A2D Technologies, Inc.
ACCIONA Energy USA, LLC
ARB Midstream
ARD Operating, LLC
Alliant Energy Corporation
Alta Mesa Services, LP - O&G
Alyeska Pipeline Service Company
American Midstream Partners, LP
American Transmission Company
Amplify Energy
Anadarko Petroleum Corporation
Apache Corporation
Apex International Energy
Archrock, Inc.
Ascent Resources Management Services, LLC
Associated Electric Cooperative, Inc.
Aux Sable Liquid Products, Inc.
Aux Sable Midstream
BASF Corporation
BHP Billiton Petroleum (Americas), Inc.
BP Exploration & Production, Inc.
BW Offshore USA Management, Inc.
Baker Hughes, Inc.
Berkshire Hathaway Energy - PacifiCorp
Black Hills Energy
Black Stone Minerals Company, L.P.
Blue Mountain Midstream, LLC
Blue Racer Midstream, LLC
Buckeye Partners, L.P.
C&J Energy Services, Inc.
CGG Services (US), Inc.
CH-IV International
CHS, Inc.
CITGO Petroleum Corporation
CNOOC Petroleum U.S.A., Inc.
CNX Resources Corporation
COG Operating, LLC
CVR Energy, Inc.
Cabot Oil & Gas Corporation - GasSearch Drilling Services
Caerus Operating LLC
Calcasieu Refining Company
Calfrac Well Service, Ltd. - Calfrac Well Services Corporation
California Resources Corporation
Calpine Corporation
CenterPoint Energy, Inc.
Chesapeake Energy Corporation
Chevron North America Exploration & Production
Chief Oil & Gas, LLC
Cimarex Energy Co.
Citation Oil & Gas Corp.
City Utilities of Springfield, MO
Clean Harbors, Inc.
Colonial Pipeline Company
ConocoPhillips
Conquest Completion Services LLC
Consumers Energy
Continental Resources, Inc.
Crescent Point Energy US Corp.
Crestwood Equity Partners, LP
DCP Midstream, LP
DNV GL Energy Insights USA, Inc.
DNV GL Energy Services USA Inc.
DNV GL Energy USA, Inc.
DNV GL Noble Denton USA, LLC.
DNV GL USA, Inc.
Danos & Curole Marine Contractors, LLC
Delta Air Lines, Inc. - MIPC, LLC
Delta Air Lines, Inc. - Monroe Energy, LLC
Denbury Resources, Inc.
Devon Energy Corporation
Diamond Offshore Drilling, Inc.
Diamondback Energy
Dominion Energy Gas Marketing, Inc (formerly SCANA Energy Marketing, Inc.)
Dominion Energy North Carolina (formerly PSNC Energy)
Dominion Energy South Carolina (formerly SC Electric & Gas)
Dominion Energy Southeast Services, Inc.
Dominion Energy, Inc.
Dominion Energy, Inc. - Gas Infrastructure
Dominion Energy, Inc. - Power Delivery
Dominion Energy, Inc. - Power Generation
Driftwood Holdings LLC
EOG Resources, Inc.
EP Energy
EnLink Midstream, LLC
Enable Midstream Partners, LP
Enbridge, Inc.
Encana Services Company, Ltd.
Encino Energy, LLC
Endeavor Energy Resources, LP
Endeavor Energy Resources, LP - Endeavor Energy Services
EnerVest, Ltd.
Enerflex Energy Systems
Enerflex Services, Inc.
Energy Transfer Partners, LP
EnergySolutions
EnergySolutions - Decommissioning & Decontamination
EnergySolutions - Operational Waste Management
Enerplus Resources (USA) Corporation
Ensco plc
Equinor US Holdings, Inc.
Equinor US Operations LLC
Explorer Pipeline, Inc.
Exterran Corporation
Fieldwood Energy, LLC
Fleur de Lis Energy, LLC
Flint Hills Resources, LP
Fluor Federal Petroleum Operations, LLC
Forum Energy Technologies
FourPoint Energy. LLC
Freeport LNG Development, L.P.
GL PwrSolutions, Inc.
Garrad Hassan America Inc.
Gavilan Resources, LLC
Genesis Energy, LP
Goodnight Midstream, LLC
Great River Energy
Gyrodata, Inc.
Halliburton Company - Halliburton Energy Services, Inc.
Halliburton Company - Landmark Graphics Corporation
Halliburton Company - Multi-Chem Group, LLC
Hawaiian Electric Company, Inc.
Helmerich & Payne, Inc.
Hess Corporation
Hi-Crush Partners, LP
Hilcorp Energy Company
Hilcorp Energy Company - Harvest Pipeline Company
Hunt Oil Company
Hunt Refining Company
Husky Energy, Inc.
INPEX Americas, Inc.
ION Geophysical Corporation
ITC Holdings Corp.
Idaho Power
Independence Contract Drilling, Inc.
Inflection Energy, LLC
Invenergy LLC
Invenergy Services LLC
J-W Energy Company - J-W Power Company
Jordan Cove LNG
Keane Group, Inc.
Key Energy Services, Inc.
Keyera Corp. (USA)
Kinder Morgan, Inc.
Kosmos Energy, Gulf of Mexico
Kosmos Energy, LLC
LOOP, LLC
Laredo Petroleum, Inc.
Legacy Reserves, LP
Limetree Bay Refining, LLC
Limetree Bay Terminals, LLC
Lloyd's Register Drilling Integrity Services, Inc.
Lloyd's Register North America, Inc. - Energy
Lloyd's Register Technical Services, Inc.
