Oil and Gas Terms Beginning with “N”

Abbreviation for natural gas liquids. Read more →

NMO, short for normal moveout, is the difference in arrival time of a reflected seismic event recorded at different source-to-receiver offsets, and the NMO correction is the processing step that removes that… Read more →

NMR (nuclear magnetic resonance) in petroleum well logging is a measurement technique in which a downhole tool creates a strong static magnetic field that aligns hydrogen proton spins in formation fluids, then applies… Read more →

What Is Nodal Analysis? Nodal analysis (also called systems analysis or production systems analysis) is a production engineering technique that evaluates the performance of the complete producing system by selecting a… Read more →

NPDES (National Pollutant Discharge Elimination System) is the U.S. federal permit program established under the Clean Water Act of 1972 that regulates the discharge of pollutants from point sources (pipes, ditches, and… Read more →

What Is NPV? NPV (Net Present Value) is the financial metric used in oil and gas project evaluation that calculates the sum of all projected future cash inflows and outflows discounted to their present-day value at a… Read more →

Natural remanent magnetism (NRM) is the permanent magnetization preserved in a rock or sediment that was acquired at the time of the rock's formation or during a subsequent diagenetic or metamorphic event, as opposed to… Read more →

Narrow-azimuth seismic data, abbreviated NAZ, is conventional towed-streamer marine seismic acquired with a single vessel that tows one or two source arrays directly in front of a spread of receiver streamers, producing… Read more →

A Newtonian fluid is a fluid whose viscosity remains constant at all shear rates when temperature and pressure are held constant, meaning that the relationship between shear stress and shear rate is linear and passes… Read more →

What Is Naphthene-Base Crude Oil? Naphthene-base crude oil (also called naphthenic crude or cycloparaffinic crude) is a crude oil in which the dominant hydrocarbon compound class consists of naphthenes, the industry… Read more →

Naphthenic hydrocarbons (also called naphthenes, cycloparaffins, or cycloalkanes) are organic compounds of carbon and hydrogen containing one or more saturated ring structures (cyclic aliphatic rings) as the principal… Read more →

Native clay refers to clay minerals that are naturally present in a reservoir or near-surface formation as an intrinsic component of the rock's mineralogy, as distinguished from clays introduced from external sources… Read more →

A native state core is a rock sample cut and handled so that it preserves the in-situ water saturation and, just as importantly, the original wettability of the reservoir, making it the gold standard for special core… Read more →

Native solids mud (also called native mud or spud mud) is a drilling fluid in which the suspended solid phase consists primarily of dispersed formation clays, sand, chert, and other lithic fragments that originated from… Read more →

A completion system designed to utilize the natural flow capability of the reservoir. Read more →

Natural frequency in mechanical and structural engineering is the frequency (measured in cycles per second, hertz, or radians per second) at which a physical system (a structure, a mechanical component, a fluid column,… Read more →

Natural gamma ray spectroscopy (NGS) is a nuclear well logging measurement that detects gamma rays emitted by naturally radioactive elements in the formation and decomposes the total gamma ray spectrum into… Read more →

What Is Natural Gas? Natural gas is a gaseous mixture of hydrocarbons, predominantly methane (CH4), extracted from geological formations and used as fuel for power generation, heating, and industrial processes, and as a… Read more →

What Are Natural Gas Liquids? Natural gas liquids (also called NGLs or plant liquids) are the mixture of heavier hydrocarbon compounds extracted from raw natural gas at gas processing plants, comprising ethane, propane,… Read more →

Natural gasoline is a liquid hydrocarbon mixture that comes out of natural gas processing. It is heavier than methane, ethane, propane, or butane, but lighter than the crude oil and condensate that show up at the… Read more →

Natural remanent magnetism (NRM) is the permanent magnetization preserved in a rock or sediment that was acquired at the time of the rock's formation or during a subsequent diagenetic or metamorphic event, as opposed to… Read more →

A naturally flowing well is one in which the energy stored in the reservoir is sufficient to lift hydrocarbons to surface and deliver them at a commercial rate without any form of artificial lift such as a pump, gas… Read more →

What Are Naturally Occurring Radioactive Materials (NORM)? Naturally occurring radioactive materials (abbreviated NORM, and sometimes called technologically enhanced NORM or TENORM when concentrated by industrial… Read more →

What Is Neat Cement? Neat cement (also called base slurry or unextended cement) is a Portland cement slurry mixed with water at the minimum water-to-cement ratio required to achieve pumpability without any chemical… Read more →

Neritic in geological and petroleum geoscience refers to the shallow marine environment and the sedimentary deposits formed in the zone between the low tide mark and the edge of the continental shelf at a water depth of… Read more →

A geophone array. Nests can contain numerous closely spaced geophones. Read more →

Nested fractal structures describe any model that incorporates more than one variable represented by fractal geometry or a fractal function, with the descriptors arranged at different scales so that fine-scale fractal… Read more →

The volume of gas produced less gas injected. Read more →

The volume of oil produced less oil injected. In hydraulic pumping, the oil injected is known as power oil. Read more →

What Is a Net Profits Interest? Net profits interest (also called NPI or net profit interest) is a non-operating interest in oil and gas production that entitles the holder to receive a specified percentage of the net… Read more →