Preparation And Application Of Shape Memory And Degradable Epoxy Resin

In response to the poor matching between the size of conventional plugging materials and the crack opening of the formation when dealing with well leaks,the low pressure-bearing capacity cannot meet the plugging requirements.Smart plugging materials such as shape memory polymer materials have been developed to seal cracks adaptively by returning to their original expansion state with the formation temperature.However,currently developed shape memory polymer materials such as shape memory epoxy resin(SMEP)have a low excitation temperature,poor strength at high temperatures and low compressibility,which do not meet the requirements for plugging high temperature formations.Therefore,there is a need to prepare a high performance(high glass transition temperature,excellent shape memory properties and compressibility)epoxy resin plugging material that is suitable for plugging high temperature formations.In addition,reservoir plugging requires the use of temporary plugging materials,i.e.,unplugging after satisfying a period of plugging.At present,the commonly used temporary plugging materials,such as gel-type temporary plugging agents,have problems such as poor temperature resistance and rapid degradation rate,which cannot meet the temporary plugging requirements of high temperature reservoirs.The paper proposes the preparation of shape memory epoxy resins(SMEP)and composite foams(SMEF)with high excitation transition temperature and both strength and toughness through molecular structure design,and the preparation of degradable epoxy resins through the introduction of dynamic ester exchange structures.The thesis focuses on the following:I.Preparation and performance study of high temperature shape memory epoxy resin materials1.Preparation of SMEP using the reaction of epoxy resin E51 with amine curing agent and acid anhydride curing agent.The effects of the type of epoxy monomer and the type and content of curing agent on the thermal properties,thermomechanical properties and memory properties of SMEP were investigated,and SMEP with excitation transition temperature of 63-137°C,shape fixation rate of 100% and shape recovery rate of 96-100% were obtained;2.The E51/MHHPA/D230/BDMA(EMDB)curing system with polymer expansion microspheres was preferred to prepare the shape memory epoxy composite foam(SMEF),and SMEF with excitation temperature 120-140°C,compression rate 31.6-54.3% and recovery rate80-95% was obtained.and the preferred formulation was scaled up for long slit plugging The results show that the performance of the large sample is close to that of the small test sample,and the plugging agent is compounded with conventional materials to seal the slit with different openings at 100 ℃,and the bearing pressure is 8.97~9.88 MPa,and the leakage volume is 20~50m L.Preparation and performance study of high temperature degradable epoxy resin materials1.High Tg,degradable epoxy resin was prepared by using zinc acetylacetonate(Zn(acac)2)to catalyze the curing reaction of epoxy and acid anhydride(MHHPA),and the effects of epoxy monomer type,dosage and zinc acetylacetonate content on the thermal properties,thermomechanical properties and high temperature degradation properties of epoxy resin were studied.The degradation rate for 30 days was14.45%.2.The E51/tetra-epoxy/ESO/MHHPA(ETOM)curing system was preferred and degradable epoxy foams were prepared using polymer microspheres with a degradation rate of 24.29% in a 10 d oil bath at180°C.