1 Oil & Gas Investment Symposium AN INTEGRATED NATURAL GAS COMPANY Charles B. “Chuck” Stanley Executive Vice President and President & CEO, Questar Market Resources Sheraton New York Hotel & Towers New York City, NY April 21, 2004

2 Regulated Services (Questar Pipeline and Questar Gas) Gas transmission, storage & distribution 50% of assets 29% of net income 67% of net income Assets: $3.3 billion December 2003 Questar is an integrated natural gas company Market Resources (includes Wexpro) Gas & oil exploration, production, gathering, marketing and trading 50% of assets

3 IDAHO UTAH WYOMING COLORADO Long Beach NEVADA CALIFORNIA Other pipelines Principal producing basins Questar Pipeline Questar Gas ARIZONANEW MEXICO Salt Lake City OVERTHRUST GREEN RIVER UINTA SKULL CREEK SAND WASH PICEANCE SAN JUAN PARADOX FERRON We’re well positioned to capitalize on strong regional fundamentals

4 Our strategies reflect our focus on returns, risk, and the Rockies Improve returns on capital Maintain a strong balance sheet Grow reserves and production Hedge production to manage price risk Expand and extend our pipeline system Capture value around key production areas

earnings guidance F $1.88 Key assumptions: Hedges in place February 2004 Forward-price curve applied to unhedged volumes $2.06 $ $

6 We focus on returns on capital * Adjusted ROA is before FAS 143 and gas-processing charges and asset-sale gains Return on Assets 12 Months Ending December 2003 Questar Market Questar Questar Resources Pipeline Gas

7 Hedging and cap-ex decisions reflect our view of long-term fundamentals Demand Destruction/Supply Response Supply Destruction $3.75 per MMbtu Equilibrium Range Supply Destruction/Demand Response $3.00 per MMbtu Time NYMEX Don’t hedge Acquisition opportunities more likely Hedge Acquisition opportunities less likely Base case economics

8 Payout ratio 50% 52% 60% 57% 37% 36% 42% 37% Yield 3.3% 2.8% 3.4% 4.5% 2.3% 2.9% 2.7% 2.3% Quarterly dividend $.205 per share 30 increases in 31 years $.82 annualized dividend Current yield: 2.3% on $36.00 stock price Dividends/Payout/Yield We pay a competitive dividend; our payout is conservative

9 Midcontinent Rockies *Nonregulated proved reserves and production (excludes Wexpro) Midcontinent Rockies Questar Market Resources is our growth driver 76% 66%

10 We’ve grown reserves more than fivefold over the past decade Bcfe Production* 10-year CAGR: 9.1% Proved reserves* 10-year CAGR: 17.8% 2004 Production Guidance Bcfe* *excludes Wexpro Canada sale

11 Questar E&P has maintained cost discipline in a higher price environment EBITDA ($ millions) Year-end reserves (bcfe) Production (bcfe) Reserve-life index (yrs) Average realized price/mcfe DD&A rate G&A costs LOE Allocated interest Total controllable costs Production taxes Total pre-FIT cost $212 1, $ $ $2.17 $227 1, $ $ $ % 17.8% 9.1% 6.3% 1.7% 1.5% 5.0% 3.4% 3.8% yr CAGR E&P Statistical Highlights 1993* $ $ $ $1.58 *Not restated for successful-efforts accounting ** Reflects 2002 Canada and San Juan basin asset sales **

12 We’ve maintained a high success rate while expanding drilling activity Total Net Wells* *includes Wexpro drilling 160 Dry & abandoned holes Successful wells Success rate: 90% 85% 89% 91% 90% 91% 96% 93% 146

13 Our Pinedale project will drive production and earnings growth Concentrated asset Proven play Deep potential Downspacing potential Developed infrastructure Gathering and processing Salt Lake City Vernal CO WY ID UT Powder River Basin Wind River Basin Great Divide Basin Washakie Basin Sand Wash Basin Green River Basin Rock Springs Uplift Uinta Basin Piceance Basin UTCO Denver Cheyenne D-J Basin Overthrust Belt Uinta Mtns Wind River Mtns Jackson Uinta Basin Pinedale Anticline Focus Area

14 Our Pinedale project provides a solid platform for long-term growth 443 Bcfe proved reserves (excl. Wexpro) at 12/31/ to 430 locations depending on spacing 20-acre downspacing likely Reserves: 8 Bcfe/well Low finding costs ($ /Mcfe) QEP net production (excl. Wexpro).2003: 15.2 Bcfe.2002: 8.6 Bcfe 30-well 2004 drilling plan WYOMING LaBarge Complex 10 Miles Jonah Field Wind River Uplift Pinedale Questar’s acreage 62% WI in 14,800 acres

15 Depth = 14,000 feet Shared Production Facility on Surface Pad Up to 16 Wells from One Surface Pad Sandstone Gas Reservoirs We’re using directional drilling from pads at Pinedale to significantly reduce surface impact 2,100 foot radius of “reach”

16 Number of Active Pads to Drill 40 Wells Per Year NO. OF PADS Seasonal Operations Year-Round Operations Year-round drilling is a “win-win-win” for the environment, the community and Questar

