1. Relief wells
Drilling the first relief well has been stalled for a few days in order to perform routine testing on the new rig’s blow-out preventer (BOP). Drilling is around the 9,000 ft mark (ie. 4,000 ft into the sea-bed) and should resume by the weekend.

2. Flow diversion: “top hat” and pipe insertion
The smaller “top hat” dome is ready, lying on the sea-bed near the damaged riser. A new proposal is to insert a 6 “ (smaller) diameter pipe inside the damaged riser. Both attempts to direct the flow of oil may be deployed later this week.

3. Top kill/junk shot
A manifold (which is needed for the attempt to deliberately clog the damaged BOP) has been lowered to the sea-bed. This Upstream Online report says that the actual “top kill/junk shot” attempt is still about a week away.

4. New BOP
[There appear to be no new developments on the proposal to install a new BOP on top of the damaged one.]

5. Congressional hearing reveals “significant problems”
Internal corporate documents which were provided to the House subcommittee revealed numerous problems:

• Hydraulic leak: a loose fitting on the BOP permitted “a large leak” of hydraulic fluid to occur.
• Modifications to the BOP: apparently the BOP was modified in 2005 to allow for routine testing but may have rendered it ineffective during an actual emergency.
• Shearing capability: the BOP lacked the capacity to cut through joints in the drill-pipe.
• Emergency controls: the explosion may have disabled communications to the BOP (at the very moment when activation was essential).
• Bad wiring and a dead battery were also cited as problems.

This MSNBC article provides further details.

6. Cementing
Testimony during the Congressional hearing on Wednesday indicated that the cement job failed a key pressure test which should have alerted the crew that something was amiss.

This Rigzone article provides further details.