New drilling technologies
Encyclopedia
The latest study of Massachusetts Institute of Technology
"The Future of Geothermal Energy – Impact of Enhanced Geothermal Systems (EGS) on the United States in the 21st Century" (2006) points out the essential importance of developing an economical deep geothermal boring technology. With current boring technologies, bore price rises exponentially with depth. Thus, finding a boring technology with which the bore price rise would be approximately linear with increasing bore depth is an important challenge.
1. Hydrothermal spallation
– Thermal spallation drilling uses a large, downhole burner, much like a jet engine, to apply a high heat flux to the rock face. This drilling technology is based on thermal processes of rock spallation and fusion.
2. Chemical plasma
– is based on crushing by high-speed combustion, but nitric acid as oxidizing agent instead of oxygen.
3. Erosion
- most patents refer to water jet rock cutting. Different modification variants are described, e.g. utilization of cavitation, turbulent processes, combination with mechanical processes, etc.
4. Laser
- during the recent decade intense research has been made into utilization of high energy laser beams for rock disintegration. Primarily conversion of military equipment is concerned. Laser energy is used for the process of thermal spallation, melting, or evaporation of rock.
5. Electric discharge
- The methods utilizing electric discharge are based on long-term experience gained in other application areas.
6. Electrical plasma
- is based on crushing by irradiation of plasma with high temperature up to 20 000°C
. It has lower energy efficiency than some of the other technologies, but it has several other advantages. Producing boreholes with wide range of diameters or drilling in water environment can be mentioned. The research team from Slovakia has developed drilling concept based on utilization of electrical plasma. The core of the research is held in Research Centre for Deep Drilling
which was opened in the premises of Slovak Academy of Sciences
in Bratislava.
Massachusetts Institute of Technology
The Massachusetts Institute of Technology is a private research university located in Cambridge, Massachusetts. MIT has five schools and one college, containing a total of 32 academic departments, with a strong emphasis on scientific and technological education and research.Founded in 1861 in...
"The Future of Geothermal Energy – Impact of Enhanced Geothermal Systems (EGS) on the United States in the 21st Century" (2006) points out the essential importance of developing an economical deep geothermal boring technology. With current boring technologies, bore price rises exponentially with depth. Thus, finding a boring technology with which the bore price rise would be approximately linear with increasing bore depth is an important challenge.
New drilling technologies requirements
This MIT study characterizes the requirements on new fast and ultra-deep boring technology as follows:- the price of boring rises linearly with depth
- bore axis with neutral floating
- the possibility to make vertical or inclined bores up to 10 km deep
- the possibility to make large diameter bores – even 5 times larger than on the ground compared to today drilling technologies
- casing formed on site in the borehole
Examples of new drilling technologies
There are more than 20 research efforts solving innovative drilling technology such as: laser, spallation, plasma, electron beam, pallets, enhanced rotary, electric spark and discharge, electric arc, water jet erosion, ultrasonic, chemical, induction, nuclear, forced flame explosive, turbine, high frequency, microwave, heating/cooling stress, electric current and several other. The most promising solutions are mentioned below:1. Hydrothermal spallation
Spallation
In general, spallation is a process in which fragments of material are ejected from a body due to impact or stress. In the context of impact mechanics it describes ejection or vaporization of material from a target during impact by a projectile...
– Thermal spallation drilling uses a large, downhole burner, much like a jet engine, to apply a high heat flux to the rock face. This drilling technology is based on thermal processes of rock spallation and fusion.
2. Chemical plasma
Plasma (physics)
In physics and chemistry, plasma is a state of matter similar to gas in which a certain portion of the particles are ionized. Heating a gas may ionize its molecules or atoms , thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions...
– is based on crushing by high-speed combustion, but nitric acid as oxidizing agent instead of oxygen.
3. Erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...
- most patents refer to water jet rock cutting. Different modification variants are described, e.g. utilization of cavitation, turbulent processes, combination with mechanical processes, etc.
4. Laser
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...
- during the recent decade intense research has been made into utilization of high energy laser beams for rock disintegration. Primarily conversion of military equipment is concerned. Laser energy is used for the process of thermal spallation, melting, or evaporation of rock.
5. Electric discharge
Electric discharge
Electric discharge describes any flow of electric charge through a gas, liquid or solid. Electric discharges include:*Electric glow discharge*Electric arc*Electrostatic discharge*Electric discharge in gases*Leader *Partial discharge...
- The methods utilizing electric discharge are based on long-term experience gained in other application areas.
6. Electrical plasma
Plasma deep drilling technology
In the recent past, there were several attempts to develop new drilling technology which would be able to substitute conventional contact-based rotary systems. These concepts were based on different principles such as water jet, hydrothermal spallation or laser. Worldwide there are several research...
- is based on crushing by irradiation of plasma with high temperature up to 20 000°C
High-energetic electrical plasma
One of the most promising approaches in deep drilling field is utilization of electrical plasmaPlasma deep drilling technology
In the recent past, there were several attempts to develop new drilling technology which would be able to substitute conventional contact-based rotary systems. These concepts were based on different principles such as water jet, hydrothermal spallation or laser. Worldwide there are several research...
. It has lower energy efficiency than some of the other technologies, but it has several other advantages. Producing boreholes with wide range of diameters or drilling in water environment can be mentioned. The research team from Slovakia has developed drilling concept based on utilization of electrical plasma. The core of the research is held in Research Centre for Deep Drilling
Research Centre for Deep Drilling
Research Centre for Deep Drilling is high-tech laboratory focused on research and development of new deep drilling concept based on electrical plasma. It was established by Geothermal Anywhere company in the premises of Slovak Academy of Sciences in Bratislava, Slovakia...
which was opened in the premises of Slovak Academy of Sciences
Slovak Academy of Sciences
The Slovak Academy of Sciences SAV is the main scientific and research institution in Slovakia fostering basic and strategic basic research...
in Bratislava.