Capitalized Exploratory Well Costs

We capitalize exploratory well costs until a determination is made that the well has found proved reserves or is deemed noncommercial. If a well is deemed to be noncommercial, the well costs are charged to exploration expense as dry hole cost.

Changes in capitalized exploratory well costs are as follows and exclude amounts that were capitalized and subsequently expensed in the same period:



	Nine Months Ended September 30, 2013
(millions)
Capitalized Exploratory Well Costs, Beginning of Period	$	900
Additions to Capitalized Exploratory Well Costs Pending Determination of Proved Reserves	586
Reclassified to Proved Oil and Gas Properties Based on Determination of Proved Reserves	(34		)
Capitalized Exploratory Well Costs Charged to Expense	(3		)
Capitalized Exploratory Well Costs, End of Period	$	1,449

The following table provides an aging of capitalized exploratory well costs based on the date that drilling commenced, and the number of projects that have been capitalized for a period greater than one year:



	September 30, 2013		December 31, 2012
(millions)
Exploratory Well Costs Capitalized for a Period of One Year or Less	$	732	$	355
Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling	717		545
Balance at End of Period	$	1,449	$	900
Number of Projects with Exploratory Well Costs That Have Been Capitalized for a Period Greater Than One Year Since Commencement of Drilling	13		14

The following table provides a further aging of those exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling as of September 30, 2013:



			Suspended Since
	Total		2012		2011		2010 & Prior
(millions)
Country/Project:
Offshore Equatorial Guinea
Carla	$	12	$	—	$	12	$	—
Diega	106		1		46		59
Felicita	36		1		2		33
Yolanda	19		1		1		17
Offshore Cameroon
YoYo	48		3		5		40
Offshore Israel
Leviathan	125		17		67		41
Leviathan-1 Deep	77		49		28		—
Tanin 1	34		2		32		—
Dolphin 1	22		—		22		—
Dalit	23		1		—		22
Offshore Cyprus
Cyprus A-1	70		13		57		—
Deepwater Gulf of Mexico
Gunflint	116		64		—		52
Other
Projects of $10 million or less each	29		20		—		9
Total	$	717	$	172	$	272	$	273

Carla/Diega Carla is a 2011 crude oil discovery on Block O; Diega (formerly Carmen) is a 2008 condensate and crude oil discovery on Blocks O and I. We continue reviewing results of the Carla O-7 and Carla I-7 wells. During the third quarter of 2013, we successfully drilled the Diega I-8 appraisal well and are commencing flow testing. We are currently evaluating regional development scenarios.

Felicita/Yolanda Felicita is a 2008 condensate and natural gas discovery on Block O. Yolanda is a 2008 condensate and natural gas discovery on Block I. We are currently evaluating regional natural gas development options for these discoveries and working with the government of Equatorial Guinea to assess longer-term natural gas commercialization across the industry.

YoYo YoYo is a 2007 natural gas and condensate discovery in the YoYo Block. During 2011 we acquired and processed additional 3D seismic information and are continuing evaluations for future drilling potential. We are also working with the government of Cameroon to assess future natural gas commercialization options.

Leviathan Leviathan is a 2010 natural gas discovery. During 2012, we continued to evaluate the discovery with the successful drilling of both the Leviathan-3 and Leviathan-4 appraisal wells. We have project and commercial teams in place and are in the process of screening multiple development concepts. In 2012, we announced that the partners in the Leviathan Project had agreed in principle on a proposal to sell a 30% working interest in the Leviathan licenses to Woodside Energy Ltd. (Woodside).

Leviathan-1 Deep In January 2012, we returned to the Leviathan-1 well and began drilling toward two deeper intervals in order to evaluate them for the existence of crude oil (Leviathan-1 Deep). We are continuing our evaluation of Leviathan-1 Deep and integrating the data from the Leviathan-1 Deep well into our model to update our analysis and design a drilling plan specifically to test the deep oil concept.

Tanin 1 Tanin 1 is a 2011 natural gas discovery located in the Alon A block, offshore Israel. We and our partners are currently reviewing development alternatives.

Dolphin 1 Dolphin 1 is a 2011 natural gas discovery located in the Hanna license, southwest of the Tamar gas field. We and our partners are currently reviewing development alternatives.

Dalit Dalit is a 2009 natural gas discovery. We and our partners are working on a development plan which would include tie-in to the Tamar platform and have submitted a development plan to the Israeli government.

Cyprus The Cyprus A-1 is a successful natural gas exploratory well drilled on Block 12 in the fourth quarter of 2011. During the third quarter of 2013, we drilled a successful appraisal well. The A-2 location has successfully defined the northern area of the discovery, and we anticipate additional appraisal activities to further refine the ultimate recoverable resources and optimize field development planning. In addition to the appraisal well, we completed the acquisition phase of a 3D seismic study and are currently processing the results. We are working with the Cyprus government regarding domestic development plans along with possible LNG export options.

Gunflint Gunflint (Mississippi Canyon Block 948/992) is a 2008 crude oil discovery. In July 2012, we drilled a successful Gunflint appraisal well. We completed drilling our second successful Gunflint appraisal well in June 2013. In October 2013, we sanctioned the development plan for Gunflint utilizing a subsea tieback to an existing host facility. First production from Gunflint is targeted for 2016.