WCS Glossary
- Anion
- Annular Blowout Preventer
- Annular Friction Losses (AFL)
- Annular Pressure Loss (APL)
- Annular Space (Annulus)
- Annular Valve
- Annular Velocity
- Annulus Friction Pressure (AFP)
- ANSI
- Antifoam
- API Gravity
- Apparent Power
- Apparent Viscosity
- Aquathermal Event
- Aromatics
- Asbestos
- ASME
- Asphalt
- Atom
- Atomic Number
- Attapulgite Clay
- Automatic J
- Autoshear
- Back-In Unit
- Back Off
- Back-Pressure
- Back Pressure (BP) / Surface Back Pressure (SBP) / Surface Applied Back Pressure (SABP)
- Back-Pressure Limit
- Back-Pressure Valve
- Back Pressure Valve
- Back Up
- Back-Up Element
- Backpressure Valve (BPV)
- Backside
- Backup
- Bail
- Bailer
- Balance
- Balance, Mud
- Balance/Underbalance/Overbalance
- Ball
- Ball Catcher
- Ball Check Valve
- Ball Sealers
- Ball Valve
- Ballooning (Formation)
- Ballooning (Tubular)
- Barite (Barytes)
- Barite Plug
- Barrel