upper Yangtze platform was dominated by persistent upwelling. The upwelling-driven primary productivity is considered as the first-order control for the OM enRichment at the outer-shelf of the Upper Yangtze platform. Seasonal upwelling may influence the middle-shelf of the Upper Yangtze Platform, where both primary productivity and preservation played essential roles in the OM accumulation. In contrast, the OM accumulation at the inner-shelf was fundamentally driven by good preservation conditions.
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relationship between the origin of organic Rich Shale and geological events of the upper ordovician lower silurian in the upper yangtze area
Marine and Petroleum Geology, 2019Co-Authors: Shu Jiang, Xiaofeng Liu, Zhanhong LiuAbstract:Abstract Based on detailed sedimentological observations and geochemical analyses, four geological events have been identified, and a genetic depositional model has been established within a sequence stratigraphic framework. The organic-Rich siliceous Shale interbedded with dense bentonite layers in the transgressive systems tract 1 (TST 1) is attributed to the first stage of high-frequency volcanism (which started at ∼447.62 Ma) associated with the collision of the Cathaysia and Yangtze Blocks. The presence of the organic-fair lime mudstone/shelly limestone indicates that Hirnantian Glaciation in the highstand systems tract (HST). The occurrence of organic-Rich siliceous Shale interbedded with scarce bentonite layers in the transgressive systems tract 2 (TST 2) is attributable to the second stage of low-frequency volcanism (which started at ∼443.83 Ma) and to postglacial effects. The formation of organic-fair mixed Shale with silty laminae is attributed to bottom-current activity in the early highstand systems tract (EHST). The occurrence of organic-poor clay-Rich Shale is due to terrigenous input in the late highstand systems tract (LHST). Our research also shows that the high marine productivity caused by volcanic ash and a high burial rate in an anoxic depositional setting led to organic matter and siliceous mineral enRichment in the TST 1 and TST 2. The favorable organic matter preservation conditions and the postglacial biotic recovery played significant roles in the formation of the organic-Rich Shale in the TST 2.
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oil content evaluation of lacustrine organic Rich Shale with strong heterogeneity a case study of the middle permian lucaogou formation in jimusaer sag junggar basin nw china
Fuel, 2018Co-Authors: Xiongqi Pang, Shu Jiang, Qifeng Wang, Xiaowei Zheng, Tao Hu, Xuguang Ding, Yi Zhao, Hui LiAbstract:Abstract Large Shale oil resources were recently been found in lacustrine organic-Rich Shale with strong heterogeneity, however, few studies have been conducted to examine their oil contents, resulting in considerable risks in lacustrine Shale oil exploration. The Middle Permian Lucaogou Formation (P 2 l) Shale in Jimusaer Sag is a typical lacustrine deposit with strong heterogeneity, and its Shale oil resource shows great potential. Integrated geochemical characterization of 265 core samples were conducted and results show that the P 2 l Shale developed in an anoxic lacustrine with stratified salty water and the organic matter in the upper sub-member Shale of the P 2 l is more oil-prone than that in the lower sub-member Shale of the P 2 l. The hydrocarbon generation potential of the P 2 l Shale decreases with the kerogen types changing from Type I to Type III, however, the residual hydrocarbon contents of the P 2 l Shale increases from Type I to II 1 kerogen, and then decreases from Type II 1 to III kerogen, this is mainly due to differentiated hydrocarbon expulsion efficiencies among different kerogen types. Based on S 1 and TOC values and the S 1 /TOC ratios, considering the oil enRichment degree, this study classified the Shale oil resources in the P 2 l Shale into four categories: enRiched, moderately enRiched, less efficient, and invalid resources. The enRiched and moderately enRiched resources are mainly Shales with Type II 1 kerogen, followed by Type II 2 kerogen, and the middle interval of the Lower P 2 l Shale is the most favourable target for further Shale oil exploration. The improved evaluation criteria are applicable for evaluating Shale oil plays with strong heterogeneity qualitatively and quantitatively in terrestrial lacustrine basins in other parts of the world.
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impact of paleosalinity dilution redox and paleoproductivity on organic matter enRichment in a saline lacustrine rift basin a case study of paleogene organic Rich Shale in dongpu depression bohai bay basin eastern china
Energy & Fuels, 2018Co-Authors: Xiongqi Pang, Shu Jiang, Qifeng Wang, Chuang Huang, Yuanyuan Chen, Xiaowei ZhengAbstract:Saline, lacustrine rift basins (SLRBs) can contain very productive Shale oil plays, in which “sweet spots” are closely related to organic-Rich Shale intervals. However, organic matter enRichment in...
