Geochemical controls on shale microstructure

Valenza, John J.; Drenzek, Nicholas J.; Marques, Flora; Pagels, Markus; Mastalerz, María

doi:10.1130/g33639.1

Cited by 169 publications

(117 citation statements)

References 18 publications

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“…A similar reduction of pore volume or porosity around the maturation stage is also observed in naturally buried samples such as gas shales and coals, interpreted to be the result of bitumen swelling and compaction [22,38,39]. Effect of pore clogging by bitumen has been assessed by Valenza et al via comparing surface areas and micropore volumes before and after solvent extraction [18]. They observed a largely consistent rise in surface area and micropore volume after the solvent extraction, especially in the oil window.…”

Section: Response Of Pore Structure Parameters To Thermal Maturitymentioning

confidence: 79%

“…Valenza et al [18] reported the geochemical controls on microstructure of North American shales having maturities from approximately 0.5% to 2.7% VRo/VRb (vitrinite or bitumen reflectance), also observing a marked increase in surface area and pore volume with increasing maturity. In the case of sample LCG, its evolution of porosity indicates that porosity can undergo a reduction to some extent in the oil window stage, which is different from a monotonically growing trend as indicated by previous studies [4,18,19]. A similar reduction of pore volume or porosity around the maturation stage is also observed in naturally buried samples such as gas shales and coals, interpreted to be the result of bitumen swelling and compaction [22,38,39].…”

Section: Response Of Pore Structure Parameters To Thermal Maturitymentioning

confidence: 99%

“…Effect of thermal maturation on porosity has recently attracted more attention because of the growing recognition that porosity in organic matter, to a large extent, is a function of thermal maturity [4,6,18,19]. The recent efforts toward understanding porosity evolution with maturation have been matched with documenting the pore networks in gas shales.…”

Section: Introductionmentioning

confidence: 99%

“…Several measurement techniques have successfully been developed to characterize the complex pore systems such as small-angle and ultra small angle neutron scattering (SANS/ USANS), low-pressure gas adsorption, mercury injection capillary pressure (MICP), and scanning electron microscopy (SEM) [5,[13][14][15][16][17]. The geological controls of pore structure in gas shales include the total organic carbon (TOC) content, thermal maturity and mineralogy, which have preliminarily been discussed in previous works [3,4,10,18,19].…”

Section: Introductionmentioning

confidence: 99%

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Evolution of nanoporosity in organic-rich shales during thermal maturation

Chen

Xiao

2014

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348

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Section: Response Of Pore Structure Parameters To Thermal Maturitymentioning

confidence: 79%

Section: Response Of Pore Structure Parameters To Thermal Maturitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Evolution of nanoporosity in organic-rich shales during thermal maturation

Chen

Xiao

2014

Fuel

348

186

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“…Maturity not only controls the gas generation of shale, but also affects the reservoir properties (Curtis et al 2012;Fishman et al 2012;Loucks et al 2009;Mastalerz et al 2013;Modica and Lapierre 2012;Valenza et al 2013). The maturity of the Lower Paleozoic shale in south China is generally rather high, but it varies significantly in different regions (Nie et al 2009).…”

Section: Geological Characteristics Of the Lower Paleozoic Shalementioning

confidence: 99%

Main controlling factors and enrichment area evaluation of shale gas of the Lower Paleozoic marine strata in south China

et al. 2015

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The Lower Paleozoic shale in south China has a very high maturity and experienced strong tectonic deformation. This character is quite different from the North America shale and has inhibited the shale gas evaluation and exploration in this area. The present paper reports a comprehensive investigation of maturity, reservoir properties, fluid pressure, gas content, preservation conditions, and other relevant aspects of the Lower Paleozoic shale from the Sichuan Basin and its surrounding areas. It is found that within the main maturity range (2.5 % \ EqR o \ 3.5 %) of the shale, its porosity develops well, having a positive correlation with the TOC content, and its gas content is controlled mainly by the preservation conditions related to the tectonic deformation, but shale with a super high maturity (EqR o [ 3.5 %) is considered a high risk for shale gas exploration. Taking the southern area of the Sichuan Basin and the southeastern area of Chongqing as examples of uplifted/folded and faulted/folded areas, respectively, geological models of shale gas content and loss were proposed. For the uplifted/folded area with a simple tectonic deformation, the shale system (with a depth [ 2000 m) has largely retained overpressure during uplifting without a great loss of gas, and an industrial shale gas potential is generally possible. However, for the faulted/folded area with a strong tectonic deformation, the sealing condition of the shale system was usually destroyed to a certain degree with a great loss of free gas, which decreased the pressure coefficient and resulted in a low production capacity. It is predicted that the deeply buried shale ([3000 m) has a greater gas potential and will become the focus for further exploration and development in most of the south China region (outside the Sichuan Basin).

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Study on pore evolution and diagenesis division of a Permian Longtan transitional shale in Southwest Guizhou, China

Guo

2020

Energy Science & Engineering

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Organic‐rich shales, deposited in marine‐continental transitional environments, are widely distributed in southern China. The pore evolution of the Late Permian Longtan Formation shale (Guizhou Province) during its diagenesis and organic matter (OM) evolution was quantitatively and qualitatively investigated through thermal simulation, mercury intrusion capillary pressure, gas adsorption, fractal dimension, and field emission‐scanning electron microscopy observation. Diagenesis and OM evolution stage were subdivided on the basis of X‐ray diffraction, rock pyrolysis, and vitrinite reflectance test; moreover, the main controlling factors of pore structure during evolution were also discussed. Shales were heated to different temperatures with their vitrinite reflectance ranged between 1.23% and 3.12%, indicating that organic matter had evolved from a low‐ to a post‐mature stage. According to the changes in clay mineral composition, hydrocarbon generation, and Tmax, we subdivided diagenesis into four parts, each of which has a good correspondence with OM evolution. Pore volume (PV) varied between 0.012162 and 0.033482 cm3/g, while the specific surface area (SSA) varied between 13.3693 and 23.0094 m2/g. Mesopores were the main contributors to the total pore volume, while mesopores and micropores were the main contributors to the total specific surface area. In this study, the evolution of pore structure was not monotonous, but intermittent: The PV and SSA of shale samples first decreased and then increased. Maturity was the most important factor affecting the evolution of pore structure. The abundance of pores in OM, associated with hydrocarbon generation, resulted in large micro‐PV and micro‐SSA; moreover, the composition of clay minerals also influenced the pore structure evolution. The transformation of kaolinite into illite increased the content of illite and illite/smectite mixed layer, hence affecting the overall meso‐PV and meso‐SSA.

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Geochemical controls on shale microstructure

Cited by 169 publications

References 18 publications

Evolution of nanoporosity in organic-rich shales during thermal maturation

Evolution of nanoporosity in organic-rich shales during thermal maturation

Main controlling factors and enrichment area evaluation of shale gas of the Lower Paleozoic marine strata in south China

Study on pore evolution and diagenesis division of a Permian Longtan transitional shale in Southwest Guizhou, China

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