Synthesis and performance evaluation of environment-friendly modified nano-calcium carbonate filtrate reducer
Nano calcium carbonate exhibits filtration reduction performance and plugging effect in drilling fluid,and it is en-vironmentally friendly.But it has poor dispersion and is easy to agglomerate,resulting in unsatisfactory results.In this pa-per,the surface of nano calcium carbonate was modified by silane coupling agent,and then the monomers with temperature and salt resistant performance were grafted onto the surface of modified particle by free radical copolymerization to obtain modified nano-calcium carbonate fluid loss reducer SDNPJ-2.It was characterized by infrared spectroscopy(FTIR)and ther-mogravimetric analysis,and the comprehensive properties were compared and evaluated.In addition,the adsorption charac-teristics of SDNPJ-2 on clay particles were investigated by particle size of bentonite base mud,Zeta potential analysis,scan-ning electron microscopy(SEM)analysis of clay and the measurement of the adsorption capacity of clay particles further re-veal the mechanisms modified nano-calcium carbonate fluid loss reducer in water base drilling fluids.The results show that SDNPJ-2 can resist high temperature of 230℃.After aging at 150℃/(16 h),adding 1%SDNPJ-2 can make 4%bentonite base slurry,25%brine base slurry,and 10%CaCl2 base slurry API fluid loss decreased by 70%,89%and 85%,respec-tively.It can resist 250000 mg/L of sodium chloride and 100000 mg/L of calcium chloride.The filtration reduction effect is better than that of the same kind of foreign product Driscal D.The BOD5 value is 558 mg/L,and the ratio of BOD5/COD is 22.6%,which is biodegradable.SDNPJ-2 is adsorbed on the clay surface through amide groups to improve its dispersion,optimize the particle size grading of the system,and effectively block the filter cake and formation pores through physical ac-cumulation.The two aspects work together achieve excellent filtration reduction effect.
nano calcium carbonatefilter loss reducerdrilling fluidtemperature and salt resistance
国家科技期刊平台
NSTL
万方数据
维普
