PORT FOURCHON, La., 14 May (bdnews24.com/Reuters) - Energy giant BP on Friday stuck by its lower estimate of oil gushing into the Gulf of Mexico and geared up for its latest effort to contain its offshore well leak as some scientists said the true amount of crude escaping could be much higher. President Barack Obama will hold a White House meeting midday on Friday with members of his Cabinet and other administration officials to discuss efforts to stop the spill and how to help affected coastal communities. The spill is threatening an ecological and economic calamity along the U.S. Gulf Coast. Scientific projections of how much oil has been spewing unchecked for three weeks from the ruptured undersea well has ranged wildly, from BP's 5,000 (210,000 gallons/795,000 litres) to 100,000 barrels (4.2 million gallons/15.9 million litres) per day. For a related graphic, click link.reuters.com/teb93k BP Chief Operating Officer Doug Suttles appeared on morning U.S. television shows defending the company's efforts to stem the flow and its estimates that about 5,000 barrels of oil were escaping per day. "I think that's a good range," Suttles said on CNN. "I don't know the precise number, but I think it's somewhere around that number." On CBS, he added: "We're mounting the biggest response ever done and it's not related to whether it's 5,000 barrels per day or a different number." BP, Halliburton and Transocean Ltd are all under intense scrutiny over the April 20 Deepwater Horizon rig explosion that killed 11 workers and triggered what could eclipse the 1989 Exxon Valdez spill and become the worst environmental disaster in U.S. history. Fisheries and tourism, two of the Gulf Coast's economic mainstays, along with birds, sea turtles and other wildlife, are threatened by the spreading slick. The accident also could cripple attempts in Washington to overhaul U.S. energy policy. U.S. Coast Guard Commandant Thad Allen said at a news briefing on Friday, "It has the potential to be catastrophic. ... I am going to act as if it is." He added, "We're attacking this as if it were a much larger spill anyway." BP, whose shares have tumbled and wiped out $30 billion of market value since the rig fire on April 20, has said the oil spill had cost it $450 million so far. BP shares were down about 2 percent in midday trade in London. "EDGES OF TECHNOLOGY" BP was moving forward on Friday with its deep sea efforts to stop the unchecked flow of oil. Suttles told ABC the company hoped to be able to insert a tube into the ruptured riser pipe by late in the day to contain at least part of the leak and siphon oil into a tanker. "The techniques we're going to try over the next 24 hours, we need to remember, are about trying to contain this leak, they won't stop it," Suttles said. Other efforts over the next few days include deploying a small containment dome, known as a "top hat," to trap the oil at the site of the leak. "I know some people feel like ... we're just kind of reaching for everything here," Suttles said on ABC. "We have the best people in the world working on this. ... We're pushing the very edges of technology." If such short-term efforts fail, it could take 90 days for the company to drill a relief well to cap the ruptured one. The White House has said Obama is "deeply frustrated" that the massive mile-deep (1.6 km deep) leak has not been plugged. Obama and officials in his administration have stressed that BP must pay for the spill's cleanup and other economic impact on the region. The president is expected to repeat that -- while putting pressure on the company to achieve results -- in a public statement after his meeting on Friday. OIL GLOBS ASHORE As the undersea effort goes on, oil has increasingly begun to show up on land since first being found in the Chandeleur Islands east of Louisiana. At Port Fourchon, the tip of southeastern Louisiana's Lafourche Parish and the main supply harbour for the Gulf's deepwater oil and gas industry, gooey, rust-colored globules were found washed up on a beach this week. Similar globs turned up on Thursday several miles (km) away on a beach called Elmer's Island in neighbouring Jefferson Parish. Elsewhere off Louisiana and west of the Mississippi Delta, oil debris has been reported on East Timbalier Island near Port Fourchon, Whiskey Island further to the west near Terrebonne Bay, and Raccoon Island still further to the west. Oil debris also washed up on Port Eads, Louisiana, near the tip of the Delta's South Pass channel, as well as on Alabama's Dauphin Island at the bottom of Mobile Bay. The U.S. National Oceanic and Atmospheric Administration said southeast winds are expected to continue through the weekend. The Mississippi Delta, Breton Sound, the Chandeleur Islands and areas directly north have a potential for "shoreline contacts" of oil by this weekend, it said. Federal authorities said more than 520 vessels are responding to assist in containment and cleanup efforts in addition to dozens of aircraft and undersea remotely operated vehicles working on the ocean floor. While the spill threatened coastlines, local businesses and animal habitats, it also created complications for Obama's energy policy. Two lawmakers introduced legislation this week in the U.S. Senate to fight climate change and expand production of renewable fuels, but the spill has dampened the public appetite for an expansion of offshore drilling -- a component originally designed to encourage Republican support.