Viscosity Enhancement Technology Of Polymer Solution And Assessment Of Oil Displacement Applied In Offshore Oilfield

The LD5-2oilfield has the characteristics of large reservoir thickness, high permeability, strongheterogeneity, high viscosity and salinity. What is more, the content of Ca²⁺ and Mg²⁺ are higher,so the saltresistance of polymer solution is put forward higer requirement and that results serious negative influencefor polymer soluti’ons gelatinizing effect. A new water treatment technology should be developed which issuitable for ocean plat structure and water characeristic.The paper carried out water treatment selection,effect evalution of softening water, performance assessment and comparison of polymer solution and Cr³⁺gel polymer which are compounded by injecting water and sotfening water. We were directed bypharmaceutial high polymer material science, physical chemistry and inorganic chemistry, acting chemistrystudy, instrument testing and physical modelling as technological means, acting oil reservori and injectingwater as object of stydy, acting viscosity, rheological properites, pol’ymers size of molecular clew, stage ofaggretation, resistance coefficient, residual resistance factor and oil recovery as evaluation index.The resultsho+wed that Ca2and Mg²⁺ could be eliminated by adding softener to injecting water, which cansubstantially improve polymer and C’r³⁺ polymer gels viscosity, viscoelasticity and rheological’proprety.What is more, polymer and Cr³⁺ polymer gels resistance coefficient and residual resistance factorand oil displacement efficiency increase dramaticlly. Mixing disincrustant and polymer powder firstly andadding them to injecting water was recommended. The composition of Cr³⁺ polymer gel were that “gaofen”polymer concentration was1600?2000mg/L, the ratio of polymer to Cr³⁺ was180:1?540:1.