Peng Dai - One of the best experts on this subject based on the ideXlab platform.
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logging identification and characteristic analysis of marine continental transitional organic Rich Shale in the carboniferous permian strata bohai bay basin
Marine and Petroleum Geology, 2016Co-Authors: Wenlong Ding, Jinchuan Zhang, Wei Zhao, Peng DaiAbstract:Abstract Currently, global Shale gas exploration and exploitation are focused on marine Shale. Recently, major Shale gas-oil breakthroughs have been made within continental and marine–continental transitional Shale in China. This study will show how transitional Shale is of great importance. Based on geological field surveys, core observations, thin section analysis, organic geochemistry and X-ray diffraction, we systematically studied the basic geological characteristics (including lithology, mineral composition, and organic geochemistry) of this transitional Shale. By comparative analysis of well logging data from 260 wells in the Taiyuan–Shanxi Shale, we will show that these methods are effective for identifying organic-Rich Shale from conventional well logs and determining its thickness distribution in the Carboniferous–Permian strata of the Taiyuan–Shanxi transitional coal-bearing formation. The results indicate that the Taiyuan–Shanxi Shale has a high TOC (most 2%–4%) and that the lithology is primarily carbonaceous Shale with type Ⅱ 2 -Ⅲ kerogens. The high thermal maturation (Ro ≥ 1.1%) favors the generation of gas. The mineral components primarily include clay minerals, quartz, and plagioclase with a moderate brittle mineral content (47 wt.%) and high clay mineral content (51 wt.%) dominated by kaolinite (43%) and mixed-layer illite-smectite (31%). The transitional organic-Rich Shale on conventional log curves is generally characterized by higher gamma ray (GR), neutron porosity (CNL), acoustic travel time (AC), resistivity (R t ), potassium (K), and uranium (U) readings and a lower density (DEN), photoelectric absorption index (PE) and thorium-uranium ratio (TH/U). After analyzing the log response characteristics of the organic-Rich Shale, the most sensitive logging curves (such as CNL, AC, DEN, PE and U) were optimized to conduct logging overlays and to construct cross-plots to qualitatively identify organic-Rich Shale. The identified organic-Rich Shale amalgamates in the middle-upper member of the Taiyuan Formation and the lower member of the Shanxi Formation consistent with the results of the TOC analysis and practical gas logging. Based on the qualitative evaluation methods of the modified △LogR and a multivariate linear regression model, we calculated the TOC of Shale wells in the Taiyuan–Shanxi formation. From this we calculated the characteristic values of organic-Rich Shale thickness. The results indicate that organic-Rich Shale in the Taiyuan formation is thicker than that in the Shanxi formation. Additionally, the thickness of organic-Rich Shale within lagoons and deep reed swamp facies are much thicker (25–35 m and 40–80 m) than other structural profile types, whereas their lateral distribution is less than that of marine Shale. The relatively small continuous thickness of the single Shale layer and high clay content may have negative effects for developing the Shale gas potential.
