v3.25.4
Suspended Wells and Exploration Expenses (Tables)
 12 Months Ended
Dec. 31, 2025
Extractive Industries [Abstract]  
Net Changes in Suspended Exploratory Well Costs
The following table reflects the net changes in suspended exploratory well costs during 2025, 2024 and 2023:

Millions of Dollars
202520242023
Beginning balance$196 184 527 
Additions pending the determination of proved reserves113 32 — 
Reclassifications to proved properties— (2)(285)
Sales of suspended wells(30)— — 
Charged to dry hole expense(36)(18)(58)
Ending balance$243 196 184 
Aging of Suspended Well Cost
The following table provides an aging of suspended well balances at December 31:
Millions of Dollars
202520242023
Exploratory well costs capitalized for a period of one year or less$110 33 — 
Exploratory well costs capitalized for a period greater than one year133 163 184 
Ending balance$243 196 184 
Number of projects with exploratory well costs capitalized for a period greater than one year13 13 14 
Aging of Exploratory Well Cost, Capitalized for More than One Year
The following table provides a further aging of those exploratory well costs that have been capitalized for more than one year since the completion of drilling as of December 31, 2025:
Millions of Dollars
Suspended Since
Total2021-20242018-20202017 and Prior
PL891—Norway(1)
31 — 31 — 
West Willow—Alaska(2)
30 — 30 — 
Narwhal Trend—Alaska(1)
25 — 25 — 
Montney—Canada(2)
15 7 8 — 
Other of $10 million or less each(1)(2)
32 4 — 28 
Total$133 11 94 28 
(1)Appraisal drilling complete; costs being incurred to assess development.
(2)Additional appraisal wells planned.