1. Relief wells
Yesterday’s update from Rigzone (link below, #3) indicates that the first relief well is already 2,000 ft below the sea floor (16,000 more to go…).
A second rig is also about to start drilling.
The time-line for both remains in the 60-90 day range.
2. Containment dome/cofferdam
The first cofferdam arrived yesterday morning, will need about 48 hours for lowering, and is expected to be operational by Monday.
Cold water temperature and extreme pressure are both significant challenges, and this article describes how BP plans to overcome them:
Cofferdam Heads to Wellsite
3. “Top Kill”
This strategy was announced yesterday and involves reconfiguring the existing damaged blowout preventer (BOP).
If successful, it would stop the flow permanently within two weeks.
This Rigzone article does not mention what the risks of this strategy may be: it sounds like a battle of competing (and very considerable) pressures, which should have some inherent risks.
Hayward: ‘Top Kill’ Might Seal Leaking Well Sooner
This Upstream Online article gives further details of the “BOP brain surgery.”
BP carries out ‘BOP brain surgery’
4. Previous BOP trouble
This Upstream Online article describes Transocean’s investigation of a “BOP issue” earlier this year off the coast of India:
Transocean admits India BOP ‘issues’
This sensible caution from a bioremediation expert at Lawrence Berkeley National Laboratory was issued three days ago:
Caution Required for Gulf Oil Spill Clean-Up, Bioremediation Expert Says
This Upstream Online article provides some details on the dispersants which are being used (as well as other good info):
Reid backs upping spill penalty to $10bn