Review of Corrosion and Scaling Problems in Cerro Prieto Geothermal Field over 31 Years of Commercial Operations

Abstract

More than 35 years have passed since the first wells were drilled in Cerro Prieto, since then about 250 wells have been constructed in different field locations. Presently an average of 150 wells are supplying steam to four power plants with a capacity of 720 MWe. The fluids produced by wells are a mixture of steam-water in different ratios. The brine produced has different chemistry conditions depending on several factors including the geology of the well, downhole temperature, downhole pressure, and water source. The scaling and corrosion characteristics of brine have caused difficult problems during the Cerro Prieto development. There are a variety of problems associated with brine produced by wells such as reservoir formation plugging, well and line plugging, reduced steam-brine flow, casing fracture, superficial equipment damage, power plant equipment damage, power production losses, etc. Comision Federal de Electricidad (CFE), who operates the field, has employed different programs and methods to avoid, minimize, and help the control of the scaling and corrosion problems. This paper describes the main experiences in handling of corrosion and silica scaling problems experienced in Cerro Prieto field through its 31 years of commercial operation.