WCS Glossary
- Report by Exception
- Reservoir
- Reservoir Pressure
- Resistivity
- Responsible Party
- Retainer
- Retarder
- Return System
- Reverse Circulation
- Reynolds Number
- Rheology
- Rig
- Riser
- Riser Gas
- Riser Pipe
- Rising Characteristic Curve
- Risk Management
- Rock Matrix
- Roller-Cone Bit
- Rotary Drilling
- Rotary Hose
- Rotary Motion Valve
- Rotary Table
- Rotating Blowout Preventer
- Rotating Control Device (RCD)
- Rotating Diverter
- Rotating Head
- Roughneck
- Roughness
- Round Trip
- Roustabout
- Royalty
- RTU
- Rupture disc
- Sack
- Safety Joint
- Safety Margin (Drilling)
- Safety Margin (Intervention, PCE)
- Safety Rams
- Safety Valve
- Safety Valves (Pop-Offs)
- Salt
- Sample Catcher
- Samples
- Sand
- Sand Content
- Sand Line
- Sandstone
- Scraper
- Scraper Pig