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)

v3.10.0.1
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, 2018
bbl
Mcf
Dec. 31, 2017
bbl
Mcf
Dec. 31, 2016
bbl
Mcf
Oil derivatives      
Proved Developed and Undeveloped Reserves [Roll Forward]      
Beginning of the period 19,157 5,546 6,458
Purchases in oil and natural gas reserves in place 0 15,132 0
Extensions and discoveries 5,205 951 1,217
Sales of oil and natural gas reserves in place (134) 0 0
Revisions of prior reserve estimates (377) 107 (3)
Current production (2,801) (2,579) (2,126)
End of period 21,050 19,157 5,546
Proved developed reserves 9,570 10,245 4,882
Proved undeveloped reserves 11,480 8,912 664
Natural gas liquids derivatives      
Proved Developed and Undeveloped Reserves [Roll Forward]      
Beginning of the period | Mcf 4,825,310 2,167,068 1,560,145
Purchases in oil and natural gas reserves in place | Mcf 0 1,098,644 0
Extensions and discoveries | Mcf 622,271 1,594,734 1,082,220
Sales of oil and natural gas reserves in place | Mcf (43,444) 0 0
Revisions of prior reserve estimates | Mcf (826,506) 314,925 (247,703)
Current production | Mcf (443,742) (350,061) (227,594)
End of period | Mcf 4,133,889 4,825,310 2,167,068
Proved developed reserves | Mcf 1,813,184 1,616,930 744,797
Proved undeveloped reserves | Mcf 2,320,705 3,208,380 1,422,271
Natural gas liquids      
Proved Developed and Undeveloped Reserves [Roll Forward]      
Beginning of the period 75,766 20,127 17,736
Purchases in oil and natural gas reserves in place 0 53,617 0
Extensions and discoveries 9,631 4,619 7,677
Sales of oil and natural gas reserves in place (112) 0 0
Revisions of prior reserve estimates 1,228 2,737 (1,439)
Current production (5,993) (5,334) (3,847)
End of period 80,520 75,766 20,127
Proved developed reserves 40,810 36,247 14,299
Proved undeveloped reserves 39,710 39,519 5,828
Investment in Grizzly Oil Sands ULC | Oil derivatives      
Proved Developed and Undeveloped Reserves [Roll Forward]      
Beginning of the period 0 0 0
Purchases in oil and natural 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
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 natural 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 natural 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