Characterization of multi-component and multi-phase fluids in the Upper Cretaceous oil shale from the Songliao basin (NE China) using <i>T</i><sub>1</sub>–<i>T</i><sub>2</sub> NMR correlation maps
Tiefeng Lin, Xin Liu, Jinyou Zhang, Yunfeng Bai, Jun Liu, Yupeng Zhang, Ying Zhao, Xinyang Cheng, Jiancai Lv, Hui Yang
Abstract
Fluid status is directly related to the potential of oil development from oil shale. The analysis of clay minerals indicates a thorough process of smectite-illitization occurred during diagenesis, resulted in the interlayer water of smectite is entirely lost. This enables the absence of structural water in collected shale samples. Five pore types are observed by Scanning Electron Microscopy technique: 1) micro-cracks, 2) intragranular, 3) intergranular, 4) dissolved, and 5) interlayer. The sample with higher porosity usually tends to contain a greater amount of free water. The T1–T2 NMR correlation maps describe five statuses of fluids in oil shale, including 1) kerogen or solid bitumen, 2) adsorbed oil, 3) free oil, 4) structural water or adsorbed water, and 5) free water. The Upper Cretaceous oil shale contains abundant free water but no structural water. NMR scans further suggest the well WF22 probably has a greatest potential for oil extraction, among six sampling wells.