The Preparation And Property Of Sulfopropyl Starch As A Filtrate Reducer For Water Based Drilling Fluid

2-hydroxy-3-sulfo-propyl starch ether(HSPS)is a kind of green chemical with corn starch as raw material.HSPS has the effect of well-bore stability,flocculating drilling cuttings and filtration reduction.And it has a definite heat resistance and salt and calcium tolerancy.Now,the development and application of HSPS are rare.So it is very crucial to explore a new preparation process of 2-Hydroxy-3-sulfo-propyl starch ether and make a systematic research on its fluid loss performance.As the industrial products of sodium 3-chloro-2-hydroxy propanesulfate(CHPS-Na)was unripe,this papper first studied the preparation process.The optimum reaction conditions of CHPS-Na are as follows: the molar ratio of sodium bisulfite to epichlorohydrin was 1.1,the molar ratio of water to sodium bisulfite was 10,the amount of phase transfer catalyst TBAB was 4%(compared to the weight of epichlorohydrin),reaction temperature was 85?,reaction time was 1.5h,dropping time was 1.5h.The yield of crude product was 73.1%.In the optimum conditions,the recrystallization liquid and once recycling mother liquor were taken part in the reaction instead of water.The yield of crude product respectively was 99.6% and 91.4%.The product was characterized by IR and 1HNMR.The reaction conditions of solvent method were optimized by orthogonal test and singlefactor test using corn starch as material and CHPS-Na as etherifying agent The result shows that starch slurry concentration has a maximum effect on performance of product,and the molar ratio of NaOH to CHPS-Na takes the second place while reaction time has the least effect.The optimum conditions of solvent method are as follows: the molar ratio of CHPS-Na to starch was 0.45,the molar ratio of NaOH to CHPS-Na was 0.9,reaction temperature was 55?,reaction time was 1.5h,starch slurry concentration was 30%.The new preparation technology of semidry method was further studied.The result shows that the reaction temperature has a maximum effect on performance of product,and the amount of solvent takes the second place while the amount of CHPS-Na has the least effect.The optimum conditions of semidry method are as follows: the molar ratio of CHPS-Na to starch was 0.3,the molar ratio of NaOH to CHPS-Na was 0.9,reaction temperature was 60?,reaction time was 1.5h,solvent content was 35%,concentration of sodium hydroxide was 30%.Fluid loss performance of HSPS was positively correlated with DS.The fluid loss performance of products by solvent method and semidry method were studied according to the standard for modified starch in GB/T 5005-2010.It shows that product made by solvent method could resist salt concentration up to 20% at the temperature of 140?.And it could be used in the operating environment that the maximum content of Ca2+ and Mg2+ was 350mg/L and 180mg/L,respectively.At the temperature of 140?,the product made by semidry method could resist salt concentration up to 25%,and it could be used in the operating environment that the maximum content of Ca2+ and Mg2+ was 450mg/L and 240mg/L,respectively.And it could resist high temperature to 150?.At the temperature of 150?,it could resist salt concentration up to 4%,and it could be used in the operating environment that the maximum content of Ca2+ and Mg2+ was 250mg/L and 120mg/L,respectively.We concluded that the product made by semidry method have better performance than the product made by solvent method.