Characteristics of dual media in tight-sand gas reservoirs and its impact on reservoir quality: A case study of the Jurassic reservoir from the Kuqa Depression, Tarim Basin, Northwest China

2017 ◽  
Vol 53 (6) ◽  
pp. 2558-2568
Author(s):  
Pengwei Wang ◽  
Zhijun Jin ◽  
Xiongqi Pang ◽  
Yingchun Guo ◽  
Xiao Chen ◽  
...  
Keyword(s):  
Tarim Basin ◽  
Northwest China ◽  
Reservoir Quality ◽  
Gas Reservoirs ◽  
Kuqa Depression ◽  
Tight Sand Gas

scholarly journals Fluid geochemistry of the Jurassic Ahe Formation and implications for reservoir formation in the Dibei area, Tarim Basin, northwest China

2018 ◽  
Vol 36 (4) ◽  
pp. 801-819 ◽  
Author(s):  
Shuangfeng Zhao ◽  
Wen Chen ◽  
Zhenhong Wang ◽  
Ting Li ◽  
Hongxing Wei ◽  
...  
Keyword(s):  
Natural Gas ◽  
Tarim Basin ◽  
Oil And Gas ◽  
Northwest China ◽  
Source Rocks ◽  
Coal Measure ◽  
Hydrocarbon Generation ◽  
Gas Reservoirs ◽  
Isotopic Analyses ◽  
Jurassic Coal

The condensate gas reservoirs of the Jurassic Ahe Formation in the Dibei area of the Tarim Basin, northwest China are typical tight sandstone gas reservoirs and contain abundant resources. However, the hydrocarbon sources and reservoir accumulation mechanism remain debated. Here the distribution and geochemistry of fluids in the Ahe gas reservoirs are used to investigate the formation of the hydrocarbon reservoirs, including the history of hydrocarbon generation, trap development, and reservoir evolution. Carbon isotopic analyses show that the oil and natural gas of the Ahe Formation originated from different sources. The natural gas was derived from Jurassic coal measure source rocks, whereas the oil has mixed sources of Lower Triassic lacustrine source rocks and minor amounts of coal-derived oil from Jurassic coal measure source rocks. The geochemistry of light hydrocarbon components and n-alkanes shows that the early accumulated oil was later altered by infilling gas due to gas washing. Consequently, n-alkanes in the oil are scarce, whereas naphthenic and aromatic hydrocarbons with the same carbon numbers are relatively abundant. The fluids in the Ahe Formation gas reservoirs have an unusual distribution, where oil is distributed above gas and water is locally produced from the middle of some gas reservoirs. The geochemical characteristics of the fluids show that this anomalous distribution was closely related to the dynamic accumulation of oil and gas. The period of reservoir densification occurred between the two stages of oil and gas accumulation, which led to the early accumulated oil and part of the residual formation water being trapped in the tight reservoir. After later gas filling into the reservoir, the fluids could not undergo gravity differentiation, which accounts for the anomalous distribution of fluids in the Ahe Formation.

Hydrocarbon accumulation processes in the Dabei tight-gas reservoirs, Kuqa Subbasin, Tarim Basin, northwest China

AAPG Bulletin ◽  
2016 ◽  
Vol 100 (10) ◽  
pp. 1501-1521 ◽  
Author(s):  
Xiaowen Guo ◽  
Keyu Liu ◽  
Chengzao Jia ◽  
Yan Song ◽  
Mengjun Zhao ◽  
...  
Keyword(s):  
Tarim Basin ◽  
Northwest China ◽  
Tight Gas ◽  
Hydrocarbon Accumulation ◽  
Gas Reservoirs ◽  
Tight Gas Reservoirs
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