Study On Viscoelasticity Of Polyvinyl Alcohol And Its Linking System Aqueous Solution

In the middle and later stage of oilfield development,the water content of produced fluid is usually as high as 90%,and there are still a large number of heterogeneous reservoirs in the formation which have not been effectively exploited.Deep profile control and flooding technology is an effective way to solve reservoir heterogeneity and enhance oil recovery.Polyvinyl PVA is a polyhydroxy water-soluble polymer.Compared to the LPS flooding system,the PVA and its Linking system have the following characteristics:the PVA molecular weight is smaller,the molecular chain is shorter,the injection of the low permeability reservoir is easy,and the PVA is easily linked with the boron crosslinker,and can occur internal crosslinking reaction at a high concentration.In this paper,the particle size distribution of PVA and its crosslinking system within the range of 2g/L~6g/L was measured at 7.5nm to 40 nm by the dynamic light scattering.The viscosity of PVA solution was lower,and the concentration,temperature and salinity of the solution had some influence on the viscoelasticity of PVA by the rheological test.The filter experiment obtained that the PVA solution can pass through the filter membrane with a diameter of 0.22 ?m,and the plugging ability is weak,and it is suitable for blocking the smaller pore size.The PVA-organo boron crosslinking system is prepared,the viscoelasticity and viscosity of the crosslinked system are obviously increased when the concentration of PVA is greater than 20g/L.The study on the viscoelasticity of PVA and its linking system aqueous solution can deepen the understanding of the properties of the linked polymer aqueous solution,develop a system targeting low-porosity and low-permeability target reservoirs,and expand the development of PVA water-soluble polymers in oil and gas fields.The application in the field has a very good theoretical and practical significance.