Property, Plant and Equipment (Tables)

6 Months Ended

Jun. 30, 2022

Property, Plant and Equipment [Abstract]

Net Changes in Capitalized Exploratory Well Costs

The following table reflects the net changes in capitalized exploratory well costs during the six-month periods ended June 30, 2022 and 2021.

(Thousands of dollars)	2022		2021
Beginning balance at January 1	$	179,481	181,616
Additions pending the determination of proved reserves	9,412		15,921
Capitalized exploratory well costs charged to expense	(10,472)		—
Balance at June 30	$	178,421	197,537

Aging of Capitalized Exploratory Well Costs

The following table provides an aging of capitalized exploratory well costs based on the date the drilling was completed for each individual well and the number of projects for which exploratory well costs have been capitalized.  The projects are aged based on the last well drilled in the project.

	June 30,
	2022				2021
(Thousands of dollars)	Amount		No. of Wells	No. of Projects	Amount	No. of Wells	No. of Projects
Aging of capitalized well costs:
Zero to one year	$	4,268	2	2	13,881	3	3
One to two years	2,813		2	2	23,811	3	3
Two to three years	26,848		3	2	30,562	2	2
Three years or more	144,492		8	2	129,283	6	—
	$	178,421	15	8	197,537	14	8