PORT OF SPAIN (Reuters) -An oil spill that has stained Tobago's coastline in the Caribbean is entering into Grenada's waters and could impact neighboring Venezuela, Tobago's Chief Secretary Farley Augustine told Reuters on Thursday. Eight days after Trinidad and Tobago's Coast Guard first spotted the oil from a capsized vessel whose owner and origin have not been confirmed, portions of the stain have moved about 144 km (89 miles) into the Caribbean Sea at a rate of 14 km per hour, Augustine said.