Characterization of a Pulsating Drill Bit Blaster

Abstract

The drill bit blaster (DBB) studied in this paper aims to maximize the drilling rate of penetration (ROP) by using a flow interrupting mechanism to create drilling fluid pulsation. The fluctuating fluid pressure gradient generated during operation of the DBB could lead to more efficient bit cutting efficiency due to substrate depressurization and increased cutting removal efficiency and the vibrations created could reduce the drill string friction allowing a greater weight on bit (WOB) to be achieved. In order to maximize these mechanisms the effect of several different DBB design changes and operating conditions were studied in above ground testing. An analytical model was created to predict the influence of various aspects of the drill bit blaster design, operating conditions and fluid properties on the bit pressure characteristics and compared against experimental results. The results indicate that internal tool design has a significant effect on the pulsation frequency and amplitude, which can be accurately modeled as a function of flowrate and internal geometry. Using this model an optimization study was conducted to determine the sensitivity of the fluid pulsation power on various design and operating conditions. Application of this technology in future designs could allow the bit pressure oscillation frequency and amplitude to be optimized with regard to the lithology of the formations being drilled which could lead to faster, more efficient drilling, potentially cutting drilling costs and leading to a larger number of oil and natural gas plays being profitable.iv