Full-Scale Pore Structure Characteristics and the Main Controlling Factors of Mesoproterozoic Xiamaling Shale in Zhangjiakou, Hebei, China

Nanoscale pore structure characteristics and their main controlling factors are key elements affecting the gas storage capacity, permeability, and the accumulation mechanism of shale. A multidisciplinary analytical program was applied to quantify the pore structure of all sizes of Xiamaling shale from Zhangjiakou, Hebei. The result implies that Mercury injection porosimetry (MIP) and low-pressure N2 curves of the samples can be divided into three and four types, respectively, reflecting different connectivity performances. The maximum CO2 adsorbing capacity increases with increasing total organic carbon (TOC) content, pore volume (PV), and surface area (SA) of the micropores are distributed in a three-peak type. The full-scale pore structure distribution characteristics reveal the coexistence of multiple peaks with multiple dominant scales and bi-peak forms with mesopores and micropores. The porosity positively correlates with the TOC and quartz content, but negatively correlates with clay mineral content. Organic matter (OM) is the main contributor to micropore and mesopore development. Smectite and illite/smectite (I/S) assist the development of the PV and SA of pores with different size. Illite promotes the development of the nanoscale PV, but is detrimental to the development of the SA. Thermal maturity controls the evolution of pores with different size, and the evolution model for the TOC-normalized PVs of different diameter scales is established. Residual hydrocarbon is mainly accumulated in micropores sized 0.3 to 1.0 nm and mesopores sized 40 nm, 2 nm and less than 10 nm. Since the samples were extracted, the pore space occupied by residual hydrocarbon was released, resulting in a remarkable increase in PV and SA.

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Erratum to “Study on the characterization of pore structure and main controlling factors of pore development in gas shale” [J. Nat. Gas Geosci 5 (5) (October 2020) 255–271/JNGGS_165]

Journal of Natural Gas Geoscience ◽

10.1016/j.jnggs.2020.12.001 ◽

2020 ◽

Author(s):

Zhuang Xu ◽

Wanzhong Shi ◽

Gangyi Zhai ◽

Nyujia Peng ◽

Chi Zhang

Keyword(s):

Pore Structure ◽

Controlling Factors ◽

Gas Shale ◽

Main Controlling Factors

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Pore Structure Characterization and the Controlling Factors of the Bakken Formation

Energies ◽

10.3390/en11112879 ◽

2018 ◽

Vol 11 (11) ◽

pp. 2879 ◽

Cited By ~ 6

Author(s):

Yuming Liu ◽

Bo Shen ◽

Zhiqiang Yang ◽

Peiqiang Zhao

Keyword(s):

Pore Structure ◽

Oil And Gas ◽

Vitrinite Reflectance ◽

Total Pore Volume ◽

Nitrogen Adsorption ◽

Controlling Factors ◽

Structure Characterization ◽

Bakken Formation ◽

Main Controlling Factors ◽

Bakken Shale

The Bakken Formation is a typical tight oil reservoir and oil production formation in the world. Pore structure is one of the key factors that determine the accumulation and production of the hydrocarbon. In order to study the pore structures and main controlling factors of the Bakken Formation, 12 samples were selected from the Bakken Formation and conducted on a set of experiments including X-ray diffraction mineral analysis (XRD), total organic carbon (TOC), vitrinite reflectance (Ro), and low-temperature nitrogen adsorption experiments. Results showed that the average TOC and Ro of Upper and Lower Bakken shale is 10.72 wt% and 0.86%, respectively. The Bakken Formation develops micropores, mesopores, and macropores. However, the Upper and Lower Bakken shale are dominated by micropores, while the Middle Bakken tight reservoir is dominated by mesopores. The total pore volume and specific surface area of the Middle Bakken are significantly higher than those of the Upper and Lower Bakken, indicating that Middle Bakken is more conducive to the storage of oil and gas. Through analysis, the main controlling factors for the pore structure of the Upper and Lower Bakken shale are TOC and maturity, while those for Middle Bakken are clay and quartz contents.

