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. On a quarterly basis, we review the status of suspended exploratory well costs and assess the development of these projects. 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:



(millions)	Nine Months Ended September 30, 2015
Capitalized Exploratory Well Costs, Beginning of Period	$	1,337
Additions to Capitalized Exploratory Well Costs Pending Determination of Proved Reserves	123
Reclassified to Proved Oil and Gas Properties Based on Determination of Proved Reserves	(24		)
Capitalized Exploratory Well Costs Charged to Expense ⁽¹⁾	(23		)
Capitalized Exploratory Well Costs, End of Period	$	1,413

⁽¹⁾ Relates primarily to onshore US exploration activity.

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:



(millions)	September 30, 2015		December 31, 2014
Exploratory Well Costs Capitalized for a Period of One Year or Less	$	154	$	247
Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling	1,259		1,090
Balance at End of Period	$	1,413	$	1,337
Number of Projects with Exploratory Well Costs That Have Been Capitalized for a Period Greater Than One Year Since Commencement of Drilling	14		13

The following table includes exploratory well costs that have been capitalized for a period greater than one year since the commencement of drilling as of September 30, 2015:




(millions)	Total by Project		Progress
Country/Project:
Onshore US
Northeast Nevada	$	40	Analyzing results from our first four exploratory vertical wells, and evaluating potential for production tests.
Deepwater Gulf of Mexico
Katmai	80		Anticipate drilling an appraisal well in 2016 to test the resource potential of this 2014 crude oil discovery.
Troubadour	48		Evaluating development scenarios for this 2013 natural gas discovery including subsea tieback to existing infrastructure.
Offshore Equatorial Guinea (Blocks O and I)
Diega/Carmen	236		Evaluating regional development scenarios for this 2008 crude oil discovery. We drilled subsequent appraisal wells. During 2014, we conducted additional seismic activity over Blocks O and I and are engaged in processing the newly-acquired seismic data to determine an appropriate development plan.
Carla	170		Evaluating regional development scenarios for this 2011 crude oil discovery. We drilled subsequent appraisal wells. During 2014, we conducted additional seismic activity over Blocks O and I and are engaged in processing the newly-acquired seismic data.
Felicita/Yolanda	59		Evaluating regional development plans for these 2008/2007 condensate and natural gas discoveries. Natural gas development teams are working with the governments of Equatorial Guinea and Cameroon to evaluate natural gas monetization options and finalize data exchange agreements between the two countries.
Offshore Cameroon
YoYo	49		Working with the government to assess commercialization of this 2007 condensate and natural gas discovery. A natural gas development team is working with the governments of Equatorial Guinea and Cameroon to evaluate natural gas monetization options and finalize a data exchange agreement between the two countries.
Offshore Israel ⁽¹⁾
Leviathan	190		During 2014, we received the Leviathan Development and Production Leases, submitted a development plan to the Israeli government, completed substantial engineering and pre-procurement activities and are currently negotiating natural gas marketing contracts in anticipation of the pending enactment of the Framework.
Leviathan-1 Deep	81		Well did not reach the target interval; developing future drilling plans to test this deep oil concept, which is held by the Leviathan Development and Production Leases. We are working on potential well design and placement.



Dalit	29		Submitted a development plan to the Israeli government to develop this 2009 natural gas discovery as a tie-in to existing infrastructure.
Dolphin 1	26		Reviewing regional development scenarios for this 2011 natural gas discovery, including a potential tieback to Leviathan. We have applied to the Israeli government for a commerciality ruling.
Offshore Cyprus
Cyprus	210		Submitted a Declaration of Commerciality and a Preliminary Development Plan for Block 12 with the government of Cyprus. We have received approval of the extension request for our exploration obligation well from the government of Cyprus.
Other
Individual Projects Less than $20 million	41		Continuing to drill and evaluate wells.
Total	$	1,259

⁽¹⁾ We are currently working to resolve antitrust and other regulatory matters with the Israeli government to enable Leviathan and other developments to move forward. See Note 2. Basis of Presentation – Update on Core Area – Israel.