Annual report pursuant to Section 13 and 15(d)

Supplemental Information on Oil and Gas Exploration and Production Activities (Unaudited) - Oil and Gas Reserves (Details)

v3.6.0.2
Supplemental Information on Oil and Gas Exploration and Production Activities (Unaudited) - Oil and Gas Reserves (Details)
bbl in Thousands, Mcf in Thousands
 12 Months Ended
Dec. 31, 2016
Mcf
bbl
Dec. 31, 2015
Mcf
bbl
Dec. 31, 2014
Mcf
bbl
Oil derivatives      
Proved Developed and Undeveloped Reserves [Roll Forward]      
Beginning of the period 6,458 9,497 8,346
Purchases in oil and gas reserves in place 0 0 173
Extensions and discoveries 1,217 2,413 4,975
Revisions of prior reserve estimates (3) (2,553) (1,313)
Current production (2,126) (2,899) (2,684)
End of period 5,546 6,458 9,497
Proved developed reserves 4,882 6,120 5,719
Proved undeveloped reserves 664 338 3,778
Natural gas liquids derivatives      
Proved Developed and Undeveloped Reserves [Roll Forward]      
Beginning of the period | Mcf 1,560,145 719,006 146,446
Purchases in oil and gas reserves in place | Mcf 0 371,663 8,863
Extensions and discoveries | Mcf 1,082,220 997,057 629,151
Revisions of prior reserve estimates | Mcf (247,703) (371,430) (6,136)
Current production | Mcf (227,594) (156,151) (59,318)
End of period | Mcf 2,167,068 1,560,145 719,006
Proved developed reserves | Mcf 744,797 652,961 345,166
Proved undeveloped reserves | Mcf 1,422,271 907,184 373,840
Natural gas liquids      
Proved Developed and Undeveloped Reserves [Roll Forward]      
Beginning of the period 17,736 26,268 5,675
Purchases in oil and gas reserves in place 0 0 353
Extensions and discoveries 7,677 5,486 22,594
Revisions of prior reserve estimates (1,439) (9,594) (304)
Current production (3,847) (4,424) (2,050)
End of period 20,127 17,736 26,268
Proved developed reserves 14,299 12,910 12,379
Proved undeveloped reserves 5,828 4,826 13,889
Investment in Grizzly Oil Sands ULC | Oil derivatives      
Proved Developed and Undeveloped Reserves [Roll Forward]      
Beginning of the period 0 14,558 13,637
Purchases in oil and gas reserves in place 0 0 0
Extensions and discoveries 0 0 0
Revisions of prior reserve estimates 0 (14,530) 990
Current production 0 (28) (69)
End of period 0 0 14,558
Proved developed reserves 0 0 1,632
Proved undeveloped reserves 0 0 12,926
Investment in Grizzly Oil Sands ULC | Natural gas liquids derivatives      
Proved Developed and Undeveloped Reserves [Roll Forward]      
Beginning of the period | Mcf 0 0 0
Purchases in oil and gas reserves in place | Mcf 0 0 0
Extensions and discoveries | Mcf 0 0 0
Revisions of prior reserve estimates | Mcf 0 0 0
Current production | Mcf 0 0 0
End of period | Mcf 0 0 0
Proved developed reserves | Mcf 0 0 0
Proved undeveloped reserves | Mcf 0 0 0
Investment in Grizzly Oil Sands ULC | Natural gas liquids      
Proved Developed and Undeveloped Reserves [Roll Forward]      
Beginning of the period 0 0 0
Purchases in oil and gas reserves in place 0 0 0
Extensions and discoveries 0 0 0
Revisions of prior reserve estimates 0 0 0
Current production 0 0 0
End of period 0 0 0
Proved developed reserves 0 0 0
Proved undeveloped reserves 0 0 0