Mallams, Jacob Robert (2020-11). Plasma Characteristics with Respect to Highly Pressurized Drilling Applications. Master's Thesis. Thesis uri icon

abstract

  • Deep earth drilling is a key technique to extract oil, gas, and geothermal heat from the earth. Energy focusing methods have been explored as an alternative approach to reach these resources. Many of these techniques require incredibly high energies and complex systems. Here the fundamental elements of a hybrid drilling/energy focusing technique is discussed. By utilizing short time span plasma discharges, energy focusing can be achieved within traditional drilling systems. These discharges induce a strong cavitation and resulting shockwave. It is believed that this focused energy will lower the required cutting force to progress through the rock. Lowering the required cutting force will allow for lower drill bit wear, quicker rate of penetration, and an overall cost savings of the project. This paper will discuss the characteristics, capabilities, and requirements associated with a plasma discharge at downhole pressures. The plasma behavior of discharges at pressures similar to downhole conditions have been explored. It has been proven that a high voltage (20+ kV) discharge is capable of discharging in pressures up to 350 atm. The consistency of this discharge is dependent on the electrode gap and supplied voltage. Higher pressures require higher voltages or smaller electrode gaps to remain consistent. Furthermore, the resulting impact of the discharge is a function of total system energy and the voltage/pressure ratio. Plasma energy has been quantified and recommendations for to maximize discharge energy is discussed. To obtain a better understanding of the discharge event, discharges have been imaged and characterized with both a high speed camera and an ICCD.

publication date

  • November 2020