Bituminous Ore Characterization by Integrating Low-Field NMR with Density and Particle Size Distribution Measurements
Niu, Y. and Kantzas, A.
CIM 2007-018 presented at the 58th Annual Technical Meeting of the Petroleum Society held in Calgary, June 12-14, 2007.
Low field NMR was demonstrated as a useful tool for a fast, non-destructive method to calculate the bitumen, water and solids content of oil sands ore. However, on occasion it was found that the presence of clay bound water ends up overlapping the bitumen NMR signals. Thus in such cases it is difficult to accurately determine fluid content from T2 relaxation only. This paper proposes a somewhat more complex method for the determination of fluid and solids content of oil sands by integrating a density measurement to the NMR algorithm. By a fast measurement of both the weight and the volume of the sample and subsequently its bulk density, an independent solid content estimate is provided, which in turn helps in tightening up the fluid content estimates. Preliminary work to date indicates that the combined density-NMR method matches much better the results of Dean-Stark extraction than NMR alone. Particle size distribution analysis of the solids after Dean-Stark extraction is also shown to correlate with the fast relaxation components of the water spectra in both oil sands ore and in water saturated sand extracted from the ore. The latter is obtained through a vacuum saturation step of the extracted sand by brine, followed by a centrifugal desaturation of the sand to irreducible saturation. The methodology was tested using samples from four wells from Athabasca oil sands. Methodology and results are presented in the paper.