Discovery of eclogite at northern margin of Qaidam Basin, NW China

1998 ◽  
Vol 43 (20) ◽  
pp. 1755-1760 ◽  
Author(s):  
Jingsui Yang ◽  
Zhiqin Xu ◽  
Haibing Li ◽  
Cailai Wu ◽  
Junwen Cui ◽  
...  
Keyword(s):  
Qaidam Basin ◽  
Nw China ◽  
Northern Margin

Source of aeolian dune sands on the northern margin of Qarhan Salt Lake, Qaidam Basin, NW China

2019 ◽  
Vol 55 (5) ◽  
pp. 3643-3653 ◽  
Author(s):  
Jiyan Li ◽  
Ling Zhou ◽  
Jialiang Yan ◽  
Xujia Cui ◽  
Yingying Cai
Keyword(s):  
Salt Lake ◽  
Qaidam Basin ◽  
Nw China ◽  
Northern Margin ◽  
Dune Sands ◽  
Qarhan Salt Lake

scholarly journals Dynamics of hydrocarbon accumulation in the west section of the northern margin of the Qaidam Basin, NW China

2013 ◽  
Vol 40 (2) ◽  
pp. 170-182 ◽  
Author(s):  
Xiaorong LUO ◽  
Ying SUN ◽  
Liqun WANG ◽  
Ancheng XIAO ◽  
Lixie MA ◽  
...  
Keyword(s):  
Qaidam Basin ◽  
Hydrocarbon Accumulation ◽  
The West ◽  
Nw China ◽  
Northern Margin

scholarly journals Impact of Diagenesis on the Low Permeability Sandstone Reservoir: Case Study of the Lower Jurassic Reservoir in the Niudong Area, Northern Margin of Qaidam Basin

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 453
Author(s):  
Wenhuan Li ◽  
Tailiang Fan ◽  
Zhiqian Gao ◽  
Zhixiong Wu ◽  
Ya’nan Li ◽  
...  
Keyword(s):  
Physical Properties ◽  
Oil And Gas ◽  
Qaidam Basin ◽  
Isotope Analysis ◽  
Lower Jurassic ◽  
Low Permeability ◽  
Hydrocarbon Generation ◽  
Northern Margin ◽  
Pore Evolution ◽  
Sandstone Reservoir

The Lower Jurassic reservoir in the Niudong area of the northern margin of Qaidam Basin is a typical low permeability sandstone reservoir and an important target for oil and gas exploration in the northern margin of the Qaidam Basin. In this paper, casting thin section analysis, scanning electron microscopy, X-ray diffraction, and stable isotope analysis among other methods were used to identify the diagenetic characteristics and evolution as well as the main factors influencing reservoir quality in the study area. The predominant types of sandstone in the study area are mainly feldspathic lithic sandstone and lithic arkose, followed by feldspathic sandstone and lithic sandstone. Reservoir porosity ranges from 0.01% to 19.5% (average of 9.9%), and permeability ranges from 0.01 to 32.4 mD (average of 3.8 mD). The reservoir exhibits robust heterogeneity and its quality is mainly influenced by diagenesis. The Lower Jurassic reservoir in the study area has undergone complex diagenesis and reached the middle diagenesis stage (A–B). The quantitative analysis of pore evolution showed that the porosity loss rate caused by compaction and cementation was 69.0% and 25.7% on average, and the porosity increase via dissolution was 4.8% on average. Compaction was the main cause of the reduction in the physical property of the reservoir in the study area, while cementation and dissolution were the main causes of reservoir heterogeneity. Cementation can reduce reservoir space by filling primary intergranular pores and secondary dissolved pores via cementation such as a calcite and illite/smectite mixed layer, whereas high cement content increased the compaction resistance of particles to preserve certain primary pores. δ13C and δ18O isotopes showed that the carbonate cement in the study area was the product of hydrocarbon generation by organic matter. The study area has conditions that are conductive to strong dissolution and mainly occur in feldspar dissolution, which produces a large number of secondary pores. It is important to improve the physical properties of the reservoir. Structurally, the Niudong area is a large nose uplift structure with developed fractures, which can be used as an effective oil and gas reservoir space and migration channel. In addition, the existence of fractures provides favorable conditions for the uninterrupted entry of acid fluid into the reservoir, promoting the occurrence of dissolution, and ultimately improves the physical properties of reservoirs, which is mainly manifested in improving the reservoir permeability.

Groundwater-surface water interactions derived by hydrochemical and isotopic (222Rn, deuterium, oxygen-18) tracers in the Nomhon area, Qaidam Basin, NW China

2018 ◽  
Vol 565 ◽  
pp. 650-661 ◽  
Author(s):  
Dan Zhao ◽  
Guangcai Wang ◽  
Fu Liao ◽  
Nuan Yang ◽  
Wanjun Jiang ◽  
...  
Keyword(s):  
Surface Water ◽  
Qaidam Basin ◽  
Nw China

scholarly journals Geochemical Significance of Clay Minerals and Elements in Paleogene Sandstones in the Center of the Northern Margin of the Qaidam Basin, China

Minerals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 505 ◽  
Author(s):  
Guoqiang Sun ◽  
Meng Wang ◽  
Jiajia Guo ◽  
Yetong Wang ◽  
Yongheng Yang
Keyword(s):  
Clay Minerals ◽  
Chemical Weathering ◽  
Qaidam Basin ◽  
Sedimentary Environment ◽  
Climatic Conditions ◽  
Northern Margin ◽  
Magmatic Arc ◽  
Average Value ◽  
Geochemical Significance ◽  
Continental Magmatic Arc

The average thickness of Paleogene sandstones reaches about 3000–4000 m at the northern margin of the Qaidam Basin. However, the provenance and sedimentary environment of these sandstones are uncertain; thus, more comprehensive research is needed. Integrated research is conducted on the provenance and weathering process based on petrographic characteristics, clay minerals, and geochemical compositions of sandstones in the center of the northern Qaidam Basin. The results of lithofacies analysis show that the Paleogene sandstones were mainly derived from an active continental magmatic arc, subduction accretion, or a fold-thrust belt. The average illite content in the Paleogene clay minerals is more than 50%, followed by chlorite and smectite, which reflect climatic and environmental characteristics that were arid to semi-arid, whereas the characteristics of carbon–oxygen isotopes reveal a mainly freshwater sedimentary environment. The corrected chemical index of alteration (CIAcorr) is between 56.3 and 75.7, with an average value of 66.5. These results indicate that the provenance of the Paleogene sandstones in the center of the northern Qaidam Basin mainly formed under cold and dry climatic conditions and experienced limited chemical weathering with a small amount that underwent intermediate chemical weathering under warm and humid conditions.

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