POTENTIALS FOR COST REDUCTION FOR GEOTHERMAL WELL CONSTRUCTION IN VIEW OF VARIOUS DRILLING TECHNOLOGIES AND AUTOMATION OPPORTUNITIES

摘要

Drilling cost is a bottleneck for commercial development of most unconventional geothermal energy projects. Direct transfer of technologies and experience from drilling of oil and gas wells generally involves costs that may be unbearable when developing cost-effective geothermal energy projects. A discussion of necessary means for reducing costs when drilling geothermal wells is presented in this paper. In recent years, several new drilling concepts have been suggested, such as tools for more efficient hard rock drilling. In addition, possibilities of implementing off-the-shelf automation technologies used in various other industries, such as supervisory control, are emphasized. Requirements for "fit-for-purpose" sensor systems, automated procedures, as well as existing automation equipment developed for drilling of oil and gas wells are investigated in terms of reduced crew costs, reliability and risk. Possible replacement of drilling crew members by utilizing "state-of-the-art" automation technologies raises questions as to how the drilling crew organization may be re-structured. Relevant aspects on drilling crew re-organization and reluctance towards changes are discussed. Furthermore, it is considered essential to understand the entire drilling operation, in terms of pinpointing cost elements and duration of the phases involved. Implementation of tools for probabilistic well cost estimation is discussed as a way forward. Implementation of discussed technologies and methodologies for geothermal drilling and well development may also prove valuable for oil and gas industry, thus ensuring competence transfer in the opposite direction of what has historically been the case.