Microfractures Due to Overpressures Caused by Thermal Cracking in Well-Sealed Upper Devonian Reservoirs, Deep Alberta Basin

Marquez, Xiomara; Mountjoy, Eric W.

doi:10.1306/64ed884a-1724-11d7-8645000102c1865d

Cited by 10 publications

(3 citation statements)

References 54 publications

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“…These expulsed HCs, formed by the spilled mobile HCs in the process of evacuating the FE-SEM chamber, confirm the occurrence of mobile HCs in the interparticle pores and dissolution-related pores. Further observations show the existence of a globular aggregate in the bulk OM (panels c and d of Figure ), which is thought to be related with the deasphalting of HCs. , Inter- and intraparticle pores are concentrated along the cleavage planes of clays (Figure f). However, most clays are dipped by black OM and present as OM–clay aggregates.…”

Section: Resultsmentioning

confidence: 87%

“…Further observations show the existence of a globular aggregate in the bulk OM (panels c and d of Figure 7), which is thought to be related with the deasphalting of HCs. 44,45 Inter-and intraparticle pores are concentrated along the cleavage planes of clays (Figure 7f). However, most clays are dipped by black OM and present as OM−clay aggregates.…”

Section: Scanning Electron Microscopy (Sem)mentioning

confidence: 99%

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Occurrence Characteristics of Mobile Hydrocarbons in Lacustrine Shales: Insights from Solvent Extraction and Petrophysical Characterization

Yang,

Nie,

Jiang

et al. 2023

Energy Fuels

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Understanding the occurrence mechanism of mobile hydrocarbons is important for "sweet spot" identification in liquid-rich shale reservoirs. This paper investigated the occurrence and distribution characteristics of mobile hydrocarbons in a set of lacustrine shales, collected from the Upper Triassic Yanchang Formation, in the Ordos Basin. A comprehensive suite of petrophysical (pore structure and pore size distribution) and geochemical (total organic carbon quantification and Rock-Eval pyrolysis) experiments were performed on shales before and after solvent extraction. The chemical components of the extracted hydrocarbons were analyzed using liquid chromatography fractionation. Scanning electron microscopy was utilized to verify the petrophysical analyses. Then, the selective occurrence characteristics of different mobile hydrocarbon compounds in multi-scaled pores of different minerals were discussed. Results show that the specific surface area, pore volume, and pore size distribution are significantly enhanced after solvent extraction. The mobile hydrocarbons in the studies shales are controlled by organic matter richness and feldspar. The free oil content, determined in programmed pyrolysis at 300 °C, increases with the increasing total organic carbon and feldspar contents. These are related to the sorption storage and volumetric storage of shale oil, respectively. An extremely high clay content is unfavorable for hydrocarbon adsorption storage as a result of the decreasing pore volume and limited pore accessibility of clay minerals. Different mobile hydrocarbon compounds prefer to store in different pore sizes. The non/low-polar hydrocarbons (aliphatic and aromatic hydrocarbons) reside in micro-and mesopores (pore diameter of <50 nm), whereas the strong polar hydrocarbons (resins and asphaltenes) prefer to reside in macropores (pore diameter of >50 nm). Direct image analyses by electron microscopy scanning show that mobile hydrocarbons remarkably exist in the dissolution-related pores and interparticle pores. Scanning electron microscopy observations support that volumetric storage of hydrocarbon in dissolution-related pores of feldspar accounts for the "sweet spot" of the investigated shales.

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Section: Resultsmentioning

confidence: 87%

Section: Scanning Electron Microscopy (Sem)mentioning

confidence: 99%

Occurrence Characteristics of Mobile Hydrocarbons in Lacustrine Shales: Insights from Solvent Extraction and Petrophysical Characterization

Yang,

Nie,

Jiang

et al. 2023

Energy Fuels

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“…Laubach (2003) presented a detailed study of the generation of natural fractures on a range of scales. Marquez & Mountjoy (1996) considered the creation of fractures by an increase in gas pressure associated with the thermal cracking of oil to gas. They argued that the initial phase creates microfractures (<1 mm in width).…”

Section: Natural Frackingmentioning

confidence: 99%

Fracking in Tight Shales: What Is It, What Does It Accomplish, and What Are Its Consequences?

Norris

Turcotte

Moores

et al. 2016

Annu. Rev. Earth Planet. Sci.

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Fracking is a popular term referring to hydraulic fracturing when it is used to extract hydrocarbons. We distinguish between low-volume traditional fracking and the high-volume modern fracking used to recover large volumes of hydrocarbons from shales. Shales are fine-grained rocks with low granular permeabilities. During the formation of oil and gas, large fluid pressures are generated. These pressures result in natural fracking, and the resulting fracture permeability allows oil and gas to escape, reducing the fluid pressures. These fractures may subsequently be sealed by mineral deposition, resulting in tight shale formations. The objective of modern fracking is to reopen these fractures and/or create new fractures on a wide range of scales. Modern fracking has had a major impact on the availability of oil and gas globally; however, there are serious environmental objections to modern fracking, which should be weighed carefully against its benefits.

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Formation of abnormal high pressure and its application in the study of oil-bearing property of lithologic hydrocarbon reservoirs in the Dongying Sag

Zhang

et al. 2009

Sci. Bull.

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Microfractures Due to Overpressures Caused by Thermal Cracking in Well-Sealed Upper Devonian Reservoirs, Deep Alberta Basin

Cited by 10 publications

References 54 publications

Occurrence Characteristics of Mobile Hydrocarbons in Lacustrine Shales: Insights from Solvent Extraction and Petrophysical Characterization

Occurrence Characteristics of Mobile Hydrocarbons in Lacustrine Shales: Insights from Solvent Extraction and Petrophysical Characterization

Fracking in Tight Shales: What Is It, What Does It Accomplish, and What Are Its Consequences?

Formation of abnormal high pressure and its application in the study of oil-bearing property of lithologic hydrocarbon reservoirs in the Dongying Sag

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