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Gl obal recoverable resources of heavy oil and oil sands have been assessed by CNPC using a geology-based assessment method combined with the traditional volumetric method, spatial interpolation method, parametric-probability method etc. The most favourable areas for exploration have been selected in accordance with a comprehensive scoring system. The results show: (1) For geological resources, CNPC estimate 991.18 billion tonnes of heavy oil and 501.26 billion tonnes of oil sands globally, of which technically recoverable resources of heavy oil and oil sands comprise 126.74 billion tonnes and 64.13 billion tonnes respectively. More than 80% of the resources occur within Tertiary and Cretaceous reservoirs distributed across 69 heavy-oil basins and 32 oil-sands basins. 99% of recoverable resources of heavy oil and oil sands occur within foreland basins, passive continental-margin basins and cratonic basins. (2) Since residual hydrocarbon resources remain following large-scale hydrocarbon migration and destruction, heavy oil and oil sands are characterized most commonly by late hydrocarbon accumulation, the same basin types and source-reservoir conditions as for conventional hydrocarbon resources, shallow burial depth and stratabound reservoirs. (3) Three accumulation models are recognised, depending on basin type: degradation along slope; destruction by uplift; and migration along faults. (4) In addition to mature exploration regions such as Canada and Venezuela, the Volga-Ural Basin and the Pre-Caspian Basin are less well-explored and have good potential for oil-sand discoveries, and it is predicted that the Middle East will be an important region for heavy-oil development.

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Nanoparticles of erbium-doped calcium fluoride were synthesised by the coprecipitation method. Micromorphology of the obtained nanoparticles was observed by transmission electron microscopy. The nanoparticles were hot-pressed in a vacuum environment to achieve Er:CaF 2 transparent ceramic. X-ray diffraction analysis confirmed the crystallization of a single fluorite phase after sintered. Transmittance spectrum of Er: CaF 2 ceramic sample was measured, and the transmittance at 1200 nm reached about 87%. Microstructures were characterized using field-emission scanning electron microscopy. The luminescence spectrum of Er:CaF 2 transparent ceramics under 488-and 978-nm excitation was measured and discussed. It was evidenced that strong cross-relaxation processes between Er 3+ ions occur at high dopant concentration, and favoring the red emission at the expense of the green one.