Study On The Mechanism Of Distillation In Flue Gas Assisted Steam Flooding

Steam injection thermal recovery is a widely used method of heavy oil exploitation.At the same time,due to people’s gradual attention to environmental issues,flue gas as a production waste gas is increasingly used in oilfields.The distillation effect of steam on the components of crude oil is one of its important mechanisms for enhancing oil recovery.Therefore,it is of practical significance to study the effect of steam distillation of heavy oil.At the same time,the study of the mechanism of distillation in the process of flue gas assisted steam flooding is a problem to be solved in the development of oil thermal recovery.In this paper,through experiments,the effect of steam distillation in the process of assisted steam flooding with heavy oil flue gas is simulated,and the effect of steam injection temperature,pressure and flue gas injection on the steam distillation effect is investigated.The steam flooding and flue gas-assisted steam flooding experiments under different phase conditions were carried out,and the temperature field,the evolution characteristics of the displacement zone during the displacement process,and the displacement characteristics of different displacement methods were obtained,and the different displacement conditions were analyzed.The residual oil composition changes,and the effect of flue gas on steam distillation is obtained.On this basis,the effects of different temperatures and pressures on the carbon number distribution of the output fractions are analyzed through numerical simulations,and the results of laboratory experiments are compared.At the same time,the effects of temperature,permeability and gas injection speed on the temperature field are studied.And carry out the evaluation of flue gas-assisted steam flooding according to the typical heavy oil reservoir model,revealing the influence on the recovery factor,so as to provide basic parameters and basis for the follow-up flue gas-assisted steam flooding development plan of ordinary heavy oil reservoirs.The research results show that in the steam distillation experiment,the steam distillation rate of heavy oil is directly proportional to the injected steam temperature and inversely proportional to the experimental pressure,and as the temperature continues to rise,the light components are distilled out preferentially.As the components get heavier and heavier,the content of saturated components and gums in the residual oil in the reactor decreases,and the content of aromatic components and asphaltenes increases,and the viscosity of the residual oil in the reactor increases.The steam distillation rate increases slightly with the addition of flue gas.The greater the peak carbon number of the distilled fraction,the less saturated and gum content in the residual oil in the kettle,and the more aromatic and asphaltene content.The higher the viscosity of the residual oil in the kettle.In the one-dimensional core tube displacement experiment,as the flue gas increases with the gas temperature,the oil displacement efficiency gradually increases.In the process of assisted steam displacement by flue gas,light components are more easily recovered and accumulate at the outlet end.The greater the proportion of flue gas in the injected gas,the more obvious the impact on the four components of the crude oil in the one-dimensional sand-packed pipe,and the greater the scope of the crude oil in the pipe.The error between the simulation results of the reservoir numerical simulation software and the laboratory experiment results is within a reasonable range and the experimental results have the same trend.As the temperature of the injected steam increases,the core tube’s heat spread and range become wider,but as the temperature increases beyond a certain range,the temperature’s influence on the temperature field gradually becomes smaller.The higher the permeability,the better the production effect and the higher the end temperature.As the gas injection rate increases,the recovery factor increases,and the tail temperature rises more obviously,but the injection rate further increases.Due to the easy formation of gas channeling channels and the heat insulation of the flue gas,the recovery factor decreases,and the core tube The temperature at the end is reduced.