Applications of Low Field NMR Techniques in the Characterization of Oil Sand Mining, Extraction and Upgrading Processes

Abstract

L ow fi eld nuclear magnetic resonance (NMR) has opened a wide spectrum of opportunities for reservoir characterization. NMR logging tools and laboratory systems can explore the physical interactions of proton bearing fl uids when they are exposed to magnetic fi elds at frequencies of 1 to 2 MHz. Several service companies currently market NMR-based logs focusing primarily on determining properties of the reservoir such as rock porosity and permeability, as well as the distribution of mobile and immobile fl uids. Parallel to the development of logging tools, laboratory based bench-top instruments have also been developed for research and calibration purposes.Low fi eld NMR technology was initially developed for formations in Texas and the North Sea. The primary targets for the development of this technique were sandstones in the Gulf of Mexico and Texas Chalks, followed by the large sandstone reservoirs in the North Atlantic. NMR has been used in the reservoir characterization of Canadian formations since the A number of techniques have previously been developed that use low fi eld nuclear magnetic resonance (NMR) relaxometry for conventional and heavy oil reservoir characterization. In the current work, the adaptation of these algorithms for use in the oil sands industry is presented. NMR based methods have been developed for identifi cation of water and bitumen content in ore and froth samples. Consistent algorithms have been used to analyze over 500 ore samples and 50 froth samples from the Athabasca oil sands in northern Alberta. Preliminary analyses are shown, with applications for in-situ fl uid determination using NMR logging tools and improved process control in oil sands processing plants.Plusieurs techniques reposant sur la relaxométrie à résonance magnétique nucléaire (RMN) pour la caractérisation des réservoirs conventionnels et d'huiles lourdes ont été mises au point antérieurement. Dans le présent travail, on présente l'adaptation de ces algorithmes à des fi ns d'utilisation dans l'industrie des sables bitumineux. Des méthodes reposant sur la RMN ont été mises au point pour la détermination de la teneur en eau et en bitume dans des échantillons de minerai et d'écume. On a utilisé des algorithmes consistants pour analyser plus de 500 échantil-lons de minerai et 50 échantillons d'écume venant des sables bitumineux d'Athabasca dans le nord de l'Alberta. Des analyses préliminaires sont présentées dans le cadre de la détermination des fl uides in situ au moyen de sondes de RMN et d'une régulation de procédé amélioré dans les usines de traitement des sables bitumineux.

NMR relaxometry and diffusometry in characterizing structural, interfacial and colloidal properties of heavy oils and oil sands

“…This method is accurate, although it is also time consuming and can take up to 48 hours [71]. NMR has the advantages over this method in that it is non-destructive, noninvasive and can produce reproducible results on the same sample.…”

“…These include investigations into wettability [21], viscosity [22], fluid saturations [23] and emulsions [24]. In the present article, a brief overview of the relevant NMR theory (full details of which can be found in established texts, e g., [25][26][27]) will be followed by an evaluation of the literature, in conjunction with some new experimental results.…”

“…Another method to determine the in-situ bitumen and water content involved calculating the bitumen and water amplitudes in a NMR relaxation spectrum and the signal amplitude per unit mass of each fluid [23]. These were then used to calculate the amplitude index.…”

“…methods for determining oil and water content in an oil sand sample is the Dean-Stark method [70,71]. This method is accurate, although it is also time consuming and can take up to 48 hours [71].…”

Experimental evaluation of different strategies for improving oil recovery at high-water-cut by quantitative etched-glass micro-models

“…The scale of distinguishability can reach up to 0.1 mm; and the clarity of images is far more satisfying when compared with CT. NMR has been intensively applied in petroleum research for the past 20 years. These applications include investigation on viscosity, emulsions, wettability, and fluid saturations (Bryan et al, 2003;Hum and Kantzas, 2006;Jiang et al, 2007;Kantzas et al, 2005). Etched-glass micro-model can be used to mimic the pore structures with high distinguishability (Sun and Qu, 2004;Sun and Tang, 2006).…”