4. Capitalized Exploratory Well Costs

The following table discloses the net changes in capitalized exploratory well costs pending determination of proved reserves during the three months ended March 31, 2016 (in millions):

Balance at January 1, 2016	$	1,415
Additions to capitalized exploratory well costs pending the determination of proved reserves		60
Capitalized exploratory well costs charged to expense		(25	)
Balance at March 31, 2016	$	1,450

Capitalized exploratory wells costs charged to expense in the preceding table primarily relate to the non-operated Melmar exploration well in the Gulf of Mexico, where noncommercial quantities of hydrocarbons were encountered. In addition, we expensed $60 million of exploratory well costs incurred during 2016 related to the Melmar exploration well that are not reflected in the preceding table.

Capitalized exploratory well costs capitalized for greater than one year following completion of drilling were $1,055 million at March 31, 2016 and primarily related to:

Australia: Approximately 75% of the capitalized well costs in excess of one year relates to our Equus project on license WA-390-P, offshore Western Australia, where development planning and commercial activities for our natural gas discoveries are ongoing. In December 2014, we executed a non-binding letter of intent with the North West Shelf (NWS), a third-party joint venture with existing natural gas processing and liquefaction facilities. In the first quarter of 2016, we continued a joint front-end engineering study with NWS and also continued discussions with potential long-term purchasers of liquefied natural gas. Successful execution of binding agreements with NWS is necessary before we can execute a gas sales agreement and sanction development of the project. In addition, in March 2016, we were awarded a retention lease through 2021 covering certain areas within the WA-390-P License which include our Equus discoveries. At our adjacent WA-474-P license which could become part of the Equus project, we commenced drilling of an exploration commitment well in 2016.

Ghana: Approximately 25% of the capitalized well costs in excess of one year relates to offshore Ghana. Since 2014, we have completed three appraisal wells and continue to progress subsurface evaluation, and development planning. The government of Côte d’Ivoire has challenged the maritime border between it and the country of Ghana, which includes a portion of our Deepwater Tano/Cape Three Points license. We are unable to proceed with development of this license until there is a resolution of this matter, which may also impact our ability to develop the license. The International Tribunal for Law of the Sea is expected to render a final ruling on the maritime border dispute in 2017. Under terms of our license and subject to resolution of the border dispute, we have declared commerciality for three discoveries, including the Pecan Field in March 2016, which would be the primary development hub for the block. The deadline to submit a plan of development for the Pecan Field is in September 2016. We have requested an extension for this deadline and will continue to work with the government on how best to progress work on the block given the maritime border dispute.