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

Caustic potash (potassium hydroxide, KOH) is a strong alkali used in Western Canada Sedimentary Basin drilling fluid chemistry as a pH control agent, emulsifier activator, and clay stabilizer additive in water-based and… Read more →

Caustic soda (sodium hydroxide, NaOH) is the most widely used alkaline pH control agent in Western Canada Sedimentary Basin water-based drilling fluid programs, added to the active mud system in pellet, flake, or liquid… Read more →

The cave effect is the systematic degradation of wireline log readings that occurs when the borehole has been enlarged beyond the nominal bit diameter by mechanical erosion, chemical dissolution, or shale sloughing… Read more →

Cavings are fragments of formation rock that fall or slough from the borehole wall into the annulus during drilling operations, transported to surface by the circulating drilling fluid and observed at the shale shaker… Read more →

Cavitation is the formation and violent collapse of vapor-filled cavities (bubbles) within a liquid when the local pressure drops below the liquid's vapor pressure, causing the implosion of those bubbles when they are… Read more →

A cellar is the excavated pit or constructed below-grade enclosure at a drilling location that houses the wellhead, BOP stack, conductor casing, and associated wellhead equipment below the rig floor level, providing the… Read more →

Oil well cement is a hydraulic binding material formulated from Portland clinker (calcium silicate compounds produced by high-temperature kiln firing of limestone and clay) that is slurried with water and pumped… Read more →

A cement accelerator is a chemical additive incorporated into an oil well cement slurry to shorten the thickening time and increase the rate of early compressive strength development, counteracting the natural slowness… Read more →

A cement additive is any chemical or material incorporated into an oil well cement slurry to modify one or more slurry properties (thickening time, compressive strength development rate, fluid loss, free water, density,… Read more →

A cement bond log (CBL) is an acoustic wireline logging tool run after primary cementing in a Western Canada Sedimentary Basin well to evaluate the quality and completeness of the cement sheath in the annular space… Read more →

A cement dispersant is a chemical additive incorporated into an oil well cement slurry to reduce the viscosity and yield point of the fresh slurry by adsorbing onto the surfaces of Portland cement particles and creating… Read more →

A cement extender is a material added to an oil well cement slurry to reduce its density below the baseline neat Class G slurry value of approximately 1,898 kg/m3 (15.8 ppg), either by replacing a portion of the cement… Read more →

A cement head is the surface pressure vessel threaded or flanged onto the top of the casing string immediately before a primary cementing job, serving as the mechanical interface between the cementing unit pump lines… Read more →

A cement plug is a column of set Portland cement placed at a specific depth inside a wellbore (either inside the casing or in open hole below the casing shoe) for the purpose of permanently or temporarily sealing a… Read more →

A cement retainer is a retrievable or drillable downhole packer-like tool set inside the casing at a specific depth to provide a mechanical back-pressure seat that prevents freshly squeezed cement from U-tubing back… Read more →

A cement retarder is a chemical additive incorporated into an oil well cement slurry to delay the onset of hydration-driven stiffening and extend the thickening time of the fresh slurry beyond what neat Class G Portland… Read more →

A cement squeeze is a remedial cementing operation that pumps cement slurry through perforations or casing defects into the annular space behind the casing, or into a formation adjacent to the wellbore, under sufficient… Read more →

Cementation, in the geological and petrophysical context, is the diagenetic process by which mineral precipitates crystallize from pore water in the intergranular pore space of a sedimentary rock after deposition,… Read more →

The cementation exponent, designated m in Archie's equation, is the petrophysical parameter that quantifies how the electrical conductivity of a water-saturated porous rock decreases as porosity decreases due to… Read more →

A cementer is the field specialist employed by a cementing service company (Halliburton, Schlumberger, BJ Services, Trican Well Service, Calfrac Well Services) who is responsible for the on-location design verification,… Read more →

Cementing in oil and gas well construction is the operation that places a Portland cement slurry in the annular space between the outside of a casing string and the borehole wall, or inside a casing string for plug… Read more →

Cementing plugs are the rubber wiper devices pumped through the inside of a casing string during oil and gas well cementing operations to physically separate the cement slurry from the drilling fluid ahead of it and the… Read more →

Centipoise (abbreviated cP) is the standard unit of dynamic viscosity used throughout the oil and gas industry to quantify the internal resistance of a fluid to flow under an applied shear stress, defined as one… Read more →

A centralizer is a mechanical device attached to the outside of a casing string at defined spacing intervals to hold the casing concentrically within the borehole and prevent it from lying on the low side of the… Read more →

Centrifugal pumps on Western Canada Sedimentary Basin drilling rigs serve as the auxiliary fluid-handling workhorses that support every phase of the drilling fluid circulation system, from mixing new mud in the mixing… Read more →

The drilling fluid centrifuge used on Western Canada Sedimentary Basin horizontal well rigs is a continuous-flow decanting centrifuge that separates the drilling mud stream into a liquid-rich overflow (containing fine… Read more →

Cesium acetate (CsCH3COO, molar mass 191.9 g/mol) is a water-soluble cesium salt that produces a clear, solids-free completion and workover brine spanning densities from 1,000 kg/m3 (freshwater base) to approximately… Read more →

Cesium formate (CsHCO2, also written CsCOOH or cesium methanoate, molar mass 177.9 g/mol) is a water-soluble cesium salt that produces a clear, solids-free completion and workover brine achieving densities from 1,000… Read more →

Chain tongs are among the highest-risk hand tools on Western Canada Sedimentary Basin service rigs and drilling rigs, responsible for a disproportionate share of hand, finger, and wrist injuries in the WCSB well service… Read more →

Chalk is a fine-grained, white to off-white carbonate rock composed predominantly of the skeletal debris of coccolithophores (single-celled marine algae that secreted microscopic calcite plates called coccoliths)… Read more →