Forecasts say that Tropical Storm Gustav could regain hurricane strength and affect major offshore oil and natural gas production areas in the Gulf of Mexico also portend a significant threat to onshore energy sites, the Houston Chronicle reported. As they prepare for a possible hit from Gustav, operators of such facilities hope improvements they made in rebuilding after the 2005 storms will improve their odds of weathering the next one. Oil futures rose $1.87 to $118.14 a barrel Wednesday on the New York Mercantile Exchange. Natural gas increased 20.7 cents to $8.485 per million British thermal units. In preparation for the storm, offshore drillers began securing wells, pulling up equipment and bringing workers ashore on Wednesday.