scholarly journals Geologic characterization of a lower Cambrian marine shale: Implications for shale gas potential in northwestern Hunan, South China

2018 ◽  
Vol 6 (3) ◽  
pp. T635-T647 ◽  
Author(s):  
Zhenghui Xiao ◽  
Jisong Liu ◽  
Jingqiang Tan ◽  
Rongfeng Yang ◽  
Jason Hilton ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
South China ◽  
Lower Cambrian ◽  
Gas Adsorption ◽  
Vitrinite Reflectance ◽  
Mean Value ◽  
Hunan Province ◽  
Quartz Content ◽  
Gas Potential

We have investigated the geologic features of the lower Cambrian-aged Niutitang Shale in the northwestern Hunan province of South China. Our results indicate that the Niutitang Shale has abundant and highly mature algal kerogen with total organic carbon (TOC) content ranging from 0.6% to 18.2%. The equivalent vitrinite reflectance (equal-Ro) value is between 2.5% and 4.3%. Mineral constituents are dominated by quartz and clay. The average quartz content (62.8%) is much higher than that of clay minerals (26.1%), and this suggests a high brittleness index. Organic-matter pores, interparticle pores, intraparticle pores, interlaminated fractures, and structural fractures are all well developed. The porosity ranges from 0.6% to 8.8%, with an average of 4.8%, whereas the permeability varies from 0.0018 to [Formula: see text] (microdarcy) (averaging [Formula: see text]). The porosity of TOC- and clay-rich shale samples is generally higher than that of quartz-rich shale samples. The gas adsorption capacity of the Niutitang Shale varies from 2.26 to [Formula: see text], with a mean value of [Formula: see text]. The TOC content appears to significantly influence gas adsorption capacity. In general, TOC-rich samples exhibit a much higher adsorption capacity than TOC-poor samples.

Characterization of the Lower Cambrian Shale in the Northwestern Guizhou Province, South China: Implications for Shale-Gas Potential

2015 ◽  
Vol 29 (10) ◽  
pp. 6383-6393 ◽  
Author(s):  
Junpeng Zhang ◽  
Tailiang Fan ◽  
Jing Li ◽  
Jinchuan Zhang ◽  
Yifan Li ◽  
...  
Keyword(s):  
South China ◽  
Shale Gas ◽  
Lower Cambrian ◽  
Guizhou Province ◽  
Gas Potential

Investigation of the methane adsorption characteristics of marine organic-rich shale: A case study of the lower Cambrian Niutitang Shale in the Fenggang block, northern Guizhou Province, South China

2018 ◽  
Vol 6 (4) ◽  
pp. T819-T833 ◽  
Author(s):  
Yang Gu ◽  
Wenlong Ding ◽  
Min Yin ◽  
Ruyue Wang ◽  
Baocheng Jiao ◽  
...  
Keyword(s):  
Specific Surface ◽  
Pore Size ◽  
Adsorption Capacity ◽  
Surface Area ◽  
South China ◽  
Pore Volume ◽  
Lower Cambrian ◽  
Methane Adsorption ◽  
Guizhou Province ◽  
Average Value

The marine shale in South China has great gas exploration potential, and exploration in the Sichuan Basin has been successful, but the degree of exploration remains low in the Guizhou Province. We used organic geochemical analyses (total organic carbon content and kerogen type), scanning electron microscopy (SEM), field emission SEM, nuclear magnetic resonance (NMR), X-ray diffraction analysis, and low-temperature [Formula: see text] and [Formula: see text] adsorption experimental methods to study the micropore types and pore structures and their effects on the methane adsorption capacity of organic-rich shales found in the Fenggang block in northern Guizhou Province. The results indicate that the microscopic surface porosity of the lower Cambrian Niutitang Formation ranges from 2.88% to 5.34%, with an average value of 3.86%. Based on nitrogen adsorption methods, the range of the average pore size distribution is 4.6–9.491 nm, with an average value of 6.68 nm. All of the samples exhibit significant unimodal distributions. The main pore size is less than 10 nm, and these pores account for most of the mesopore volume, which is generally consistent with the NMR results. The methane adsorption capacity of the shale samples gradually increases in the range of 0–8 MPa at 30°C and reaches a maximum at approximately 10 MPa. Positive correlations were found between the gas content and specific surface area, total pore volume, and micropore volume. These strong correlations indicate that the Niutitang Shale has a high specific surface area, a high pore volume, and narrow-diameter pores, demonstrating that it has a high gas adsorption capacity. The results of this study provide valuable information regarding the adsorption characteristics of marine shales and the factors that affect those characteristics.

