 Although it is not an official nickname, it is widely known by fans of local hip-hop artist DJ Screw and his style of music, known as "chopped and screwed".Houston is considered by many to be "The Energy Capital of the World," because the city is home to more than 5,000 energy-related firms.The city is a leading domestic and international center for virtually every segment of the oil and gas industry—exploration, production, transmission, marketing, service, supply, offshore drilling, and technology.