Identification of Complex Ancient Volcanic in Carboniferous, Northern Xinjiang

Based on recent exploration of Carboniferous volcanic of Kelameili gas field in Junggar Basin, northern Xinjiang, a series of technology have been formed to identify lithology and lithofacies of complex ancient volcanic. Carboniferous volcanic types in this gas field are complicated and diversified; the identical lithology is different in texture, structure and component, as well as relevant typical characteristics, making it hard to identify lithology and lithofacies. According to the observation from 16 wells in Ludong area with 92 tubes of cores, 235 typical pictures and 631 sections, the article denominated the volcanic lithology. The lithologic and electric relationship of volcanic were built by the data of cores, sections and calibration logging, which laid a foundation for building the volcanic lithologic-electric plate. Density-gamma crossplot, acoustic-gamma crossplot and resistivity-gamma crossplot in Ludong area are made, and several complex volcanic types are identified, such as rhyolites, basalts, basaltic volcanic breccias, andesites and andesitic firing breccias. Through logging-seism-combined identification technology of volcanic lithofacies, the seismic properties of different volcanic types are distinguished, finally the distribution of explosive facies, outflow facies and volcanic sendimentary facies are divided both on plane and profile.

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Fossil woods from the Olenekian (late Early Triassic) Shaofanggou Formation in the Junggar Basin, Northern Xinjiang, North‐west China

Geological Journal ◽

10.1002/gj.4193 ◽

2021 ◽

Author(s):

Xiao Shi ◽

Jiabin Lang ◽

Ning Li ◽

Wenchao Shu ◽

Hui Li ◽

...

Keyword(s):

Junggar Basin ◽

Early Triassic ◽

West China ◽

North West ◽

Northern Xinjiang

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Fractures in Volcanic Reservoir: a case study of Zhongguai uplift in Northwestern Margin of Junggar Basin, China

Earth Sciences Research Journal ◽

10.15446/esrj.v22n3.75426 ◽

2018 ◽

Vol 22 (3) ◽

pp. 169-174 ◽

Cited By ~ 2

Author(s):

Cunhui Fan ◽

Qirong Qin ◽

Feng Liang ◽

Zenghui Fan ◽

Zhi Li

Keyword(s):

Oil And Gas ◽

Volcanic Rocks ◽

Junggar Basin ◽

Pressure Change ◽

Reservoir Permeability ◽

Northwestern Margin ◽

Genetic Mechanisms ◽

Relationship Of ◽

Oilfield Development

Fractures in Carboniferous volcanic rocks located at Zhongguai Area (China) highly influence the accumulation and productivity of oil and gas. As such, the study of development periods and genetic mechanisms of tectonic fractures could throw useful information regarding the evaluation and development of that reservoir. Their tectonic origins caused high-angle and oblique shear fractures. The primary orientation of those fractures appears close to EW (270°±10°), NW (300°±15°), NE (45°±15°), and SN (0°±10°). At least four fracture generations can be found in Carboniferous volcanic rocks at Zhongguai Area. Combined with a tectonic evolution, they are based on the segmentation relationship of the fracture fillings, the thermometry measurement of the fracture filling inclusion, and the acoustic emission, as well. Affected by a new horizontal principal stress, the opening and permeability of nearly EW fractures are the best. In this way, a priority in the development of well's patterns should be considered close to EW fractures. The pressure change in the process of exploitation may damage the reservoir permeability of fractured volcano rocks severely. Accordingly, well patterns should be adjusted to dynamic changes of permeability happened during the oilfield development since some differences have been detected in distinct fracture sets.

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Fracture Fillings and Implication of Fluid Activities in Volcanic Rocks: Dixi Area in Kelameili Gas Field, Junggar Basin, Northwestern China

Minerals ◽

10.3390/min9030154 ◽

2019 ◽

Vol 9 (3) ◽

pp. 154 ◽

Cited By ~ 1

Author(s):

Mingyou Feng ◽

Tian Liu ◽

Tong Lin ◽

Xiaohong Liu ◽

Ningxin Li ◽

...

