
	2022		2021

	(In millions)
Exploration and Production
Unproved properties	$	149	$	184
Proved properties	2,660		2,877
Wells, equipment and related facilities	25,182		23,745
	27,991		26,806
Midstream	4,571		4,342
Corporate and Other	30		30
Total — at cost	32,592		31,178
Less: Reserves for depreciation, depletion, amortization and lease impairment	17,494		16,996
Property, Plant and Equipment — Net	$	15,098	$	14,182

Capitalized Exploratory Well Costs: The following table discloses the amount of capitalized exploratory well costs pending determination of proved reserves at December 31 and the changes therein during the respective years:


	2022		2021		2020

	(In millions)
Balance at January 1	$	681	$	459	$	584
Additions to capitalized exploratory well costs pending the determination of proved reserves	298		222		111
Reclassifications to wells, facilities and equipment based on the determination of proved reserves	(93)		—		(111)
Capitalized exploratory well costs charged to expense	—		—		(125)

Balance at December 31	$	886	$	681	$	459
Number of Wells at December 31	43		35		22

During the three years ended December 31, 2022, additions to capitalized exploratory well costs primarily related to drilling at the Stabroek Block (Hess 30%), offshore Guyana. At December 31, 2022, 36 exploration and appraisal wells on the Stabroek Block, with a total cost of $732 million, were capitalized pending determination of proved reserves. Other additions to capitalized exploratory wells costs in 2022 included the Huron-1 well (Hess 40%) in the Gulf of Mexico, and the Zanderij-1 well on Block 42 (Hess 33%), offshore Suriname.

Reclassifications to wells, facilities and equipment based on the determination of proved reserves in 2022 resulted from the sanction of the Yellowtail Field development, the fourth sanctioned project on the Stabroek Block. In 2020, reclassifications to wells, facilities and equipment resulted from sanctions of the Payara Field development, the third sanctioned project on the Stabroek Block, and an additional phase of development at the North Malay Basin, offshore Peninsular Malaysia.

Capitalized exploratory well costs charged to expense in 2020 of $125 million primarily related to the northern portion of the Shenzi Field (Hess 28%) in the Gulf of Mexico. The preceding table excludes well costs incurred and expensed during 2022 of $56 million (2021: $11 million; 2020: $67 million).

Exploratory well costs capitalized for greater than one year following completion of drilling were $585 million at December 31, 2022, separated by year of completion as follows (in millions):

Guyana: Approximately 91% of the capitalized well costs in excess of one year relate to successful exploration and appraisal wells where hydrocarbons were encountered on the Stabroek Block (Hess 30%). In the fourth quarter of 2022, the operator submitted a development plan for the Uaru Field, the fifth development project on the Stabroek Block, to the Government of Guyana for approval. The operator also plans further appraisal drilling on the block and is conducting pre-development planning for additional phases of development.

JDA: Approximately 7% of the capitalized well costs in excess of one year relates to the JDA (Hess 50%) in the Gulf of Thailand, where hydrocarbons were encountered in three successful exploration wells drilled in the western part of Block A-18. The operator has submitted a development plan concept to the regulator to facilitate ongoing commercial negotiations for an extension of the existing gas sales contract to include development of the western part of the block.

Malaysia: Approximately 2% of the capitalized well costs in excess of one year relates to North Malay Basin (Hess 50%), offshore Peninsular Malaysia, where hydrocarbons were encountered in one successful exploration well. Pre-development studies are ongoing.