Laser-induced electro-response of oil shale: Principles and applications

This study introduces a laser-induced electro-response (LIER) method to address the challenges arising from the harsh detection environment and energy consumption in the conversion engineering of oil shale. LIER system with pulsed laser and continuous-wave laser was used to investigate the feasibility of oil yield detection and realtime pyrolysis characterization, respectively. The equivalent circuit model for oil shale measurement under the pulse laser irradiation was established, considering the laser-induced plasma and photoelectric effect. While the laser-induced thermal effect is the main cause of the LIER response of oil shale under continuous-wave laser irradiation. Due to the complex interactions between laser and oil shale, the LIER of oil shale is affected by many factors, such as external electric field, laser source type, laser wavelength, and laser energy or power. The external electric field can improve the responsivity of LIER. The LIER signal of oil shale strongly positively correlates with oil yield. Hence, the LIER evaluated oil yield more quickly without pyrolysis than traditional methods, which is helpful for the exploration for oil shale. In addition, the multi-stage LIER responses were monitored in real time during the combustion and pyrolysis processes of oil shale samples in air and N2 atmosphere, respectively, realizing an evaluation of the organic and mineral decomposition, which provides a supplementary approach to conventional chemical techniques. These results show that LIER has great significance for the precise evaluation and effective development of oil shale reservoirs, which will drive the advances in the exploration for oil shale.