PRIME ACCOUNTS

Anadarko Petroleum Corporation (including Union Pacific, Kerr McGee, and Western Gas)

Apache Corporation

ARMA Energy Corp.

Bill Barrett Corporation

Brownlie, Wallace, Armstrong & Bander Exploration

Cabot Oil & Gas Corporation (Rocky Mountains)

Chesapeake Energy Corporation

Chevron North America Exploration and Production Company

(including Texaco, Unocal, and Pure – Permian Basin)

Cox Exploration

Duncan Oil

Eland Energy (including Wintershall Energy)

El Paso Production Company (including Coastal – Rocky Mountains and California)

EnCana Oil & Gas (USA) (including Tom Brown and Matador)

Kirkwood Oil & Gas

Marathon Oil Company

Occidental Permian/OXY USA (Permian Basin)

Paramount Resources/Summit Resources

Questar Exploration and Production Company (including Celsius)

Quintana Petroleum Corporation

True Oil Company

XTO Energy Inc.

Yates Petroleum Corporation