This article was originally on a blog post platform and may be missing photos, graphics or links. See About archive blog posts. BP Senior Vice President Kent Wells on Wednesday morning detailed some of concerns voiced by experts that prompted the federal government to demand that the oil company delay a crucial well test that could determine whether a new cap can be used to shut off all of the oil leaking into the Gulf of Mexico. The test, which had been set to begin Tuesday, seeks to measure the interior pressure of the well in an attempt to gauge whether there are any leaks along the pipe running 13,000 feet into the earth. If there are no leaks, BP could close off the well with a new tight-fitting cap that was successfully affixed Monday. But if leaks are suspected, BP will let the oil continue to flow out of the well, at first collecting some of it -- and by late July, all of it -- using a system of riser pipes and containment ships. The testing delay was announced with little explanation late Tuesday night by Coast Guard Adm. Thad Allen, the federal oil-spill response commander. Wells, in a morning press conference, said the '24-hour timeout' was ordered due in part to questions about whether the test would be able to determine a key issue: Whether the oil, if leaking, was coming from a shallow or a deep part of the well. 'What we want to do is avoid that oil is being put out in the shallow environment,' Wells said. 'There's always the potential, remote as it might be, that it could breach up to the surface.' The threat of a crater forming on the sea bed around the well head -- with oil flowing from multiple points -- would be a potentially catastrophic scenario that would make containing the oil extremely difficult. But according to Darryl Bourgoyne, director of the petroleum research lab at Louisiana State University, leaks deep in the well may not be much of a problem--so long as it was so deep that 'the fluid would stay in the subsurface, and cratering wouldn't be a risk.' The permanent fix for the well, which has been leaking up to 60,000 barrels of oil per day since an April 20 rig blowout, will come when it is intersected far beneath the earth's surface by one of two relief wells underway. The closest of those wells, currently at 17,840 feet in length, is scheduled to plug the faulty well with mud and concrete sometime in mid-August. Wells said that work on that well was delayed until the integrity test could be completed -- which puts a permanent solution another one to two days behind schedule. -- Richard Fausset in Atlanta