Drilling and Other Property and Equipment

12 Months Ended

Dec. 31, 2012

Drilling and Other Property and Equipment

8. Drilling and Other Property and Equipment

Cost and accumulated depreciation of drilling and other property and equipment are summarized as follows:

	December 31,
	2012			2011
	(In thousands)
Drilling rigs and equipment	$	7,107,279		$	7,431,713
Construction work-in-progress		990,964			504,805
Land and buildings		64,296			60,926
Office equipment and other		60,239			49,035
Cost		8,222,778			8,046,479
Less accumulated depreciation		(3,357,806	)		(3,379,010)
Drilling and other property and equipment, net	$	4,864,972		$	4,667,469

During 2012, we entered into contracts for the construction of a fourth drillship, the Ocean BlackLion, and the Ocean Apex, a deepwater floater rig. Construction work-in-progress, including capitalized interest, at December 31, 2012 included $741.1 million, $167.4 million and $82.5 million related to the construction of our four drillships, the Ocean Onyx, and the Ocean Apex, respectively.

Construction work-in-progress, including capitalized interest, at December 31, 2011 included $14.6 million and $490.2 million related to the construction of the Ocean Onyx and the first three of our four drillships, respectively. See Note 11.

During 2012, we sold six of our jack-up rigs for an aggregate pre-tax gain of approximately $76.5 million and retired the aggregate net book value of $55.4 million. In addition, in December 2012, we transferred four of our drilling rigs with an aggregate net book value of $73.2 million to “Assets held for sale” in our Consolidated Balance Sheets. See Note 1.