Dynamic imaging of oil shale pyrolysis using synchrotron X‐ray microtomography

Saif, Tarik; Lin, Qingyang; Singh, Kamaljit; Bijeljic, Branko; Blunt, Martin J.

doi:10.1002/2016gl069279

Cited by 77 publications

(36 citation statements)

References 63 publications

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“…Some scholars, based on the combination of CT technology and three-dimensional reconstruction, studied the structure of microscale pore clusters during oil shale pyrolysis [38], the consistency of thermal weight loss and porosity [39], and estimation of permeability [40]. Yang et al [41] quantitatively characterized the pore structure during pyrolysis by mercury intrusion porosimetry (MIP).…”

Section: Introductionmentioning

confidence: 99%

Influence of In Situ Pyrolysis on the Evolution of Pore Structure of Oil Shale

Liu

Yang

et al. 2018

Energies

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The evolution of pore structure during in situ underground exploitation of oil shale directly affects the diffusion and permeability of pyrolysis products. In this study, on the basis of mineral analysis and thermogravimetric results, in combination with the low-pressure nitrogen adsorption (LPNA) and mercury intrusion porosimetry (MIP) technique, the evolution of pore structure from 23 to 650 • C is quantitatively analyzed by simulating in situ pyrolysis under pressure and temperature conditions. Furthermore, based on the experimental results, we analyze the mechanism of pore structure evolution. The results show the following: (1) The organic matter of Fushun oil shale has a degradation stage in the temperature range of 350-540 • C, and there is no obvious temperature gradient between decomposition of kerogen and the secondary decomposition of bitumen. The thermal response mechanisms of organic matter and minerals are different in each temperature stage, and influence the change of pore structure. (2) Significant changes occur in pore shape at 350 • C, where thermal decomposition of kerogen begins. The ink-bottle pores are dominant when the temperature is less than 350 • C, whereas slit pores dominate when the temperature is greater than 350 • C. (3) The change in pore structure of oil shale is much less significant from 23 to 350 • C. The pore volume, porosity, and specific surface area (SSA) of samples increase rapidly with temperature varying from 350 to 600 • C. The variation of each parameter is dissimilated from 600 to 650 • C: the porosity and pore volume increases with a small gradient from 600 to 650 • C, and SSA decreases significantly. (4) The lithostatic pressure does not cause change in the evolution discipline of the pore structure, but the inhibitory effect on the pore development is significant.

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Section: Introductionmentioning

confidence: 99%

Influence of In Situ Pyrolysis on the Evolution of Pore Structure of Oil Shale

Liu

Yang

et al. 2018

Energies

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“…When the temperature was 350 • C, there was only a small crack along the bedding plane, and when the temperature reached 400 • C, the number of large cracks increased. From the TG curve (Figure 5), the kerogen of oil shale began to be pyrolyzed to oil and gas at 400 • C [30], and the oil and gas in the shale expanded synchronously. When the pressure exceeds the tensile strength of oil shale [24], new cracks formed.…”

Section: Anisotropy Of Crack Propagationmentioning

confidence: 99%

“…From the TG curve (Figure 5), the kerogen of oil shale began to be pyrolyzed to oil and gas at 400 °C [30], and the oil and gas in the shale expanded synchronously. When the pressure exceeds the tensile strength of oil shale [24], new cracks formed.…”

Section: Anisotropy Of Crack Propagationmentioning

confidence: 99%

“…From the thermogravimetric (TG) curve, the weight loss stage of the oil shale can be divided into three phases: (1) from room temperature to 200 • C, the main loss of this phase was the free water and bound water. From the DSC curve, the absorption of heat in the temperature range was mainly due to the evaporation of water [19]; (2) from 200 • C to 400 • C, the loss of material was mainly mineral water and a small amount of volatile components, and less heat absorption occurred based upon the DSC curve [30]; (3) from 400 • C to 600 • C was the main phase of oil shale pyrolysis [31], among which 400-500 • C was the most intense. Also, from the DSC curve, the heat absorption mainly occurred from 400 • C to 500 • C, and mainly due to the pyrolysis of the kerogen within the oil shale.…”

Section: Crack Propagation Experimentsmentioning

confidence: 99%

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Anisotropy in Thermal Recovery of Oil Shale—Part 1: Thermal Conductivity, Wave Velocity and Crack Propagation

et al. 2018

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Abstract:In this paper, the evolution of thermal conductivity, wave velocity and microscopic crack propagation both parallel and perpendicular to the bedding plane in anisotropic rock oil shale were studied at temperatures ranging from room temperature to 600 • C. The results show that the thermal conductivity of the perpendicular to bedding direction (K PER ) (PER: perpendicular to beeding direction), wave velocity of perpendicular to bedding diretion (V PER ), thermal conduction coefficient of parallel to beeding direction (K PAR ) and wave velocity of parallel to beeding direction (V PAR ) (PAR: parallel to bedding direction) decreased with the increase in temperature, but the rates are different. K PER and V PER linearly decreased with increasing temperature from room temperature to 350 • C, with an obvious decrease at 400 • C corresponding to a large number of cracks generated along the bedding direction. K PER , V PER , K PAR and V PAR generally maintained fixed values from 500 • C to 600 • C. 400 • C has been identified as the threshold temperature for anisotropic evolution of oil shale thermal physics. In addition, the relationship between the thermal conductivity and wave velocity based on the anisotropy of oil shale was fitted using linear regression. The research in this paper can provide reference for the efficient thermal recovery of oil shale, thermal recovery of heavy oil reservoirs and the thermodynamic engineering in other sedimentary rocks.

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“…[32][33][34] There are several investigations of the pore structure of oil shale under conventional heating using the micro-CT tool. [32][33][34] There are several investigations of the pore structure of oil shale under conventional heating using the micro-CT tool.…”

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confidence: 99%

The experimental study of microwave heating on the microstructure of oil shale samples

Zhu

Yang

Liu

et al. 2019

Energy Science & Engineering

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The microstructure of oil shale plays a vital role in the seepage and production of shale oil and gas and can be modified by microwave irradiation. In this study, the experimental work aims to visualize and analyze the microstructure of oil shale under microwave heating with different heating parameters by traditional two‐dimensional (optical microscope and scanning electron microscope) and advanced three‐dimensional (micro‐CT) methods. Volumetric reconstructions of oil shale before and after microwave heating were completed to directly visualize the pore structure and fracture network of the samples. The similarities and differences between microwave heating and conventional heating were also investigated. Finally, based on the three‐dimensional CT data, the porosity and the degree of anisotropy of the samples were calculated. Traditional two‐dimensional imaging methods showed that microwave heating led to more pores and fractures due to the differential thermal stress caused by rapid heating, which differed from conventional heating. Porosity calculations based on the CT image data indicated that a long heating time and a high output power could lead to a large porosity value. Oil shale obtained by drilling horizontally into the bedding plane showed the largest porosity and lowest heterogeneity of pore distribution after heating and had a different fracture morphology. The results from this study are important for the exploitation of oil shale using microwave heating, and the application of these analytical techniques is useful for the evaluation of the flow behavior of transformation products.

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Dynamic imaging of oil shale pyrolysis using synchrotron X‐ray microtomography

Cited by 77 publications

References 63 publications

Influence of In Situ Pyrolysis on the Evolution of Pore Structure of Oil Shale

Influence of In Situ Pyrolysis on the Evolution of Pore Structure of Oil Shale

Anisotropy in Thermal Recovery of Oil Shale—Part 1: Thermal Conductivity, Wave Velocity and Crack Propagation

The experimental study of microwave heating on the microstructure of oil shale samples

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