Evaluation of Lower Cambrian Shale in Northern Guizhou Province, South China: Implications for Shale Gas Potential

2013 ◽  
Vol 27 (6) ◽  
pp. 2933-2941 ◽  
Author(s):  
Shuangbiao Han ◽  
Jinchuan Zhang ◽  
Yuxi Li ◽  
Brian Horsfield ◽  
Xuan Tang ◽  
...  
Keyword(s):  
South China ◽  
Shale Gas ◽  
Lower Cambrian ◽  
Guizhou Province ◽  
Gas Potential

Characterization of quartz in the Wufeng Formation in northwest Hunan Province, south China and its implications for reservoir quality

2019 ◽  
Vol 179 ◽  
pp. 979-996 ◽  
Author(s):  
Zhaodong Xi ◽  
Shuheng Tang ◽  
Songhang Zhang ◽  
Yongxiang Yi ◽  
Feng Dang ◽  
...  
Keyword(s):  
South China ◽  
Hunan Province ◽  
Reservoir Quality

Nitrogen-rich gas shale logging evaluation and differential gas-bearing characterization of lower Cambrian formation in northern Guizhou, south China

2020 ◽  
Vol 115 ◽  
pp. 104270 ◽  
Author(s):  
Shuangbiao Han ◽  
Songtao Bai ◽  
Zhiyuan Tang ◽  
Yurun Rui ◽  
Dajian Gong ◽  
...  
Keyword(s):  
South China ◽  
Lower Cambrian ◽  
Gas Shale ◽  
Gas Bearing

scholarly journals Application of a Modified Low-Field NMR Method on Methane Adsorption of Medium-Rank Coals

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Xiaozhen Chen ◽  
Taotao Yan ◽  
Fangui Zeng ◽  
Yanjun Meng ◽  
Jinhua Liu
Keyword(s):  
Adsorption Capacity ◽  
Coalbed Methane ◽  
Gas Adsorption ◽  
Vitrinite Reflectance ◽  
Methane Adsorption ◽  
Coal Rank ◽  
Nmr Method ◽  
Low Field ◽  
Low Field Nmr ◽  
The Absolute

Methane adsorption capacity is an important parameter for coalbed methane (CBM) exploitation and development. Traditional examination methods are mostly time-consuming and could not detect the dynamic processes of adsorption. In this study, a modified low-field nuclear magnetic resonance (NMR) method that compensates for these shortcomings was used to quantitatively examine the methane adsorption capacity of seven medium-rank coals. Based on the typical T 2 amplitudes obtained from low-field NMR measurement, the volume of adsorbed methane was calculated. The results indicate that the Langmuir volume of seven samples is in a range of 18.9–31.85 m3/t which increases as the coal rank increases. The pore size in range 1-10 nm is the main contributor for gas adsorption in these medium-rank coal samples. Comparing the adsorption isotherms of these coal samples from the modified low-field NMR method and volumetric method, the absolute deviations between these two methods are less than 1.03 m3/t while the relative deviations fall within 4.76%. The absolute deviations and relative deviations decrease as vitrinite reflectance ( R o ) increases from 1.08% to 1.80%. These results show that the modified low-field NMR method is credible to measure the methane adsorption capacity and the precision of this method may be influenced by coal rank.

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