In an e-mail Tuesday to The Associated Press, engineer John Wright says there's always drama in the delicate final steps of digging a relief well.
But Wright also pointed out that during four decades of capping blowouts he's dug 40 wells across the world without missing.
"Perhaps it is a bit like golf," Wright said. "The more you practice the luckier you get."
Adding to the drama: The weather. The National Hurricane Center is watching a cluster of thunderstorms in the far eastern Gulf of Mexico that could blow into a tropical storm, and that forecasters say may pass near the oil spill site just as the final 100 feet of the relief well is drilled.
In a June video put out by BP, Wright expressed "high confidence" the relief well would take care of the problem.
But he is still anxious each time he nears the end.
Wright will guide the relief well drill, about the size of a grapefruit, into the target, which is less than half the size of a dartboard more than two miles beneath the seafloor and three miles from the surface. BP says that could happen as soon as Friday.
"There has always been some drama at the last moment that makes you think you might miss. It comes down to a judgment call," Wright said in an e-mail to The Associated Press.
Wright says stopping the oil before the relief well finished has taken some of the pressure off him.
If Wright hits the mark, engineers will perform a "bottom kill" by pouring in mud and cement to permanently seal the blown-out well that's spewed an estimated 207 million gallons since April.
If he misses, engineers will pull the drill bit up, pour concrete in the off-track hole, and then try again.
A "static kill" last week pushed mud and cement into the top of the crippled well, leaving very little chance oil could leak into the Gulf again, officials said.
Finishing the new well and sealing the broken one with mud and cement should be the final act of the three-month oil spill drama that has upended the lives of fishermen and others along the Gulf Coast.
The government's point man for the spill, retired Coast Guard Adm. Thad Allen, is planning a three-day trip to Louisiana, Mississippi and Alabama this week to talk with local officials about how to speed up cleanup as the peak of hurricane season approaches.
Oil spill costs continue to mount for BP. The oil giant announced Monday it has spent $6.1 billion responding to the spill since the April 20 explosion on the Deepwater Horizon killed 11 workers, sending the rig to the bottom of the sea and oil spewing 5,000 feet (1,500 meters) underwater.
Also, the Justice Department and BP announced they have finished negotiations to implement a $20 billion fund for victims of the Gulf oil spill and that BP has made a $3 billion initial deposit.
More on the Gulf Oil Spill: