Oil giant BP has finished work on a relief well in the Gulf of Mexico that will pave the way for the company to permanently seal the leaking Macondo well.The head of the relief well is situated about 100 feet from the Macondo well and intersects with it around 6,000 yards below the surface of the sea."BP engineers and the federal science team have concluded that the Development Driller III relief well has intersected the Macondo well," Thad Allen, the appointed federal spill commander, was quoted as saying late on Thursday.With the relief well completed BP can now start work on the "bottom kill" stage of the recovery programme, a process that entails heavy mud and cement being pumped from the relief well into the lower part of the original well in order to permanently seal it."We intend to proceed with preparation to cement the annulus and complete the bottom kill of the well," Allen said in a statement.Allen added that the tests indicated that BP's temporary fix on 5 August, which involved pouring in cement to the top of the well, had sealed off the reservoir from all parts of the Macondo well. The "bottom kill" process will be a more permanent solution and will hopefully bring to an end a tragic episode in which 11 lives were lost and more than 4m barrels of oil spewed out into the sea.