Study On The Effect Of Residual Boron In Plant Glue Fracturing And Drainage Fluid On Rehydration

In order to reduce the discharge and realize the rational utilization of resources,a large number of backflow fluid will be produced in the process of operation.In order to reduce the discharge and realize the rational utilization of resources,it has become the research focus that the fracturing fluid will be used for the redistribution of fracturing fluid after treatment.Boron cross-linking agent is used to crosslink the fracturing fluid,resulting in a large number of residual boron crosslinker in the fracturing backflow fluid,which becomes the key factor affecting the recycling and reuse of the fracturing backflow fluid.Therefore,the study on the removal of residual boron cross-linking agent from fracturing backflow fluid is of great significance to realize the reuse of fracturing backflow fluid.In this study,the content of boron was determined by methimine-H acid spectrophotometry,and it was determined that polyhydroxyl compounds could not interfere with the determination of boron,and the competitiveness of methimine-H acid combined with boron was stronger than that of polyhydroxyl compound.By comparing the results of boron determination between ICP and methimine-H acid,it was determined that the competitiveness of methimine-H acid was stronger than that of tartaric acid.The removal of residual boron cross-linking agent by barium borate precipitation method was studied,and the effects of pH value,reaction time and material ratio on the removal of residual boron crosslinker were investigated.The results showed that barium borate method had a significant effect on boron removal,and plant gum oligosaccharide had little effect on boron removal by barium borate method.The optimum conditions were as follows:the reaction time of pH=10.5,tartaric acid with boron was 1 h,the binding time between barium and borate ion was 2 h,and the reaction ratio was H2BO3-:Ba2+:C4H4O62-=2:5:4.The minimum boron content affecting the dissolution of guar gum was studied,and the feasibility of redispensing solution after boron removal by precipitation method was investigated.After boron removal by precipitation method,the residual boron content is higher than the minimum boron content which affects the dissolution of guar gum,and the masking agent can be masked before the remixing can be realized.The masking agent was screened,and mannitol was determined to be the masking agent in this study,and the optimum conditions were as follows:the molar ratio of boron to mannitol was 1:1.8.The properties of cyclic redispensing solution were studied,and the sugar content,molecular weight and molecular size were characterized.The results showed that with the increase of cycle times,the effect of gel breaker on molecular weight decreased(decreased viscosity)was obvious,but the degradation effect was weak.