Oil yield is an important indicator for oil shale to optimize the comprehensive utilization. Generally, oil shale is highly anisotropic owing to the combined effects similar to shale. In this paper, THz-TDS was employed to investigate the anisotropic response of oil shale samples from Longkou, Yaojie, and Barkol with different oil yields. All the samples had significant anisotropy of the refractive index (n) and absorption coefficient (α) with symmetries at a location of 180°, which corresponded with the bedding plane and the partial alignment of particles. Additionally, the D values of experiment n in the vertical and parallel directions of the bedding plane were calculated as Δn′ = n ⊥ − n ∥ , and samples from Beipiao and Huadian were also tested in the horizontal and vertical directions for a sufficient number of THz parameters. Linear regression was built between the Δn′ of the samples from five regions and the oil yield, described as y = 60.86x+3.72 for oil yield (y) and Δn′ (x), with the correlation coefficient R equaling 0.9866, and the residual sum of squares was 1.182, indicating THz technology could be an effective selection for evaluating the oil yield of oil shale.

High-water-cut crude oil is currently the main form of underground oil in China. The high water content and the distribution of oil and water have an important impact on the rheological property and exploration efficiency. Terahertz (THz) waves are extremely sensitive to hydrogen bonds and intermolecular forces, and consequently, the responses of oil, water and air exhibit obvious differences. In this work, a series of crude oils with high water content were investigated by using THz timedomain spectroscopy (THz-TDS). Linear models were built between amplitudes of THz-TDS and the absorbance and water content from 50.05% to 100.00% with correlation coefficients (R) of 0.99 and >0.93, respectively. In addition, oil and water were determined to be distributed at different positions, based on THz signals in a series of oriented scans. Moreover, the transparent parts for visible light are identified by scanning the local points. The positions with low and high THz intensities refer to water and air regions, respectively. Therefore, THz technology is expected to act as a supplementary method to characterize highwater-cut crude oil, which will promote the efficiency and safe operation of pumping units and oil pipelines.

No abstract

A novel, simple, cost-effective, reliable, and practical automatic column chromatography separation device capable of simultaneously purifying samples for radiogenic and non-traditional stable isotope analysis has been developed. The device avoids the use of any pump and features eluent driving by the siphon effect (gravity) and quantitative control by infrared droplet counting. Several factors affecting the control of droplets were investigated, including types and concentrations of eluents and the height of the liquid level. Results showed that accurate dripping of the eluent could be readily achieved by controlling the number of droplets under selected conditions. The separation performance of the device was first demonstrated by the elution of Sr and Cd in synthetic matrix solutions. The recoveries of Sr and Cd samples were better than 87.6 and 95.0%, respectively, and the whole procedure blank was about 0.3 ng for Sr and 0.1 ng for Cd. Finally, the reliability of the device was further validated by the purification of Sr and Cd from different geological reference materials (NIST 2711a, Nod-A-1, BCR-2, and BHVO-2). The determined Cd and Sr isotope values agree well with their reference values within the uncertainty range. All these results clearly demonstrate the reliability and practicability of the proposed device, which provides a promising method for the automated purification of isotope samples.

No abstract