Proof of Concept in a Full-Scale Field Test for the Novel Micro-Turbine Drilling Technology from a Cased Borehole in Granite Rock

N. Geissler, F. Garsche, V. Samus, B. Polat, F. Di Mare, R. Bracke. SPE Journal (2023), 10 November 2023.


In deep geothermal reservoirs, formations are typically of very low permeability, and fractures, natural or artificial, are needed to enhance production or injection from or into these reservoirs. There are various stimulation methods known from the oil and gas industry to increase the productivity of oil and gas reservoirs. Essentially, this is achieved by creating pathways around the wellbore to connect fault zones with high permeability. Conventional methods to connect reservoir and wellbore include perforation (Lestz et al. 2002), hydraulic stimulation (Chen et al. 2022), matrix treatments, and RJD (Dickinson and Dickinson 1985; Abdel-Ghany et al. 2011; Cinelli and Kamel 2013; Reinsch et al. 2018; Nagar et al. 2020). These technologies are altogether unsuitable in geothermal applications due to the very inadequate penetration depths of perforation technologies, harsh environmental impacts of both hydraulic stimulation (Xie et al. 2015) and matrix treatments, and the applicability of RJD limited to soft rocks with minimum porosities of about 3–4% (Peters et al. 2015).

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