Composition Analysis And Modification Properties Of Guar Gum In Oilfield

In this paper,the stability analysis and quality identification of guar gum were carried out by using the method of thermogravimetric analysis,and compared with the common oilfield chemicals.In addition,3-chloro-2-hydroxypropyl sulfonate and sodium phosphate as modifiers were used to modify guar gum.Viscosity and water insoluble were used as the main evaluation indexes.The optimum technological conditions were obtained by orthogonal experiment,and characterized by infrared analysis,thermogravimetric analysis and elemental analysis,by this way,mechanism of the reaction was discussed.And then the rheological experiment,the filtration experiment and the inhibition evaluation experiment were carried out as effectiveness evaluation.The details are as follows:(1)The decomposition temperature of the guar gum ranges from 230 ? to 350 ?,the decomposition temperature of the xanthan gum ranges from 210 ? to 450 ?,the decomposition temperature of the soluble starch ranges 260 ? to 450 ?,the decomposition temperature of the corn starch ranges from 270 ? to 450 ?,the polyacrylamide is easily decomposed by heat,the decomposition temperature of the polyvinyl alcohol ranges from 200 ? to 550 ?,and the decomposition temperature of the carboxymethyl cellulose ranges from 200 ? to 500 ?.It is feasible to identify the polyacrylamide contained in the guar gum by thermogravimetric method.(2)The guar gum was modified with sodium 3-chloro-2-hydroxypropanesulfonate as the sulfonating agent.The apparent viscosity and water insoluble content were evaluated by orthogonal experiment and single factor analysis.The reaction conditions were as follows: the reaction temperature was 26 ?,the reaction time was 2.0 h,the mass fraction of NaOH was 1.0%,the mass fraction of CHPS-Na was 0.5%.The apparent viscosity of the 0.6% aqueous solution of the optimized sulfonation product was 104.3 mPa·s,which was 33% higher than that of guar gum collagen powder(78.4 mPa·s).(S=O)and carbon-sulfur bond(S-C)in the vicinity of wave number 1195 cm-1,617 cm-1,it was confirmed that the sulfonic acid group was successfully introduced in the infrared analysis.In the DSC analysis,the endothermic peak of the sulfonated product appears in advance,the melting temperature decreases,the flexibility of the molecular chain increases and the molecular hydrogen bond density decreases,and S increases greatly.The content of C element in the elemental analysis is reduced by 1.580%.The content of S element increased by 0.142%,and the sulfonic acid group was successfully introduced into the guar gum.The thermal decomposition peak of the sulfonated product in the thermogravimetric experiment showed that the heat resistance of the modified product was enhanced.The results show that the sulfonation product is enhanced with the temperature resistance of the original powder,and the anti-filtration performance is improved and the inhibition of the formation is enhanced.(3)The guar gum was modified with sodium phosphate as the esterifying agent,and the apparent viscosity and water insoluble content were used as evaluation indexes.The orthogonal experiment and single factor analysis were used to optimize the modification conditions: The reaction temperature was 30 ?,the dosage of NaOH was 1.0% of the mass fraction of guar gum,the dosage of sodium phosphate was 0.1% of the mass fraction of guar gum and the reaction time was 2.0 h.The apparent viscosity of the 0.6% aqueous solution of the optimized phosphoric acid esterification product was 103.7 mPa·s and 32% higher than that of guar gum collagen powder(78.4 mPa·s).The phosphorylation of the product was carried out in the wave number of 1085 cm-1(P=O)and phosphorus oxyfluoride(P-O-C)in the vicinity of 1,856 cm-1 confirmed the successful introduction of the phosphate ester P-O-C.The melting temperature of the phosphorylated product was decreased in the DSC experiment In the molecular chain,the introduction of phosphate ester,the intermolecular and intramolecular hydrogen bond density decreased,S greatly increased;In the thermogravimetric experiment,the pyrolysis peak of the phospholipidized product was delayed in the presence of the original gel,indicating that the heat resistance of the modified product was enhanced.The results showed that the phospholysis product was stronger than the original powder,Anti-filter loss performance can be improved,the inhibition of the formation has been enhanced.