Environmental response to volcanic activity and its effect on organic matter enrichment in the Permian Lucaogou Formation of the Malang Sag, Santanghu Basin, Northwest China

2020 ◽  
Vol 560 ◽  
pp. 110024
Author(s):  
Yongshuai Pan ◽  
Zhilong Huang ◽  
Tianjun Li ◽  
Xiaobo Guo ◽  
Xiongfei Xu ◽  
...  
Keyword(s):  
Organic Matter ◽  
Volcanic Activity ◽  
Northwest China ◽  
Environmental Response ◽  
Lucaogou Formation

Oil–source rock correlation for tight oil in tuffaceous reservoirs in the Permian Tiaohu Formation, Santanghu Basin, northwest China

2015 ◽  
Vol 52 (11) ◽  
pp. 1014-1026 ◽  
Author(s):  
Jian Ma ◽  
Zhilong Huang ◽  
Xiaoyu Gao ◽  
Changchao Chen
Keyword(s):  
Organic Matter ◽  
Crude Oil ◽  
Source Rock ◽  
Stable Carbon Isotope ◽  
Northwest China ◽  
Source Rocks ◽  
Tight Oil ◽  
Stable Carbon ◽  
Lucaogou Formation ◽  
Oil Source

Tight oil in the Permian Tiaohu Formation in the Santanghu Basin, northwest China, has a peculiar property such that the reservoir is sedimentary organic matter-bearing tuff characterized by high porosity (10%–25%) and very low permeability, mainly in the range of 0.01–0.50 mD. Biomarker and stable carbon isotope compositions of selected crude oils and source-rock extracts were analyzed to determine the source rock of the tight oil. Source rocks in the Lucaogou Formation consist of various rock types dominated by mudstones containing organic matter with intense yellow–green fluorescence. Mudstones in the Lucaogou Formation have total organic carbon (TOC) values mainly in the range of 1.0–8.0 wt%, hydrocarbon generation potential (S1 + S2) mostly >6 mg/g, and chloroform extractable bitumen “A” generally >0.1%. The maceral composition is predominantly fluorescing amorphinite. The hydrogen index (HI) varies from 300 to 900 mg HC/g TOC, indicating dominant Type I and Type II kerogen. Compared with the mudstones and tuffs in the Tiaohu Formation, the mudstones in the Lucaogou Formation are the best source rocks. The biomarker characteristics of mudstone extracts in the Lucaogou Formation differ from those in the Tiaohu Formation, based on the gammacerane index, β-carotane content, and the relative contents of C27, C28, and C29 regular steranes. Crude oil samples in the tuff show low pristane/phytane (Pr/Ph) ratios, high gammacerane indices, high β-carotane, and a dominance of the C29 regular sterane followed by C28 and C27 steranes, as well as depleted stable carbon isotope compositions. Oil–source correlation with biomarkers and δ13C values shows that the crude oil in the tuffs mainly originates from underlying source rocks in the Lucaogou Formation. The sedimentary organic matter in the tuffs also makes a small contribution to the tuffaceous reservoir. Therefore, the tuffaceous tight reservoir in the Tiaohu Formation is unusual in that the oil is not indigenous; rather, it migrates a long distance to accumulate in the upper reservoir.

scholarly journals Mechanism Analysis of Organic Matter Enrichment of Upper Ordovician-Lower Silurian Shale in the Upper Yangtze Area: Taking Jiaoye-1 Well in the Jiaoshiba Block as an Example

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Xiaoxue Liu ◽  
Zhenxue Jiang ◽  
Kun Zhang ◽  
Yan Song ◽  
Lin Jiang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Volcanic Activity ◽  
Lower Layer ◽  
Sedimentary Organic Matter ◽  
Biological Productivity ◽  
Upper Ordovician ◽  
Longmaxi Formation ◽  
Lower Silurian ◽  
The One ◽  
Yangtze Area