Keyword(s):

Carbon Dioxide ◽

Volcanic Rocks ◽

Junggar Basin ◽

Hydrothermal Fluids ◽

Northwestern China ◽

Volatile Components ◽

Gas Field ◽

Weakly Alkaline ◽

Quartz Veins ◽

Calcite Veins

The Carboniferous Batamayineishan Formation of the Kelameili Gas Field is a specific weathered crust-related volcanic reservoir that has a significant production rate in the Junggar Basin, Northwestern China, attributed to debatable processes of fluid evolution. The results suggest that various types of fluids occurring in volcanic rocks lead to the filling of quartz and calcite in fractures and their associated alteration haloes. The silica that formed quartz veins was mainly derived from deep hydrothermal fluids, while the carbon dioxide that formed calcite veins originated from sources characterized by mixing and alteration of deep hydrothermal and hydrocarbon fluids. Siliceous hydrothermal fluids rich in sulphur dioxide and other volatile components were driven by a pressure gradient and buoyancy, and circulated both laterally and vertically along the fractures, forming quartz veins and tension fractures under different temperature conditions. Moreover, changes in salinity, pressure, and carbon dioxide of deep fluids, varying from acidic to weakly alkaline, resulted in earlier calcite precipitation in contraction fractures and weathered fractures. Tectonic uplift resulted in the long-term exposure of volcanic rocks, where fresh water mixed with the partially alkaline fluid escaping the basin to form calcite cements, thus retaining the characteristics of a seepage environment in the weathered fractures. Structural fractures occurred due to tectonic movements during the burial period. Filling and leakage of hydrocarbons caused pore fluids to convert from acidic to alkaline, precipitating late sparry calcite in dissolution fractures. Late hydrothermal fluid metasomatism, brought about by infiltration into the permeable zone, caused partial dissolution of local calcite along cleavage cracks.

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An overview of types and characterization of hot fluids associated with reservoir formation in petroliferous basins

Energy Exploration & Exploitation ◽

10.1177/0144598718763895 ◽

2018 ◽

Vol 36 (6) ◽

pp. 1359-1375 ◽

Cited By ~ 3

Author(s):

Wenxuan Hu ◽

Xiaolin Wang ◽

Dongya Zhu ◽

Donghua You ◽

Haiguang Wu

Keyword(s):

Gulf Coast ◽

Noble Gas ◽

Close Association ◽

Eastern China ◽

Spatial Relationship ◽

Junggar Basin ◽

Gas Field ◽

Isotopic Signatures ◽

Carbonate Cements ◽

Deep Faults

Increasing petroleum explorations indicate that the formation of many reservoirs is in close association with deep hot fluids, which can be subdivided into three groups including crust-derived hot fluid, hydrocarbon-related hot fluid, and mantle-derived hot fluid. The crust-derived hot fluid mainly originates from deep old rocks or crystalline basement. It usually has higher temperature than the surrounding rocks and is characterized by hydrothermal mineral assemblages (e.g. fluorite, hydrothermal dolomite, and barite), positive Eu anomaly, low δ18O value, and high 87Sr/86Sr ratio. Cambrian and Ordovician carbonate reservoirs in the central Tarim Basin, northwestern China serve as typical examples. The hydrocarbon-related hot fluid is rich in acidic components formed during the generation of hydrocarbons, such as organic acid and CO2, and has strong ability to dissolve alkaline minerals (e.g. calcite, dolomite, and alkaline feldspar). Extremely 13C-depleted carbonate cements are indicative of the activities of such fluids. The activities of hydrocarbon-related hot fluids are distinct in the Eocene Wilcox Group of the Texas Gulf Coast, and the Permian Lucaogou Formation of the Jimusaer Sag and the Triassic Baikouquan Formation of the Mahu Sag in the Junggar Basin. The mantle-derived hot fluid comes from the upper mantle. The activities of mantle-derived hot fluids are common in the rift basins in eastern China, showing a close spatial relationship with deep faults. This type of hot fluid is characterized by high CO2 content, unique gas compositions, and distinct noble gas isotopic signatures. In the Huangqiao gas field of eastern China, mantle-derived CO2-rich hot fluids have created more pore spaces in the Permian sandstone reservoirs adjacent to deep faults.