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Logging identification and characteristic analysis of marine–continental transitional organic-Rich Shale in the Carboniferous-Permian strata, Bohai Bay Basin
Marine and Petroleum Geology, 2016Co-Authors: Wenlong Ding, Jinchuan Zhang, Wei Zhao, Peng DaiAbstract:Abstract Currently, global Shale gas exploration and exploitation are focused on marine Shale. Recently, major Shale gas-oil breakthroughs have been made within continental and marine–continental transitional Shale in China. This study will show how transitional Shale is of great importance. Based on geological field surveys, core observations, thin section analysis, organic geochemistry and X-ray diffraction, we systematically studied the basic geological characteristics (including lithology, mineral composition, and organic geochemistry) of this transitional Shale. By comparative analysis of well logging data from 260 wells in the Taiyuan–Shanxi Shale, we will show that these methods are effective for identifying organic-Rich Shale from conventional well logs and determining its thickness distribution in the Carboniferous–Permian strata of the Taiyuan–Shanxi transitional coal-bearing formation. The results indicate that the Taiyuan–Shanxi Shale has a high TOC (most 2%–4%) and that the lithology is primarily carbonaceous Shale with type Ⅱ 2 -Ⅲ kerogens. The high thermal maturation (Ro ≥ 1.1%) favors the generation of gas. The mineral components primarily include clay minerals, quartz, and plagioclase with a moderate brittle mineral content (47 wt.%) and high clay mineral content (51 wt.%) dominated by kaolinite (43%) and mixed-layer illite-smectite (31%). The transitional organic-Rich Shale on conventional log curves is generally characterized by higher gamma ray (GR), neutron porosity (CNL), acoustic travel time (AC), resistivity (R t ), potassium (K), and uranium (U) readings and a lower density (DEN), photoelectric absorption index (PE) and thorium-uranium ratio (TH/U). After analyzing the log response characteristics of the organic-Rich Shale, the most sensitive logging curves (such as CNL, AC, DEN, PE and U) were optimized to conduct logging overlays and to construct cross-plots to qualitatively identify organic-Rich Shale. The identified organic-Rich Shale amalgamates in the middle-upper member of the Taiyuan Formation and the lower member of the Shanxi Formation consistent with the results of the TOC analysis and practical gas logging. Based on the qualitative evaluation methods of the modified △LogR and a multivariate linear regression model, we calculated the TOC of Shale wells in the Taiyuan–Shanxi formation. From this we calculated the characteristic values of organic-Rich Shale thickness. The results indicate that organic-Rich Shale in the Taiyuan formation is thicker than that in the Shanxi formation. Additionally, the thickness of organic-Rich Shale within lagoons and deep reed swamp facies are much thicker (25–35 m and 40–80 m) than other structural profile types, whereas their lateral distribution is less than that of marine Shale. The relatively small continuous thickness of the single Shale layer and high clay content may have negative effects for developing the Shale gas potential.
Qifeng Wang - One of the best experts on this subject based on the ideXlab platform.
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oil content evaluation of lacustrine organic Rich Shale with strong heterogeneity a case study of the middle permian lucaogou formation in jimusaer sag junggar basin nw china
Fuel, 2018Co-Authors: Xiongqi Pang, Shu Jiang, Qifeng Wang, Xiaowei Zheng, Tao Hu, Xuguang Ding, Yi Zhao, Hui LiAbstract:Abstract Large Shale oil resources were recently been found in lacustrine organic-Rich Shale with strong heterogeneity, however, few studies have been conducted to examine their oil contents, resulting in considerable risks in lacustrine Shale oil exploration. The Middle Permian Lucaogou Formation (P 2 l) Shale in Jimusaer Sag is a typical lacustrine deposit with strong heterogeneity, and its Shale oil resource shows great potential. Integrated geochemical characterization of 265 core samples were conducted and results show that the P 2 l Shale developed in an anoxic lacustrine with stratified salty water and the organic matter in the upper sub-member Shale of the P 2 l is more oil-prone than that in the lower sub-member Shale of the P 2 l. The hydrocarbon generation potential of the P 2 l Shale decreases with the kerogen types changing from Type I to Type III, however, the residual hydrocarbon contents of the P 2 l Shale increases from Type I to II 1 kerogen, and then decreases from Type II 1 to III kerogen, this is mainly due to differentiated hydrocarbon expulsion efficiencies among different kerogen types. Based on S 1 and TOC values and the S 1 /TOC ratios, considering the oil enRichment degree, this study classified the Shale oil resources in the P 2 l Shale into four categories: enRiched, moderately enRiched, less efficient, and invalid resources. The enRiched and moderately enRiched resources are mainly Shales with Type II 1 kerogen, followed by Type II 2 kerogen, and the middle interval of the Lower P 2 l Shale is the most favourable target for further Shale oil exploration. The improved evaluation criteria are applicable for evaluating Shale oil plays with strong heterogeneity qualitatively and quantitatively in terrestrial lacustrine basins in other parts of the world.
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impact of paleosalinity dilution redox and paleoproductivity on organic matter enRichment in a saline lacustrine rift basin a case study of paleogene organic Rich Shale in dongpu depression bohai bay basin eastern china
Energy & Fuels, 2018Co-Authors: Xiongqi Pang, Shu Jiang, Qifeng Wang, Chuang Huang, Yuanyuan Chen, Xiaowei ZhengAbstract:Saline, lacustrine rift basins (SLRBs) can contain very productive Shale oil plays, in which “sweet spots” are closely related to organic-Rich Shale intervals. However, organic matter enRichment in...
