Quantification and characterization of hydrocarbon-filled porosity in oil-rich shales using integrated thermal extraction, pyrolysis, and solvent extraction

Gorynski, Kyle E.; Tobey, Mark; Enriquez, Daniel; Smagala, Thomas M.; Dreger, Jill L.; Newhart, Richard

doi:10.1306/08161817214

Cited by 20 publications

(6 citation statements)

References 20 publications

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“…A strong positive linear correlation ( R 2 = 0.92) is observed between S 1 and the sum of Oil‐1, Oil‐2, Oil‐3, and Oil‐4 (Sum Oil‐1–4) (Figure 6a). The S 1 values are systematically smaller than Sum Oil‐1–4, mainly due to the upper limit of pyrolysis temperature for Sum Oil‐1–4 being 350°C, while that for S 1 is 300°C (Beti & Ring, 2019; Gorynski et al, 2019). Moreover, S 1 , Oil‐1, Oil‐2, Oil‐3, and Oil‐4 all exhibit a positive linear correlation with TOC, suggesting that the absolute content of crude oil and each pyrolysis fraction in the shale increases with increasing organic matter abundance (Figure 6b–f).…”

Section: Resultsmentioning

confidence: 98%

Impact of petroleum expulsion and evaporation losses on shale oil assessment using pyrolysis techniques

You,

Liu,

Song

et al. 2023

Geological Journal

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Shale reservoirs contain petroleum that undergoes losses through oil expulsion and evaporation, with uncertain implications on shale oil reserves and mobility evaluation. This study focuses on understanding the influence of these losses on open‐system pyrolysis, the primary method for assessing shale oil content and mobility. Comprehensive analyses were performed on 26 lacustrine shale samples from the Chang7 Member, encompassing total organic carbon (TOC), programmed pyrolysis, solvent extraction, and gas chromatography–mass spectrometry (GC–MS). The research examines the impact of petroleum losses on petroleum fractions, the oil saturation index (OSI), and multi‐step pyrolysis outcomes. The findings indicate that Chang7 shale with TOC content above 7% experiences more substantial petroleum losses than those with TOC below 7%. Petroleum losses result in significant fractional distillation of crude oil in the shale, leading to the deterioration of shale oil properties and a notable reduction in free oil content in S1, ultimately causing a decline in OSI values. As a result, Chang7 shale with TOC below 7% demonstrates a higher potential for shale oil recovery, whereas Chang7 shale with TOC exceeding 7% should be considered more significant as a hydrocarbon source rock. Moreover, multi‐step pyrolysis is not suitable for assessing petroleum mobility in shale with low free oil content (OSI values below 100 mg/g). This limitation arises from the loss of free low‐boiling components in Chang7 shale, and the currently detected low‐boiling pyrolysis products may predominantly exist in an adsorbed state.

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Section: Resultsmentioning

confidence: 98%

Impact of petroleum expulsion and evaporation losses on shale oil assessment using pyrolysis techniques

You,

Liu,

Song

et al. 2023

Geological Journal

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“…The occurrence of HC in shales is closely related to the physical structure and chemical property of pore networks and minerals. − Shales have complex pore types and pore networks, including organic matter (OM)-hosted pores, intergranular pores, intercrystalline pores, intragranular pores, etc. , The pore size in shales is generally less than a few micrometers, and the dominant pore sizes are less than 1 μm. , Thus, pores in shales are commonly classified as micropore (pore diameter < 2 nm), mesopore (2 < pore diameter < 50 nm), and macropore (pore diameter > 50 nm), recommended by the International Union of Pure and Applied Chemistry (IUPAC) classification . These nanometer-sized pores result in a complicated interaction between the rock matrix and liquid HCs and consequently control HC occurrence and migration in shale systems.…”

