Glossary
Browse the IADC Lexicon alphabetically or by category. Get comprehensive definitions of drilling industry terms.
Valve Positioners
Definition(s)
Valve Positioners
Valve positioners compare the control signal to the actuator's position and move the actuator accordingly. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsValve Flow Coefficient
Definition(s)
Valve Flow Coefficient
Specifies the friction coefficient for a valve. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsValve Actuators Hydraulic/Electro-hydraulic
Definition(s)
Valve Actuators Hydraulic/Electro-hydraulic
Hydraulic and electro-hydraulic valve actuators convert fluid pressure into motion.. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsValve Actuators Pneumatic
Definition(s)
Valve Actuators Pneumatic
Pneumatic valve actuators that convert air pressure into motion. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsMotor Actuators Electric/Electronic
Definition(s)
Motor Actuators Electric/Electronic
Valve
actuators using a motor to drive a combination of gears that generates the desired torque or thrust level. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsValve Actuators Manual
Definition(s)
Valve Actuators Manual
By definition, require no outside power source. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsValve Actuators
Definition(s)
Valve Actuators
General - devices that, in response to a signal, automatically move the valve to the desired position using an outside power source. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsUpsurge
Definition(s)
Upsurge
Positive pressure surge. Upsurge pressure is above the normal operating pressuren. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsUnloader
Definition(s)
Unloader
See: pocket unloader. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsUnderbalanced Operation (UBO)
Definition(s)
Underbalanced Operation (UBO)
A well construction or maintenance activity employing appropriate equipment and controls where the pressure exerted in the wellbore is intentionally less than the pore pressure in any part of the exposed formations with the intention of bringing formation fluids to the surface. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsUnderbalanced
Definition(s)
Underbalanced
Conducted in a state of underbalance. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsUltimate Potential
Definition(s)
Ultimate Potential
An estimate of recoverable reserves produced by the time all exploration and development activity is completed. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsUBD Zone
Definition(s)
UBD Zone
Section of well, in the context of Underbalanced Operations, where performing UBD. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsTurbulent Flow
Definition(s)
Turbulent Flow
Occurs when fluid particles in the line or vessel flow in random directions and forward at the same velocity. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsTurbine Meter
Definition(s)
Turbine Meter
A meter using a multi-bladed rotor to which the fluid imparts a rotational velocity that is proportional to the mean velocity of the stream; counting rotor revolutions derives volume. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsTuning
Definition(s)
Tuning
Tweaking physical system characteristics until predicted flow and pressure values match actual data. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsTransition Region
Definition(s)
Transition Region
Flow regime where the fluid flow is turbulent but not fully developed turbulence. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsTransition Flow
Definition(s)
Transition Flow
Multiphase-fluid flow regime characterized by a chaotic mixture of liquid and gas, with neither phase appearing to be continuous. Also known as churn flow, transition flow is an intermediate flow condition between slug flow and mist flow. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsTransit Time
Definition(s)
Transit Time
Time it takes the carrier to transport a batch from the supply point to the delivery point. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsTransient Model
Definition(s)
Tension Tool
On- or off-line simulation that considers dynamic fluid flow characteristics over a specified time span. Also called unsteady state model. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsTransient Analysis
Definition(s)
Transient Analysis
Method of flow analysis of a line or vessel system that takes into consideration changing flowing or pressure conditions over time usually using a computer program. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsTransient Flow
Definition(s)
Transient Flow
Unsteady (changing) flow or pressure condition that changes with time. A transient can also refer to a transition between two steady state conditions. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsTransient
Definition(s)
Transient
Unsteady (changing) flow or pressure condition that changes with time. A transient can also refer to a transition between two steady state conditions. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsTraceability
Definition(s)
Traceability
Ability to document the history of an object.- NOTE: Traceability can relate to both the origin of materials and finished parts as well as associated processing history.