Oil Well Cap Still Working After 48 Hour Test Period Passes 1.02K Jeff Neumann 07/18/10 08:59AM Filed to: oil spill oil spill Bp gulf of mexico Disasters deepwater horizon It's been three days since BP's latest oil well cap was fitted, and so far no evidence of further leakage has been found. BP is hopeful the cap will contain the oil until a relief well is finished next month.