WCS Glossary
- Darcy
- Darcy Equation
- Dart Valve
- Dead Band
- Dead Well
- Deadman
- Deflection
- Defoamer
- Degasser
- Degree-day
- Degree of Tolerance
- Dehydration
- Dehydrator
- Densitometer
- Density
- Depthometer
- Derrick
- Derrickman
- Desander
- Design Capacity
- Design Pressure
- Design Thermal Analysis (DTA)
- Determined Viscosity
- Deviation
- Diameter
- Die Collar
- Differential Head
- Differential Pressure
- Direct Use
- Directional Drilling
- Discharge Control
- Discharge Nozzle
- Discharge Pressure
- Discharge Pressure Allowable
- Discharge Set Point
- Discharge Valve
- Displacement
- Displacement (compressor)
- Displacement Meter
- Displacement (pipe)
- District Heating
- Diverter
- Dog Leg
- Doghouse
- Dolomite
- Double
- Down Surge
- Downhole
- Downhole Pumping MPD
- Drafting