17 Uinta Basin provided about 1/3 of 2003 nonregulated production Vernal Greater Altamont/Bluebell UTAH Greater Natural Buttes Greater Monument Butte Wonsits Valley Red Wash Island COLORADO Gas Oil Questar acreage Wasatch gas Green River oil 304 Bcfe proved reserves at 12/31/03 QEP net production::.2003: 29.0 Bcfe.2002: 26.8 Bcfe Typical well IP’s at 1 MMcf/d 118,275 net leasehold acres Over 120 Wasatch locations yet to drill Currently evaluating deep potential Emerging Green River gas play

18 We hold significant acreage in the greater Green River Basin Deep potential Downspacing potential Stratigraphic plays on flanks of old fields Hydraulic fracturing 3-D seismic Coal-bed methane Pinedale Moxa Arch Rock Springs Uplift Uplift QMR AcreageGas Fields QMR’s Acreage Position 632,000 gross acres 418,000 net acres

19 We intend to grow our Midcontinent E&P business Less basis (price) risk than the Rockies Long-lived reserves and production In-house knowledge and experience Multi-target drilling opportunities (stacked pay) Abundant pipeline/gathering infrastructure 1,828,000 gross/423,000 net leasehold acres Private land ownership and year-round access

20 Capital Expenditures Operating Costs Successful wells & Dry holes non-drilling costs Excluded from investment base cost absorbed by shareholders via higher depreciation Wexpro receives a return of and earns a return on its investment base Questar Gas reimburses cost of producing reserves Wexpro’s earnings are not sensitive to commodity prices Wexpro earns a 19-20% after-tax return on its investment base

21 Wexpro’s growing investment base yields growing net income $17 $19 $21 $24 $73 $98 $109 $161 $125 $28 $165 $31 Investment base Net income $173 $33 * Before FAS 143 charge ($32.6MM after) $ Millions

22 IDAHO UTAH WYOMING COLORADO Long Beach NEVADA CALIFORNIA Other pipeline systems Producing basins Questar Pipeline system Questar Gas system Questar Gas cities served Salt Lake City Questar Pipeline - Core system 1,907miles Southern Trails (East)488 Overthrust 88 Total system2,483miles - Total daily capacity: 2,920Mdth -Storage capacity: 139.5Bcf - Rate base: $565 million Questar Gas - Cities served: Customers: 770,500 - Deliveries: 132 MMdth - Rate base: $617 million ARIZONANEW MEXICO Southern Trails Pipeline Our regulated companies provide a stable earnings base

23 3,000 6,000 9,000 12,000 15,000 0 = Direction of Flow Southeast Southwest Western Central Midwest 3,000 6,000 9,000 12,000 15,000 0 Southeast Southwest Western New LNG Imports New pipelines will be needed to move Rockies gas to distant markets Source: EIA and others

24 Long Beach Southern system Salt Lake City Transportation volumes up 7% in 2003 Tie Line 112 – 52,000 dth/d expansion to QGC – Cost $13MM, revenue $3.3MM – In service – Oct Northern System Expansion – 85,000 dth/d to Kern River – Cost $4.1MM, revenue $1.4MM – In service – May 2003 Southern System Expansion under development Evaluating storage projects UTAH Northern expansion Clay Basin Southern Trails Kern River We’ve extended and expanded our pipeline system Northern system Tie Line 112

25 Questar Gas customer growth has averaged 3% per year since 1985 Customers …. and we must invest $70-80MM per year to keep pace with customer growth +2.7% Growth In 2003

26 We intend to improve QRS performance in 2004 Improve returns on capital Get contracts / expand our pipeline Manage cost of new pipeline safety requirements Resolve Southern Trails Pipeline Resolve Utah gas-processing dispute without refund

27 Our credit ratings are strong; we will maintain strong ratings Moody’sS&P Senior unsecured debt ratings: Questar GasA2A+ Questar PipelineA2A+ Questar Market ResourcesBaa3BBB+ Questar Corp - Short-termP2A1

28 Our balance sheet is strong; we will maintain a strong balance sheet Total debt % Equity % $1,692 $1,774 $1,876 $2,610 $2,333 Debt Equity Capitalization (including short-term debt) ($ Millions) $2,372

29 We generate strong cash flow to fund capex, dividend and debt reduction $230 $318 $416 Cash Flow From Operations (before working-capital changes) 54% 57% 67% QMR QRS QMR QRS $328 59% $469 66% ($ Millions)

capital budget reflects good investment opportunities funded from cash flow ($ Millions) $335 $415

31 Investors should monitor our progress toward 2004 goals Earn 12.0% ROA Grow nonregulated production 8% to 100 bcfe Drill and complete 30 Pinedale wells Grow proved reserves 3.5% to 1200 bcfe Hedge up to 80% of 2005 production at prices above 2004 Resolve Southern Trails Pipeline Resolve Questar Gas processing dispute without refund Earn 11.2% ROE in Questar Gas

32 This presentation contains forward- looking statements about the operations and expectations of Questar Corp. and its subsidiaries. Management believes they are reasonable expectations of the company’s performance. Actual results may vary materially from our stated expectations and projections. Additional information concerning the factors that could cause materially different results are found in Questar’s Form 10-K and 10-Q reports on file with the SEC, and in the company’s annual report. Questar is built on a strong foundation AN INTEGRATED NATURAL GAS COMPANY