Property, Plant and Equipment (Tables)

3 Months Ended

Mar. 31, 2020

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 three-month periods ended March 31, 2020 and 2019.

(Thousands of dollars)	2020			2019
Beginning balance at January 1	$	217,326		207,855
Additions pending the determination of proved reserves	816			32,416
Capitalized exploratory well costs charged to expense	(39,709		)	(13,145	)
Balance at March 31	$	178,433		227,126

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.

	March 31,
	2020				2019
(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	$	24,637	3	3	$	78,016	3	2
One to two years	31,541		2	2	—		—	—
Two to three years	—		—	—	27,270		1	1
Three years or more	122,255		6	—	121,840		5	1
	$	178,433	11	5	$	227,126	9	4

Schedule of Recognized Impairments

The following table reflects the recognized impairments for the three months ended March 31, 2020.

	Three Months Ended
(Thousands of dollars)	March 31, 2020
U.S.	$	927,821
Other Foreign	39,709
	$	967,530