Challenges with drilling for geothermal applications
The cost associated with establishing geothermal wells has been estimated to account for up to 50 % of the total cost per installed megawatt, and a predominant part of this is associated with the wear of drilling tools. Apart from the direct material and personnel cost associated with maintenance, a worn out drill bit is significantly less effective when drilling in hard rock. The drilling parameters, such as applied pressure and RPM, are crucial for rate of penetration but they also affect the wear of the drill bit. The optimal drilling parameters are seldom based on scientific theory and is instead based on the experience of the field operator. The contribution of Luleå University of Technology is to use numerical simulations in order to shine light on what is otherwise considered somewhat of a black box process.
Innovative methods for predicting rock drilling
In order to numerically evaluate the hard rock drilling process and subsequent wear, a description of the target rock material is required. To this end, novel numerical models based on particle-based-methods are used to model the rock fracture and interaction with the drill bit. These models are calibrated towards experiments and will be validated by comparing the results with full-scale drilling operations at GeoFit’s pilot sites. The final model will be able to aid drilling companies in choosing optimal drilling parameters, evaluating wear and predicting borehole conditions as well as vibrations in adjacent soil and rock.
Visit https://geofit-project.eu/for more information about the vision of GeoFit and the partners involved in the project.