Oil and Gas Terms Beginning with “N” — Page 3

A nonideal gas, also called a real gas, is one whose pressure, volume, and temperature relationship departs measurably from the ideal gas law and must instead be described by an equation of state of the form pV = znRT,… Read more →

A nonparticipating royalty (NPR) is a mineral interest that entitles its owner to a specified fraction of the gross production from a tract of land (free of production costs, as royalties always are) without the… Read more →

A nonparticipating royalty interest, abbreviated NPRI, is a real property interest in oil and gas that entitles its owner to a defined share of production (or its monetary equivalent) from a tract of land while… Read more →

A normal device is a type of conventional electrical resistivity logging tool in which a current-emitting electrode (A) and a measure voltage electrode (M) are placed close together on the logging sonde with a second… Read more →

What Is a Normal Fault? Normal fault (also called a gravity fault or extensional fault) is a dip-slip fault in which the hanging wall, the rock block above the inclined fault plane, has moved downward relative to the… Read more →

Normal incidence is the case in which a seismic wavefront is parallel to a subsurface interface and its raypath is perpendicular, or normal, to that interface as the wave impinges upon it. In other words, the energy… Read more →

Normal mode in petroleum well logging and acoustic measurement refers to a specific propagation mode of elastic wave energy in a fluid-filled borehole — a guided wave that travels along the borehole axis as a… Read more →

Normal moveout, abbreviated NMO, is the increase in reflection traveltime that occurs as the distance between the seismic source and receiver grows, for energy reflected from a flat, horizontal interface. NMO correction… Read more →

Normal pressure (also called hydrostatic pressure or normal pore pressure) describes the condition in a subsurface formation where the pore fluid pressure equals the pressure exerted by a continuous column of formation… Read more →

Normal-moveout correction (NMO) is a seismic data processing step that compensates for the geometric time delay introduced when a downgoing acoustic wave reflects off a subsurface interface and returns to receivers… Read more →

Normality (symbol N) is a measure of solution concentration used in analytical chemistry and oilfield laboratory testing that expresses the number of gram equivalents of a reactive solute dissolved per liter of… Read more →

What Is a Nuclear Fluid Densimeter? A nuclear fluid densimeter is a production logging tool that measures in-situ fluid density in a completed well by passing gamma rays from a radioactive source through the wellbore… Read more →

Nuclear magnetic resonance (NMR) is a physical phenomenon in which atomic nuclei with non-zero spin quantum numbers absorb and re-emit electromagnetic radiation at specific resonant frequencies determined by the… Read more →

What Is NMR Measurement in Petroleum Well Logging? Nuclear magnetic resonance (NMR) measurement in petroleum logging uses the magnetic properties of hydrogen atoms in pore fluids to characterise formation porosity, pore… Read more →

Numerical methods in petroleum engineering and geoscience are mathematical techniques that solve governing equations (differential equations, integral equations, systems of algebraic equations) by discretizing… Read more →

A numerical model in petroleum engineering and geoscience is a mathematical representation of a subsurface system (a reservoir, basin, wellbore, or geological formation) encoded entirely in numerical form (as arrays of… Read more →

What Is Numerical Reservoir Simulation? Numerical reservoir simulation (also called reservoir modeling or numerical simulation) is the use of finite-difference or finite-element mathematical methods to solve the coupled… Read more →