Most geothermal wells produce low pressure steam or hot brine from relatively shallow depths. However, effects up to 600 degrees F temperatures and 100% aqueous environments create well completion and operating problems that are unique to even experienced petroleum engineers. Unusual problems with casing that is otherwise properly designed for basic tension, burst and collapse are presented. Primary cementing limitations caused by severe hole conditions are also emphasized. First of its kind completion tools and methods and special problems in a major Australian geothermal development are reviewed.

Introduction
In several areas of Australia, geothermal resources have been favorably assessed and wells are now being drilled and completed with the potential to supply power for electricity generation. Such wells typically will flow large volumes of superheated water from which commercial quality steam will be separated. Viable operations are already supplying electricity in several areas around the globe, including nearby developments in Australia. These developments represent a challenging set of downhole conditions and reservoir characteristics with unique problems caused by high volume, hot water flows.

This paper is an overview of state of the art technology, problems encountered and limitations relevant to the completion and production of geothermal wells. Technical discussion will include:

1. Casing failure modes, design considerations and the effects of unique hole conditions.
2. Completion methods as applied to a specific project in Australia.

Extensive testing and tool design work were conducted as part of a program to commercialize a geothermal development in the Cooper Basin area of Australia. Two important objectives were early definition of practical problems and rapid technology development.

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