Abraxas Petroleum Corp

AC Exploration

Acock /Anaqua Operating Company

Acock Engineering & Associates, LP

Advanced Resources Intl

AEC Oil & Gas (USA), Inc.

Aexco

AGIP

Agio Oil & Gas Corporation

Al Furat Petroleum Company

Allegro Investments, Inc.

Alliance Oil and Gas Company, LLC

Allied Operating Texas. LLC

Allis Chalmers Production Services, Inc.

Alpine Production, LLC

Alta Mesa Resources, Inc.

Altura

American Exploration & Production

Americo Energy Resources

Amoco

Anadarko Petroleum Corporation

Anglo Suisse Offshore Partners, LLC

Antara Resources, Inc.

Abraxas Petroleum Corp

AC Exploration

Acock /Anaqua Operating Company

Acock Engineering & Associates, LP

Advanced Resources Intl

AEC Oil & Gas (USA), Inc.

Aexco

AGIP

Agio Oil & Gas Corporation

Al Furat Petroleum Company

Allegro Investments, Inc.

Alliance Oil and Gas Company, LLC

Allied Operating Texas. LLC

Allis Chalmers Production Services, Inc.

Alpine Production, LLC

Alta Mesa Resources, Inc.

Altura

American Exploration & Production

Americo Energy Resources

Amoco

Anadarko Petroleum Corporation

Anglo Suisse Offshore Partners, LLC

Antara Resources, Inc.

Apache Corporation

Approach Resources, Inc.

Aquila Energy Resources

Araxas Energy

Arena Offshore

Arco

Arkema, Inc.

Arnold Oil Properties

Ascent Operating, L.P.

Atoka Earth Co., Inc

ATP Oil & Gas

Atropos Production Co.

Aurora Oil & Gas

Avalon Exploration, Inc.

Aviara Energy Corp.

B & W Exploration

Baker Energy

Baker Oil Tools

BASA Resources, Inc.

BASF Corporation

Bass Enterprises

Baytex Energy USA, Ltd

BC Operating, Inc..

BK Energy Corporation

Barrett Resources

Basal Corporation

Basin Exploration Inc

Bass Enterprises

Beartooth

Benchmark Research & Technology

Berco Resources, LLC

Bettis Brothers, Inc.

BHP Billiton Petroleum Americas, Inc.

Bishop Petroleum, Inc.

Black Brush Oil & Gas, L.P.

Black Diamond Minerals, LLC

Blue Fin Services, LLC

Blue Ridge Group

Bluescape Resources

Bolding Chemical, Inc

Bonneville Fuels Corporation

Border Ladner Gervais

Borehole Seismic, LLC

Boss Exploration and Production, Corp.

BP America, Inc.

Bridge Petroleum

Bridge Resources Corp.

Brigham Oil & Gas

British Borneo Exp, Inc

Browning Oil Company

Burleson Petroleum

Burlington Resources

Burnett Oil Company, Inc.

C2E Capital

CWF Energy, Inc

C.W. Trainer

Cabot Oil and Gas Corporation

Cadence Energy

Calloway Engineering

Calpine Natural Gas Company

Calvin Resources, Inc.

Cambridge Production

Camden Resources

Cane River Resources

Capataz Operating

Carbo Ceramics

Carbon Energy Corp

Cardinal River Energy

Carrizo Oil & Gas, Inc.

Carrizo Marcellus

Carson Energy, Inc.

Caskids Operating Co.

Cawley, Gillespie & Associates

Caza Petroleum

Cenco, Inc.

Century Exploration, Inc.

Chaparral Energy, LLC

Charlie Tomerlin

Chemical Blending Services

Chesapeake Operating, Inc.

Chevron USA Production

Cheyenne Petroleum Company

Chroma Oil & Gas, LP

Cimarron Energy

Cimarex Energy

Cinco Natural Resources

Citation Oil & Gas Corporation

Clampitt & Associates

Clayton Williams Energy, Inc.

CNG Producing Company

Coastal Consulting

Coastal International

Coastal Oil & Gas

Cobb & Associates

Cobra Oil & Gas Corportion

CoHo Resources

Collins & Ware, Inc.

Common Resources

Conoco Phillips Company

Conquest Oil

Cornerstore E & P

Coronado Energy Production

Cox & Perkins Exploration

Crest Resources

Crimson Exploration

Crow Creek Energy ll, LLC

Crusader Energy Corp.

Custer & Wright

Cypress E & P Corporation

DJ Resources, Inc.

Dale Operating

Dallas Production, Inc.

Davis Brothers Oil Producers

Davis Petroleum Company

Dean Lake Operator

Deka Exploration Inc.

