scholarly journals Characteristics of micro- and nano-pores in shale oil reservoirs

2020 ◽  
Author(s):  
Debin Xia ◽  
Zhengming Yang ◽  
Tiening Gao ◽  
Haibo Li ◽  
Wei Lin
Keyword(s):  
Fractal Dimension ◽  
Pore Structure ◽  
Oil And Gas ◽  
Fractal Theory ◽  
Oil Reservoirs ◽  
Practical Significance ◽  
Oil Reservoir ◽  
Shale Oil ◽  
Structure Characteristics ◽  
Shale Oil Reservoirs

Abstract Porosity is the most common form of reservoirs, and its size, shape, and connectivity directly affect the capacity of oil and gas storage and production. To study the micro–nano-pore structure characteristics of shale oil reservoirs and quantitatively characterize its heterogeneity, this work uses high-precision high-pressure mercury intrusion (HPMI) experimental techniques to study the micro–nano-pore structure characteristics of shale oil, and based on the experimental data, fractal theory is used to quantitatively characterize its heterogeneity. The results of the study show that the micro–nano-pores in the shale oil reservoir are concentrated and continuous, and the pore radius is mainly distributed among the range of 30–500 nm, nanoscale pores are an important part of the pores of the shale oil reservoir. The fractal dimension of the shale oil reservoir is larger than the fractal dimension of typical tight oil reservoirs, indicating that the heterogeneity of shale oil reservoir is stronger. The research results have some theoretical and practical significance for the production of inter-salt shale oil reservoirs.

Characteristics of shale oil reservoirs in Qianjiang Formation, Qiangjiang Depression, Jianghan Basin, China

2020 ◽  
Author(s):  
Jing Luo ◽  
Furong Wang
Keyword(s):  
Pore Volume ◽  
Salt Lake ◽  
Nitrogen Adsorption ◽  
Oil Reservoirs ◽  
Oil Reservoir ◽  
Shale Oil ◽  
Type Ii ◽  
Salt Rock ◽  
Jianghan Basin ◽  
Shale Oil Reservoirs

<p>The Jianghan Basin is a typical eastern fault depression salt lake basin in China, in which the Paleogene strata of the Qianjiang Sag are rich in shale oil resources. As a salt lake sedimentary basin, the developed Qianjiang Formation is a set of inter-salt oil-bearing strata, in which the salt rock strata are especially developed. There are many salt rhythms in the study area and a salt rhythm consists of a argillaceous dolomite layer between a salt rock formation and a salt rock formation. This study focuses on the 10th rhythm of the Qian 3<sup>4</sup> section of Qianjiang Depression (Eq3<sup>4</sup>10). The samples were investigated by organic geochemical analysis and X-ray diffraction, and the pore structure characteristics of the reservoir were studied by argon ion polishing scanning electron microscope and low temperature nitrogen adsorption test. The research indicates that the average TOC of Eq3<sup>4</sup>10 in Qianjiang Depression is 2.11% and the main distribution is 1%~3%; the type of organic matter is mainly Type II<sub>2</sub> and Type II<sub>1</sub>; the overall maturity of organic matter is low maturity stage(Tmax is 412~441℃with an average of 423℃). The XRD data indicates that the mineral composition of the Qianjiang Formation shale oil reservoir is complex and have strong heterogeneity(quartz content in 2.3%~18.6% with an average of 9.5%, calcite content in 6.9~43.8% with an average of 12.8%, dolomite content in 2.5%~ 61.2% with an average of 27.2%, clay mineral content in 1.0%~45.2% with an average of 20.5%, glauberite content from 7.1% to 92.7% with an average of 22.9%). The pore types of shale oil reservoirs in Qianjiang Sag are complex and diverse and mostly are intergranular pores, which are mainly developed between detrital minerals or between detrital minerals and carbonate minerals. In carbonate mineral particles and quartz particles, some intragranular pores are visible, including calcite dissolution pores, internal pores of calcite and clay minerals, and internal pores of pyrite particles. And organic pores are rare in reservoirs due to the low maturity(Ro ranges between 0.5% and 0.7%). Nitrogen adsorption experiments showed that the pore size distribution of Eq3<sup>4</sup>10 samples was dominated by mesopores and macropores. And the pore volume of the Eq3<sup>4</sup>10 sample was most affected by the macropore pore volume, averaging 66.22%, followed by the mesopore pore volume with an average of 31.45%. To study and understand the characteristics of shale oil reservoir in Qianjiang Depression is conducive to mastering the regularity of shale oil enrichment and provides a basis for the exploration and development of shale oil.</p>

scholarly journals Integrating SANS and fluid-invasion methods to characterize pore structure of typical American shale oil reservoirs

