Petroleum is an unincorporated community in Nottingham Township, Wells County, in the U.S. state of Indiana. History Petroleum was platted in 1894, and is so named because it was laid out in an oil field. The post office at Petroleum has been in operation since 1894. Geography Petroleum is located at . References Unincorporated communities in Wells County, Indiana Unincorporated communities in Indiana Fort Wayne, IN Metropolitan Statistical Area