Oil and Gas Terms Beginning with “R” — Page 2

The radius of investigation is the distance from a producing or injecting well at which the pressure disturbance caused by the well's rate change has propagated significantly into the reservoir during a given time… Read more →

What Is a Ram Blowout Preventer? A ram blowout preventer (BOP) is a hydraulically actuated pressure-control device mounted on the wellhead that closes across the wellbore to contain formation fluids during a well… Read more →

A ram preventer (also called a ram blowout preventer or ram BOP) is a pressure-sealing device installed in the blowout preventer stack at the surface wellhead or subsea wellhead that uses hydraulically actuated steel… Read more →

Random error is the nonreproducible component of a measurement that arises from the underlying physics of the sensing process rather than from any fixed flaw in the instrument or method. Where a systematic error pushes… Read more →

Random noise in seismic data acquisition and processing is stochastic energy recorded on seismic traces that has no consistent amplitude, phase, or moveout relationship between adjacent traces or between successive shot… Read more →

The random-walk method is a stochastic, particle-based technique for modelling how fluids and solutes move through a reservoir, in which transport is represented not by solving a smooth differential equation on a grid… Read more →

The difference between the maximum load reached in the upstroke and the minimum load registered in the downstroke. Read more →

Rarefaction in seismic wave physics is the phase of a compressional (P-wave) or acoustic wave cycle in which the propagating disturbance causes the particles of the elastic medium to move apart from their equilibrium… Read more →

(noun) A component of the total skin factor in a well that increases with flow rate, caused by non-Darcy (turbulent or inertial) flow in the near-wellbore region, particularly in high-rate gas wells. The rate-dependent… Read more →

A rathole is an extra length of hole drilled below the deepest interval of interest so that expendable downhole equipment has somewhere to go after it has done its job, most commonly the spent carriers from perforating… Read more →

Crude oil direct from the wellbore, before it is treated in a gas separation plant. It usually contains nonhydrocarbon contaminants. Read more →

Gas coming directly from the wellbore containing nonhydrocarbon contaminants and hydrocarbons that can be liquefied. Read more →

Ray tracing in seismic geophysics is a computational technique for predicting the travel paths and arrival times of seismic wave energy through a heterogeneous subsurface velocity model by following the trajectories of… Read more →

A raypath is the geometrical path followed by a seismic wave as it travels through the earth from source to reflector to receiver, governed by Snell's law of refraction (which requires that the ratio of the sine of the… Read more →

Real-time data in oil and gas operations refers to measurements, sensor readings, and operational parameters that are transmitted from the point of measurement to surface or to a remote monitoring center with latency… Read more →

To ream is to enlarge an existing wellbore to its intended diameter by passing a specialized cutting tool (a reamer) through a section of hole that has been drilled or has become smaller than the design specification —… Read more →

A receiver in exploration geophysics is the device that detects seismic energy, in the form of ground motion on land or a pressure pulse in fluid offshore, and transforms it into an electrical signal that can be… Read more →

In oilfield cementing and drilling operations, to reciprocate means to move the casing string or drill string alternately upward and downward in a cyclic motion while pumping, as a technique to improve fluid… Read more →

A type of fluid pump in which reciprocating pistons or plungers displace the fluid. Read more →

A recirculating mixer is a mechanical system used at the drilling rig to continuously blend drilling fluid additives — particularly high-density weighting materials such as barite, hematite, and calcium carbonate, as… Read more →

(verb) To detect, measure, and store geophysical or well data using electronic instruments for subsequent processing and interpretation. In seismic acquisition, recording involves capturing the electrical signals… Read more →

Recorded data in oilfield context refers to measurements captured and stored in downhole memory by MWD (measurement while drilling) or LWD (logging while drilling) tool electronics for retrieval when the tool is… Read more →

(noun) A downhole or surface instrument that records physical measurements such as pressure, temperature, flow rate, or depth over time during well testing, production logging, or reservoir monitoring operations. Modern… Read more →

A recorder carrier in oil and gas wireline and production testing operations is a downhole tool assembly designed to house and protect recording instruments (pressure gauges, temperature sensors, flow meters, and data… Read more →

Recoverable gas lift gas, often called spent gas lift gas, is injection gas that has travelled down the casing annulus, entered the tubing through gas lift valves, aerated the produced column, and returned to surface… Read more →

The fraction of hydrocarbons that can or has been produced from a well, reservoir or field; also, the fluid that has been produced. Read more →

What Is Recovery Factor in Oil and Gas? The recovery factor is the fraction of original oil in place (OOIP) or original gas in place (OGIP) that is ultimately recovered through all production methods over the economic… Read more →

A recovery forecast is a prediction of the total amount of hydrocarbon production that will ultimately occur from a well, reservoir, or field over its producing life. It is frequently expressed two ways: as an absolute… Read more →

Red mud (also called red clay or tannate mud) is a historical water-based drilling fluid system used in oil and gas well drilling from approximately the 1920s through the 1950s, formulated with naturally occurring clay… Read more →

Redox is the contracted form of reduction-oxidation, a fundamental class of chemical reactions in which one reactant is reduced (gains electrons, with its oxidation state decreasing) while the other reactant is oxidized… Read more →