SPE Drilling & Completion
Volume 26, Number 4, December 2011, pp. 519-530

SPE-125093-PA

Avoiding Losses in Depleted and Weak Zones by Constantly Strengthening Wellbores

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DOI  More information 10.2118/125093-PA http://dx.doi.org/10.2118/125093-PA

Citation

  • van Oort, E., Friedheim, J., Pierce, T., and Lee, J. 2011. Avoiding Losses in Depleted and Weak Zones by Constantly Strengthening Wellbores. SPE Drill & Compl  26 (4): 519-530. SPE-125093-PA. http://dx.doi.org/10.2118/125093-PA.

Discipline Categories

  • 1.1.2 Performance Measurement, Technical Limit
  • 1.4.2 Drilling Fluids, Handling, Processing and Treatment
  • 1.2.5 Materials Selection (Casing, Fluids, Cement)
  • 1.7 Fundamental Research in Drilling & Completions
  • 1.2.7 Pressure Management (MPD, Underbalanced Drilling)

Keywords

  • drilling fluids

Summary

Drilling depleted or weak zones has always been a challenge, but with the aging of fields and the desire to drill to deeper in-field plays, the situation is becoming more exacerbated. The typical problems associated with drilling these types of intervals are lost circulation, stuck pipe, and wellbore instability, resulting in significant and expensive nonproductive time (NPT) and costly remediation operations. Conventional lost-circulation remedies (e.g., pumping lost-circulation pills and squeezing) have given way to popular wellbore-strengthening solutions. Our approach to strengthening, based on beneficial manipulation of fracture-propagation pressure and continuous application of specialized wellbore-strengthening additives, has had tremendous success in reducing downhole mud losses by more than 80% in Gulf of Mexico (GOM) deepwater operations and dropping the cost of these incidents out of the top 10 contributors to NPT.

This paper focuses on the various theories and approaches to wellbore strengthening and what the available field and literature data actually support. Building upon this, the approach of gaining wellbore fortification through fracture-propagation-resistance (FPR) enhancement is introduced, for which experimental results, field data, and case histories are shared. Central to our application of FPR to drill-challenging deepwater production wells is the notion of providing continuous wellbore protection through a novel and unique solids-recovery and reintroduction method that allows for drilling with high concentrations of wellbore-strengthening materials (WSMs) in the drilling fluid.

© 2011. Society of Petroleum Engineers

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History

  • Original manuscript received: 14 April 2011
  • Meeting paper published: 4 October 2009
  • Revised manuscript received: 30 August 2011
  • Manuscript approved: 6 September 2011
  • Published online: 19 December 2011
  • Version of record: 27 December 2011