Water injection has been widely applied in tapping oil and gas resources underground, however scaling corrosion in the water injection system was a universal problem, posing a huge threat to the longevity of downhole tubing.

In this paper, SEM and XRED were employed to study the mechanism of scaling and corrosion in the water injection system, non-metallic composite tubing was developed and evaluated in terms of its ability to resist scaling and corrosion, field operation was carried out to testify this approach.

The results indicated that inorganic scale was formed as a result of Cl, Mg+, Ca+ contained in the injection water, parameters including temperature and pressure played a role in this process, the scale could become highly corrosive in the weak acid environment; nonmetallic composite tubing was developed based on self-propagating high temperature synthesis technique, it was composed of three layers, ceramics inside, ceramic-metal combination middle, metal outside respectively, its scale rate was 1/70 compared to the conventional tubing, meanwhile the mechanical properties were better than its metal counterpart, field operation was performed in several oilfields, demonstrating strong scale and corrosion resisting characteristics, the statistic over 3years indicated that nonmetallic composite tubing guaranteed the smooth water flooding operation downhole, while conventional tubing was suffering from severe corrosion.

This paper contributed to better understanding the scale and corrosion in the water injection system and its prevention technique of nonmetallic composite tubing, through the pioneering example and profound insights we were able to explore new horizons and yielded more benefits to development of water injection operation.

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