Radial jet drilling for Dutch geothermal applications

Abstract

Radial jet drilling is a well stimulation technique that has drawn the attention of operators of geothermal doublets suffering from injectivity problems and therefore poor doublet performance. With radial jet drilling, several open hole laterals are created using hydraulic jetting from the main well bore, which enhance the connectivity of the well to the rock and thereby the well productivity or injectivity. Simulations on representative Dutch geothermal doublets show a potential performance increase by a factor of up to 3 when 8 laterals of 100 meter are successfully jetted and geological conditions are favourable. For fewer or shorter laterals, or in less favourable conditions, the performance increase is considerably less. It should be noted that there appears to be a mismatch between modelled performance
enhancement and observed enhancement as documented in publications. Major uncertainties in the production estimates are the long-term (>1 year) stability of the jetted laterals, the actual achieved trajectory of the lateral (which is not observed) and the effect of sub-surface heterogeneity.