Determining the content of bitumen, water and solids in oil sands 'ore' using low-field nuclear magnetic resonance.

摘要

Low-field nuclear magnetic resonance (NMR) logging has been used to characterize the formation fluids for reservoir evaluation and assess the formation producibility since the 1990s. Alberta's oil sands, the largest source of bitumen in the world, are making a greater contribution to the world oil supply. In order to evaluate the oil sands potential resource, optimize the processibility of the oil sands and generate the maximum economic returns, it is necessary to determine the amount of bitumen, water and solids properly. Low-field NMR technology has been proven to be a fast and non-destructive method to predict the content of bitumen and water. However, it has been found in previous studies that in most case, the signals from clay bound water and bitumen overlap, thus the estimation of fluid content needs correction.; In this work, to replace the time-consuming and expensive Dean-Stark extraction method, a fast, simple, non-invasive and cost-efficient method was proposed. A densitometry technique, with simultaneous pore volume measurement, is developed to provide the volume of the ore sample and complement the NMR and weight measurements. A density algorithm is introduced to determine fluid and solid content. Results from pore volume measurement are comparable with those from Dean-Stark extraction and conventional low-field NMR. Particle size distribution provides additional verification for the results from the NMR measurement. A combined NMR-pore volume technique has been applied to the samples from two different geological depositional environments and four wells, and the results have been encouraging.