Study On Controlling Factors Of Viscosity Of Polymer Solution In Daqing Oilfield

Polymer flooding is the primary means of increasing oil precipitation in Daqing Oilfield,ground water is mainly applied in compounding polyacrylamide in the initial stage, which isless of viscosity in controlling factors and maintaining well of solution viscosity. In recentyears, the employ of oilfield produced water is mainly used, owing to the complexity ofproduced water composition, many factors could affect its viscosity, and controlling factors ofpolyacrylamide viscosity is various, so its viscosity reduces greatly, which restricts theutilization of polymer. The issue analyzes quality and depth of the oilfield water component ingeneral preparation of polyacrylamide in Daqing Oilfield, and the results show that thesalinity, pH of ordinary water and deep water is the same basically, and inorganic and traceorganic ion content is the same basically, and organics is microscale; oil, PAM, suspendedsolids content of deep water is less than that of ordinary water. To determine the viscosity ofpolyacrylamide solution prepared with water control, there are employed two kinds of waterquality, and classifying the main control factors, evaluating and positioning factorsexperimentally, to discover controlling trends and patterns of factors. The results show thatthere are two types of factors, they are physical factors and chemical factors in preparedpolyacrylamide with water depth of field, and some factors influence greatly, such astemperature, high cationic, organic and other control factors all of which can greatly reducethe viscosity of polyacrylamide.One process of preparation water is oxygen exposure, and the research studies theinfluence of ordinary water, the depth of water and oxygen exposure water on viscosity inpreparation of polymer solution, and the results show that oxygen, Fe²⁺, S^2-, bacterial-thesefour factors effect the viscosity of the polymer solution, when the oxygenation reaches2.6mg/L experimentally, and polyacrylamide viscosity reaches maximum.To achieve the viscosity mechanism and conclusions, we collect different water indifferent topography. Using sample preparation method of rapid freezing during the study,ensuring samples polymer molecules form and original hydration status is consistent, using ascanning electron microscope （SEM） measurement, and the results show that: when thepresence of divalent ions in the polymer solution system, and molecules degree of stretchingshrinks obviously, when at the presence of montmorillonite suspended solids, polymer twines,network skeleton thins, which improves divalent ions and suspended solids effect theviscosity of the polymer solution obviously, and also explains that high viscosity of depthwater than ordinary water in preparation of polymer solution.Oilfield injection system structure is complex, and polymer solution mixed istransported long distances through pipelines, and the viscosity may change in injectionsystems under different locations. The results show that: the same concentration of thepolymer solution, parts of the solution viscosity of the size: mixer outlet <wellhead <pump outlet, the reason is that polymer at the wellhead is network structure, distributed uniformly,but might uneven while sampling, and the low viscosity comes out prior, therefore, thesolution viscosity decreases. And the polymer solution is mixed in the mixer outlet unevenly,and because of mechanical degradation action, viscosity is increased.The issue starts from water analysis used in preparation of polyacrylamide in oilfield,and discusses polyacrylamide solution viscosity control factors in substances contained in thewater and oxygen exposure process, and viscosity changes rules and mechanisms ontopography angle. Results will be provided guidance methods and data for produced waterquality controlling, preparation of water oxygen exposure process controlling, polymerviscosity controlling. It will bring great significance for oil production from the theoreticaland practical aspects.