Formulation Of CO₂-sensitive Foam System With High Temperature And Salt Tolerance For Mobility Control

It is good method to control mobility and flow profile and to block gas channeling by using foam in the process of CO₂ flooding.To study and screen a new kind of systems of CO₂ foam agent by using the chemical activity of CO₂ is a desirable way to solve the problem of poor stability of foam under the high temperature,high pressure and low permeability oil reservoir condition.CO₂-sensitive,that is,chemical agents can be converted into surfactant compounds,having higher chemical activity,if it can meet and react with CO₂ in oil reervoir during CO₂ flooding.The new compounds can generate foam,which is more stable than from conventional surfactant under the condition of high temperature and high salt,emulsion or crosslinking system.All of that have ability to selective blocking and flow profile control.The long chain alkylanmine,which were chosen in this paper,can be changed into surfactants in the acidic environment where dissolve with CO₂,therefore,it can generate foams that have well ability in stable and high temperature tolerance.As a consequence,the foams can be used to control mobility.The methods studying on research are based on theoretical analysis and laboratory experiment.An improved high temperature and high pressure foam visualization device is used to test the foaming ability and stability of CO₂ foam;the displacement equipment is applied to evaluate the blocking and mobility control ability of CO₂ foam with the condition of oil reservoir;the interface tensiometer / rheometer is used to test interfacial tension between gaseous CO₂ and aqueous solution of chemical agent under high temperature and high pressure.Besides,it also has been done that the adsorption capacity of chemical agents on quartz sand with UV spectrophotometer and bench test device of laboratory.At the end,it is compared among the adsorption capacity of different type chemicals.The data of foam visualization experiment show that the agents of N-TA-DL and N-TA-OA have well foam generation ability,and it can generate a large amount of foam with CO₂,while it almost cannot produce foam or few foam.in the N2.The results of displacement experiment show that N-TA-DL and N-TA-OA also have well flow control ability in the condition of 130 °C and 150000 mg/L.The more important is that the agent of N-MA-OC has well flow control performance due to its viscosity of aqueous solution of chemical agent.Moreover,the experimental result of adsorption capacity shows that the adsorption quantity of N-DAL-DL is higher than other four kinds of chemical agent in the surface of quartz sand and it can be reduced by decreasing the pH value of aqueous solution of N-DAL-DL.