Impairment Charges and Reversals (Tables)

6 Months Ended

Jun. 30, 2019

Disclosure Of Impairment Loss Recognised Or Reversed [Abstract]

Summary of Forward Prices Used to Determine Future Cash Flows

The forward prices as at June 30, 2019, used to determine future cash flows from crude oil, NGLs and natural gas reserves were:

	Remainder       of 2019		2020		2021		2022		2023		Average Annual Increase Thereafter
WTI (US$/barrel) (1)		59.92		63.57		66.67		69.30		71.98		2.0	%
WCS (C$/barrel) (2)		59.41		59.93		62.82		66.19		69.30		2.1	%
Edmonton C5+ (C$/barrel)		74.00		78.06		80.90		84.24		87.79		2.0	%
AECO (C$/Mcf) (3) (4)		1.39		1.91		2.37		2.66		2.79		2.1	%

(1) West Texas Intermediate (“WTI”).

(2) Western Canadian Select (“WCS”).

(3) Alberta Energy Company (“AECO”) natural gas.

(4) Assumes gas heating value of one million British thermal units (“MMBtu”) per thousand cubic feet.

The forward prices as at June 30, 2018, used to determine future cash flows from crude oil, NGLs and natural gas reserves were:

	Remainder       of 2018		2019		2020		2021		2022		Average Annual Increase Thereafter
WTI (US$/barrel)		68.42		65.77		67.87		69.67		72.35		2.1	%
WCS (C$/barrel)		59.66		61.15		64.41		66.51		68.22		2.1	%
Edmonton C5+ (C$/barrel)		88.18		81.66		82.01		83.30		85.15		2.1	%
AECO (C$/Mcf)		1.90		2.37		2.83		3.13		3.36		2.0	%