Wenbin Luo - One of the best experts on this subject based on the ideXlab platform.
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Reconstruction of redox conditions during deposition of organic-Rich Shales of the Upper Triassic Yanchang Formation, Ordos Basin, China
Palaeogeography Palaeoclimatology Palaeoecology, 2017Co-Authors: Wei Yuan, Guangdi Liu, Alan Stebbins, Xiaobing Niu, Wenbin LuoAbstract:The concentration and distribution of organic matter, phosphate nodules, and framboidal pyrite preserved in Shales are controlled by organic matter decomposition and the cycles of phosphorus, sulfur, and iron, which, in turn, are controlled by bottom-water redox conditions. The organic-Rich Shale in the 7th member of the Upper Triassic Yanchang Formation (Ch7) contains high organic carbon concentrations and abundant phosphate nodules and pyrite framboids, providing an opportunity to better understand the redox conditions at the time of deposition. Framboidal pyrite in the Ch7 organic-Rich Shales are composed of octahedral, pyritohedral, and spherulitic microcrystals with uniform crystal size. SEM photographs and statistical data suggest that pyrite framboids have large mean diameters (10.0 to 18.1 μm) and standard deviations (2.8 to 5.9 μm). This may indicate that the organic-Rich Shale was deposited under oxic-suboxic bottom-water conditions. The Corg:P ratios of the organic-Rich Shale exhibit considerable variation, ranging from 7.2 to 216, but the majority of them (83.2%) belong to the lower-intermediate range (
Xiaowei Zheng - One of the best experts on this subject based on the ideXlab platform.
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oil content evaluation of lacustrine organic Rich Shale with strong heterogeneity a case study of the middle permian lucaogou formation in jimusaer sag junggar basin nw china
Fuel, 2018Co-Authors: Xiongqi Pang, Shu Jiang, Qifeng Wang, Xiaowei Zheng, Tao Hu, Xuguang Ding, Yi Zhao, Hui LiAbstract:Abstract Large Shale oil resources were recently been found in lacustrine organic-Rich Shale with strong heterogeneity, however, few studies have been conducted to examine their oil contents, resulting in considerable risks in lacustrine Shale oil exploration. The Middle Permian Lucaogou Formation (P 2 l) Shale in Jimusaer Sag is a typical lacustrine deposit with strong heterogeneity, and its Shale oil resource shows great potential. Integrated geochemical characterization of 265 core samples were conducted and results show that the P 2 l Shale developed in an anoxic lacustrine with stratified salty water and the organic matter in the upper sub-member Shale of the P 2 l is more oil-prone than that in the lower sub-member Shale of the P 2 l. The hydrocarbon generation potential of the P 2 l Shale decreases with the kerogen types changing from Type I to Type III, however, the residual hydrocarbon contents of the P 2 l Shale increases from Type I to II 1 kerogen, and then decreases from Type II 1 to III kerogen, this is mainly due to differentiated hydrocarbon expulsion efficiencies among different kerogen types. Based on S 1 and TOC values and the S 1 /TOC ratios, considering the oil enRichment degree, this study classified the Shale oil resources in the P 2 l Shale into four categories: enRiched, moderately enRiched, less efficient, and invalid resources. The enRiched and moderately enRiched resources are mainly Shales with Type II 1 kerogen, followed by Type II 2 kerogen, and the middle interval of the Lower P 2 l Shale is the most favourable target for further Shale oil exploration. The improved evaluation criteria are applicable for evaluating Shale oil plays with strong heterogeneity qualitatively and quantitatively in terrestrial lacustrine basins in other parts of the world.
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impact of paleosalinity dilution redox and paleoproductivity on organic matter enRichment in a saline lacustrine rift basin a case study of paleogene organic Rich Shale in dongpu depression bohai bay basin eastern china
Energy & Fuels, 2018Co-Authors: Xiongqi Pang, Shu Jiang, Qifeng Wang, Chuang Huang, Yuanyuan Chen, Xiaowei ZhengAbstract:Saline, lacustrine rift basins (SLRBs) can contain very productive Shale oil plays, in which “sweet spots” are closely related to organic-Rich Shale intervals. However, organic matter enRichment in...
