Deepwater Horizon: Well integrity test holds key to next step

Offshore staff

HOUSTON– With completion of the capping stack installation on the Macondo well possible today, the ensuing well integrity test will lead to determination of the next step to be taken at BP’s Gulf of Mexico spill site, according to Coast Guard Admiral Thad Allen, national incident commander.

When the cap is installed, all production will be taken off the Q4000 and Helix Producer and go through the new cap. At that point, Allen said, a sequence of valve closures will shut off the flow of hydrocarbons into the water and will give a check on the actual flowing pressure of the well. If all goes according to plan, this could start as soon as this afternoon.

The new cap is a form of small BOP and is designed to give control of the existing choke and kill lines in addition to choke and kill lines on the cap itself. Allen said the first step will be to close the main ram in the cap, check the pressure, then close the kill line and check the pressure again, and then begin to slowly close the choke line valve using an ROV while constantly monitoring the pressure. When all the valves are shut, pressure build up will be monitored for between six and 48 hours, depending upon the force encountered.

The results of these pressure tests and the ability of the system to hold the sustained pressures will lead to determination of the next step. Allen said the ideal circumstance would be for the pressure to hold at 8,000 to 9,000 psi for as much as 48 hours. Then, the incident command and BP will have options regarding production of the hydrocarbons.

In any case, the relief well drilling still is seen as the final answer to the flow. The first well, being drilled by the Development Driller III, is at 17,843 ft, within 60-70 ft of its target depth and less then 41/2 ft horizontally away from the wellbore.


07/13/2010