Characteristics of dissolved pores and dissolution mechanism of zeolite-rich reservoirs in the Wuerhe Formation in Mahu area, Junggar Basin

2021 ◽  
pp. 014459872110287
Author(s):  
Ji Li ◽  
Wenjie Zhang ◽  
Baoli Xiang ◽  
Dan He ◽  
Shengchao Yang ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Manganese Content ◽  
Junggar Basin ◽  
Dissolution Mechanism ◽  
Primary Role ◽  
High Iron Content ◽  
Thin Sections ◽  
Main Site ◽  
Dissolution Zone ◽  
Diagenetic Fluids

The reservoir in the Wuerhe Formation in the Mahu Sag, northwestern Junggar Basin, China, exhibits complex dissolution and cementation related to zeolite. The source and mechanism of diagenetic fluids are crucial in studying the reservoir genesis. Thus we investigated the key reservoirs fluids related to the zeolite and discussed their significance in the zeolite-rich reservoir of the Permian Wuerhe Formation in the Mahu Sag. Based on thin sections and electron microscope observations of rock samples and analyses of physical properties, C-O isotopes, and major elements, it is found that the reservoir underwent mainly two stages of fluid-related dissolution and cementation processes, in which the hydrocarbon-bearing fluid played the primary role in forming the high-quality reservoir. Dissolution pores are the most important storage space, and zeolite cement is the most important dissolution mineral. The geochemical characteristics of zeolite and calcite cement indicate the presence of two diagenetic fluids. The iron-rich calcite and orange-red heulandite is related to early diagenetic fluids with high iron content and higher carbon isotope values, whereas the calcites, with high manganese content and lower carbon isotope values, are formed by late acidic organic diagenetic fluids related to oil and gas activities. The hydrocarbon-bearing fluids form different spatial diagenetic zones, including the dissolution zone, buffer zone, and cementation zone, and the dissolution zone near the oil source fault is the main site of zeolite dissolution. The late fluid has the characteristics of multi-stage activity, which makes the spatial zoning expand gradually, resulting in multiple superpositions of dissolution and cementation and increasing the complexity and heterogeneity of the reservoir diagenesis. This study expands the understandings of the dissolution activities of different fluids in zeolite-rich reservoirs and also has reference significance for dissolution activity of hydrocarbon fluid in other types of reservoirs.

Global carbon isotope signal in the Middle Triassic on Svalbard

2021 ◽  
Author(s):  
Victoria S. Engelschiøn ◽  
Øyvind Hammer ◽  
Fredrik Wesenlund ◽  
Jørn H. Hurum ◽  
Atle Mørk
Keyword(s):  
Carbon Isotope ◽  
Depositional Environment ◽  
Middle Triassic ◽  
Barents Sea ◽  
Water Productivity ◽  
Sedimentary Environment ◽  
The Arctic ◽  
Late Triassic ◽  
Triassic Boundary ◽  
Thin Sections

<p>Several carbon isotope curves were recently published for the Early and Middle Triassic in Tethys. Recent work has also been done on the Early Triassic of Svalbard, but not yet for the Middle Triassic. This work is the first to measure δ<sup>13</sup>C for different Middle Triassic localities on Svalbard, which was then part of the Boreal Ocean on northern Pangea. Our aim is to understand the controls on the Svalbard carbon isotope curve and to place them in a global setting.</p><p>Correlating Triassic rocks around the world is interesting for several reasons. The Triassic Period was a tumultuous time for life, and the Arctic archipelago of Svalbard has shown to be an important locality to understand the early radiation of marine vertebrates in the Triassic. Much effort is also made to understand the development of the Barents Sea through Svalbard’s geology.</p><p>Carbon isotope curves are controlled by depositional environment and global fluctuations. Global factors such as the carbon cycle control the long-term carbon isotopic compositions, while short-term fluctuations may reflect the origin of organic materials in the sediment (e.g. algal or terrestrial matter), stratification of the water column, and/or surface water productivity. Carbon isotopes can therefore be useful to understand the depositional environment and to correlate time-equivalent rocks globally.</p><p>The dataset was collected through three seasons of fieldwork in Svalbard with localities from the islands Spitsbergen, Edgeøya and Bjørnøya. Detailed stratigraphic sampling has resulted in high-resolution δ<sup>13</sup>C curves. These show three strong transitions; 1) on the boundary between the Early and Middle Triassic, 2) in the middle of the formation and 3) at the Middle and Late Triassic boundary. Several Tethyan localities show a possibly similar Early-Middle Triassic signal. Current work in progress is sedimentological analysis by thin sections and X-ray fluorescence spectroscopy (XRF) to further understand the sedimentary environment.</p>

