Efficient drilling of hard rocks in mineral exploration requires a comprehensive knowledge of the energy spent at the bit. The use of mechanical pecific energy (MSE) proposed in the past for drilling performance studies does not consider the impact of fluid hydraulics and therefore the concept of Drilling Specific Energy (DSE) was later developed to apply the hydraulics parameters into the drilling performance optimization. With respect to the purpo e of mineral exploration, coiled tube (CT) Turboclrilling ha be n propos d r c nlly for d ep hard rocks mineral exploration applications, with everal advantag s over conventional drilling method. oiled tube (CT) is a continuous pipe and con equently a downhole motor i needed to provid rotation and mechanical power to the bit. UD . is to be u ed a a drilling performance indicator when downhole motor are part of the bottom hole as embly (BRA) it hould be modified in such a way that it include motor pecification in the calculation. In this paper, a methodology is presented for performance optimization in CT Turbodrilling with re pect to pecific energy perfonnance model. As a r ult, a hydraulic sp cific nergy performance indicator i d fin d for CT Turbodrilling in hard rocks mineral exploration.
In mjneral exploration, the main purpose of drilling is to acquire large number of samples to test them in the lab and obtain information about the vertical and lateral distribution of the geological formations, the structural regime, ore and its grade. This would detern1ine if the site is feasible for fhrther investigations and studies. With this in mind, perhaps obtaining core samples over whole overburden is not always essential and having cuttings of small sizes could be used for the analyses needed during the exploration phase.
