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Accelerating-Rate Calorimeter (ARC), Ramped-Temperature-Oxidation (RTO), and Combustion Tube (CT) tests are used for screening and designing air injection processes for enhanced oil recovery. These tests use different size samples of reservoir materials, operating under different conditions, have different interpretation requirements, and yield different types of information. ARC data have been used to provide rapid screening of the suitability of (especially) high pressure light oil reservoirs for air injection. Small reservoir samples are used, air injection displacement efficiency is not captured, but they provide explicit quantitative oxidation rate information. RTO experiments use larger quantities of core and reservoir fluids and allow some fluid displacement and production. Due to the nature of this type of test, a much larger fraction of the oil is consumed compared to field application, and oxidation data over a broad range of temperatures is implicitly provided. Finally, combustion tube tests provide the closest dynamic analog to actual reservoir conditions and have the largest core and fluid requirement. This paper describes a systematic procedure used to consolidate the data from these tests into a robust kinetic model for the design and implementation of air injection processes in heavy oil mature fields. The model considers both low and high temperature oxidation reactions, thermal cracking, and the compositional changes that the oil undergoes. Application of the model at the field scale shows temperature levels, produced gas compositions, and fuel and air requirements comparable with those derived from the combustion tube tests. |