Delta Petroleum Corporation

Devon Energy Corporation

Domain Energy Corp

Dominion Energy & Production

Dugan Production

Dunn Tank Service

Drillmar Oil & Gas, Inc.

Drum Energy

DSTJ

Dyne Exploration Co

Dyna Coil

Eagle Consulting LLC

EagleRidge Energy, LLC

ECA Holdings, LP

ECHO Production

Ecosphere Technologies, Inc.

Edge Petroleum Corporation

EEX Corporation

El Paso Energy Corp.

Empersa Energy, L.P

Encana Oil & Gas, Inc.

Encore Operating, L.P

Endeavor Natural Gas, L.P

Energy Corporation

Energy Development Corporation

Energy XXI

Enervest Operating

ENI Petroleum

Enron Oil & Gas

Enserch Oil & Gas

Ensign Oil & Gas

EOG Resources, Inc.

Escondido Resources II, LLC

Essenjay Petroleum Corp

Essex Storage Services, Inc.

ETOCO, Inc.

Evans Energy II, LLC

Evergreen Operation

EXCO Resources Inc

Exeter Energy Services L.L.C.

Exploration Technologies, Inc.

Extex Production, Inc

Exxon Company USA

Fairway Minerals Corporation

Falcon Seaboard Resources

Fancher Oil, LLC

Fina Oil & Chemical

First Source Energy Group

FMC Corporation

Focus Oil and Gas

Force Industries Group

Forest Oil Corporation

Fortson Oil Company

Forza Operating

Fossil Resources, Inc.

Front Line Group

Future Petroleum Company, LLC

FW Oil Interests

Gaedeke Oil & Gas, LLC

Gas Research Institute

Gas Technology Institute

Genesis Producing

Geo-Atlan-Tex

Geo-Met Operating Company, Inc.

GLB Exploration, Inc.

Global Energy Development PLC

Goldking Energy Corporation

Grace Oil Company

Great Western

Greenwood Holdings, Inc

Gunn Oil Company

Gunnison Energy Corporation

HS Resources Institute

Hackey Oil & Gas

Haas Petroleum Engineering Services

Hadaway Engineering Services

Halliburton Energy Services

Hanagan Petroleum Corp

Hannathon Petroleum

Hardy Oil & Gas

Harrison Interest, Inc.

Hayden Energy, Inc.

Headington Oil Company

Helis Oil & Gas Co, LLC

Helix Company

Henderson Oil & Gas

Heritage Energy Company

Heritage Resources

Hess Corporation

Hilcorp Corporation

HMX Ploration

Hollimon Oil Corporation

Houston Energy, LP

Hudson Oil Company of Texas

Hunt Oil Company

Hurd Enterprises, Ltd.

Husky Ventures, Inc.

Hydrocarbon Operating

Implicit Oil & Gas

Incline Energy, Inc.

Indigo Minerals, LLC

Inflection Energy, LLC.

Integrated Petroleum Resources

IP Petroleum

James A. Whitson

James E Smith & Associates

John Wright Company

Johns Energy LLC

Jolen Operating Company

Jorford Corporation

J & W Engineering

JMA Energy Company, LLC

JMA Resources, Inc.

J.M. Huber Corporation

J-W Operating Company

KA Compass, LLC

Kan Map, Inc.

Katana Energy

Katy Resources

KCS Medallion

KCS Resources

Kelly Oil & Gas

Kerr McGee Corporation

Kinder Morgan

King Ranch Oil & Gas

Krescent Energy Company, LLC

Kytex Inc

Laguna Oil & Gas

Lamar Oil & Gas Inc.

Lamay Corporation

Land and Natural Resources Dvlpmt, Inc.

Langham Petroleum

Laredo Energy

Latigo Petroleum, Inc.

Layline Petroleum LLC

Legend Natural Gas II, LP

Leor Energy

Lewis Burleson, Inc.

Lewis Petro Properties, Inc.

Liberty Resources, Inc.

Lightning Oil Company

Lime Rock Resources

Linn Operating, Inc…

LLOG Exploration Co LLC

Loudon Exploration, Inc.

Louis Dreyfus Natural Gas

Lundberg Operating Company, Inc

Lynx Operating Company, Inc.

Maersk Oil & Gas

Magnum Hunter Resources Corp.

Magnum Producing, LP

Mainland Energy Corp

Marathon Oil Company

Mariner Energy, Inc.

Maritech Resources, Inc.

