Lost Production as Consequense of Silica Scaling in Cerro Prieto Geothermal Wells Mexico

Abstract

Mineral scale depositation occurs in many of the Cerro Prieto wells, but the main problems occurs by silica (SiO2) scale both pipes and reservoir zones close to the downhole. In Cerro Prieto geothermal field three types of scales are found; calcium carbonate (calcite), amorphous silica (SiO2), and metallic sulfides (mainly iron, and lesser lead and cooper). The scale causes lost production and it is necessary to make around 12 workover each year to recover the steam lost. When scaling problems occurred inside casing production is more easier to recover the production that scaling occurred in the reservoir zones, because it caused a skin damage (permeability decrease) in the reservoir zones close to the bottomhole. This paper analyze and discus the scaling problems and discuss the task developed to avoid and minimized the decline wells production, as to recover the production using workover alternatives