Relief well timing depends on oil's spread

THEODORE, Ala. Officials say the relief well is the best hope for shutting down the oil leak set off by the April 20 explosion aboard the /*Deepwater Horizon*/ drilling rig, which killed 11 workers and began an environmental catastrophe for the region.

Retired Coast Guard Adm. Thad Allen said that the well should intercept and penetrate the Deepwater Horizon well pipe about 18,000 feet below sea level within seven to 10 days. However, crews won't know how long it will take to stop the oil until they actually get there.

Allen said that the gushing well has several concentric rings, and oil could be coming up through multiple rings. The plan is to pump heavy mud and then cement into the well to overcome the upward pressure of the huge oil reservoir below.

If the oil is coming through the outer ring of the well, then they will have to pump in mud and cement to stop that layer first. Then they would have to drill through the hardened cement and repeat the process in each ring until they reach the center pipe and do it again.

This process will continue into the middle of August, which is the deadline /*BP*/ and government officials have held for several weeks. If the oil is only coming up the center pipe, then it's possible to stop the leak sooner.

Shaving even days off timeline would stop millions of gallons of oil from escaping into the /*Gulf*/. The broken well has spewed between 86 and 169 million gallons of oil, according to federal estimates.

Latest Developments:

  • Another tropical depression formed in the Gulf on Wednesday and was closely following the path of Alex to the coast at the border of Texas and Mexico. It was expected to have little effect on the eastern Gulf.

  • Allen said on Thursday that he has asked BP to respond within 24 hours with detailed plans to place a new containment cap to place over the well head. The current cap is flexible, allowing some oil to escape. In theory, the new cap should collect most of the gushing oil to be sent to the surface ships for removal or burning. But switching to the new cap would temporarily allow more oil to escape.
  • Another hope for collecting oil from the surface will be tested more this week: The "A Whale," a giant skimmer converted from an oil tanker, is supposed to be able to clean more than 21 million gallons of oily water a day. Tests done last weekend were inconclusive because of choppy seas. Allen said that he doubts the giant skimmer will be effective in scooping up numerous smaller slicks.
  • Florida Gov. Charlie Crist has called a special session of the state Legislature to get a constitutional ban on offshore oil drilling in Florida waters on the November ballot. Crist has said he has the support of Panhandle legislators, where some beaches have been oiled by the massive Gulf of Mexico spill. But legislative leaders in areas so far unaffected have been uncooperative. The amendment would require 60 percent approval from voters in November.

The Associated Press contributed to this report.

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