Supplementary Information on Oil, Ngl and Natural Gas Reserves (Unaudited) (Details 4)	12 Months Ended
	Sep. 30, 2012 Mcfe
Changes in proved undeveloped reserves
Beginning proved undeveloped reserves	44,575,844
Proved undeveloped reserves transferred to proved developed	(5,393,421)
Revisions	(22,369,152)
Extensions and discoveries	24,458,980
Purchases	9,612,804
Ending proved undeveloped reserves	50,885,055