Characterizing of Oil Shale Pyrolysis Process with Laser Ultrasonic Detection

Abstract

The laser ultrasonic technique was proposed to characterize the pyrolysis process of the oil shale. The ultrasonic velocity was produced by a noncontact all-optical method in the three regions of Barkol, Yaojie, and Longkou of China. It was found that the ultrasonic velocity was related with the pyrolysis temperature of the oil shale. The pyrolysis process was divided into three stages due to the ultrasonic propagation speed in the oil shale. The ultrasonic velocity had small changes from 20 to 320 °C in the first stage, a sharp decline between 320 and 470 °C in the second stage, and another small change above 470 °C in the third stage. The variation of the velocity was qualitatively explained, which was considered to be closely related with the characteristics of pyrolysis process in oil shale. An empirical equation of the velocity attenuation was proposed to estimate the beginning and the end of the decomposition of the kerogen. It is a new way to characterize the process of the pyrolysis of oil shale by using the laser ultrasonic technique.

Laser-Induced Voltage of Oil Shale during Retorting

“…12 Finally, the peaks above 600 °C represent the dissociation of carbonates. 13 The exothermic peak appears at 346 °C14 and is attributed to the preliminary pyrolysis of kerogen. 15 These results are consistent with those of gas chromatography coupled with thermogravimetry, Fourier transform infrared spectroscopy, and mass spectrometry (TG-FTIR-MS) measurements.…”

“…Stage 2 showed a significant mass loss (approximately 19%) . Finally, the peaks above 600 °C represent the dissociation of carbonates . The exothermic peak appears at 346 °C and is attributed to the preliminary pyrolysis of kerogen .…”

Experimental Study on the Uniaxial Compression Failure and Ultrasonic Transmission of Brittle Shale Considering the Bedding Effect

“…Xiong et al (2014) and Z. Q. Lu et al (2016) conducted an ultrasonic transmission test on shale cores with different bedding angles and determined that there is a positive linear relationship between the P-wave and S-wave velocities, where the P-wave and S-wave velocities and the attenuation coefficient decreased with an increasing bedding angle and that the P-wave and S-wave velocities in shales had significant linear positive correlations with both the core density and bedding density. Z.…”

Mechanism of the Laser-Induced Voltage Generated in Oil Shale under the Irradiation of a 532 nm Laser

“…During the pyrolysis of oil shale, it is very important to analyze the dynamic characteristics of the organic evolution and oil production, which contributes to the understanding of the complex petrophysical changes in the hydrocarbon-recovery process. , With the development and comprehensive utilization of various advanced techniques, considerable information regarding the pyrolysis kinetics of kerogen and the oil-yielding potential of raw oil shale has been obtained by terahertz time domain spectroscopy (THz-TDS), laser ultrasonic technique, solid-state 13 C nuclear magnetic resonance (solid-state 13 C NMR), Fourier transform infrared spectroscopy (FTIR) spectroscopy combined with thermogravimetric analysis, X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). − As a widely used means in material characterization, the laser-induced voltage (LIV) effects have been observed in various bulk materials and thin films, which is sensitive to their interior composition and structures. Based on this effect, the evaluation of oil and gas reservoirs has also been achieved .…”