Synthesis Of Solid Crosslinker And Performance Evaluation Of Crosslinking System

The polymer chromium crosslinking system used in water flooding oilfield is used as profile control agent.The polymer organic chromium crosslinking system has good effect on blocking high permeability layer,improving formation heterogeneity,increasing injection water wave and area and so on.In conventional HPAM organic chromium crosslinking system,most of the crosslinking agents are gray green or bluish green paste acetic acid,which is soluble in hot water and insoluble in alcohol.There are many unfavorable factors in the storage,transportation and preparation of chromium acetate crosslinking agent.In this paper,CrCl₃ and CH₃COONa are used as main raw materials,and a new solid cross-linking agent is synthesized by adding various organic acids and auxiliaries.The solid crosslinking agent is stable.The solid crosslinking agent powder is analyzed by infrared spectrum analysis,UV visible spectrum analysis and other chemical analysis methods.The main composition is a mixture of organic chromium and its corresponding coordination body.The best synthetic scheme is optimized.The ratio of synthesis is chromium chloride,sodium acetate=1:3.5,pH 3⁵ and temperature 70?.The polymer crosslinking system was prepared by the synthesized solid crosslinker powder,and the factors affecting the bonding and viscosity of the crosslinking system were analyzed,including the molecular weight of the polymer HPAM,the pH of the crosslinking system,the amount of crosslinking agent and so on.The properties of the preferred polymer crosslinking system are evaluated.The crosslinking system has good shear resistance,high viscosity retention and viscosity recovery after shearing.The polymer crosslinking system has a good thermal stability under 55?;the water retention rate of the crosslinking system can reach 82.56%and the water resistance rate can reach 98.09%.The residual resistance coefficient and plugging rate of the polymer crosslinking system were measured by indoor displacement experiments,and the injection ability of polymer crosslinking system was evaluated.The displacement efficiency of crosslinking system prepared by different crosslinking agents was compared.The injection scheme of solid crosslinking agent powder flooding fluid is optimized,and the best injection formulation,injection volume,injection timing and injection sequence are selected.