Marshall & Winston

Marquez Energy, LLC

MB Exploration, LLC

McClure Oil Company

McElvain Oil & Gas Properties

McKay Oil Corp

McKenzie Methane

Medco Energy U.S. LLC

MexPetrol

Meridian Oil

Merit Energy Company

Messina, Incorporated

MGC Resources

Mid Continent Exploration

Midcon Gas Services

Middleton Oil Company

Midland Resources, Inc

Midstates Petroleum Corporation

Milagro Exploration

Millennium Offshore Group

Miller Energy

Miller Exploration Company

Milo Petroleum Company

MIM Holdings Ld

Mission Resources

Mitchell Energy

Mobil E&P US

Modern Exploration

Morris Exploration

Mosbacher Energy Company

Murphy Exploration & Production Co.

Mustang Fuel Corp

Natchez Production, Inc.

National Energy Group

Natural Gas Pipeline Co. of America

National Oilwell

Nearburg Producing Company

Neuman Production

New Dominion, L.L.C

New Tech Engineering

Newfield Exploration Co

Newfield Exploration Mid-Cont. Inc.

Nexen Petroleum, Inc.

Nextera Energy

NFR Energy

Noble Energy

Norcen Explorer, Inc

North Central Oil Corp

Northshore Petroleum, LLC

North Texas Llano

Norton Company

O & G Well Services

OGX Resources

O.I.L. Energy Corporation

Ocean Energy

Odegard Energy

Odyssey Petroleum

Oklahoma RB Operating

Opal Energy, Inc.

Osborne Oil & Gas

O’Ryan Oil & Gas

Output Exploration

Oxbow Properties

Oxy USA, Inc.

P & A Operation, Inc.

Paloma Resources, LLC

Panther Energy Company, LLC

Par Development

Paris Oil & Gas Corporation

Parker & Parsley

Parsec Resources

Parten Operating Company

Patriot Resources, LLC

Pearl Energy

Pathfinder Exploration, LLC

Pedernales Energy, LLC

Peace River Group

Peoples Energy Production, LLC

Pennzoil

Penwell Energy Corp.

Peoples Energy Corp.

Perkins & Trotter

Peregrine Petroleum

Petroleum Research & Consulting Service

Petrobras America, Inc.

Petrohawk Energy Corporation

Petrogulf Corporation

Petrojarl, Inc.

Petroleum, ETC

Petroquest Energy

PetroMax Operating Company, Inc.

PetrotexEngineering

Petsec Resources, Inc.

Peyto Exploration & Development Corp

Phillips Petroleum Company

Pinnacle Energy Services

Pioneer Natural Resources

PITCO

Pitts Energy Company

Plains Exploration & Production (PXP)

Plano Petroleum, LLC

Pogo Producing Company

Post Rock Energy

Primex Operating Company

Protechnics

Protégé Energy II, LLC

Pure Resources

Questar Exploration & Production

Quesar Energy Services, Inc.

Ram Energy

Ram Operating, LLC

Ramey Petroleum Consultant

Rayden

Read & Stevens

Red Fork Energy

Redman Operating Company

Reef Exploration, Inc.

Reliance Energy, Inc.

Repsol YPF

Reserve Operating Corp

Resolute Wyoming

Restech Houston Inc

Rex Energy Corporation

Rhombus Energy

Riata Energy

Ricks Exploration, Inc

Ridgeway Arizona Oil Corp

Riley Huff Energy Group

Rimco

Rio Bravo

Rio Petroleum

River Producing Company

Rocky Mountain Consulting

Rosetta Resources, Inc.

Royal Production Company

Roywell Services, Inc.

Rutherford Oil Corporation

Running Foxes Petroleum

Sabco Oil & Gas Corporation

Samson Canada Ltd

Samson Resources Company

San Isidro Development Company

Sanchez Oil & Gas Corporation

Sandlewood Exploration

SandRidge Energy

Santa Fe Energy

Sanjel Corporation

Santrol

Scana Petroleum

Schoch & Company

Seeco. Inc.

Seneca Resources

SG Interests

Shana Petroleum Company

Sharon Resources, Inc.

Shell Oil Company

Sheridan Oil & Gas

Sierra Resources, LLC

Sinclair Oil & Gas Company

SMC Oil & Gas, Inc.

SND Energy Company

Snyder Oil Company

Sojourner Drilling Corporation

Source Rock Energy Partners

South Texas Consolidated Energy

South Texas Oil Company

Southern Bay

Southern Star Energy, Inc.

Southwest Resources

Southwestern Energy Company

Sovereign Resources, Inc.

Sparta Petroleum

Spice Inc.

Spirit Energy

SRW Operating, LLC

SM Energy Company

Star Resources

Steller Energy and Investment Corp

Stim Lab, Inc.

