Comparison of diagenetic characteristics and pore evolution in outcrops and cores of tight sandstone reservoirs in the Triassic Yanchang Formation, the Ordos Basin, China

AAPG Bulletin ◽  
2020 ◽  
Vol 104 (11) ◽  
pp. 2429-2452
Author(s):  
Zongquan Hu ◽  
Herong Zheng ◽  
Wei Yin ◽  
Chunyan Liu ◽  
Chuanxiang Sun ◽  
...  
Keyword(s):  
Ordos Basin ◽  
Tight Sandstone ◽  
Yanchang Formation ◽  
Pore Evolution ◽  
The Ordos Basin ◽  
Sandstone Reservoirs

scholarly journals Quantitative evaluation of the diagenesis and porosity evolution of tight sandstone reservoirs: A case study of the Yanchang formation in the Southern Ordos basin, China

2019 ◽  
Vol 9 (1) ◽  
pp. 15-26
Author(s):  
Meng Xiao ◽  
Dawei Chen ◽  
Guiqiang Qiu ◽  
Xuanjun Yuan ◽  
Chunfang Chen
Keyword(s):  
Pore Size ◽  
Average Pore Size ◽  
Ordos Basin ◽  
Influential Factor ◽  
Tight Sandstone ◽  
Average Pore ◽  
Yanchang Formation ◽  
Porosity Evolution ◽  
Pore Evolution ◽  
Sandstone Reservoirs

Evaluation of the pore evolution is key to gaining a better understanding of oil migration and accumulation in tight oil exploration for tight sandstone; to study the diagenesis and porosity evolution of tight sandstone reservoirs, we analysed the 8th member of the Yanchang Formation by core observation, thin section observation, cathodoluminescence, scanning electron microscopy, and logging data analysis. The following conclusions can be drawn (1) In the typical tight sandstone reservoir, numerous secondary pores developed at burial depths in the range of 1300 m to 1400 m, and approximately 1500 m to 1600 m. (2) Compaction was the most influential factor of reservoir density and decreased the average pore size by 24.8%. Carbonate cementation decreased the porosity by 8.2%. The most important diagenetic process for increasing the reservoir porosity was dissolution, which increased the pore size by 5.1%. In addition, chlorite played an active role in inhibiting secondary quartz growth and preserving primary pores. (3) The early gas invasion can inhibit diagenesis, and the organic acids produced by the later oil can increase dissolution, so that the high oil saturation phenomenon becomes more obvious.

scholarly journals Imaging‐Based Characterization of Perthite in the Upper Triassic Yanchang Formation Tight Sandstone of the Ordos Basin, China

2019 ◽  
Vol 93 (2) ◽  
pp. 373-385 ◽  
Author(s):  
Shuheng DU ◽  
Guoxin SHI ◽  
Xinjian YUE ◽  
Gen KOU ◽  
Bo ZHOU ◽  
...  
Keyword(s):  
Ordos Basin ◽  
Upper Triassic ◽  
Tight Sandstone ◽  
Yanchang Formation ◽  
The Ordos Basin

scholarly journals Classification and evaluation of tight sandstone reservoirs based on diagenetic facies: a case study on Chang 6 reservoir in the center-west Ordos Basin

2021 ◽  
Author(s):  
Gao Zhanwu ◽  
Shi Jian ◽  
Xie Qichao ◽  
Zhou Yan ◽  
Zhou Shuxun
Keyword(s):  
Ordos Basin ◽  
Quality Analysis ◽  
Reservoir Quality ◽  
Tight Sandstone ◽  
Pore Evolution ◽  
Sandstone Reservoirs ◽  
Four Levels ◽  
Comprehensive Classification ◽  
Diagenetic Facies ◽  
Feldspar Dissolution

AbstractTight sandstone reservoirs dominated by are developed in the Chang 6 oil layer group of the Yanchang Formation in the central-western part of the Ordos Basin. Featuring the lacustrine delta facies, Chang 6 formation in the center-west area of Ordos Basin shows an increasing petroleum reserve expectation. Its exploitation practice, however, has many problems caused by tight sandstone reservoir features. According to diagenetic and pore analysis, the diagenetic facies in the study area are grouped into four types: chlorite-film-intergranular-pore, feldspar-dissolution, clay-cemented-micropore, carbonate-cemented-tightness for their obvious differences in mineral feature and pore evolution. By introducing the comprehensive classification parameter synthesized from 9 other parameters, the reservoir quality is divided up into four levels: I(Feci > 1), II(3 ≤ Feci ≤ 7), III(-2 ≤ Feci ≤ 3), IV(Feci ≤ -2). The reservoir quality division matches well with the diagenetic facies group. To decide the diagenetic type and reservoir quality division in all wells, the logging data are utilized with the Fisher discriminant method, which has obtained a good performance. The method enables the reservoir quality analysis expanding to all wells from samples, which is helpful for exploitation of the study area.

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