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PORE STRUCTURE CHARACTERISTICS AND THEIR CONTROLLING FACTORS OF LACUSTRINE SHALE: A CASE STUDY FROM CANGDONG SAG IN BOHAI BAY BASIN, CHINA

10.1130/abs/2019am-340799 ◽

2019 ◽

Author(s):

Shouxu Pan ◽

◽

Ming Zha ◽

Changhai Gao ◽

Xiujian Ding

Keyword(s):

Pore Structure ◽

Controlling Factors ◽

Bohai Bay ◽

Bohai Bay Basin ◽

Structure Characteristics ◽

Lacustrine Shale

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Pore structure characteristics and its effect on adsorption capacity of Niutitang marine shale in Sangzhi block, southern China

Interpretation ◽

10.1190/int-2019-0044.1 ◽

2019 ◽

Vol 7 (4) ◽

pp. T843-T856

Author(s):

Xinghua Wang ◽

Arash Dahi Taleghani ◽

Wenlong Ding

Keyword(s):

Organic Matter ◽

Pore Structure ◽

Adsorption Capacity ◽

Southern China ◽

Quartz Content ◽

Isothermal Adsorption ◽

Structure Characteristics ◽

Marine Shale ◽

Lp Formula ◽

Organic Pores

Characteristics of shale pore structures may play an important role in natural gas accumulation and consequently estimating the original gas in place. To determine the pore structure characteristics of Niutitang marine shale in the Sangzhi block, we carried out [Formula: see text] adsorption-desorption (LP-[Formula: see text]GA), [Formula: see text] adsorption (LP-[Formula: see text]GA), and methane isothermal adsorption on shale samples to reveal the pore size distribution (PSD) and its impact on the adsorption capacity. Results indicate that the Niutitang Shale is in stages of maturity and overmaturity with good organic matter, and they also indicate well-developed interparticle, intraparticle, and organic pores. Quartz and clay are found to be the main minerals, and the high illite content means that the Niutitang Shale is experiencing the later stage of clay mineral transformation. Various-sized shale pores are well-developed, and most of them are narrow and slit-like. For pores with diameters of 2–300 nm measured with LP-[Formula: see text]GA, mesopores (2–50 nm) contribute most of the total specific surface area (SSA) and total pore volume (TPV) in comparison to macropores (50–300 nm). For micropores ([Formula: see text]) tested by LP-[Formula: see text]GA, the PSD appears to be multimodal; shale pores of 0.50–0.90 nm diameter contribute most of the SSA and TPV. [Formula: see text]-SSA and [Formula: see text]-SSA indicate positive correlations with their corresponding TPV. The total organic matter (TOC) has good correlation with the SSA and TPV of micropores. The Langmuir volume positively correlates with the total SSA. Additionally, the TOC content has a good correlation with the Langmuir volume, which is consistent with the observation of well-developed fossils of diatoms and organic pores. As an important source of organic matter, more diatoms mean more organic matter, larger TOC values and quartz content, larger SSA and TPV of micropores, and, of course, stronger shale adsorption capacity. The results provide important guidance for the exploration and development of shale gas existing in the Sangzhi block.

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Full-scale pore structure and its controlling factors of the Wufeng-Longmaxi shale, southern Sichuan Basin, China: Implications for pore evolution of highly overmature marine shale

Journal of Natural Gas Science and Engineering ◽

10.1016/j.jngse.2019.04.020 ◽

2019 ◽

Vol 67 ◽

pp. 134-146 ◽

Cited By ~ 14

Author(s):

Yang Wang ◽

Luofu Liu ◽

Shanshan Zheng ◽

Zehua Luo ◽

Yue Sheng ◽

...

Keyword(s):

Pore Structure ◽

Sichuan Basin ◽

Controlling Factors ◽

Full Scale ◽

Marine Shale ◽

Longmaxi Shale ◽

Pore Evolution

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Pore Structure Characteristics of Tight Carbonate Reservoir in Qingxi Sag, Jiuquan Basin

Lithosphere ◽

10.2113/2021/5524247 ◽

2021 ◽

Vol 2021 (Special 1) ◽

Author(s):

Xiangye Kong ◽

Jianhui Zeng ◽

Xianfeng Tan ◽

Xianglu Gao ◽

Yu Peng ◽

...

Keyword(s):

