Oil and Gas Terms Beginning with “R”

The R-signal (resistive signal) in induction logging is the part of the alternating-current signal at the receiver coil of an induction logging tool that is in-phase with the transmitter coil current — providing the… Read more →

RCRA, the Resource Conservation and Recovery Act, is the principal United States federal statute governing the generation, transportation, treatment, storage, and disposal of solid and hazardous waste, enacted by… Read more →

Relative humidity (RH) in the context of drilling fluids is the water activity of a brine solution expressed as a percentage — defined as the ratio of the water vapor pressure of the solution to the water vapor pressure… Read more →

Run in hole (RIH), abbreviated from the full phrase "run in hole" and used interchangeably with the verb "trip in," describes the operation of lowering any tubular string, tool string, or downhole assembly into the… Read more →

Rm (mud resistivity) is the electrical resistivity of the drilling mud at a specified temperature, one of the four formation water and mud resistivity parameters (Rm, Rmf, Rmc, and Rw) used in the borehole correction… Read more →

Abbreviation for remotely operated vehicle. Read more →

Abbreviation for Recommended Practice. Read more →

The closing and sealing component on a blowout preventer. Types include blind, pipe, or shear rams. Read more →

What Is a Rayleigh Wave? A Rayleigh wave is a dispersive seismic surface wave in which particles trace retrograde elliptical paths in the vertical plane containing the propagation direction, concentrating most energy… Read more →

A tool that enlarges holes to specified size, stabilizes the bit, straightens wellbores, and maintains even diameter in boreholes. Read more →

What Are Reserves? Reserves are the estimated quantities of oil, natural gas, and natural gas liquids that are anticipated to be commercially recoverable from known accumulations from a given date forward under existing… Read more →

What Is Reservoir Rock? Reservoir rock is a porous and permeable rock unit that contains recoverable quantities of oil, gas, or both within its interconnected pore spaces, and allows those fluids to flow through its… Read more →

Abbeviation for horizontal resistivity. Read more →

Rich-azimuth towed streamer acquisition (RATS) is a marine seismic data acquisition method that uses one or more seismic vessels towing multiple streamers and air gun sources in geometries designed to sample reflection… Read more →

A zero-phasewavelet commonly convolved with a reflectivitytrace to generate a synthetic seismogram. Read more →

Abbreviation for vertical resistivity. Read more →

Rwa is the apparent resistivity of formation water, calculated from log measurements of porosity (phi) and deep formation resistivity (Rt) using the Archie equation rearranged with water saturation Sw set to 1 (i.e.,… Read more →

What Is a Rabbit? A rabbit is a drift gauge run through casing, tubing, drill pipe, valves, or completion equipment to prove the inside diameter is open enough for the next tool. API Spec 5CT casing and tubing practice… Read more →

What Is Racking Back Pipe? Racking back pipe is the rig floor operation of removing stands of drillpipe or drill collars from the drill string during a trip out of the hole and standing them vertically in the derrick's… Read more →

An array of sources or receivers radiating outward from a central point, usually a borehole. Read more →

A radial differential temperature log is a wellbore measurement that records the difference in temperature between multiple points at the same depth but at different radial positions within the borehole — typically… Read more →

Radial processing (also called radial trace transform processing or RT processing) is a seismic data processing technique that applies a coordinate transformation to shot records from the conventional offset-time (x-t)… Read more →

Radial refraction is a borehole seismic survey method in which a surface energy source is fired from many different locations and azimuths toward a receiver, usually a three-component geophone, clamped inside a… Read more →

Radial resolution in well logging is the characteristic distance that quantifies the ability of a logging measurement to resolve formation property changes in the radial direction perpendicular to the wellbore axis — in… Read more →

Radial response in well logging describes the spatial sensitivity function of a downhole measurement tool as a function of distance from the borehole wall into the formation, quantifying how far into the undisturbed… Read more →

Radio silence in oil and gas operations is a designated period or condition during which all non-essential radio transmissions on the rig or facility are suspended and all electronic ignition sources including mobile… Read more →

A radio-safe detonator is an electrical initiator used in wireline and electronic firing-head perforating operations that is engineered to be immune to radio-frequency energy and stray electrical currents, so it cannot… Read more →

A radioactive tracer in petroleum engineering is a radioisotope-tagged compound — typically a liquid, solid particulate, or gas — that is injected into a wellbore or reservoir fluid stream and subsequently detected by… Read more →

What Is a Radioactive Tracer Log? A radioactive tracer log is a production logging technique that uses short-lived radioactive isotopes injected into the wellbore — typically with injection fluid, acid, or cement — to… Read more →

The radius of curvature method in directional drilling is a computational approach for calculating the three-dimensional position of a wellbore between two survey stations, in which the borehole path is assumed to… Read more →