Schlumberger

Case Study: ENI Saves 50 Hours, USD 1 Million with ONYX 360 Rolling PDC Cutters, Offshore Australia

Innovative cutting methodology significantly increases ROP and estimated run lengths, eliminating potential bit trips in highly abrasive sandstone

Challenge: Reduce potential bit trips while increasing ROP and run length in vertical section of Plover formation, characterized by abrasive sandstone interbedded with siltstone and silty claystone.

Solution: Improve cutter durability using 8 1/2-in MDSiR813 PDC bit fitted with ONYX 360 rolling PDC cutters.

Result:

  • Increased run length by 40% by drilling 126 m to section TD in one run at an average ROP of 4.3 m/h in the first well, exceeding average offset ROP by 19%.
  • Drilled 142 m in one run at an average ROP of 9.3 m/h in the second well, saving 50 hours and more than USD 1 million.

Hard, abrasive sandstone limits bit durability

ENI Australia drilled vertical sections in the Plover formation of Browse basin offshore Australia when they encountered highly abrasive sandstone interbedded with siltstone and silty claystone. The rough lithology caused accelerated wear on fixed-cutter only PDC bits, resulting in multiple bit trips due to low ROP and short run intervals. Consequently, the operator sought to reach each section TD in a single run while improving durability across the shoulder of the drill bit to increase the run interval length.

Rolling PDC cutters improve run length in challenging formation

To increase interval and ROP in the challenging application, Smith Bits recommended an 8 1/2-in MDSiR813 PDC bit with ONYX 360 rolling PDC cutters. The rolling cutters evenly distribute wear around the entire diamond edge, eliminating localized wear flats typically seen on conventional fixed PDC cutters. This technology enables the cutter edge to stay sharper longer, significantly improving cutter durability and run length.

ONYX 360 cutters increase run length and ROP, eliminate bit trips

On the first well, the 8 1/2-in MDSiR813 PDC bit with ONYX 360 rolling cutters drilled 126 m to section TD, extending the run length by 40% at an average ROP of 4.3 m/h in a single run.

On the second well, Smith Bits enhanced the bit design to increase cutter sharpness and bit efficiency. As a result, ENI was able to drill 142 m in one run at an average ROP of 9.3 m/h, saving 50 hours and more than USD 1 million off AFE.


Download: ENI Saves 50 Hours, USD 1 Million with ONYX 360 Rolling PDC Cutters, Offshore Australia (0.14 MB PDF)

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When compared with fixed-cutter-only bits, PDC bits that included ONYX 360 rolling cutters demonstrated run length increases of up to 57%, resulting in fewer bit trips and lower drilling costs.
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