Studies on the Scaling of High Pressure and Low Permeability Oil Reservoir Water Injection Well

Abstract

Injection wells scaling and scale inhibitor were studied in this paper, in consideration of the severe scaling problem of a high pressure injection wells in low permeability reservoirs. The result shows that the injected water contains some scale ions, such as carbonate calcium and magnesium ions. It also demonstrates that the main component of the scale is calcium carbonate, while the scale at bottom hole contains more silicon dioxide. Besides, the scaling of water injection wells mainly appear in the lower parts of the well and its thickness along the well increases rapidly. The indoor experiments of anti-scaling agent indicate that the anti-scaling agent is of good performance in scale prevention and its best concentration is 15 mg/L. In addition, it is also found that the scale inhibiting efficiency of scale inhibitor 2 is higher when the injected water is at low temperature, while scale inhibitor 1 shows better performance when the temperature of injected water is over 75 ℃. Key words : High pressure and low permeability oil reservoir; Water injection well; Scaling; Scale inhibitor