Well Collision Avoidance Management and Principles

Introduction – Well Collision Avoidance:

• Not a new subject, but
• Current guidance
  • Disparate
  • Company specific
  • Occasionally contradictory
• Goal: Standardise
  • Rules
  • Process
  • Nomenclature
  • Improve efficiency
  • Reduce implementation errors
  • Input to API RP78 development
• Nomenclature:
  • Reference Well: The well being drilled
  • Offset Wells: Adjacent wells

Well Collision Avoidance

• “The adoption of a particular minimum allowable separation rule, no matter how conservative, does not ensure an acceptably low probability of collision”

Offset Well Risk Classification

• HSE Risk Well
  • Collision with it could result in an uncontrolled release of material:
    • Hydrocarbons
    • Chemical (e.g. H2S)  Nuclear (e.g. radioactive material)
    • Biological
    • Physical (e.g. geothermal)
  • or undermine facilities. (e.g. working mines, piles) Does not have to be at surface:
    • Sub-surface blowouts
    • Sub-sea releases
• Non-HSE Risk Well
  • Can be addressed solely in financial terms
    • Temporal risks - damage after the collision
    • Remediation (access and time)

Well Collision Frequency

• Why the interest?
  • Unreported incidents?
  • No uncontrolled flow?
  • Changes in industry practices?

Well Collision Example

• Description
  • Offshore: Whilst drilling a fast ROP top hole section with a recognised collision risk, the well built angle faster than expected. The first few MWD surveys failed QA\QC due to suspected magnetic interference. The rig crew rejected them entirely and continued to drill blind. They drilled into an offset well causing a kick, throwing the drillstring out of the hole. When investigated, plotting the rejected MWD surveys showed the well heading straight towards the offset …
• Cause
  • Failure to plot, and manage anomalous

...

View the entire Presentation:

Well Collision Avoidance Management and Principles

S.J. Sawaryn, Consultant

 

More from Meeting 45