NEW ORLEANS (AP) â¿¿ Oil and natural gas driller McMoRan Exploration Co. posted a fourth-quarter loss Friday on impairment and write-down costs along with a sharp drop in revenue. Revenue fell 31 percent compared to a year ago, as sales and prices of oil and natural gas dropped compared to a year ago. Natural gas prices were down sharply. The company's results included a $93.5 million write-off charge and $34.5 million in impairment costs related to lower valuations for oil and natural gas fields. McMoRan lost $1.2 million, or a penny per share. A year ago it made a profit of $28.4 million, or 16 cents per share. Revenue fell to $84.2 million from $121.9 million. Analysts expected a loss of 11 cents per share on $88.3 million in revenue, according to FactSet. McMoRan Exploration agreed to sell itself to Freeport-McMoRan Copper & Gold Inc. in December for about $2.1 billion. Freeport-McMoRan also agreed to buy Plains Exploration & Production Co. for $6.9 billion. The purchases are expected to create a natural resources conglomerate with assets ranging from oil rigs in the Gulf of Mexico to a huge copper mine in Indonesia. In 2012 McMoRan Exploration lost $145.6 million, or 90 cents per share, after losing $58.8 million, or 37 cents per share, in 2011. Revenue fell 32 percent, to $376.9 million from $555.4 million. The company's shares lost 3 cents to $15.96 in afternoon trading.