TY - THES

T1 - Concepts of Downhole Power Generation during the Drilling Process in the Geothermal Industry

AU - Eckerstorfer, Helene

N1 - embargoed until 05-02-2025

PY - 2020

Y1 - 2020

N2 - While hydrocarbons, nowadays, are still an indispensable source of the global energy supply, the process of drilling wells to access these invaluable resources is a risk-, energy- and cost- intensive operation. The volatile oil price environment of recent years drives operators to explore new ways of energy- and ultimately cost saving strategies that are environmentally compliant and meet safety standards. Downhole electrical energy harvesting techniques provide a potential for re-using a specific fraction of the energy that is put into the drilling process which would otherwise dissipate into the surrounding formation as vibration and heat. The aim of this thesis is to explore the implementation of a power source as part of the drillstring that converts the currently unused energy forms which are present downhole into electrical energy to operate low-energy-consumption tools such as valves and measurement devices. Aside from recycling some of the energy in the drilling system, these methods can make the use of downhole batteries redundant, which can prevent expensive round trips in case of battery failure or altogether avoid the risk of losing batteries in the borehole. To assess and compare concepts of different energy harvesting systems and their implementation in the downhole environment, expected power output, efficiency, current, and voltage are calculated and simulated based on existing literature. The results are discussed in the context of the prevailing boundary conditions downhole, also taking into account the effect of pressure and temperature on the durability of the devices.

AB - While hydrocarbons, nowadays, are still an indispensable source of the global energy supply, the process of drilling wells to access these invaluable resources is a risk-, energy- and cost- intensive operation. The volatile oil price environment of recent years drives operators to explore new ways of energy- and ultimately cost saving strategies that are environmentally compliant and meet safety standards. Downhole electrical energy harvesting techniques provide a potential for re-using a specific fraction of the energy that is put into the drilling process which would otherwise dissipate into the surrounding formation as vibration and heat. The aim of this thesis is to explore the implementation of a power source as part of the drillstring that converts the currently unused energy forms which are present downhole into electrical energy to operate low-energy-consumption tools such as valves and measurement devices. Aside from recycling some of the energy in the drilling system, these methods can make the use of downhole batteries redundant, which can prevent expensive round trips in case of battery failure or altogether avoid the risk of losing batteries in the borehole. To assess and compare concepts of different energy harvesting systems and their implementation in the downhole environment, expected power output, efficiency, current, and voltage are calculated and simulated based on existing literature. The results are discussed in the context of the prevailing boundary conditions downhole, also taking into account the effect of pressure and temperature on the durability of the devices.

KW - hydrocarbons

KW - energy harvesting

KW - drilling process

KW - Kohlenwasserstoffe

KW - Energiegewinnung

KW - Bohrprozess

M3 - Master's Thesis

ER -