| Abstract |
Materials suitable for utilisation of deep and acidic geothermal resources have not been critically dejhed, Experimental and theoretical assessment work involving volcanic and acidic well fluids has advanced the understanding of the fluid chemistries and corrosion mechanisms, and practical performance of a range of engineering alloys exposed to these fluids: For example, carbon and low alloy steels have limited resistance, suitable high alloy materials are costly and intermediate alloy materials have not been fully evaluated. In this paper thermodynamic models are used to calculate the chemistry of the well inflow from measured surface chemistry and enthalpy. This information, together with wellbore simulation, allows the calculation of chemical conditions throughout the wellbore. Estimates of corrosion chemistry are incorporated into available models of corrosion based on the current materials performance knowledge base. These models assist in development of materials selection guidelines for deep and acidic geothermal well fluids and identifi delciencies in the current knowledge base. A materials testing program aimed at resolving these knowledge delciencies and exploring engineering solutions to the materials selection problems is described. |