Carrizo Oil & Gas Inc is a Houston-based independent energy company. The Company together with its subsidiaries is engaged in the exploration, development and production of oil and gas in the United States and United Kingdom. It explores in the Eagle Ford Shale in South Texas, the Niobrara Formation in Colorado, the Barnett Shale in North Texas, the Marcellus Shale in Pennsylvania, New York and West Virginia, the Utica Shale in Ohio and Pennsylvania, and the U.K. North Sea in its Huntington Field development project. It generates exploration prospects through geological and geophysical analysis of 3-D seismic and other data. It continues its primary exploration effort and capital program on resource plays, where individual wells tend to have lower risk and moderate potential, such as its development drilling in the Eagle Ford and Marcellus Shales. The Company's customers are Enterprise Products Operating, LLC, Shell Trading (U.S) Company, Enterprise Trading, Inc., DTE Energy Trading, Inc. The Company's competitors include integrated oil and gas companies and numerous independent oil and gas companies, individuals and drilling and income programs. Its operations are subject to various federal, state, local and foreign laws and government regulations.