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Emeritus Professor of Reservoir Engineering, Delft University of Technology, Doornweg 7, 2243 GS Wassenaar, The Netherlands
The term ‘improved oil recovery’ (IOR) can hardly be misunderstood: it covers all methods and activities that increase the economic oil recovery. As such, it covers primary, secondary and tertiary recovery methods. Here some definitions may be useful:
The terms primary, secondary and tertiary do not necessarily indicate a sequence. In many cases water is injected from the beginning, so that there is no primary phase; for heavy crudes primary and secondary methods are often ineffective and consequently tertiary recovery (e.g. steam injection) is the first and only phase. Usually, the term ‘conventional’ covers both primary and secondary recovery methods.
Primary and secondary recovery methods are essentially aimed at improving the volumetric sweep-efficiency. A notable exception is high-pressure gas injection for the purpose of oil swelling and reducing the gas-oil interfacial tension. The effect of EOR methods can be either a better volumetric sweep-efficiency, a better microscopic displacement efficiency or both.
The purpose of this introductory article is to discuss briefly the contents of this volume and to focus attention on the prospects for what is often seen as an ‘endangered species’ in the improved recovery world, namely enhanced
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This 250-word extract was created in the absence of an abstract.
