Glossary
Browse the IADC Lexicon alphabetically or by category. Get comprehensive definitions of drilling industry terms.
NPSHR Capacity Curve
Definition(s)
NPSHR Capacity Curve
Shows the relationship between NPSHR and capacity.
Non-Recoverable Energy
Definition(s)
Non-Recoverable Energy
Head between the total energy head line and the total head line; energy that is no longer useful for moving oil down the line or vessel because it has been converted to heat and absorbed by the ground surrounding the line or vessel.
Node
Definition(s)
Node
Connection point between different devices in a pipeline model.
Nitrogen, (NO2) cryogenic
Definition(s)
Nitrogen, (NO2) cryogenic
Inert gas, satisfies the operational requirements of underbalance drilling in terms of safety and operational flexibility. Can be expensive in underbalance operations due to transportation, storage and volume requirements. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsNetwork
Definition(s)
Network
Group of persons or components that share information or interact with each other in order to perform a function. Sample Usage: Power plants, substations, and transmission lines constitute a network that creates and distributes electricity. Annotation: Network is used across DHS to explain the joining of physical, cyber, and other entities for a particular purpose or function. Source: DHS Risk Lexicon, U.S. Department of Homeland Security, 2010 Edition. September 2010 Regulatory GuidanceNetwork
System model of pipes and equipment.
Net Standard Volume
Definition(s)
Net Standard Volume
Volume of a fluid at standard pressure and temperature after the deduction of S&W.
Net Pumping Requirement
Definition(s)
Net Pumping Requirement
Total volume of commodity that the line or vessel must pump every day of the month through each section of pipe in order to meet the Notice of Shipment
Net Positive Suction Head Required (NPSHR)
Definition(s)
Net Positive Suction Head Required (NPSHR)
Minimum NPSH required by the pump to prevent cavitation.
Net Positive Suction Head Available (NPSHA)
Definition(s)
Net Positive Suction Head Available (NPSHA)
Actual NPSH available at the pump suction for the particular operating conditions; NPSHA is the difference between NPSHR and NPSH.
Net Positive Suction Head (NPSH)
Definition(s)
Net Positive Suction Head (NPSH)
Head above the vapor pressure of the liquid existing at the pump
suction nozzle.
Needle Valve
Definition(s)
Needle Valve
A globe valve incorporating a needlepoint disc that allows extremely fine flow control.
Near Balance
Definition(s)
Near Balance
A drilling procedure using underbalance techniques to keep the bottom hole pressure near the pore pressure. This technique is often used in very sour
wells.
Natural Gas Liquids (NGL)
Definition(s)
Natural Gas Liquids (NGL)
Petroleum fluid primarily composed of ethane, propane, and butane NGL is a gas at atmospheric pressure but transported as a
Source: IADC UBO / MPD Glossary, December 2011. Global Standards
liquid by maintaining it under high pressure.
Multi-stage Pump
Definition(s)
Multi-stage Pump
Pump that has two or more impellers mounted on the same shaft and an equal number of liquid pressurization stages.