Abstract
Saline waters, including brackish water, are produced from wells, in Israel Negev Desert, for use as industrial water in the local chemical and mineral industries. The water systems are composed of three main components: production wells, with cemented and uncemented steel casings and fitted with vertical, submersible turbine pumps; distribution pipelines, made mainly of asbestos-cement and carbon steel, but including other nonmetallic materials: rigid polyvinyl chloride, fibre-glass reinforced polyester and cross-linked polyethylene; open reservoirs, lined with rubber geomembranes. Data were collected on the saline water corrosivity, and field measurements of corrosion rates, pH and dissolved gases (O2, H2S and CO2) content were made on the well head, pipelines and reservoirs. The corrosion products and deposits collected were chemically analysed and their morphology and structure were studied by SEM and XRD. The pH values of the pipeline waters are in a narrow range of 6.7 to 7.7, their total dissolved solids range from 2.0 to 13.0 g/l and their electrical conductivity is from 3.4 x 10-3 to 1.7 x 10-2 S/cm. The electrochemical corrosion behaviour of carbon steel in saline water, at different levels of H2S and pH, was determined by electrochemical laboratory simulation tests. The main factor enhancing corrosion of steel as well as asbestos-cement, is dissolved H2S which establishes an acidic corrosion mechanism in the well casings and tubings, and in pipelines near the well head. This study and its experimental procedures will serve as a model for corrosion investigations in arid regions in North-West Mexico, e.g. Sonora, Baja California and Chihuahua.
