Abu Dhabi's Crown Prince Sheikh Mohammed bin Zayed Al Nahyan said the emirate is considering making an investment in BP, according to press reports."We are still thinking about it," he was quoted by Bloomberg as saying when asked about buying a stake in the firm. "We are looking across the board. We have been partners with BP for years."Sheikh Mohammed's comments come after BP chief executive Tony Hayward met with the crown prince last week. Hayward was reported as saying that he would be comfortable with Abu Dhabi taking a stake of up to 10% in the oil giant.BP needs to find a way to finance its liabilities following the Deepwater Horizon oil disaster. The shares more than halved after the Gulf of Mexico well exploded on 20 April killing 11 workers, and they traded below 300p a share three weeks ago for the first time in 14 years.BP's shares are currently back above 400p as hopes were rising that the group is near to stemming the flow of oil spilling into the Gulf of Mexico after a new 75-tonne steel cap was lowered over the damaged well late last night.Reports suggested that for a brief period shortly after the new cap was installed oil stopped leaking from the Macondo well, though it resumed soon after through a valve to relieve a pressure build-up.BP will now start a 48-hour test of the new cap, during which it says the oil could be stopped again though this does not indicate that the oil leaking from the well has been stopped for good."It is expected, although cannot be assured, that no oil will be released to the ocean for the duration of the test. This will not however be an indication that flow from the wellbore has been permanently stopped," the statement said.The drilling of a relief well will continue through the period and "remains the sole means to permanently seal and isolate the well," BP added.The new cap replaces a smaller version that has been in place since June and had captured some of the estimated leakage of 60,000 barrels of oil a day.BP shares have started to recover during the last few days on a combination of bid talk, asset sale rumours and hopes it might soon permanently cap the leak.