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The earliest Asian bats (Mammalia: Chiroptera) address major gaps in bat evolution

Biology Letters ◽

10.1098/rsbl.2021.0185 ◽

2021 ◽

Vol 17 (6) ◽

pp. 20210185

Author(s):

Matthew F. Jones ◽

Qiang Li ◽

Xijun Ni ◽

K. Christopher Beard

Keyword(s):

Central Asia ◽

Junggar Basin ◽

Placental Mammal ◽

Early Eocene ◽

Northern Xinjiang ◽

Dental Evolution ◽

Bat Evolution ◽

Postcranial Anatomy

Bats dispersed widely after evolving the capacity for powered flight, and fossil bats are known from the early Eocene of most continents. Until now, however, bats have been conspicuously absent from the early Eocene of mainland Asia. Here, we report two teeth from the Junggar Basin of northern Xinjiang, China belonging to the first known early Eocene bats from Asia, representing arguably the most plesiomorphic bat molars currently recognized. These teeth combine certain bat synapomorphies with primitive traits found in other placental mammals, thereby potentially illuminating dental evolution among stem bats. The Junggar Basin teeth suggest that the dentition of the stem chiropteran family Onychonycteridae is surprisingly derived, although their postcranial anatomy is more primitive than that of any other Eocene bats. Additional comparisons with stem bat families Icaronycteridae and Archaeonycteridae fail to identify unambiguous synapomorphies for the latter taxa, raising the possibility that neither is monophyletic as currently recognized. The presence of highly plesiomorphic bats in the early Eocene of central Asia suggests that this region was an important locus for the earliest, transitional phases of bat evolution, as has been demonstrated for other placental mammal orders including Lagomorpha and Rodentia.

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Identification of secondary microbial methane and biodegradation: Case study from Luliang oil and gas field, Junggar Basin, China

Journal of Natural Gas Geoscience ◽

10.1016/j.jnggs.2019.10.003 ◽

2019 ◽

Vol 4 (5) ◽

pp. 267-278 ◽

Cited By ~ 1

Author(s):

Deyu Gong ◽

Yueqian Zhang ◽

Wenjian Guo ◽

Rui Qi ◽

Shan Lu ◽

...

Keyword(s):

Oil And Gas ◽

Junggar Basin ◽

Gas Field ◽

Oil And Gas Field

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Characterization of Low Molecular Weight Hydrocarbons in Jingbian Gas Field and its Application to Gas Sources Identification

Energy Exploration & Exploitation ◽

10.1260/0144-5987.29.6.777 ◽

2011 ◽

Vol 29 (6) ◽

pp. 777-795 ◽

Cited By ~ 13

Author(s):

Guoyi Hu ◽

Shuichang Zhang

Keyword(s):

Molecular Weight ◽

Stable Carbon Isotopes ◽

Ordos Basin ◽

Low Molecular Weight ◽

Gas Field ◽

Average Value ◽

Weathered Crust ◽

Relationship Of ◽

Compound Specific Carbon Isotope ◽

Coal Measures

Chemical and isotopic compositions of C6-C7 low molecular weight hydrocarbons (LMWHs) were used to determine the origin of gas in the Ordovician weathered crust (O1m5) reservoir of Jingbian gas field in Ordos Basin, China. GC quantification of LMWHs for 55 gas samples [20 of them from the Xiashihezi Formation (P1x) and Shanxi Formation (P1s) reservoirs, and the rest from the O1m5 reservoir] were conducted. The compound specific stable carbon isotopes of LMWHs for 24 gas samples (five gas samples from the P1s reservoir) were analyzed with GC-C-IRMS. The results show that cycloalkanes are abundant components and their concentrations range from 23.8–52.5% with an average of 41.1% among LMWHs. Methylcyclohexane (MCH) is the most abundant one among normal heptane ( n-C7), MCH and dimethylcyclopentane (DMCP), ranging from 50.1–81.4% with an average value of 71.6%. A13C enrichment for nine compounds of C6-C7 fraction was observed, and the δ13C values range from −25.4–16.3%. Based on the correlation of the Mango parameters (K1 and K2), the relationship of n-C7, MCH and DMCP and compound specific carbon isotope of C6-C7 compounds, the gas in the O1m5 reservoir shares the same origin with that in the P1x, P1s reservoirs, the natural gas in Ordovician weathered crust reservoir and Permian sandstone reservoir sourced from coal measures in Carboniferous and Permian.

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