Middle East 1994

Problem: A production well drilled in 1956 began to leak and charge a shallow aquifer. A workover rig identified a hole in the 2 3/8" tubing and 7" casing created by this corrosive aquifer. Communication with other wells in the field were established and sour gas was present in several cellars. The well was blowing out underground and several attempts to P&A the well using a workover rig were unsuccessful.
Remedial Strategy: Unconventional plugging techniques would be required for this blowing well. A remedial operation with a relief well was planned to intersect the existing blowout wellbore at the top of the reservoir. Hydraulic communication would be established and thixotropic light weight cement circulated back to the casing break. The remedial well would be spudded at a distance of approximately 85' from the problem well and well control measures would be required when drilling through the shallow zone.
Special Services: John Wright Company (JWCO) was contracted to plan and supervise the drilling and special services for this critical well. This would include pre-planning and on-site supervision of all drilling operations, directional drilling, wellbore surveying, casing detection, pumping, and cementing. Vector Magnetics, responsible for casing detection services, and Well Flow Dynamics, responsible for kill simulations, worked together with the JWCO to create a single team.
Challenges: The project was complicated by the following:
  • There were no borehole surveys of any kind on the flowing well
  • Control of the pressured sour gas infiltrated aquifer would require caution
  • A relatively shallow target of unknown bottomhole location would be difficult
  • A modified casing program would be required to safely drill to the reservoir
  • Low formation strength and fluid loss problems required special techniques.
Results:
  • Team concept for special services was successfully and efficiently utilized.
  • The complex 3-D wellpath was modified continuously by ranging results.
  • Dogleg rates up to 12/100ft were required, with an average 6-7/100ft rate.
  • The blowout well had ~4 inclination which was very uncommon in the field.
  • Drilling and flaring sour gas with a rotating head was required in the top hole.
  • The initial communication was at 1889 ft TVD with the relief well and temporarily killed the blowout.
  • Communication was immediately established upon entering the reservoir.
  • Light weight thixotropic cement was circulated to kill and P&A the well.