The Research And Evaluation Of Injection Wells Deep Displacement Formula

This paper aims at overcoming the disadvantages of water absorbing resin body expansion particles which has finite injection depth and poor matching during the process of profile modification of Water-absorbing resin's expanded granular in water injection well.Using monomer A,monomer B,crosslinking agent and redox initiator via aqueous polymerization in order to screen out optimum formula under different temperature which has reasonable gel time,high gel strength,high water-retention rate,high water-absorption,low injection pressure and effect of distance.The optimal concentration and ratio of monomer A,monomer B and cross-linking agent as well as NaOH were determined through single factor variable method,then the oxidant and reducing agents in trigger system were changed to conduct orthogonal experiments.According to the gel time,Water absorption,water retention and gel strength,the optimum trigger systems at each temperature gradient(40?,50? and 70? as well as 80?)were filtrated out.The infrared spectroscopy and scanning electron microscope indicated that the samples with strong water swelling possess similar graft polymer structure that forms the three-dimensional network structure;A conclusion can be drew by analysing the influencing factors of gelatification: Na+ has a obvious effect on gel time,but small impact on the gel strength.However,Ca2+ and Mg2+ have obvious effects on the gel strength,but unconspicuous effects on gel time.The gel time and the gel strength of all formulas have few changes during pH of 4~8.When the pH is smaller than 4,the solution cannot form gelling.When the pH is bigger than 8,the gel time and stability become worse;The results from Core Laboratory showed that the plugging ratio of the blocking agents are more than 98% for different rock cores,the breakthrough pressures are between 1.20 MPa and 3.42 MPa.In addition,profile control and displacement agent has a good flushing resistance.Parallel core simulating experiment showed that profile control and displacement agent has high selective plugging and injection profile is well improved.