Note 17 - Supplemental Gas and Oil Information (Unaudited)

The Company is making the following supplemental disclosures of gas and oil producing activities, in accordance with accounting standards for extractive activities - oil and gas and SEC Regulation S-X.

The Company uses the successful efforts accounting method for its cost-of-service gas and oil properties.

Cost-of-Service Activities

The following information is provided with respect to cost-of-service gas and oil properties managed and developed by Wexpro and governed by the Wexpro Agreement. Information on the standardized measure of future net cash flows has not been included for cost-of-service activities because the operations of and return on investment for such properties are regulated by the Wexpro Agreement.

Capitalized Costs of Cost-of-Service Activities

Capitalized costs of cost-of-service gas and oil properties net of the related accumulated depreciation, depletion and amortization are shown below:



	December 31,
	2012		2011
	(in millions)
Wexpro	$	780.4	$	708.6
Questar Gas	7.8		8.5
Total capitalized costs of cost-of-service activities	$	788.2	$	717.1

Costs Incurred for Cost-of-Service Activities

Total development costs incurred by Wexpro for cost-of-service gas and oil-producing activities were $147.5 million in 2012, $149.1 million in 2011 and $87.0 million in 2010. The costs incurred to develop proved undeveloped reserves were $50.4 million in 2012, $69.7 million in 2011 and $8.5 million in 2010.

Results of Operations for Cost-of-Service Activities

Following are the results of operations for cost-of-service gas- and oil-producing activities, before corporate overhead and interest expenses:



	Year Ended December 31,
	2012			2011			2010
	(in millions)
Revenues
From unaffiliated customers	$	36.1		$	31.5		$	24.6
From affiliated company⁽¹⁾	274.1			253.6			240.2
Total revenues	310.2			285.1			264.8
Production costs	50.1			51.2			48.1
Depreciation, depletion and amortization	77.4			63.9			62.1
Total expenses	127.5			115.1			110.2
Revenues less expenses	182.7			170.0			154.6
Income taxes	(64.8		)	(62.0		)	(54.9		)
Results of operations for cost-of-service gas- and oil-producing activities excluding corporate overhead and interest expenses	$	117.9		$	108.0		$	99.7

⁽¹⁾Primarily represents revenues received from Questar Gas pursuant to the Wexpro Agreement. Revenues include reimbursement of general and administrative expenses amounting to $26.5 million in 2012, $23.5 million in 2011 and $19.8 million in 2010.

Estimated Quantities of Cost-of-Service Proved Gas and Oil Reserves

Estimates of cost-of-service proved gas and oil reserves have been prepared in accordance with professional engineering standards and the Company's established internal controls. The estimates were prepared by Wexpro's reservoir engineers, individuals who possess professional qualifications and demonstrated competency in reserves estimation and evaluation. Because gas reserves managed, developed and produced by Wexpro are delivered to Questar Gas at cost-of-service, SEC guidelines with respect to standard economic assumptions are not applicable. The SEC acknowledges this potential circumstance and provides that companies may give appropriate recognition to differences arising because of the effect of the rate-making process. Accordingly, in cases where differences arise because of the effect of the rate-making process, Wexpro uses a minimum-producing rate or maximum well-life limit to determine the ultimate quantity of reserves attributable to each well.

Wexpro has limited proved undeveloped reserves to acreage in areas directly offsetting a proved developed well. The Company annually reviews all proved undeveloped reserves to ensure an appropriate plan for development exists. All proved undeveloped reserves are converted to proved developed reserves within five years of the proved undeveloped reserve booking. At December, 2012, all of the Company's proved undeveloped reserves were scheduled to be developed within five years from the date such locations were initially disclosed as proved undeveloped reserves. In 2012, Wexpro converted 15% of total 2011 year-end proved undeveloped reserves to developed status.

Revisions of prior estimates reflect the addition of new proved undeveloped reserves associated with current development plans, revisions to prior proved undeveloped reserves, revisions to infill drilling development plans, as well as the transfer of proved undeveloped reserves to unproved reserve categories due to changes in development plans during 2012 and 2011. Wexpro changed its development plans in 2012 due to success in increasing production, which resulted in a higher proportion of cost-of-service gas in Questar Gas's natural gas supply. Wexpro reduced the pace of development and therefore has revised downward proved undeveloped locations that are economic today but will not be drilled within five years of the initial recording date. The Company's year-end development plans are consistent with SEC guidelines for proved undeveloped reserve development within five years.

In establishing reserves, the SEC allows the use of techniques that have been field tested and demonstrated to provide reasonably certain results with consistency and repeatability in the formation being evaluated or in an analogous formation. In general, the Company uses numerous data elements and analysis techniques in the estimation of proved reserves. These data elements and techniques include, but are not limited to, production tests, well performance data, decline curve analysis, wireline logs, core data, pressure transient analysis, seismic data and interpretation, and material balance calculations. Although the Company utilizes these reliable technologies, no reserves were recorded more than one location away from production, from increasing recovery factor estimates, or from extending down-dip reservoir limits associated with the use of reliable technology.

Wexpro's estimates of proved reserves were made by the Company's engineers and are the responsibility of management. The Company requires that reserve estimates be made by qualified reserves estimators (QREs), as defined by the Society of Petroleum Engineers' standards. The QREs interact with engineering, land and geoscience personnel to obtain the necessary data for projecting future production, costs, net revenues and ultimate recoverable reserves. Management approves the QREs' reserve estimates annually. All QREs receive ongoing education on the fundamentals of SEC reserves reporting through internal and external training over the policies for estimating and recording reserves in compliance with applicable SEC definitions and guidance.

Estimated quantities of cost-of-service proved gas and oil reserves are set forth below:



	Natural Gas		Oil and NGL		Natural Gas Equivalents
	(Bcf)		(Mbbl)		(Bcfe)
Proved Reserves
Balances at December 31, 2009	649.4		4,483		676.3
Revisions - previous estimates	(202.3	)	(1,297	)	(210.1	)
Extensions and discoveries	341.5		2,107		354.2
Production	(50.2	)	(437	)	(52.9	)
Balances at December 31, 2010	738.4		4,856		767.5
Revisions - previous estimates	(153.9	)	(259	)	(155.5	)
Extensions and discoveries	224.7		1,214		232.0
Production	(50.5	)	(467	)	(53.3	)
Balances at December 31, 2011	758.7		5,344		790.7
Revisions - previous estimates	(158.4	)	(122	)	(159.0	)
Extensions and discoveries	154.4		1,612		164.0
Production	(57.5	)	(665	)	(61.5	)
Balances at December 31, 2012	697.2		6,169		734.2

Proved Developed Reserves
Balances at December 31, 2009	477.1		3,070		495.5
Balances at December 31, 2010	463.8		3,138		482.6
Balances at December 31, 2011	491.2		4,420		517.7
Balances at December 31, 2012	523.9		4,967		553.7

Proved Undeveloped Reserves
Balances at December 31, 2009	172.3		1,413		180.8
Balances at December 31, 2010	274.6		1,718		284.9
Balances at December 31, 2011	267.5		924		273.0
Balances at December 31, 2012	173.3		1,202		180.5