C D Exploration Inc.
C. L. Brittan & Associates Inc.
Cactus Funding Corp.
Cade Oil & Gas LLC.
Caib Financial Advisers SP. ZOO.
Calcrude Oils Ltd.
Calibre Energy Inc.
California Natural Gas Storage LLC.
Calpine Corp.
Calsilite-Ruston Inc.
Calver Resources
Cambridge Energy Corp.
Canacol Energ Inc.
Canadian Forest Oil Ltd.
Canadian Imperial Bank of Commerce
Canadian Occidental Petroleum
Canadian Talon Resources Ltd.
Candax Energy Inc.
Cantera Resources Inc.
Capco Energy Inc.
Capital C Energy LLC.
Cargill Financial Services Corp.
Carnes Oil Corp.
Carrizo Oil & Gas Inc.
Carscallen Lockwood LLP.
Caspian Energy Corp.
Castle Energy Corp.
Cavell Energy Corp.
Cayman International Exploration Co.
CDS Energy SA.
Celero Energy
Celtic Oil & Gas Inc.
Centurion Energy International
CER Corp.
Challenger Minerals Inc.
Champion International Co.
Chaparral Energy Inc.
Chase Manhattan Bank
Chemical Bank
Chernogorskye Limited Liability Co.
Chesterfield Energy Corp.
Chevron Corp.
Chi Energy Inc.
Chilton Energy
Choctaw II Oil & Gas Ltd.
Chotin Asset Management Corp.
Cimarex Energy Co.
CIS Oil & Gas
City and County of Denver (Colorado)
City of Broomfield
City of Longmont
Clanahan, Tanner, Downing & Knowl
Classic Oil & Gas Inc.
Clean Energy Systems Inc.
Clyde Petroleum Exploratie BV.
CMS Energy Inc.
CNG Producing Co.
CNR International Ltd.
Coalinga Corp.
Cockrell Oil Corp.
Coffield, Ungaretti and Harris
Coho Energy Inc.
Cold Lake Resources Ltd.
Collarini Engineering Inc.
Collins & Ware Inc.
Colorado State Land Board
Colton Gulf Coast Inc.
Columbia Natural Resources Corp.
Cominco Fertilizers
Compania General de Combustibles SA.
Compass Operating
Concept Energy Corp.
Concord Oil Co.
Concordia Resources Inc.
Condor Petroleum
Conocophillips Co.
Conrad & Patricia Tvedt
Consolidated Eurocan Ventures Ltd.
Consolidated Petroleum Partners Inc.
Contango Oil & Gas Co.
Continental Resources Inc.
Contrarian Capital Management
Conwest Exploration (Delaware) Inc.
Coomooroo Exploration (Delaware) Inc.
Copano Field Services
Copeland, Cook, Taylor and Bush
Coral Energy
Cordillera Energy Partners
Cornerstone Private Capital
Cotton Valley Resources Corp.
Courag Energy
Cowry Enterprises Ltd.
Crane Holdings Inc.
Credit Lyonnais
Crescendo Resources LP.
Crete Oil Co. Inc.
Crimson Resources
Crow Creek Energy LLC.
CRSS Capital Inc.
Crutcher - Tufts Production Co.
CSV Holdings Inc.
CTS Properties
Cventures Inc.
Cymraec Resources Inc.
Cypress Petroleum Consultants
C N G Producing Co.
Cabot Oil & Gas Corp.
Caddis Capital
Cadence Production Inc.
Cairn Energy PLC.
Calgary Louisiana Energy LLC.
California Bank & Trust
Callon Petroleum Co.
Calpine Natural Gas Co.
Calvalley Petroleum Ltd.
Cambrian Capital Corp.
Camden Reserves Inc.
Canadian 88 Energy Corp.
Canadian Hunter Exploration Ltd.
Canadian Natural Resources Ltd.
Canadian Petroleum International Resources Ltd.
Canadian Venture Exchange
Cano Petroleum Inc.
Canyon Energy Inc.
Capex SA.
Capital Risk LLC.
Cargill Energy
Carl Oil and Gas Co.
Carpatsky Petroleum
Carrolton Resources
Casa Inglesa Ltd.
Castex Energy Inc.
Castle Peak Resources LLC.
Caxton-Iseman Capital Inc.
Cazador Reserves Inc.
CDX Energy LLC.
CE Arco Energy Corp.
Celsius Energy Co.
Central Oklahoma Oil & Gas Co.
Century Offshore Management Corp.
Chadmatt Resources Corp.
Chamaelo Energy Inc.
Chandler Energy Inc.
Charger Resources
Chase Petroleum Ltd.
Cheniere Energy Inc.
Chesapeake Energy Corp.
Chestnut Ridge Storage LLC.
Cheyenne Petroleum Co.
Chieftan Capital Management Inc.
Choctaw Corp.
Chorney Oil Co.
CIBC World Markets Corp.
Circumpacific Energy Corp.
Citicorp Securities Inc.
City Investing Co. Ltd.
City of Houston
City Oriente
Clarity Energy Ltd.
Clayton Williams Energy
Cleveland-Cliffs Inc.
Club Oil & Gas Ltd.
CM Production LLC.
CNC Compania de Nitrogeno de Cant
Coal Creek Minerals LLC.
Coastal Oil & Gas Corp.
Cody Energy LLC.
Cogen Technologies
Cola Resources LLC.
Coleman Oil & Gas Inc.
Collier Resources Co.
Colorado Interstate Gas Co.
Colt Resources Corp.
Columbia Gas Transmission Corp.
Comerica Bank
Commonwealth Oil & Gas Co. Ltd.
Compass Bank
Comstock Resources Inc.
Concord Energy Corp.
Concord Operating Inc.
Condor Exploration LLC.
Conoco Inc.
Conquest Resources Corp.
Consolidated Edison Co. of New York Inc.
Consolidated Oil & Gas Inc.
Constellation Energy
Continental Land & Fur Co. Inc.
Contour Production Co.
Convest Energy Corp.
Coogee Chemicals Pty. Ltd.
Coors Energy Co.
Copano Gathering System
Coplex Group of Cos.
Cordex Petroleums Inc.
Corpus Christi Natural Gas Co.
Cottonwood Production Corp.
Covington and Burling
Cox & Perkins Exploration Inc.
Crawford County Oil LLC.
Credit Suisse
Crimson Exploration Inc.
Cronus Offshore Inc.
Crow Horizons Co.
Cruiser Oil & Gas Ltd.
Crystal Oil Co.
CTI Petroleum Canada Inc.
CV Emerald Co.
CXY Energy Inc.
Cypress E & P Corp.
Cyprus Power Corp.