The Study Of Water Absorbing Material With Binary Interpenetrating Networks And Montmorillonite For In-depth Fluid Diverting Agent

To change the present situation of inefficient water displacement and noneffective water circulating in domestic high water-cut oil field, according to the requirement of materials which are used as the in-depth fluid diverting agent, on the basis of investigating and summarizing of in-depth fluid diverting agent system development of internal and external, the water absorption materials with interpenetrating polymer networks and montmorillnite (WIPN) were prepared via two processes on the directing of interpenetrating polymer networks theory. The materials can slowly absorb water and maintain high strength after absorbing water.With mechanical property and water absorbing property as the evaluating indicator, the effect factors of sopping network forming were studied, the factors include initiator, crosslinking agent and montmorillnite; the effects of temperature, indicator and monomer to reaction rate were researched. The effect factors of control swelling network establishing were discussed. The existence of interpenetrating polymer networks was confirmed by SEM, TEM, small angle X-ray diffraction and etc analysis techniques.On the basis of Flory’s material water absorbing thermodynamics theory, the water absorbing formula of WIPN was deducted; it shows that the crosslinking density of control swelling network is the main factor of delaying water absorbing. It was found by studying water absorbing dynamics that the water absorbing process of WIPN is composed with four stages. To obtain 10g/g water absorbing rate, it need more than 20 days; it need over 50 days to achieve the approximate water absorbing balance, it can be see that the aim of delaying water absorbing was achieved. The effects of temperature, mineralization degree and pH value to water absorbing property were discussed.The mechanical property of WIPN after water absorbing was studied by RS600 rheometer and Istron Universal Tester. The results show that the elastic modulus G’is more than 104Pa; the viscous modulus G’’is between 102Pa and 103Pa; the sample, which absorb water 25.8g/g, is broken by compress when its deformation is over 80%; the broken press is between 0.6 MPa and 0.8 MPa. Those indicate that the materials hold excellent elasticity and recovery property. The experiment of restricted swelling was designed and done. The results indicate that the water absorption rate is more; the swelling force of WIPN is less; the water absorbing expansion of WIPN can be realized when the oil reservoir space is limited.If the grain size of WIPN particles is less than the pore throat diameter, it can be injected successfully and cause permeability reducing. After the WIPN particles absorb, it can migrate in micropore and reduce further permeability. The dosage of WIPN particles is more; the effect of reducing permeability is more notable. When the WIPN particles are injected in high permeability area, they can improve permeability difference by water absorbing and cause displacement fluid diverting and enhance oil recovery. If the throat size is less than the WIPN particles diameter, the water absorbed particles can pass the throat by stretching and deforming, particles can come back the previous condition after passing throat.The results show that WIPN can be used in reservoirs in which the temperature is between 40℃and 80℃, the mineralization degree is less than 200000mg/L.