UPDATE 3-BP to start pressure testing Gulf well cap Tuesday

* If new system works, BP says no oil will leak

* Relief well on track to meet blown-out well by end-July
(Adds quotes from briefing, professor)

By Kristen Hays

HOUSTON, July 13 (BestGrowthStock) – BP Plc (BP.L: ) (BP.N: ) said it
will begin pressure tests at its undersea oil gusher in the
Gulf of Mexico on Tuesday afternoon after it placed a new
containment cap and seal on the wellhead late on Monday, the
top official overseeing the spill said.

Kent Wells, senior vice president of exploration and
production for BP, told reporters at 2:30 p.m. CDT (1930 GMT)
the test would begin in “a couple of hours.”

“It looks really promising right now,” said Satish
Nagarajaiah, professor in civil and mechanical engineering at
Rice University in Houston.

Nagarajaiah said that even if the well integrity test
fails, BP has options for containing the flow, including
siphoning and the relief wells.

Retired U.S. Coast Guard Admiral Thad Allen said earlier
that before starting the test, BP would shut down two
oil-capture vessels and shut three escape routes for crude on
the new stack as well as a hydraulic valve inside of it.

If the well can sustain up to 9,000 pounds per square inch
of pressure for the first six hours of the 48-hour test, the
cap could shut off all flow until a relief well kills the leak
by mid-August, Allen said.

But if pressures linger for the first six hours at 6,000
psi or less, “we’ll know we can’t sustain that in the long
run,” he said.

Either way, BP will have a four-vessel oil-capture system
in place by mid-July that can handle up to 80,000 barrels a
day, he said. If the cap can shut off all flow, the vessels
will be in place as a backup, Allen said.

Wells told reporters Tuesday morning that BP and government
scientists would monitor well integrity test at “very minute
intervals.”

High pressures would indicate the wellbore is intact after
the April 20 blowout, but low pressures would be a sign oil and
gas are leaking out the sides, Wells said.

“Everybody hope and pray we see high pressures here,” Wells
said.

He said relief wells remain the sole means to permanently
kill the leak. The first of those wells has another 30 feet (9
metres) to drill before inserting pipe and preparing to
intercept the blown-out well by the end of July, Wells said.
(Additional reporting by Alyson Zepeda and Chris Baltimore;
editing by John O’Callaghan and Jerry Norton)

UPDATE 3-BP to start pressure testing Gulf well cap Tuesday