Oil giant BP says it is investigating a \"sheen\" of oil observed in the Gulf of Mexico but that there was no indication it was the result of a new oil spill. A sheen, a shiny coating floating on the surface of the sea, can be the result of leaked or spilled oil. BP said the sheen, reported last week by the U.S. Coast Guard, was observed in an area away from any of its existing operations, The Wall Street Journal reported Thursday. BP confirmed it has two abandoned exploration well sites in the area, and sent an unmanned submersible to explore the two sites. Cloudy water was observed around one site, BP said, but a naturally occurring shallow-water flow could be the source of the cloudy water. \"We will confirm the contents of the material and report back to the Bureau of Ocean Energy Management, Regulation and Enforcement,\" BP said. \"At this time we don\'t believe it to be hydrocarbon, but silt kicked up from the shallow water flow. We don\'t believe the cloudy water is the source or contributed to the sheen.\"