Improving Drilling Efficiency through Heterogeneous Formations and Reduce Stick Slip Levels after the Implementation of Self-Adjust Depth of Cut Technology in Oil Well

Abstract

This paper describes the improved drilling efficiency of 8-1/2-inch PDC bits with self-adjusting depth of cut control technology, and its achievements in minimizing the level of vibrations and meeting directional objectives through heterogeneous formations. An 8-1/2-inch PDC bit equipped with self-adjusting depth of cut control was selected to improve drilling efficiency and mitigate high level of vibrations encountered through a challenging directional application. This selection was made due to its ability to autonomously adjust the amount of depth of cut control and adapt to the current environment. Observations of drilling and vibration data revealed the benefits of the technology in delivering the directional section through multiple formations with excellent performance and successfully mitigating the different type of vibrations. The 8-1/2-inch self-adjusting bit was used in three wells to deliver four directional sections. The implemented bit was able to reduce drilling costs by attaining a 10 % improvement in rate of penetration, a 36% reduction in torque variation, and 100% completion of each run with zero NPT. In addition, the adaptive technology significantly reduced stick slip vibration and prolonged downhole tool life by its unique dynamic self-adjusting depth of cut control. A comparison study of the effects of lithology changes on different bit types showed the capability of this unique technology to overcome formation challenges and obtain the best drilling efficiency. The introduction of the only PDC bit in the industry that can autonomously adapt its level of depth of cut control to the current drilling environment successfully improved drilling efficiency, delivered higher drilling performance, and minimized vibration levels.