Cheniere Energy Inc. is closing in on its goal of becoming the first company to export natural gas from the lower 48 states, following six months of deals that may have finally resolved investors' persistent doubts. Since October, the Houston-based company has closed four deals to supply liquefied natural gas, or LNG, to utilities abroad. Then, last month, it signed a $2 billion deal with private equity titan the Blackstone Group, securing critical funding toward a $5 billion export terminal.