A Comprehensive Model of Slimhole Geothermal Well Drilling Design

The application of slimhole geothermal well, where its final diameter is less than 6”, is based on economic factor, especially when exploration activities and reservoir assessment are conducted. Design of slimhole drilling is less expensive because the tangible and the intangible costs are lower. However, the slimhole well design has more engineering challenges comparing to conventional well: the highest pressure loss in annulus, higher directional difficulty index (DDI), the wellbore instability, lower pipe clearance restricts, etc. This paper investigates all of the drilling aspects of slimhole well design using basic concept of drilling engineering.common calculations in the industry. A model of decision making of slimhole well design based on engineering and economic view will be built so that all significant factors that can limit the use of slimhole can be identified and optimized.