Organic matter is the material basis of shale hydrocarbon generation. The current organic matter content in shale is controlled by the original sedimentary organic matter abundance. Therefore, the study of the enrichment mechanism of sedimentary organic matter in shale has become an important issue to be solved. The Upper Yangtze area is the important exploration and exploitation area of marine shale gas in China. The shale of the Upper Ordovician Wufeng Formation-Lower Silurian Longmaxi Formation in the Yangtze area is the research object. Choosing redox indicator and biological productivity indicator, the study explores the enrichment mechanism of sedimentary organic matter from two aspects, sealing of water and volcanic activity. The results show that excess siliceous mineral in the shale of the Wufeng Formation-Longmaxi Formation in the Upper Yangtze area is bioorigin. Excess siliceous mineral can be used as one of the indicators of biological productivity. On the one hand, layer phenomenon occurred since the strong water sealing during the sedimentary period of Wufeng and the lower section of the Longmaxi Formation, which results in the high content of oxygen in surface water. On the other hand, the active volcanic activity brought volcanic ash which was beneficial to biological reproduction. Both of these factors led to higher biological productivity during this period. At the same time, the strong sealing of water made the lower layer of the water more reductive, and the active volcanic activity caused climate change, enhancing the reduction of the lower layer of the water, which made the rich organic matter deposited from the surface water well preserved. In the sedimentary period of the upper section of the Longmaxi Formation 1st member in the Upper Yangtze area, on the one hand, due to the weakened sealing of water, the oxygen content of the upper water decreased. On the other hand, the volcanic activity weakened until it stopped, and the source of volcanic ash rich in nutrient elements decreased. These two aspects led to lower biological productivity during this period. At the same time, the weaker water sealing could lead to a decrease in the reduction of the lower layer of the water, and the gradual cessation of volcanic activity no longer affected the climate, causing the destruction of sedimentary organic matter by oxidation.

scholarly journals Dark Septate Endophytes Isolated From Wild Licorice Roots Grown in the Desert Regions of Northwest China Enhance the Growth of Host Plants Under Water Deficit Stress

2021 ◽  
Vol 12 ◽  
Author(s):  
Chao He ◽  
Wenquan Wang ◽  
Junling Hou ◽  
Xianen Li
Keyword(s):  
Organic Matter ◽  
Drought Stress ◽  
Soil Organic Matter ◽  
Active Ingredient ◽  
Root Biomass ◽  
Host Plants ◽  
Glycyrrhizic Acid ◽  
Northwest China ◽  
Total Biomass ◽  
Osmotic Stress Tolerance

This study aimed to explore dark septate endophytes (DSE) that may improve the cultivation of medicinal plants in arid ecosystems. We isolated and identified eight DSE species (Acremonium nepalense, Acrocalymma vagum, Alternaria chartarum, Alternaria chlamydospora, Alternaria longissima, Darksidea alpha, Paraphoma chrysanthemicola, and Preussia terricola) colonizing the roots of wild licorice (Glycyrrhiza uralensis) in the desert areas of northwest China. Moreover, we investigated the osmotic stress tolerance of the DSE using pure culture, along with the performance of licorice plants inoculated with the DSE under drought stress in a growth chamber, respectively. Here, five species were first reported in desert habitats. The osmotic-stress tolerance of DSE species was highly variable, A. chlamydospora and P. terricola increased the total biomass and root biomass of the host plant. All DSE except A. vagum and P. chrysanthemicola increased the glycyrrhizic acid content; all DSE except A. chartarum increased the glycyrrhizin content under drought stress. DSE × watering regimen improved the glycyrrhizic acid content, soil organic matter, and available nitrogen. Structural equation model analysis showed that DSE × watering regimen positively affected soil organic matter, and total biomass, root length, glycyrrhizic acid, and glycyrrhizin (Shapotou site); and positively affected soil organic matter, available phosphorus, and glycyrrhizin (Minqin site); and positively affected the root length (Anxi site). DSE from the Shapotou site accounted for 8.0, 13.0, and 11.3% of the variations in total biomass, root biomass, and active ingredient content; DSE from the Minqin site accounted for 6.6 and 8.3% of the variations in total biomass and root biomass; DSE from the Anxi site accounted for 4.2 and 10.7% of the variations in total biomass and root biomass. DSE × watering regimen displayed a general synergistic effect on plant growth and active ingredient contents. These findings suggested that the DSE–plant interactions were affected by both DSE species and DSE originating habitats. As A. chlamydospora and P. terricola positively affected the total biomass, root biomass, and active ingredient content of host plants under drought stress, they may have important uses as promoters for the cultivation of licorice in dryland agriculture.

A re-assessment and calibration of redox thresholds in the Permian Lucaogou Formation of the Malang Sag, Santanghu Basin, Northwest China

2021 ◽  
pp. 105406
Author(s):  
Yongshuai Pan ◽  
Zhilong Huang ◽  
Xiaobo Guo ◽  
Rui Wang ◽  
Gary G. Lash ◽  
...  
Keyword(s):  
Northwest China ◽  
Lucaogou Formation

scholarly journals Effects of Straw Incorporation on Soil Organic Matter and Soil Water-Stable Aggregates Content in Semiarid Regions of Northwest China

PLoS ONE ◽  
2014 ◽  
Vol 9 (3) ◽  
pp. e92839 ◽  
Author(s):  
Peng Zhang ◽  
Ting Wei ◽  
Zhikuan Jia ◽  
Qingfang Han ◽  
Xiaolong Ren ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Water ◽  
Northwest China ◽  
Semiarid Regions ◽  
Water Stable Aggregates ◽  
Straw Incorporation
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