Development And Evaluation Of Anti Ultra-high Temperature, Salt Tolerant And Lubricative Filtrate Loss Reducer For Drilling Fluid

In view of the problems of the existing fluid loss additive is poor in anti temperature, salt tolerant and resisting high valence ion ability, is single on the functions, is poor adaptability in complex geological conditions, anti temperature, salt tolerant and lubricative fluid loss additive for drilling fluid is synthesized to meet the needs of deep well of high temperature and high salinity. The fluid loss additive is characterized and analyzed, and the filtration reducing mechanism is researched to provide the necessary basis for the site construction.The fluid loss additive is synthesized by super-concentrated inverse emulsion polymerization. Acrylamide, 2-acrylamide-2-methyl propane sulfonic acid, itaconic acid,dimethyl diallyl ammonium chloride and N-vinyl-2-pyrrolidone are chosen as water-soluble monomer, diesel oil as oil phase,(NH4)2S2O8 and NaHSO3 as redox initiator, nonionic surfactant as emulsifier in the process of reaction. Single factor experiment analyzes the felicitous condition of super-concentrated inverse emulsion polymer fluid loss additive,namely oil/water volume ratio is 18:82, emulsifier dosage is 11.0 % of the quality of oil phase,water phase pH value is 10~11, reaction temperature is 55 ℃, initiator dosage is 0.4 % of total monomer amount of substance.Characterization of super-concentrated inverse emulsion polymer fluid loss additive is analyzed. Construction of super-concentrated inverse emulsion polymer fluid loss additive is characterized. Percent conversion of super-concentrated inverse emulsion polymerization is95.0 %. Solid content is 91.4 %. The dissolution time of 10.0 g/L super-concentrated inverse emulsion polymer fluid loss additive is 1.5 min. Infrared spectral analysis confirmed the structure of the product. Thermogravimetric analysis shows that the product still has good thermal stability at 280 ℃. Anti-swelling rate is up to 63.6 % when the concentration of fluid loss additive is 15.0 g/L. Dynamic light scattering analysis shows that the particle size of fluid loss additive molecules manifests single peak, and decreases when adding the salt. Theparticle size distribution of fluid loss additive molecules is widening. The particle size of fluid loss additive molecules is increasing as the concentration of fluid loss additive increasing when salt content is certain.Drilling fluid joined super-concentrated inverse emulsion polymer fluid loss additive is analyzed. The API filter loss of fresh water base slurry is 4.8 mL, salt aqueous slurry is 5.0m L, saturated salt aqueous slurry is 6.2 mL, compound salt aqueous slurry is 4.8 mL when the concentration of fluid loss additive is 10.0 g/L. The filter loss of fresh water base slurry is 8.0m L, salt aqueous slurry is 9.2 mL after ageing 16 h at 180 ℃. The unctuosity of fresh water base slurry adding filter loss addictive than fresh water base slurry increases 42.1 %, and the adhesion coefficient of fresh water base slurry adding filter loss addictive than fresh water base slurry decreases 31.5 %. Super-concentrated inverse emulsion polymer fluid loss additive and commonly used drilling fluid additives have good compatibility. The API filter loss of fresh water base slurry adding fluid loss additive and commonly used drilling fluid additives is 2.8 mL, and salt aqueous slurry is 2.4 mL. The API filter loss of fresh water base slurry adding fluid loss additive and commonly used drilling fluid additives is 2.8 mL, and salt aqueous slurry is 2.4 mL after aging 16 h at 180 ℃.Scanning electron microscopy(SEM) analysis shows that the filtration pore of filter cake of the fresh water base slurry is circular aperture state, filtration pore of filter cake of the salt aqueous slurry is fractured state. Structure morphology of filter cake of drilling fluid adding fluid loss additive is obviously improved, namely filter cake becomes densification, the number and pore diameter of filtration pores decrease, the filter loss deduces. The number of filtration pores of filter cake of the fresh water base slurry and salt aqueous slurry increase,the pore diameter of filtration pore decreases, filter cake thickens and filter loss increases after aging.