Research On Modeling And Analysis For Carbon Dioxide Enhanced Oil Recovery And Sequestration Process

With the development of social economy and industry process,the fossil fuel demand is increasing and the greenhouse gas from fuel burning has been a serious threat to the earth's environment.Now China's carbon dioxide emission has been more than other countries which means the huge pressure of emission reduction.Recently the technology of carbon capture,utilization and storage?CCUS?has received widely attention,and has been the major measurement of energy conservation and emission reduction.As it is the important part of CCUS,carbon dioxide enhanced oil recovery and sequestration technology becomes a research focus in oil industry.Carbon dioxide enhanced oil recovery and sequestration technology has two important parts:carbon dioxide enhanced oil recovery?CO₂-EOR?and carbon sequestration technology.Because of the special physicochemical property,carbon dioxide could achieve physical miscible phase state with crude oil which could effectively improve the displacement efficiency and enhance oil recovery.In this paper,based on the existing project model of CO₂flooding,the graph method was proposed to obtain the oil recovery which reduces the counting amount,and then some parameters were studied about the influence on the oil recovery.With the crude oil produced from the reservoir,partly carbon dioxide would be remained on the reservoir which is important for the carbon sequestration.To study the carbon sequestration technology,this paper built the sequestration mathematic model and analyzed the influence of reservoir geological factors.Then combining with the calculation of aquifer influx,the model was improved with assumed conditions;the concept of sequestration equivalent was introduced to verity the un-ignorable effect of aquifer influx.Using the reservoir simulation software—CMG,the comparison results between the existing modeling and the improved modeling showed that the improved modeling is more precise on the carbon sequestration prediction.Carbon dioxide enhanced oil recovery and sequestration technology not only has the economic value but also contains the environment benefit which signifies that the built model should combine carbon sequestration and oil recovery.Based on the existing model,the new performance index was built with the improvement of the weights and the represent parameters.Compared with the existing model,the improved model would be more suitable to apply to the engineering optimization of carbon sequestration and enhanced oil recovery technology.Taking the improved model as the performance index,the project case of the technology could be optimized using the CMG reservoir simulation software.And the optimization results indicated that the improved performance index could be effectively applied to the optimization of carbon sequestration and enhanced oil recovery project.