Evaluation of the subject geological area suitability for oil recovery by High-Pressure Air Injection method

摘要

Abstract. The considerable decline of conventional oil and gasreserves and respectively their production introduces new challenges to theenergy industry. It resulted in the involvement of hard-to-recover reservesusing advanced enhanced oil recovery (EOR) techniques. Thermal methods ofEOR are recognized as most technically and commercially developed methodsfor the highly viscous crude oil. High-Pressure Air Injection (HPAI) is oneof the thermal production methods that reduce oil viscosity and increasesrecovery. HPAI has already been effectively applied for different types ofreservoirs development and proven to be economically feasible.The application performance of the HPAI technology strongly depends on thequality of experimental and numerical modeling conducted on the targetobject basis. Before the field tests, physicochemical and thermodynamiccharacteristics of the process were studied. Further consequent numericalmodeling of laboratory-scale oxidation experiments and field-scalesimulation was conducted to estimate HPAI method feasibility based on theresults of oxidation studies. A medium pressure combustion tube (MPCT)oxidation experiment was carried out to provide stoichiometry of thereactions and field design parameters. A 3D numerical model of the MPCTexperiment was constructed taking into account the multilayer design,thermal properties, heating regimes, and reaction model. The “history”matched parameters such as fluid production masses and volumes, temperatureprofiles along the tubes at different times and produced gas compositiondemonstrated good correspondence with experimental results. The resultsobtained during the experiment and modeling of MPCT (fluid properties,relative phase permeability, kinetic model, technological parameters) wereused in field-scale modeling using various thermal EOR scenarios. Airbreakthrough into production wells was observed, thus a 2 % oxygenconcentration limit where implied. The overall performance of four differentscenarios?was compared within 30 years timeframe. The development system wasalso examined to achieve the maximum economic indicators with theidentifications of risks and main uncertainties.