Study on scaling mechanism of injected water in Yujiaping Oilfield

Abstract

Oilfield injected water scaling often has a great impact on production and development. In this study, the scaling mechanism of injection well was studied, and the scale samples were analyzed by X-ray diffraction and other methods to determine the elements and mineral composition of scale samples and finally determine the main components of scale samples, providing a basis for subsequent water quality treatment. The results show that scale formation in Yu jia ping oil area is mainly caused by corrosion, inorganic salt scale caused by chemical reaction and sediment carried by injected water. Among them, inorganic salt scale is the main scaling component, and its main reason is the changes of ions in the injected water under different chemical environments. After a series of chemical and physical reactions, some ions in the injected water will form insoluble, insoluble and slightly soluble inorganic salts. After long-term accumulation, it is easy to form scale, namely the so-called inorganic salt scale. Inorganic salt scale is generally composed of sulfate and carbonate, the more typical calcium carbonate, calcium sulfate, barium sulfate, etc.