Experimental study of low-temperature combustion characteristics of shale rocks

Chen, Wei; Zhou, Yu; Yang, Leilei; Zhao, Ningning; Lei, Yafeng

doi:10.1016/j.combustflame.2018.04.033

Cited by 22 publications

(24 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“… 1 , 38 The identification of minerals through X-ray diffraction (XRD) spectrograms substantiates the fact that the Wenjiaba shale samples have a high level of heterogeneity. 33 The stronger diffraction peaks of quartz (Q) indicate that there is a higher content of quartz in the raw shale sample, compared to the other mineral compositions. 1 It is well recognized that quartz has strong hydrophilicity.…”

Section: Results and Discussionmentioning

confidence: 99%

“… 51 When the combustion temperature increased to 400 °C, a part of the organic matter was oxidized and released as crude oil or natural gas. 33 , 37 , 47 Meanwhile, parts of blocked pore throats were reopened during combustion. 33 When the shale samples were heated up to 800 °C, parts of minerals (e.g., pyrite and carbonate minerals) were decomposed.…”

Section: Results and Discussionmentioning

confidence: 99%

“… 31 , 32 During combustion, organic matter and parts of inorganic minerals inside shale are oxidized. 33 Meanwhile, the permeability of shale is also increased after combustion. 34 These changes in the composition and structure can have a great effect on the shale wettability.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Experimental Study of the Wettability Characteristic of Thermally Treated Shale

Yang

Gu²,

Chen

et al. 2020

ACS Omega

Self Cite

View full text Add to dashboard Cite

Extraction of shale gas from shale reservoirs is significantly affected by shale wettability. Recently, thermal recovery technologies (e.g., combustion) have been tested for shale gas recovery. This requires an understanding of the wettability change mechanism for thermally treated shale samples. In this study, the effect of combustion on shale wettability was investigated. Shale samples were first processed to obtain smooth surfaces and then combusted at temperatures of 200, 400, and 800 °C. The initial contact angles and dynamic behavior of water droplets on shale surfaces were recorded using the sessile drop method. It was found that pores and fractures were generated on the shale surfaces following high-temperature combustion. The pore volume and diameter increased with increasing combustion temperature, which improved the connectivity of hydrophilic pore networks. Compared to a raw shale sample, the shale sample combusted at 400 °C showed a smaller initial water contact angle and a more rapid decrease in the contact angle because of the oxidation of organic matter and generation of pore structures. Water droplets were found to completely spread over the surface of the shale sample combusted at 800 °C because of the generation of fractures. Moreover, the van der Waals potential between water droplets and combusted shale samples was determined to be stronger. However, the initial contact angle and dynamic behavior of water droplets did not show a significant change for the shale sample combusted at 200 °C. As a result, high-temperature combustion (≥400 °C) can be used to significantly improve the hydrophilicity of shale.

show abstract

Section: Results and Discussionmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Experimental Study of the Wettability Characteristic of Thermally Treated Shale

Yang

Gu²,

Chen

et al. 2020

ACS Omega

Self Cite

View full text Add to dashboard Cite

show abstract

“…As shown in Table 1, the shale sample has a high ash content of 87.58%, and the total organic matter is around 10%, including 2.39% fixed carbon and 7.44% volatile matter. The high content of organic matter provides a large amount of potential adsorption sites for shale gas (Chen et al 2018a). According to the kerogen-type descriptions, the kerogen type of these shale samples is dominated by Type II with the H/C atomic ratios about 1.07 and O/C atomic ratios about 0.145 (Jarvie 2015).…”

Section: Shale Propertiesmentioning

confidence: 99%

“…Recently, the combustion treatment has been proposed for shale gas recovery (Chapiro and Bruining 2015;Chen et al 2017b). Combustion treatment not only provides energy for gas desorption from pore surfaces but also promotes the gas transport by improving the permeability (Chen et al 2017b(Chen et al , 2018a(Chen et al , 2019c. However, pore system evolution during combustion process involves complicated physical and chemical processes.…”

