Note 15. Supplemental CO₂ and Helium Disclosures (Unaudited)

Based on engineering reports prepared by DeGolyer and MacNaughton, proved CO₂ reserves, and helium reserves associated with our helium production rights, were estimated as follows (in MMcf):



	Year Ended December 31,
	2012	2011	2010
CO₂ Reserves
Gulf Coast region ⁽¹⁾	6,073,175	6,685,412	7,085,131
Rocky Mountain region ⁽²⁾	3,495,534	2,195,534	2,189,756

Helium Reserves Associated with Denbury's Production Rights
Rocky Mountain region ⁽³⁾	12,712	12,004	7,159

(1)

Proved CO₂ reserves in the Gulf Coast region consist of reserves from our reservoirs at Jackson Dome and are presented on a gross working interest (8/8ths) basis, of which our net revenue interest was approximately 4.8 Tcf, 5.3 Tcf and 5.6 Tcf at December 31, 2012, 2011 and 2010, respectively, and include reserves dedicated to volumetric production payments of 57.1 Bcf, 84.7 Bcf and 100.2 Bcf at December 31, 2012, 2011 and 2010, respectively.


(2)	Proved CO₂ reserves in the Rocky Mountain region consist of our reserves at Riley Ridge (presented on a gross working interest (8/8ths) basis) and our overriding royalty interest in LaBarge Field, of which our net revenue interest was approximately 2.9 Tcf, 1.6 Tcf and 0.9 Tcf at December 31, 2012, 2011 and 2010, respectively.

(3)

Reserves associated with helium production rights include helium reserves located in acreage in the Rocky Mountain region for which we have the right to extract the helium. The U.S. government retains title to the helium reserves and we retain the right to extract and sell the helium on behalf of the government in exchange for a fee. The helium reserves are presented net of the fee we will remit to the U.S. government.