An integrated approach to the study of the processes of air-injection for enhanced oil recovery

UDK: 622.276.654.001

Key words: air injection, differential scanning calorimeter, reactor (kinetic cell), combustion tube

Authors: A.V. Vasilevsky, E.A. Nikitina, S.I. Tolokonsky, S.A. Charuev (VNIIneft AO, RF, Moscow)

Development of technologies and methods enhancing oil recovery with thermal, physical, chemical methods and its combinations being widespread among them is crucial challenge for developing stranded and unconventional hydrocarbon reservoirs. The high pressure air injection in productive stratum is resulting in occurrence of complex thermo-chemical and thermo-dynamical reactions. Application efficiency of the injection should be estimated by preliminarily defining of hydrocarbon chemical conversion mechanism while interacting with air`s oxygen and experimental studying of thermal air impact on oil-containing rock in reservoir conditions.

To address these challenges VNIIneft AO has developed a comprehensive approach to assess the possibility of this technology utilization for the particular field conditions. The cornerstone of developed technique consists in subsequent carrying out of complex experimental researches (physical modeling of in-situ combustion process) with high pressure differential scanning calorimeter (DSC1), thermochemical reactor and combustion tube to obtain data required for mathematical modeling of in-situ oxidizing/combustion on particular field. Complex approach to study a mechanism of in-situ combustion occurrence is based on its dividing into stages differing physical and chemical processes with specific reactions of chemical conversion for hydrocarbon and non-hydrocarbon oil components and on definition of principal parameters for the oil displacement modeling while thermal impacting with an oxygen in the air.

While interaction with air`s oxygen in the low-temperature area the largest amount of different reactions is occurring in accordance with chemical conversion mechanism of hydrocarbon groups. Thus, an area of low temperature oxidizing commonly being not taken into account in modeling of the thermal method presented has a major role during in-situ combustion. The studying of the reactions specified for the areas of low temperature oxidizing and building of the chemical conversion model fully taking into account the oxidizing process of reservoir oil with oxygen in the air are the essential advantages of the developed technique.
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