New Approach for Determination of Bitumen and Water Contents in Tar Sands

A new interpretive algorithm has been developed for bitumen spectra analysis in tar sands. This algorithm utilizes Low Field NMR method for measurements. With the use of appropriate basic components spectra database the algorithm extracts information on bitumen contents, immovable and movable water saturations. The basic components spectra database can be built by analysis of spectra for similar types of rock or by analyzing representative set of samples from the field under study. Representative set of bitumen spectra in the bulk is also included into this database. Application of methods of multivariate analysis made it possible to differentiate between samples coming from different geological formations without any a priori knowledge about these formations. The algorithm has been tested by comparison with the results of direct measurements of bitumen/water contents carried out on an exam set of 30 samples. All the NMR results are within the measurement uncertainty of the direct measurements. Having an advantage of rapidity of processing with high reliability and accuracy this nondestructive NMR-based approach can be a vital alternative to standard direct measurements (solvent extraction) in situations, where the abovementioned qualities of the method are crucial. Introduction The oil reserves presented by heavy oils and bitumen are accounted for roughly 6 trillions barrels, accumulated in oil bearing deposits around the world. The majority of these reserves are lumped in Canada, the Former Soviet Union, Venezuela and Nigeria. The recent five years developments in NMR research offer number of methodological approaches and formal algorithms for laboratory and field NMR applications used for bitumen/water contents characterization in bulk volume (stable-emultions) and in porous media (laboratory and in-situ measurements). The terms bitumen as used in those papers refers to hydrocarbons with viscosity values 1,000 cp –10,000 cp and higher at ambient temperature conditions (20C30C). The real NMR application for bitumen/water content determination in porous media can be affected by