Preparation And Foam Stabilization Of Carrageenan/Locust Bean Gum Composite Gel System

Foam flooding has the advantages of"plugging,profile control,and oil displacement"in one,which can significantly improve oil recovery and has great application prospects in oilfield development.Adding polymers to the bulk phase significantly improves foam stability and improves foam flooding.Conventional polymers are chemically synthesized polymers,and their foam stabilization is significantly reduced under harsh reservoir conditions of high temperature and high salinity.Although most polymer foam stabilizers can improve their temperature and salt tolerance after modification,they will still cause damage to the reservoirs.Therefore,the development of a polymer foam stabilizer that is environmentally friendly and has excellent foam stabilization effect in high temperature and high salinity reservoirs is one of the keys to enhancing the oil recovery of foam flooding.In this study,an environmentally friendly carrageenan/locust bean gum（KC/LBG）composite gel system that can be used for foam stabilization was developed.The effects of Si O₂ nanoparticles and various cations on the gelation of KC/LBG（KL）were studied.What’s more,a gel foam stabilization system with high viscoelasticity,good water holding performance,good temperature and salt resistance was screened out.The physicochemical properties and microstructure of the gel materials were characterized by rheological tests,SEM,FTIR,TGA/DSC,etc.The foam properties of green surfactant alkyl glycoside（APG）and the effect of KC/LBG composite gel system on the stability of APG foam system were further explored.Therefore the mechanism of the gel system to stabilize foam was revealed.Our results show that under the condition that the total concentration is 0.5 wt%and the mixing ratio of KC and LBG is 5:5,when 0.5 wt%nanoparticles and 3 wt%K⁺were simultaneously added to the KL matrix（KL-K-NP200）,the viscoelasticity of the gel was significantly improved up to 416.66 Pa,indicating that the gel network inside the bulk phase became denser.DSC-TGA experiments show that:KL-K-NP200 gel has strong water holding capacity,its glass transition temperature reaches 104.17℃,and it has excellent thermal stability.Static foam experiments show that KL-K-NP200 gel can significantly improve the stability of APG foam.When the APG concentration was 0.075wt%,the half-life was as high as 89 min.at the same time.APG/KL-K-NP200 syntactic foam system has excellent temperature and salt resistance.This was attributed to the formation of a complex between APG and KL-K-NP200 through hydrogen bonding,which enhanced the adsorption of APG at the gas-liquid interface.In addition,the highly viscoelastic gel network in the bulk phase helps to retard liquid film drainage and enhance foam stability.In summary,this study prepared a natural gel foam system with high viscoelasticity,strong water holding capacity and good temperature resistance,which provide a certain research basis for the application of biogel materials in foam flooding.