Houston Exploration has acquired 100 percent working interests in six offshore leases from ATP Oil & Gas Corporation. Varying from 25 to 100 percent, the Gulf of Mexico locales include blocks on Matagorda Island, Vermilion, South Timbalier and Galveston. With total bidding amounting to $1 million, the company is also involved in the formation of another joint venture with KeySpan Energy. The project will entail the exploration and development of the company's current unspoiled offshore acreage.