화학공학소재연구정보센터
Chemical Engineering Research & Design, Vol.78, No.5, 715-720, 2000
Influence of reservoir rock and fluids on crude oil oxidation using an accelerating rate calorimeter
Air injection is a very promising technique for improved oil recovery from deep, light oil reservoirs that have been previously water flooded-with the proviso that all of the oxygen can be removed by reaction with the crude oil. A high pressure accelerating rate calorimeter (ARC) has been used to follow the adiabatic exotherm obtained when oil reacts with air, and when reservoir rock and water are present. The experiments were conducted on four light crude oils, starting at the respective reservoir temperature. The very sensitive ARC apparatus is able to automatically follow the self-heat rate adiabatically, closely simulating conditions in an actual reservoir, but in a batch manner, i.e. closed 'bomb'. The exotherms obtained generally exhibit two regions. First, a low temperature oxidation (LTO) region, extending up to about 250 to 300 C, followed by a high temperature oxidation (HTO) region, which can extend up to 500 C, or more. The individual exotherm characteristics of each oil depend on the physical and chemical properties as well as the associated reservoir rock and reservoir fluid. The 'fast' exotherm observed for oil and air alone, is modified substantially in the presence of reservoir rock and water due the heat capacity of these materials. The measured exotherms enable suitable reaction rate models for the oil oxidation kinetics to be derived, which can be used in reservoir simulation studies.