Research On Oil Flooding With Nano-powder Foam

Foam fluid is used in the process of oil and gas reservoir exploitation because of its dual functions of plugging profile control and emulsification flooding.Although the research of foam flooding has made some progress in recent years,its poor foam stability makes it easy to defoam in a short time under the complex environment of high temperature and high salt,which leads to the limited application of foam flooding technology.The stability of foam under complex reservoir environment requires high-performance foam stabilizer to maintain,so the design and synthesis of efficient foam stabilizer is an important part of the wider promotion of foam flooding technology.Through a large number of domestic and foreign literature on foam flooding and foam system stability,systematically summarize the mechanism of foam stability and the influencing factors that affect foam stability.After clarifying the foam stabilizing mechanism of different types of foam stabilizers,it was found that nano-graphene oxide and nanoparticle foam stabilizers possess similar properties.Therefore,this paper,based on nanographene oxide,designs and synthesizes two nano-foam stabilizers with comprehensive foam stabilization mechanism to improve the stability of the foam system.For high salt environment,the graphene oxide was grafted with xanthan gum.And the grafted product was characterized by Infrared,XPS,Raman,Transmission electron microscopy,and thermogravimetry.Then the grafted product was compounded in the foam system for static evaluation and dynamic evaluation of oil displacement.The results show that the grafted product has a comprehensive foam stabilizing effect.When the salinity of30,000 ppm and the concentration is 0.05%,the half-life of liquid separation reached 30 min;the height of the emulsified layer is increased to 17 mm.Finally the comprehensive recovery is increased to 21.11%.For reservoirs with high residual oil content,graphene oxide is grafted to polyethylene glycol.The grafted products are tested by Infrared,XPS,Raman,Transmission electron microscopy,and Zeta potential.And its performance is evaluated.The results indicate that the grafted product can be well adsorbed on the Plateau boundary of the foam.When the salinity is 20,000 ppm and the concentration is 0.04%,the oil resistance is increased to 10%;the comprehensive recovery is increased to 22.54%.