Stable carbon isotope characteristics of desert plants in the Junggar Basin, China

2011 ◽  
Vol 27 (1) ◽  
pp. 115-124 ◽  
Author(s):  
Jian-Ying Ma ◽  
Wei Sun ◽  
Hui-Ling Sun ◽  
Shao-Ming Wang
Keyword(s):  
Carbon Isotope ◽  
Stable Carbon Isotope ◽  
Junggar Basin ◽  
Desert Plants ◽  
Stable Carbon

scholarly journals Geochemical Characteristics of Gas and Flowback Water in Lake Facies Shale: A Case Study From the Junggar Basin, China

2021 ◽  
Vol 9 ◽  
Author(s):  
Lin Zhang ◽  
Dan Liu ◽  
Yongjin Gao ◽  
Min Zhang
Keyword(s):  
Carbon Isotope ◽  
Shale Gas ◽  
Isotope Composition ◽  
Ordos Basin ◽  
Junggar Basin ◽  
Source Rocks ◽  
Flowback Water ◽  
Lucaogou Formation ◽  
The Difference

The chemical and isotopic compositions of the natural gas and the co-produced flowback water from the XJC 1 well in Junggar Basin, China, were analyzed to determine the origin of gases in the Permian Lucaogou Formation (P2l) and the Triassic Karamay Formation (T2k) in the Bogda Mountain periphery area of the Southern Junggar Basin. The value of carbon isotope composition of the P2l lacustrine shale gas in the Junggar Basin was between the shale gas in Chang 7 Formation of Triassic (T1y7) in the Ordos Basin and that in the Xu 5 Formation of Triassic (T3x5) in the Sichuan Basin. The difference in gas carbon isotope is primarily because the parent materials were different. A comparison between compositions in the flowback water reveals that the P2l water is of NaHCO3 type while the T2k water is of NaCl type, and the salinity of the latter is higher than the former, indicating a connection between P2l source rock and the T2k reservoir. In combination with the structural setting in the study area, the gas filling mode was proposed as follows: the gas generated from the lacustrine source rocks of the Permian Lucaogou Formation is stored in nearby lithological reservoirs from the Permian. Petroleum was also transported along the faults to the shallow layer of the Karamay Formation over long distances before it entered the Triassic reservoir.

Natural fractures in deep tight gas sandstone reservoirs in the thrust belt of the southern Junggar Basin, northwestern China

2020 ◽  
Vol 8 (4) ◽  
pp. SP81-SP93 ◽  
Author(s):  
Guoping Liu ◽  
Lianbo Zeng ◽  
Xiaojun Wang ◽  
Mehdi Ostadhassan ◽  
Zhenlin Wang ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Rock Mechanics ◽  
Hanging Wall ◽  
Damage Zone ◽  
Laboratory Data ◽  
Junggar Basin ◽  
Thrust Belt ◽  
Natural Fractures ◽  
Thin Sections ◽  
Sandstone Reservoirs

The development of natural fractures is a significant characteristic of the Jurassic deep tight sandstone reservoirs in the thrust belt of the southern Junggar Basin, and these reservoirs have a great potential for natural gas resources. Based on the analyses of outcrops, cores, thin sections, and other laboratory data, natural fractures in these reservoirs are mainly tectonic ones, which appear in groups and vary in scale, dip angle, and density. We have classified fractures in thin sections into intragranular, grain boundary, and transgranular ones depending on their relationship with minerals grains. Almost 58% of the whole fracture population is opening-mode fractures, and calcite is the main filling mineral for the remaining ones. Fracture apertures vary based on their types, where transgranular fractures are the widest, followed by grain boundary and intragranular ones. Lithology, rock mechanical mechanics layers, and structures control the development of natural fractures. Fractures are more frequent in siltstone and fine sandstone. Sandstones with larger mineral grains are more likely to develop grain boundary and intragranular fractures. Intralayer fractures are the dominant ones, which intersect the rock mechanics interface at high angles or perpendicularly. The linear density of these fractures decreases when the thickness of the rock-mechanics layer increases. Furthermore, fractures have a higher degree of development in the hanging wall of the faults, with the degree decreasing when the distance from the fault plane increases. Additionally, the development degree of fractures in the damage zone is better than the adjacent rocks, and the width of damage zones is a function of the amount of fault displacement.

