Oil and Gas Terms Beginning with “R” — Page 5

A retort in drilling fluid analysis is a specialized mud distillation unit used to measure the volumetric content of water, oil, and solids in a drilling fluid sample — providing the fundamental compositional analysis… Read more →

What Is the Retort Method? The retort method is a laboratory technique for determining fluid saturations in a core sample by crushing and heating the sample to 650°C, vaporising oil and water that are collected,… Read more →

Retort solids are the residual inorganic material remaining in the retort cup after a measured volume of drilling fluid has been heated to vaporize all liquid phases (water and oil), with the volume percentage of solids… Read more →

A retrievable bridge plug is a temporary downhole pressure isolation device that is set across the casing or liner bore at a specified depth to create a mechanical barrier between the formation below and the wellbore… Read more →

A retrievable gun is a perforating gun built to be recovered intact from the wellbore after it has fired, in contrast to expendable or semi-expendable systems whose components are designed to be left downhole or to… Read more →

A retrievable packer is a downhole wellbore isolation tool that seals the casing-tubing annulus at a specific depth and can be unset and retrieved from the wellbore after its operational purpose is served, in contrast… Read more →

Retrogradation in oil and gas geoscience refers to two distinct phenomena sharing the same term: in sequence stratigraphy and sedimentology, retrogradation describes the landward and upward shift in the position of… Read more →

What Is Retrograde Condensation? Retrograde condensation is the counterintuitive thermodynamic phenomenon in which a hydrocarbon gas mixture forms liquid droplets as pressure is reduced at constant temperature — the… Read more →

Returns in drilling operations refers to the drilling fluid (mud) that circulates from the surface down through the drillstring, exits through the drill bit nozzles at the bottom of the hole, and travels back up the… Read more →

Reverse circulation is a drilling fluid circulation method in which the drilling fluid is pumped downward through the annular space between the drill string and the borehole wall and returns upward through the interior… Read more →

What Is Reverse Combustion? Reverse combustion is a variant of in-situ combustion enhanced oil recovery in which ignition is initiated at a production well while air is injected at a separate injection well, causing the… Read more →

A reverse fault is a geological fault in which the hanging wall (the rock block above the fault plane) has moved upward relative to the footwall (the rock block below the fault plane) as a result of compressional… Read more →

A reverse circulating valve (RCV) is a downhole tool installed in the drill string or completion string that allows fluid to be pumped down the annulus (the space between the outside of the pipe and the borehole wall)… Read more →

A rheological property is a physical characteristic describing how a material deforms and flows under applied stress, and for drilling fluids this encompasses plastic viscosity (PV), yield point (YP), gel strength at 10… Read more →

Rheology is the science of the deformation and flow of matter — in drilling fluid engineering, the study of how a mud system responds to applied stress by measuring plastic viscosity, yield point, gel strengths, and… Read more →

A rheology modifier is a chemical additive used to alter the flow behavior (viscosity, yield point, gel strength, and flow regime) of drilling fluids, completion fluids, cement slurries, fracturing fluids, or production… Read more →

Rhombohedral packing (also called close-packing or face-centered cubic packing) is the tightest possible arrangement of equal spheres in three dimensions, in which each sphere is in contact with 12 neighboring spheres… Read more →

Rich gas is natural gas that carries a significant fraction of heavier hydrocarbons (ethane, propane, butanes, and natural gasoline) dissolved in the methane stream, giving it a higher heating value and, more… Read more →

A rich gas condensate is a gas-phase reservoir fluid carrying a high proportion of intermediate and heavy hydrocarbon components, such that when reservoir pressure is reduced below the dewpoint at reservoir temperature,… Read more →

In a glycol dehydrator, glycol that contains water released by wet gas while percolating upward in the absorber. Read more →

Lean oil that has absorbed heavier hydrocarbon components from a gas stream Read more →

To pull apart the Earth's crust. Read more →

A rig is the integrated machine used to drill an oil or gas wellbore — a complex assembly of mechanical, hydraulic, electrical, and structural systems that together perform the rotation, weight transfer, fluid… Read more →

To rig down is to systematically dismantle a drilling or service rig and its associated equipment so the unit can be safely transported and re-erected at the next location. The term covers the full teardown sequence… Read more →

The rig floor is the elevated working platform of a drilling rig that surrounds the rotary table or top drive and serves as the primary work area for the drilling crew during all pipe-handling, connection-making, and… Read more →

To rig up means to assemble and connect all the equipment needed for an operation so it is ready to function safely and on demand. The term is used across nearly every phase of a well's life, from the initial mast and… Read more →

Right angle set, abbreviated RAS in cementing engineering literature and sometimes written right-angle-set, describes a specific consistency-versus-time profile exhibited by a well cement slurry during the thickening… Read more →

A right of first refusal, commonly shortened to ROFR and also called a preferential right to purchase or preemptive right, is the right that other parties to a lease, well, unit, or concession hold to acquire the… Read more →

Right-angle set is the hyphenated form of the same cementing-engineering term used interchangeably with right angle set or RAS in API and ISO well cementing literature, and it refers to a specific shape of the… Read more →

A rigless operation is any well intervention or maintenance activity performed without the deployment of a drilling rig or service rig over the wellbore, relying instead on lighter mobile equipment such as coiled tubing… Read more →