Effect of high silica content on scale deposition and pipe-wall loss in oilfield steam generators

Studies were conducted on site in the Coalinga, Belridge, and Midway Sunset fields in California to research the cause of metal losses detected in the radiant section return bends and immediate piping downstream from the steam generators. Surveillance of silica content in the influent and effluent streams of the selected steam generators and the results of X-ray inspection of bends, elbows, welds, and pipings indicated that (1) a correlation is likely to exist between the silica and bicarbonate concentration in the feed- water and the silicate scale buildup, and incident rate of wall loss and (2) the cause of wall loss/pipe failures is a combination of corrosion and erosion mechanisms accelerated at higher steam qualities