Sterling Energy

Stokes & Spiehler

Stonegate Production Company, LLC

Storm Cat Energy USA

Strand Energy, LLC

Strata Production

Stream Energy

Strickland Engineering

Stroud Production, LLC

Sue-Ann Operating. L.C

Suemaur Exploration

Sun River Energy

Sunlight Exploration

Swift Energy Company

Swits Oil

Sydson Energy

Synergy Oil & Gas LP

Tag Operating

Tailsman Energy

Tallgrass Energy

Tarpon Operating & Dev, LLC

TDC Energy

Tecton Energy Company

Teleo Operating

Tempest Energy Resources

Tetra Technologies

Texaco

Texas Crude Energy, Inc.

Texas Independent Exploration

Texland Petroleum, Inc

The Redmon Oil Company, Inc.

The Wiser Oil Company

Timber Sharp Drilling

Titus Energy LLC

Tom Brown

Total Minatome

Trail Ridge Energy Partners, Inc.

Trap Rock Company

Traton Engineering

Triad Hunter

Tres Management

Treybig Enterprises Inc

Triad Energy Corp

Tri-C Resources

Triangle Three Resources

Triple Diamond Energy

Turrentine Oil & Gas

Twister Gas Services

TXCO

Unconventional Gas Resources

Union Gas Operating

Union Texas Petroleum, Inc.

Unit Petroleum Company

Unocal

US Enercorp, Ltd

Vaalco Energy, Inc

Vantage Energy

Vecta Energy Corporation

Ventex Oil & Gas, Inc.

Verdad Oil & Gas Corporation

Vessels Oil & Gas Company

V-F Petroleum

Vialogy

Virtex Operating Co. Inc.

VP Engineering

Wagner & Brown, Ltd

Wagner Oil Company

Wapiti Energy, LLC

Ward Petroleum

Warren Corporation

Waverly Production LP

W. B. Osborn Oil & Gas Operations

Weber Energy Group

Well Enhancement Services, LLC

Welsh Petroleum

West Star Operating Company

Westech Energy Corporation

White Oak Energy

Whittier

Whiting Petroleum Corp.

Wildhorse Operating Co.

William M. Null Oil Producers

Williams Oil Company

Wiser Oil Company

Woodbine-Petro-Jarhi Production Co.

Wynn Crosby Energy

XNP Resources, LLC

XTO Energy, Inc.

Yates Petroleum Company

Yucca Energy, Inc.

Yuma Exploration and Production

Zilkha Energy Company

Adelphi Energy Limited

Aduro Resources LTD

Anton Oilfield Services

Barnwell of Canada

Bauerberg-Klein

BP Exploration (epsilon) Ltd

BP Kuwait

BP Oman

Buru Energy Limited

Exxon Mobil – Germany

Force Energy Limited

Gran Tierra Energy-Columbia – Ltd

Hunt Oil Company – Canada

Imperial Oil Limited

Lakes Oil NL

Latent Petroleum

LukOIl Overseas Holding, LTD

Seven Generations Energy

BJ Services

C & J Speciality

Cudd Pumping Service

Diamondback Energy Services

Dowell Schlumberger

FracTech Services

Halliburton Energy Services

International Nowsco Services

Key Energy Services

Liberty Pressure Pumping, LP

Nowsco Well Service

ResTech, Inc.

Schlumberger

Superior Pumping Services

Trican

Weatherford International Ltd.

Andrews & Kurth, LLP

Arnold, White & Durkee

Ayers & Ayers

Caperton, Rogers & Miller

Baker Botts, LLP

Baker & Hostetler

Barnes & Lewis, LLC

Beirne, Maynard & Parsons, LLP

Ben K. Barron, P.C.

Bettis, Boyle and Stovall

Brown, Simms, Wise & White

Byrne, Cardenas & Smitherman

Christenson & Jenson Law Firm

Cotton, Bledsoe, Tighe & Dawson

Cook, Yancey, King & Galloway

Downer, Kyle & Willhite

Elkins & Yount

Fultz & Davis

Griggs & Harrison

Goforth & Lewis

Hargis & Harpold

Heidelberg & Woodliff

Hunton & Williams

Leslie G. MacLaughlin, Attorney

Loyd Bolding, Attorney

McGuire Woods, LLP

Oldham & Associates

Perkins & Trotter

Rathwell & Nizialek, PC

Rosenblatt & Associates

Scott Douglass & McConnico, LLP

Sacks & Associates

Shannon, Gracey, Ratliff & Miller, LLP

Stokes & Spiehler

Strasburger Attorneys at Law

Woodard, Hall & Primm

W.F. Palmer

Zabel Freeman