Preparation And Characterization Of High Temperature And High Salt Calcium Emulsion Fluid Loss Reducer

In order to solve the problem of the stability and difficult adjustment of water-based drilling fluids under high salt calcium pollution in the salt-gypsum layer,this paper uses 2-acrylamido-2-methylpropanesulfonic acid(AMPS),N,N-dimethyl Acrylamide(DMAA),N-vinylpyrrolidone(NVP)and dimethyldiallyl ammonium chloride(DMDAAC)were used as monomers to synthesize high temperature resistant and high salt calcium emulsion fluid loss control agent GB-1.The optimal synthesis conditions are: AMPS,DMAA,NVP,DMDAAC mass ratio 5:1:1:3,initiator potassium persulfate dosage 0.5%,pH=7,reaction temperature 70?,nitrogen reaction time 5h.The results of indoor evaluation show that the emulsion fluid loss control agent GB-1developed and prepared by optimizing the design of monomer ratio,reaction temperature,reaction time and initiator dosage can resist high temperature of 180?and calcium resistance of 12000 ppm.And through the use of infrared spectroscopy(IR),TGA thermogravimetric analysis,filter cake scanning electron microscopy(SEM)and elemental energy spectroscopy(EDS)to analyze the microscopic mechanism of action of GB-1,the results prove the element composition and molecular structure of the synthesized product All meet the target expectations,the molecular weight is moderate,the molecular weight distribution is relatively reasonable,and all have good thermal stability.Therefore,the emulsion fluid loss control agent GB-1 has the advantages of low initial viscosity,excellent injection performance,and good shear resistance,so as to more effectively improve the stability of the water-based drilling fluid against high temperature and high salt calcium.