Edoardo Rossi

ETH Zurich | ETH Zürich

In this paper, the feasibility of a thermally assisted drilling method is investigated. The working principle of this method is based on the weakening effect of a flame-jet to enhance the drilling performance of conventional, mechanical drilling. In order to investigate its effectiveness, we study rock weakening after rapid, localized flame-jet hea...

Combined thermo-mechanical drilling is a novel technology to enhance drilling performance in deep hard rock formations. In this work, we demonstrate this technology in the field by implementing the concept on a full-scale drilling rig, and we show its feasibility under realistic process conditions. We provide evidence that the novel drilling method...

To enhance the drilling performance in deep hard rocks and reduce overall drilling efforts, this work proposes a Combined Thermo-Mechanical Drilling (CTMD) technology. This technology employs a heat source (e.g., a flame jet) and includes two main drilling modes: (I) thermal spallation drilling, investigated in the companion paper and (II) flame-as...

Accessing hydrocarbons, geothermal energy and mineral resources requires more and more drilling to great depths and into hard rocks, as many shallow resources in soft rocks have been mined already. Drilling into hard rock to great depths, however, requires reducing the effort (i.e., energy), time (i.e., increasing the rate of penetration) and cost...

To improve the economics and viability of accessing deep georesources, we propose a combined thermo–mechanical drilling (CTMD) method, employing a heat source to facilitate the mechanical removal of rock, with the aim of increasing drilling performance and thereby reducing the overall costs, especially for deep wells in hard rocks. In this work, we...

Advanced Geothermal Systems (AGS) generate electric power through a closed-loop circuit, after a working fluid extracts thermal energy from rocks at great depths via conductive heat transfer from the geologic formation to the working fluid through an impermeable wellbore wall. The slow conductive heat transfer rate present in AGS, compared to heat...

To improve the economics and viability of accessing deep georesources, we propose a combined thermo-mechanical drilling (CTMD) method, employing a heat source to facilitate the mechanical removal of rock, with the aim of increasing drilling performance and thereby reducing the overall costs, especially for deep wells in hard rocks. In this work, we...

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Access to deep energy resources (geothermal energy, hydrocarbons) from deep reservoirs will play a fundamental role over the next decades. However, drilling of deep wells to extract deep geo-resources is extremely expensive. As a fact, drilling deep wells into hard, crystalline rocks represents a major challenge for conventional rotary drilling sys...

In order to meet the increasing worldwide energy demand in the next decades, access to deep geothermal, oil or gas reservoirs will be key in the future global energy supply. Construction of deep wells, especially for deep geothermal energy, require major costs, mainly related to the involved drilling operations. Indeed, drilling costs are found to...

The development of deep geothermal systems to boost global electricity production relies on finding cost-effective solutions to enhance the drilling performance in hard rock formations. In this work, we investigate a novel drilling method combining thermal spallation and conventional drilling. This method aims to reduce the rock removal efforts of...

The creation of deep reservoirs for geothermal energy or oil and gas extraction is impeded by insufficient stimulation. Direction and extension of the created fractures are complex to control and, therefore, large stimulated and interconnected fracture networks are difficult to create. This lack of control and efficiency poses an inherent risk of u...

Thermal Spallation Drilling (TSD) is an alternative rock reduction technology, where a flame jet locally destructs the rock surface. The technology has the potential to feature high rates of penetration, an efficient energy transport and reduced wear rates. In this manuscript, the possible benefits and limitations of the technology are presented, t...

Thermal cracking of rocks is an intensively studied topic in different research areas and for various engineering problems. In this context, we present a modeling approach which describes thermal spalling of rocks with a focus on thermal spallation drilling. This drilling technology uses high thermal loads to locally destruct the surface of the roc...

Thermal diffusivity, heat capacity, and thermal conductivity of Central Aare granite are reported in the temperature range from 25°C to 500°C. Each rock sample underwent three consecutive heating and cooling cycles. Significant irreversible changes in the properties due to thermal crack formation could be observed. After the first thermal cycle, bo...