Southeast Asia 2002

Problem:   While development drilling well control was lost and gas broached to the seabed under the platform. The well subsequently bridged and the broach stopped. It was later discovered that the tubing and all protective strings of casing in a well adjacent to the blowout were severed below the conductor and open to the sea. This left an unacceptable single well control barrier, a TRSSV in the tubing and a packer in the 9-5/8” casing, to protect the platform from another subsea broach.
Remedial Strategy:  The basic design strategy was to drill an intervention well from an adjacent bridge-connected platform and intersect the problem well at its production casing string both above and below the producing reservoir. After intersection was confirmed using electromagnetic homing-in technology, the wells would be perforated and cement circulated down the relief well drillstring, through a cement retainer, up the problem well’s production casing and back into the relief well’s annulus. As a final assurance, a balanced cement plug would be set across the upper perforations and squeezed into the problems well’s tubing.
Special Services:  John Wright Company (JWCO) was contracted to supervise the special services for the relief well to include: pre-planning, on-site supervision, directional drilling, surveying, casing detection, intersection and kill hydraulics. Well Flow Dynamics provided hydraulic modeling, Vector Magnetics provided electromagnetic ranging services and SDI provided gyro surveys and gyro MWD. All companies worked together with JWCO to create a single special services team.
Challenges: The project was complicated by the following:
  • The platform was considered a worldwide critical asset by the owner and all operations were designed with significant safety factors to protect the asset.
  • Multiple contingency plans were required for each operation.
  • The problem well was a directional well at 47° inclination with uncertain surveys. Subsequent to the first intersection, the plan called for steering the relief well 400m at 4m proximity to the problem well with significant magnetic interference.
  • Dual intersection techniques required low incidence angles and exceptionally precise directional control.
  • A relief well of this type had never been attempted before.
  • The project was completed according to plan without significant problems or delays.
  • The special services team was integrated seamlessly with the drilling team to create an effective and efficient operation.
  • The dual intersection was executed without significant delays.
  • Hydraulic communication was established with oriented TCP guns at the upper and lower intersections.
  • Cement was circulated from the relief well into the casing and across the reservoir section of the problem well and back into the relief well. Cement was squeezed into the upper intersection.
  • The relief well was converted into a producing well.