Loews Corporation - Boardwalk Pipeline Partners, LP
LyondellBasell Industries
MD America Energy, LLC
MDU Resources Group, Inc.
MDU Resources Group, Inc. - Montana Dakota Utilities
MEGlobal Americas, Inc.
Mach Resources LLC
Magellan Midstream Partners, L.P.
Marathon Oil Corporation
Merit Energy Company
Midcoast Energy, LLC
Minnesota Valley Electric Cooperative
Mitsui & Co. Energy Marketing and Services (USA), Inc.
Mitsui E&P USA, LLC
Motiva Enterprises, LLC
Murphy Oil Corporation
NAES Corporation
NCS Multistage, LLC
NOVA Chemicals
National Fuel Gas Distribution Corporation
National Fuel Gas Midstream Company, LLC
National Fuel Gas Supply Corporation
National Grid
NextDecade
NextEra Energy, Inc. - Nextera Energy Gas Producing, LLC
NiSource, Inc.
NiSource, Inc. - Columbia Gas of Kentucky, Inc.
NiSource, Inc. - Columbia Gas of Maryland, Inc.
NiSource, Inc. - Columbia Gas of Massachusetts
NiSource, Inc. - Columbia Gas of Ohio, Inc.
NiSource, Inc. - Columbia Gas of Pennsylvania, Inc.
NiSource, Inc. - Columbia Gas of Virginia, Inc.
NiSource, Inc. - Northern Indiana Public Service Company
Noble Corporation
Noble Energy, Inc.
Northwest Natural Gas
NuStar Energy, L.P.
OGE Energy Corp.
ONE Gas, Inc.
ONE Gas, Inc. - Kansas Gas Services Division
ONE Gas, Inc. - Oklahoma Natural Gas Division
ONE Gas, Inc. - Texas Gas Services Division
ONEOK, Inc.
Oak Ridge Natural Resources
Oasis Petroleum Inc.
Occidental Petroleum Corporation (Oxy)
Oceaneering International, Inc.
Oil Search (Alaska), LLC
Oiltanking U.S.A. Holding, LLC
PDC Energy, Inc.
PJM Interconnection, LLC
Pacific Drilling Services, Inc.
Parkland USA
Patterson UTI Drilling Company, LLC
Pilot Flying J
Pioneer Natural Resources Co.
Plains All American Pipeline, L.P.
Port Houston
Precision Drilling Corporation
QEP Resources, Inc.
RKI Energy Resources, LLC
Range Resources Corp.
Red Bluff Resources Operating, LLC
Repsol Oil Gas USA, LLC
Repsol Services Company
Rockpoint Partners Management - Lodi Gas Storage
Rockpoint Partners Management - Salt Plains Storage
Rockpoint Partners Management - Wild Goose Storage
SGC
STEP Energy Services (USA) Ltd.
STEP Energy Services Holdings Ltd
STEP Technologies (USA) Ltd
Sable Permian Resources, LLC
San Joaquin Facilites Management, Inc.
SandRidge Energy, Inc.
Schlumberger Limited
Secure Energy Services USA, Inc.
SemGroup Corporation
SemGroup Corporation - Houston Fuel Oil Terminal Company
SemGroup Corporation - Rose Rock Midstream
SemGroup Corporation - SemGas
Sentinel Peak Resources, LLC
Shelf Drilling US, Inc.
Sinclair Services Company
Southern Company - Alabama Power Company
Southern Company - Georgia Power
Southern Company - Mississippi Power Company
Southern Company - Southern Company GAS
Southern Company - Southern Company Services, Inc.
Southern Company - Southern Nuclear Operating Company, Inc.
Southern Company - Southern Power Company
Southern Company - SouthernLINC Wireless
Southwest Gas Corporation
Southwestern Energy Company
Spire, Inc.
Suncor Energy (U.S.A) Marketing, Inc.
Sunoco, Inc.
Superior Energy Services, Inc.
Superior Energy Services, Inc. - Completion Services
Superior Energy Services, Inc. - Connection Technology
Superior Energy Services, Inc. - Fluid Management
Superior Energy Services, Inc. - HB Rentals
Superior Energy Services, Inc. - International Snubbing Services
Superior Energy Services, Inc. - Stabil Drill
Superior Natural Gas Corporation
TGS-NOPEC Geophysical Company
TPC Group, LLC
TRC Companies, Inc.
Tapstone Energy, LLC
Tellurian, Inc.
Tervita Environmental Services Inc.
The University of Texas System - Oil & Gas Division
The Williams Companies, Inc.
Total E&P USA, Inc.
Total Petrochemicals & Refining USA, Inc.
TransCanada Corporation (US)
TransCanada Corporation - PipeLines, LP
Unit Corporation
Unit Corporation - Superior Pipeline Company, LLC
Unit Corporation - Unit Drilling Company
Unit Corporation - Unit Petroleum Company
Universal Pressure Pumping, Inc.
Urban Oil and Gas Group
Venari Resources, LLC
Vermilion Energy USA
Vine Oil & Gas, LP
WGL Holdings, Inc. - Washington Gas
WPX Energy, Inc.
Weatherford International, LLC
Wheelabrator Technologies, Inc.
White Rock Oil & Gas, LLC
Whiting Petroleum Corporation
Xcel Energy, Inc.
Xcel Energy, Inc. - Northern States Power Company, a Wisconsin Corporation
Xcel Energy, Inc. - PSCo
Xcel Energy, Inc. - Southwestern Public Service Co.
Yokogawa Corporation of America