Annual report pursuant to Section 13 and 15(d)

Supplemental Information on Oil and Natural Gas Properties (unaudited) (Proved Developed and Undeveloped Oil and Gas Reserve Quantities) (Details)

v3.6.0.2
Supplemental Information on Oil and Natural Gas Properties (unaudited) (Proved Developed and Undeveloped Oil and Gas Reserve Quantities) (Details)
 12 Months Ended
Dec. 31, 2016
MBoe
MMcf
MBbls
Dec. 31, 2015
MBoe
MMcf
MBbls
Dec. 31, 2014
MBoe
MMcf
MBbls
Proved developed and undeveloped reserves:      
Beginning of period, MBOE proved developed | MBoe 28,617 18,201 7,470
End of period, MBOE proved developed | MBoe 43,232 28,617 18,201
Beginning of periodc, MBOE proved developed | MBoe 25,654 14,623 7,387
End of period, MBOE proved developed | MBoe 48,348 25,654 14,623
Crude Oil [Member]      
Proved developed and undeveloped reserves:      
Beginning of period | MBbls 43,348 25,733 11,898
Revisions to previous estimates | MBbls (5,738) (1,632) (243)
Purchase of reserves in place | MBbls 25,054 2,932 3,223
Sale of reserves in place | MBbls (1,718) (23)  
Extensions and discoveries | MBbls 14,479 19,127 12,547
Production | MBbls (4,280) (2,789) (1,692)
End of period | MBbls 71,145 43,348 25,733
Beginning of period, proved developed | MBbls 22,257 14,006 5,960
End of period, proved developed | MBbls 32,920 22,257 14,006
Beginning of period, proved undeveloped | MBbls 21,091 11,727 5,938
End of period, proved undeveloped | MBbls 38,225 21,091 11,727
Natural Gas [Member]      
Proved developed and undeveloped reserves:      
Beginning of period | MMcf 65,537 42,548 17,751
Revisions to previous estimates | MMcf 13,929 4,870 (215)
Purchase of reserves in place | MMcf 36,474 2,915 8,591
Sale of reserves in place | MMcf (2,765) (105)  
Extensions and discoveries | MMcf 17,194 19,621 18,641
Production | MMcf (7,758) (4,312) (2,220)
End of period | MMcf 122,611 65,537 42,548
Beginning of period, proved developed | MMcf 38,157 25,171 9,059
End of period, proved developed | MMcf 61,871 38,157 25,171
Beginning of period, proved undeveloped | MMcf 27,380 17,377 8,692
End of period, proved undeveloped | MMcf 60,740 27,380 17,377