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Jianhua Zhao ◽  
Zhijun Jin ◽  
Qinhong Hu ◽  
Zhenkui Jin ◽  
Troy. J. Barber ◽  
...  
Keyword(s):  
Pore Structure ◽  
Oil Reservoirs ◽  
Shale Oil ◽  
Shale Oil Reservoirs ◽  
Typical American

scholarly journals Quantitative analysis of nano-scale pore structures of broad sense shale oil reservoirs using atomic force microscopy

2021 ◽  
pp. 014459872110225
Author(s):  
Rui Shen ◽  
Wei Xiong ◽  
Xiaoming Lang ◽  
Lei Wang ◽  
Hekun Guo ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Atomic Force Microscopy ◽  
Broad Sense ◽  
Oil Reservoirs ◽  
Oil Reservoir ◽  
Shale Oil ◽  
Force Microscopy ◽  
Atomic Force ◽  
Pore Structures ◽  
Shale Oil Reservoirs

The rapid and cost-effective quantitative characterization of broad-sense shale oil reservoirs is highly challenging due to the complex lithology and strong heterogeneity of the strata. In this paper, the pore structures and surface roughness of samples of various lithologies from a shale oil reservoir were studied using atomic force microscopy (AFM) and the open-source Gwyddion analytical software. The surface morphology was reconstructed both two-dimensionally and three-dimensionally using the AFM data for the mudstone, siltstone, and dolarenite in a broad-sense shale oil reservoir. The surface roughness was evaluated with respect to parameters such as the arithmetic average roughness, root mean square roughness, surface skewness, and kurtosis coefficient. The pores of various scales were quantitatively identified using the watershed algorithm. The samples were also evaluated using focused ion beam scanning electron microscopy for comparison, and the derived pore scales are consistent with those obtained from the AFM analysis. In conclusion, the utilization of AFM and open-source software provides a new easy-to-operate method, which can be widely applied to characterize the surface roughness and pore structures of unconventional oil and gas reservoirs.

Research on Micro Pore Structure of the Shale Oil Reservoirs in Xingouzui Formation in the Jianghan Basin

2015 ◽  
Vol 89 (s1) ◽  
pp. 37-38
Author(s):  
Ying HU ◽  
Shuangfang LU ◽  
Wenhao LI ◽  
Pengfei ZHANG ◽  
Qian LI ◽  
...  
Keyword(s):  
Pore Structure ◽  
Oil Reservoirs ◽  
Shale Oil ◽  
Jianghan Basin ◽  
Shale Oil Reservoirs

Pore structure and controlling factors of dolomite-bearing high-salinity shale reservoir in Qianjiang Formation, Jianghan Basin, China

2020 ◽  
Vol 8 (4) ◽  
pp. T675-T686
Author(s):  
Tong Zhou ◽  
Jianzheng Su ◽  
Shichao Fan ◽  
Zhaofeng Li ◽  
Xiaoxue Liu ◽  
...  
Keyword(s):  
Pore Structure ◽  
Pore Volume ◽  
High Salinity ◽  
Total Pore Volume ◽  
Oil Reservoir ◽  
Shale Oil ◽  
Average Pore ◽  
Salt Minerals ◽  
Shale Oil Reservoirs ◽  
Mercury Injection Capillary Pressure

