Experimental Study On Oxygen Consumption In Air Flooding Process

This study takes crude oil from a block in Dagang oilfield as the research object.Through the combination of reservoir fluid test analysis,physical experiment and reservoir numerical simulation,the oxygen consumption law in the air flooding process and the prediction of oxygen content in the production well were studied.The following four aspects work have been doneFirstly,the crude oil composition,formation water ion content and clay mineral composition and content of the region were determined,and the types and contents of reducing substances in reservoir fluids and minerals were determined.Experimental study on the mechanism of consumption of oxygen and reservoir clay minerals found that the oxygen consumption rate of crude oil in the presence of various minerals is from large to small: chlorite,illite,montmorillonite,quartz sand and kaolinite.Secondly,the mechanism of consumption of oxygen and reservoir and the analysis of main controlling factors were carried out by using high temperature and high pressure reactor.Through the analysis of the main controlling factors of oxygen consumption rate under different conditions of temperature,pressure,formation water and oxygen content,it can be seen that the low-temperature oxidation reaction of oxygen and crude oil in the air accounts for the majority of consumption.Then,using the slender tube sand filling model,the experimental study on the displacement of oxygen consumption under dynamic conditions was carried out.As the volume of gas injection increases,the rate of increase in production rate becomes slower,and the degree of recovery is the highest when the injection pressure is 22 MPa.When the gas injection volume is 0.5 PV,1 PV,1.5 PV,and 2 PV,the degree of recovery is the highest when the oil saturation is 40%.Recovery is positively correlated with temperature and pressure.Finally,using CMG numerical simulation software,the numerical simulation of the oxygen content of the production wells under the five-point well pattern was carried out and the prediction model was established.The research solve the main control factors of oxygen consumption rate and the prediction of oxygen content in the air flooding process,and provide guidance for on-site enhanced oil recovery production and production safety of air flooding.