Section: Introductionmentioning

confidence: 99%

Thermally enhanced shale gas recovery: microstructure characteristics of combusted shale

et al. 2020

Self Cite

View full text Add to dashboard Cite

Recently, thermal recovery technologies such as combustion have been studied for shale gas recovery. Thus, understanding of the microstructure of combusted shale is essential for evaluating the effects of thermal treatment on shale gas transport capacity. In this study, the effect of combustion on shale microstructure changes was investigated. Firstly, different-sized shale samples were combusted at 450 °C for 30 min. Afterward, shale microstructure properties including surface topographies, porosity and permeability of the raw and combusted shale samples were measured and compared. It was found that the pore volume and specific surface area increased after combustion, especially for small pulverized samples. According to surface topography obtained from atomic force microscope, more rough surfaces were obtained for the combusted shale due to larger pores and generation of thermal fractures caused by the removal of organic matter. Based on the mercury intrusion porosimetry measurements, the porosity of the shale samples increased from 2.79% to 5.32% after combustion. In addition, the permeability was greatly improved from 0.0019 to 0.6759 mD, with the effective tortuosity decreased from 1075.40 to 49.27. As a result, combustion treatment can significantly improve the gas transport capacity.

show abstract

Experimental study on pore structure evolution of thermally treated shales: implications for CO2 storage in underground thermally treated shale horizons

Hazra,

Chandra,

Vishal

et al. 2024

Int J Coal Sci Technol

View full text Add to dashboard Cite

Extracting gas from unconventional shale reservoirs with low permeability is challenging. To overcome this, hydraulic fracturing (HF) is employed. Despite enhancing shale gas production, HF has drawbacks like groundwater pollution and induced earthquakes. Such issues highlight the need for ongoing exploration of novel shale gas extraction methods such as in situ heating through combustion or pyrolysis to mitigate operational and environmental concerns. In this study, thermally immature shales of contrasting organic richness from Rajmahal Basin of India were heated to different temperatures (pyrolysis at 350, 500 and 650 °C) to assess the temperature protocols necessary for hydrocarbon liberation and investigate the evolution of pore structural facets with implications for CO2 sequestration in underground thermally treated shale horizons. Our results from low-pressure N2 adsorption reveal reduced adsorption capacity in the shale splits treated at 350 and 500 ºC, which can be attributed to structural reworking of the organic matter within the samples leading to formation of complex pore structures that limits the access of nitrogen at low experimental temperatures. Consequently, for both the studied samples BET SSA decreased by ∼58% and 72% at 350 °C, and ∼67% and 68% at 500 °C, whereas average pore diameter increased by ∼45% and 91% at 350 °C, and ∼100% and 94% at 500 °C compared to their untreated counterparts. CO2 adsorption results, unlike N2, revealed a pronounced rise in micropore properties (surface area and volume) at 500 and 650 ºC (∼30%–35% and ∼41%–63%, respectively for both samples), contradicting the N2 adsorption outcomes. Scanning electron microscope (SEM) images complemented the findings, showing pore structures evolving from microcracks to collapsed pores with increasing thermal treatment. Analysis of the SEM images of both samples revealed a notable increase in average pore width (short axis): by ∼4 and 10 times at 350 °C, ∼5 and 12 times at 500 °C, and ∼10 and 28 times at 650 °C compared to the untreated samples. Rock-Eval analysis demonstrated the liberation of almost all pyrolyzable kerogen components in the shales heated to 650 °C. Additionally, the maximum micropore capacity, identified from CO2 gas adsorption analysis, indicated 650 °C as the ideal temperature for in situ conversion and CO2 sequestration. Nevertheless, project viability hinges on assessing other relevant aspects of shale gas development such as geomechanical stability and supercritical CO2 interactions in addition to thermal treatment.

show abstract

Experimental study of low-temperature combustion characteristics of shale rocks

Cited by 22 publications

References 30 publications

Experimental Study of the Wettability Characteristic of Thermally Treated Shale

Experimental Study of the Wettability Characteristic of Thermally Treated Shale

Thermally enhanced shale gas recovery: microstructure characteristics of combusted shale

Experimental study on pore structure evolution of thermally treated shales: implications for CO2 storage in underground thermally treated shale horizons

Contact Info

Product

Resources

About