Pore Structure ◽

Tube Bundle ◽

Pore Space ◽

Carbonate Reservoir ◽

Reservoir Rock ◽

Tight Oil ◽

Type I ◽

Structure Characteristics ◽

Small Pore ◽

Tight Carbonate

Abstract The Xiagou Formation is the main tight oil reservoir in Qingxi Sag of Jiuquan Basin. Given the poor physical properties and other factors restricting tight oil exploitation and production in this area, studies should focus on microscopic pore structure characteristics. In this study, a nano-CT scanner, a SEM, and an NMR were used to study the pore structure characteristics of a tight carbonate reservoir in Qingxi Sag, Jiuquan Basin. The Xiagou Formation reservoir mainly consists of gray argillaceous dolomite and dolomitic mudstone. The pore categories are mainly elliptic, irregular, intergranular, and intragranular and mostly filled with clay and carbonate cement. Pore space is small, the intergranular or organic pores are mostly separated, and pore-throat is weakly connected. The throats mostly develop with lamellar and tube bundle-like characteristics and with poor seepage ability. The pore-throats mostly span from nanometer to micrometer sizes, and pore diameters are mainly concentrated in the range of 0.01–0.1 and 1–10 μm. It is a unimodal pattern mainly composed of micropores, or a bimodal regular allocation dominated by micropores supplemented by macropores. The relationship between micropore (<0.1 μm) and macropore (>1 μm) content allocation and mean pore diameter strongly controls the permeability of reservoir rocks. When macropore content reaches more than 85%, or when pore content totals less than 3%, the permeability of a reservoir remarkably increases. At a higher ratio of the average finest throat sectional area and throat-pore of reservoir rock, the throat radius lies closer to the connecting pore radius, pore and throat connectivity improves, and reservoir seepage ability becomes stronger. Based on reservoir capacity and seepage ability, pore structures of the tight carbonate reservoirs in study area are classified into type I (small-pore–thin-throat), type II (thin-pore–thin-throat), and type III (microporous-microthroat) with rock permeability>0.1 mD, 0.05–0.1 mD, and <0.05 mD, respectively. The type I pore structure reservoir should be regarded as an indicator of tight oil “sweet spots” reservoir in the study area.

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Study on the characterization of pore structure and main controlling factors of pore development in gas shale

Journal of Natural Gas Geoscience ◽

10.1016/j.jnggs.2020.09.003 ◽

2020 ◽

Vol 5 (5) ◽

pp. 255-271 ◽

Cited By ~ 1

Author(s):

Zhuang Xu ◽

Wanzhong Shi ◽

Gangyi Zhai ◽

Nyujia Peng ◽

Chi Zhang

Keyword(s):

Pore Structure ◽

Controlling Factors ◽

Gas Shale ◽

Main Controlling Factors

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The Characteristics and Main Controlling Factors for the Formation of Micropores in Shale from the Niutitang Formation, Wenshuicun Section, Southwest China

Energies ◽

10.3390/en14237858 ◽

2021 ◽

Vol 14 (23) ◽

pp. 7858

Author(s):

Danlong Li ◽

Meiyan Fu ◽

Yun Huang ◽

Dong Wu ◽

Rui Xue

Keyword(s):

Clay Mineral ◽

Lower Cambrian ◽

Mineral Content ◽

Southwest China ◽

Pore Diameter ◽

Micropore Volume ◽

Controlling Factors ◽

Average Pore ◽

Main Controlling Factors ◽

Niutitang Formation

The characteristics of shale micro-pore development and its main influencing factors have important theoretical guiding significance for shale gas exploration and resource evaluation. In order to clarify the micro-pore development characteristics of lower Cambrian shale and the main controlling factors of micro-pore development, we used the lower Cambrian Niutitang formation shale, in the Wenshuicun section of the Guizhou Province in southwest China. The micro-pore development characteristics of the shale in the region were studied by argon ion profile field emission scanning electron microscopy and a low-temperature liquid nitrogen adsorption and desorption experimental system. The relationship between micro-pore and kerogen maceral composition, total organic carbon (TOC) content and different mineral content was analyzed in combination with mineral and geochemical characteristics. Inorganic pores (clay mineral pores, dissolution pores and pyrite intergranular pores) and micro-fractures (clay mineral shrinkage crack, tectonic fractures and overpressure fractures) were the main type of pore developed in the shale of the Niutitang formation in the Wenshuicun section, and no organic pores had developed. The pore size of shale is usually 2–50 nm, accounting for 58.33% of shale pores, e.g. mesopores. Clay mineral content has an obvious positive correlation with macropore volume and average pore diameter, and an obvious negative correlation with micropore volume. In addition, the content of feldspar in brittle minerals has a strong negative correlation with macropore volume and average pore diameter, and a strong positive correlation with micropore volume and BET-specific surface area. TOC content and the content of different kerogen macerals have no obvious correlation with the development of shale micropores in this region. It is concluded that inorganic mineral composition is the main controlling factor of micro-pore development within lower Cambrian shale, and organic matter abundance and maceral content have little influence on the micro-pore development. This study provides a case study for the characteristics of micropores in lower Cambrian shale in China.

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