Section: Introductionmentioning

confidence: 99%

“…Pores with a small size tend to have a strong interaction between the pore wall and filled fluid and play an important role in both gas and liquid HC sorption storage. Some researchers reported the occupying pore space of shale oil using nitrogen adsorption on solvent-extracted shales. ,,− However, most of these studies do not consider the component difference of HCs residing in different pore sizes. As a result of the affinity difference of varied HC components, it is supposed that different chemical components of shale oil probably reside in different scaled pores in this paper.…”

Section: Introductionmentioning

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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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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“…Previous studies have shown that the oil mainly occurs in two states in shale: free and adsorbed. ,− Therefore, characterizing the quantity of shale oil accurately and quantitatively in different physical states has always been a divergent scientific issue. At present, solvent extraction and pyrolysis methods are widely used to predict the physical state and the amount of hydrocarbons in liquid-rich unconventional systems. ,− Compared with solvent extraction, pyrolysis is an efficient and fast screening tool to evaluate the in-situ hydrocarbon characteristics in shale plays. ,,− However, because of the carry-over effect, the standard pyrolysis S 1 value cannot be directly regarded as an indicator of shale oil content. ,, Its use may lead to an erroneous estimation of the quantities of hydrocarbons. , Therefore, the article that cites Jarvie's method proposed the two-step pyrolysis method, which can distinguish and evaluate oil in different physical states and has been widely cited in subsequent studies. ,,− …”

Section: Introductionmentioning

confidence: 99%

Occurrence Space and State of Petroleum in Lacustrine Shale: Insights from Two-Step Pyrolysis and the N₂ Adsorption Experiment

Liu

Jiang

et al. 2022

Energy Fuels

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The pore structure and occurrence state of hydrocarbons in shale reservoirs are significant factors affecting shale oil production. However, how pore structure affects the occurrence of shale oil remains unclear. This paper aims at analyzing the major distribution space of shale oil with various physical states in shale pores using experimental approaches. Therefore, the original samples and solvent-extracted samples of lacustrine shale from the Permian Fengcheng Formation in Junggar Basin were investigated using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Rock-Eval pyrolysis, and N 2 adsorption/desorption methods. The findings demonstrate that the Fengcheng shale has high oil content, with free oil accounting for 57.17% of the total oil yield. The pore size distribution characteristics of original and solvent-extracted shale samples indicate that shale oil is mainly stored in mesopore pores with diameters between 5 and 40 nm. The threshold limit of pore diameter for the movable oil in shale reservoirs is between 3.5 and 19 nm. Also, by comparing shale oil mobility in various basins, it is found that petroleum mobility occurs when the total oil yield in the shale reaches 6 mg HC/g Rock. Meanwhile, the threshold value of petroleum mobility in different basins is related to the pore shape. Parallel plate pores within shales are more favorable for petroleum mobility. This research presents the mobility of the shale oil threshold, which is critical for shale oil exploration and exploitation.

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Quantification and characterization of hydrocarbon-filled porosity in oil-rich shales using integrated thermal extraction, pyrolysis, and solvent extraction

Cited by 20 publications

References 20 publications

Impact of petroleum expulsion and evaporation losses on shale oil assessment using pyrolysis techniques

Impact of petroleum expulsion and evaporation losses on shale oil assessment using pyrolysis techniques

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

Occurrence Space and State of Petroleum in Lacustrine Shale: Insights from Two-Step Pyrolysis and the N₂ Adsorption Experiment

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Quantification and characterization of hydrocarbon-filled porosity in oil-rich shales using integrated thermal extraction, pyrolysis, and solvent extraction

Cited by 20 publications

References 20 publications

Impact of petroleum expulsion and evaporation losses on shale oil assessment using pyrolysis techniques

Impact of petroleum expulsion and evaporation losses on shale oil assessment using pyrolysis techniques

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

Occurrence Space and State of Petroleum in Lacustrine Shale: Insights from Two-Step Pyrolysis and the N2 Adsorption Experiment

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Occurrence Space and State of Petroleum in Lacustrine Shale: Insights from Two-Step Pyrolysis and the N₂ Adsorption Experiment