scholarly journals The effects of resource availability and environmental conditions on genetic rankings for carbon isotope discrimination during growth in tomato and rice

2005 ◽  
Vol 32 (12) ◽  
pp. 1089 ◽  
Author(s):  
Jonathan P. Comstock ◽  
Susan R. McCouch ◽  
Bjorn C. Martin ◽  
Charles G. Tauer ◽  
Todd J. Vision ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Nutrient Availability ◽  
Carbon Isotope Discrimination ◽  
Intercellular Co2 Concentration ◽  
Environmental Parameters ◽  
Stomatal Aperture ◽  
Environment Interaction ◽  
Primary Role ◽  
Allocation Pattern ◽  
Isotope Discrimination

Carbon isotope discrimination (Δ) is frequently used as an index of leaf intercellular CO2 concentration (ci) and variation in photosynthetic water use efficiency. In this study, the stability of Δ was evaluated in greenhouse-grown tomato and rice with respect to variable growth conditions including temperature, nutrient availability, soil flooding (in rice), irradiance, and root constriction in small soil volumes. Δ exhibited several characteristics indicative of contrasting set-point behaviour among genotypes of both crops. These included generally small main environmental effects and lower observed levels of genotype-by-environment interaction across the diverse treatments than observed in associated measures of relative growth rate, photosynthetic rate, biomass allocation pattern, or specific leaf area. Growth irradiance stood out among environmental parameters tested as having consistently large main affects on Δ for all genotypes screened in both crops. We suggest that this may be related to contrasting mechanisms of stomatal aperture modulation associated with the different environmental variables. For temperature and nutrient availability, feedback processes directly linked to ci and / or metabolite pools associated with ci may have played the primary role in coordinating stomatal conductance and photosynthetic capacity. In contrast, light has a direct effect on stomatal aperture in addition to feedback mediated through ci.

scholarly journals Carbon isotope and origin of the hydrocarbon gases in the Junggar Basin, China

2018 ◽  
Vol 3 (5) ◽  
pp. 253-261
Author(s):  
Lixin Pei ◽  
Wenzhe Gang ◽  
Chuanzhen Zhu ◽  
Yazhou Liu ◽  
Wenjun He ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Junggar Basin ◽  
Hydrocarbon Gases

Geochemical Characteristics of Oils from Chepaizi Area, Northwestern Junggar Basin, China

2009 ◽  
Vol 27 (2) ◽  
pp. 91-103 ◽  
Author(s):  
Luofu Liu ◽  
Weibin Wang ◽  
Lin Wu ◽  
Yande Zhao ◽  
Zhijun Chen ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Lower Layer ◽  
Junggar Basin ◽  
Source Rocks ◽  
Petroleum Exploration ◽  
Nitrogen Compounds ◽  
Chemical Compositions ◽  
Accumulation Pattern ◽  
Oil Source ◽  
Oil Gas

In recent years, great progress in petroleum exploration has been made obtained for Chepaizi Swell along the northwestern margin of Junggar Basin. But, the hydrocarbon sources of this area are still unknown, and this results in difficulty of determining the migration path system and migration trend. This also leads to difficulty in studying the oil-gas accumulation pattern of the area. In order to understand the oil sources, samples were systematically collected in the Swell and were analyzed for investigation of physical properties, chemical compositions and characteristics of bio-markers, carbon isotope and nitrogen compounds of the oils from Chepaizi. Through comparisons of physical and chemical characters, oils from different intervals of Chepaizi can be classified into two groups. One is the oils trapped in layers of Jurassic and below Jurassic (named as Lower Series of Strata oils), and another is those in layers of Cretaceous and above Cretaceous (named as Upper Series of Strata oils). Oils from the same group have similar densities, viscosities, group compositions and characteristics of saturated hydrocarbon, bio-marker and carbon isotope, while the oils from different groups are obviously different for the above-mentioned parameters. By fine oil-oil correlation, one can know that the lower-layer oils have the same oil source (from the Permian source rocks), and the upper-layer oils also have the same source (mainly from the Jurassic source rocks). In Chepaizi, the hydrocarbons stored in reservoirs originated mainly from Jurassic and Permian rocks. However, Cretaceous source rocks also have some contribution to oil-gas supply for oil pools. The oil-source division results based on nitrogen compounds (carbazoles) are completely identical with those by common geochemical indices, indicating that carbazoles are of importance in oil type division and oil-source correlation.

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