| Title | Using advanced bit sensor modules for measuring vibrations, torque, and weight on bit to optimise PDC bit drilling efficiency in geothermal applications |
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| Authors | A. Aspiras, A. Rebrikov, S. Mohamed, Y. Wiratomo, A. Johns, A. Li |
| Year | 2025 |
| Conference | New Zealand Geothermal Workshop |
| Keywords | PDC bit, geothermal drilling, in-bit sensor, downhole weight on bit measurement vibration, bit wear, offset analysis, Drill bit design, performance improvement, continuous improvement, drilling optimization |
| Abstract | Vibration is one of the major contributors that reduce bit performance in geothermal drilling, resulting in excessive wear, low rates of penetration (ROP) and pulling out of hole before reaching total depth (TD). Conventional surface and downhole tools fail to detect vibrations occurring directly at the bit, with sensors located above in the bottomhole assembly (BHA). An advanced in-bit sensor system was developed to record memory-based measurements of vibration types, downhole torque (DTQ), and downhole weight on bit (DWOB). This integration of the in-bit sensor system offers valuable insights into the subsurface conditions during PDC bit drilling in geothermal applications, thus enabling reduced bit wear and improved drilling performance in challenging environments. Data collected from the in-bit memory module revealed that torsional vibrations were most prominent during hard rock drilling, while stick-slip vibrations frequently occurred in transition zones where the BHA unwinds due to reduced formation resistance. Analysis of in-bit measurements also indicated that bit damage on the shoulder and gauge areas was primarily caused by lateral impact while rotating off-bottom. The results also showed that managing bit aggressiveness within a controlled critical depth of cut (DOC) effectively reduced stick-slip amplitudes. Insights gained from the data will impact subsequent drill bit design improvements and operational adjustments, enhancing both technical and economic performance in geothermal drilling operations. Accurate identification of vibration sources during drilling facilitated the creation of a targeted drilling parameters roadmap aimed at ensuring dynamic stability of the bit/BHA combination across varying lithologies, significantly reducing bit wear and optimising ROP. |