Case Study: Successful Application of ULTRADRIL High Performance Water Based Mud (HPWBM) with POROSEAL mitigates problematic Nahr Umr Shale in 8 ½” interval, Offshore Abu Dhabi

Challenge: Previous wells drilled in this area utilized a PHPA/Polymer system for drilling of the shale intervals, however when logging it was often observed that the interval was found to be over-guaged. Due to issues related to troublesome Nahr Umr shale section, the operator required a High Performance Water Base Mud (HPWBM). Previous attempts in 2004 to use a HPWBM system lead to severe wellbore instability issues.

Solution: The M-I SWACO ULTRADRIL with POROSEAL system was introduced with the purpose of ensuring shale stability and reducing the occurrence of over-guage hole to assist in cementing operations. The system was chosen because of its highly inhibitive nature, achievable enhanced drilling performance, and shale stabilization through reduced pore pressure transmission with POROSEAL and ULTRHIB. Adding to the fact that this system had been proven in other offshore applications in Abu Dhabi, and project-specific laboratory evaluations showed ULTRADRIL was fit for required goals.

Result: The 8-1/2” interval was drilled and 7” liner was successfully run to bottom without any drilling fluid related issues. The ULTRADRIL system with POROSEAL additive was able to ensure:

  • Elimination of the need for backreaming certain intervals
  • No NPT due to drilling fluids was observed
  • No stuck pipe/No bit balling
  • Reduction in previously observed drag readings

  • Download: Successful Application of ULTRADRIL High Performance Water Based Mud (HPWBM) with POROSEAL (0.51 MB PDF)

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