High-salinity shale is a unique and promising shale-oil reservoir in continental basins. We have collected representative samples from different lithologies from wells in the Qianjiang Depression to test the pore structure and basic character from prospective high-salinity oil-bearing shales. We conducted field emission scanning electron microscopy and X-ray diffraction analyses to study the high-salinity shale pore morphology and composition, respectively. We used mercury injection capillary pressure to understand the high-salinity shale macropore distribution, and we used low-pressure nitrogen (N2) adsorption to study the mesopore distribution. The results show that the high-salinity shale-oil reservoir mainly is composed of carbonate (dolomite and calcite), clay, and saline minerals (anhydrite, glauberite, and halite). Many intergranular pores were developed in the high-salinity shale. The mesopores and macropores both were developed well in argillaceous dolomite. The average pore volume of macropores is 0.0588 ml/g, which accounts for approximately 59% of the total pore volume. Therefore, in the high-salinity shale-oil reservoirs that we tested, macropores were more important than other pores. The symbiosis of dolomite and calcite improved the porosity of the high-salinity shale-oil reservoir, and the salt minerals increased the pore complexity.

scholarly journals Effects of Clay Content on Pore Structure Characteristics of Marine Soft Soil

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1160
Author(s):  
Wencan Jiao ◽  
Dong Zhou ◽  
Yetian Wang
Keyword(s):  
Fractal Dimension ◽  
Pore Structure ◽  
Pore Volume ◽  
Fractal Theory ◽  
Soft Soil ◽  
Total Pore Volume ◽  
Clay Content ◽  
Beibu Gulf ◽  
Structure Characteristics ◽  
Small Pore

This study investigates the pore structure characteristics of a marine soft soil of the Beibu Gulf, Guangxi Province, China and its variation with clay content. Pore-size distribution was measured by Mercury intrusion porosimetry (MIP) and analyzed based on fractal theory. The analysis of the results relies on the distinction of several types of pores: micropores, small pores, mesopores and macropores, separated by the critical pore diameters of 0.02 μm, 0.18 μm and 0.78 μm, respectively. Mesopores and small pores were dominant, accounting for more than 75% of the total pore volume. Small pore volume increases with clay content at the expense of the mesopore volume. Between 22.31% and 32.31% clay, the connectivity of pores improves with clay content, while the tortuosity of pores increases from 22.31% to 32.31% of clay and then decreases between 32.31% and 37.31% clay. Marine soft soil in the Beibu Gulf is characterized by multiple fractal dimensions. Macropores had a large (close to 3) fractal dimension, independent of clay content. Mesopores and small pores had a smaller fractal dimension comprised between 2.1 and 2.4, while the fractal dimension of micropores did not exceed 1.5. The fractal dimension of mesopores and micropores are influenced significantly by the clay content. The study of the porosity of the marine soft soil of the Beibu Gulf could serve as a useful basis for the prediction of its hydraulic properties.

scholarly journals Effect of Hydrophobic Silica Nanochannel Structure on the Running Speed of a Colloidal Damper

2021 ◽  
Vol 11 (15) ◽  
pp. 6808
Author(s):  
Gengbiao Chen ◽  
Zhiwen Liu
Keyword(s):  
Fractal Dimension ◽  
Silica Gel ◽  
Fractal Theory ◽  
Percolation Model ◽  
Silica Gels ◽  
Practical Significance ◽  
Running Speed ◽  
Fractal Percolation ◽  
Micropore Structure ◽  
Hydrophobic Silica

A colloidal damper (CD) can dissipate a significant amount of vibrations and impact energy owing to the interface power that is generated when it is used. It is of great practical significance to study the influence of the nanochannel structure of hydrophobic silica gel in the CD damping medium on the running speed of the CD. The fractal theory was applied to observe the characteristics of the micropore structure of the hydrophobic silica gel by scanning electron microscopy (SEM), the primary particles were selected to carry out fractal analysis, and the two-dimensional fractal dimension of the pore area and the tortuous fractal dimension of the hydrophobic silica gel pore structure were calculated. The fractal percolation model of water in hydrophobic silica nanochannels based on the slip theory could thus be obtained. This model revealed the relationship between the micropore structure parameters of the silica gel and the running speed of the CD. The CD running speed increases with the addition of grafted molecules and the reduction in pore size of the silica gel particles. Continuous loading velocity testing of the CD loaded with hydrophobic silica gels with different pore structures was conducted. By comparing the experimental results with the calculation results of the fractal percolation model, it was determined that the fractal percolation model can better characterize the change trend of the CD running velocity for the first loading, but the fractal dimension was changed from the second loading, caused by the small amount of water retained in the nanochannel, leading to the failure of fractal characterization.

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