Characterization of multi-component and multi-phase fluids in the Upper Cretaceous oil shale from the Songliao basin (NE China) using T1-T2 NMR correlation maps

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 T-1-T-2 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.

Automated summary

The fluid status of oil shale is closely related to its development potential. Clay mineral analysis shows the loss of interlayer water in smectite during diagenesis, resulting in the absence of structural water in collected shale samples. Scanning Electron Microscopy reveals five pore types, with higher porosity samples tending to contain more free water. NMR correlation maps describe five fluid statuses in oil shale, with Upper Cretaceous oil shale containing abundant free water but no structural water. NMR scans suggest that well WF22 has the greatest potential for oil extraction among six sampling wells.