Oil and Gas Terms Beginning with “C” — Page 6

A device to carry data from a receiver to a recorder, such as from a group of geophones. Simultaneous recording of 500 to 2000 channels is common during 3D seismic acquisition, and 120 to 240 channels during onshore 2D… Read more →

What Is a Channel Wave? Channel wave (also called a guided wave or formation channel wave) is a seismic wave that propagates along a low-velocity geological layer sandwiched between higher-velocity formations, with its… Read more →

What Is Channeling? Channeling in oil and gas refers to the preferential flow of injection fluid (water, gas, steam, or chemicals) through high-permeability pathways in the reservoir, bypassing significant volumes of… Read more →

A distinguishing feature of a waveform in a seismicevent, such as shape, frequency, phase or continuity. Read more →

What Is a Charged Zone? A charged zone in petroleum engineering refers to a subsurface formation that is pressurised by hydrocarbons or overpressured pore fluid — a zone that has been "charged" by petroleum migrating… Read more →

What Is a Check Valve? A check valve (also called a non-return valve or one-way valve ) is an automatic valve that permits fluid flow in only one direction, opening when upstream pressure exceeds downstream pressure by… Read more →

What Is a Check Shot Survey? A check shot survey is a seismic velocity measurement made at discrete depth intervals inside a borehole, used to calibrate the sonic log velocity to the seismic velocity field and establish… Read more →

To combine a metal ion and a complexing agent to form a ring structure. Read more →

What Is a Chelating Agent? A chelating agent (or chelant) is an organic compound with multiple binding sites (Lewis base donor groups) that form stable, soluble ring-structured complexes (chelates) with metal ions —… Read more →

What Is Chelation? Chelation (also called metal sequestration or complexation treatment ) is the chemical process in which a multidentate ligand -- a molecule with multiple electron-donor sites -- forms several… Read more →

A 20- to 50-gallon [3.2- to 7.9 m3] container for liquid mud additives, usually located above the suction pit on a drilling rig. The chemical barrel is used to slowly dispense various types of liquids into the active… Read more →

What Is a Chemical Cutter? A chemical cutter is a wireline or coiled tubing-deployed well intervention tool that severs stuck or abandoned tubulars — including production tubing, drill pipe, or casing — by directing a… Read more →

What Is Chemical Diversion? Chemical diversion (also called diverting agent treatment or diverter placement ) is a stimulation technique used during matrix acidizing to redirect acid from high-permeability,… Read more →

What Is a Chemical Diverter? Chemical diverter (also called a diverting agent or temporary plugging material) is a substance pumped into a wellbore during acid stimulation or hydraulic fracturing to temporarily block… Read more →

What Is Chemical Flooding? Chemical flooding is an enhanced oil recovery (EOR) technique in which chemical agents are injected into the reservoir to alter the displacement mechanics of a waterflood and improve oil… Read more →

What Is Chemical Injection? Chemical injection (also called production chemical dosing or flow assurance chemical treatment) is the continuous or batch introduction of specialty chemicals into production flowlines,… Read more →

What Is a Chemical Neutron Source? Chemical neutron source (also called a radioisotope neutron source or passive neutron source) is a device that produces a continuous flux of neutrons through nuclear reactions… Read more →

The amount of oxygen needed to oxidize reactive chemicals in a water system, typically determined by a standardized test procedure. COD is used to estimate the amount of a pollutant in an effluent. Compare to… Read more →

1. n. [EOR]The change in the Gibbs free energy of a system when an infinitesimally small amount of a component is added under constant pressure and temperature while keeping the mass of the other components of the… Read more →

What Is a Chemical Wash? Chemical wash (also called surfactant pre-flush or chemical spacer ) is a low-viscosity spacer fluid pumped ahead of a cement slurry during primary cementing operations. Typically formulated… Read more →

A technique in which a slug of material is introduced into the flowstream of a producing well to determine the flow rate of one or more of the fluids. The marker has specific properties, such as high neutron… Read more →

A sedimentaryrock and a variety of quartz made of extremely fine-grained, or cryptocrystalline, silica, also called chalcedony. The silica might be of organic origin, such as from the internal structures of sponges… Read more →

What Is a Chloride Test? Chloride test (also called chloride titration or Cl - analysis) is a standard drilling fluid quality control procedure that measures the concentration of chloride ions (Cl - ) in the mud… Read more →

[(Mg,Al,Fe) 12(Si,Al) 8O20(OH) 16]A platy, pale green mineral of the mica group of sheet silicates, also considered to be a type of clay mineral, found in sedimentary and low-grade metamorphic rocks. Chlorite is a… Read more →

What Is a Choke? A choke is a device containing a calibrated orifice that restricts fluid flow rate or controls downstream pressure across well control operations, production systems, and injection flow lines worldwide.… Read more →

What Is a Choke Line? A choke line is the high-pressure steel pipe that routes wellbore fluid from a dedicated outlet on the blowout preventer (BOP) stack to the surface choke manifold, providing the pressure-controlled… Read more →

What Is a Choke Manifold? A choke manifold is a surface pressure control assembly installed on the wellhead or integrated into the drilling and completion equipment — comprising choke valves, isolation valves, pressure… Read more →

A type of salt in which chromium atoms are in the plus-6 valence state, such as potassium chromate, K2CrO4. Chromium compounds of various types have been used in lignite and lignosulfonate and other mud additives to… Read more →

Pertaining to a mud additive (usually lignosulfonate or lignite) that does not contain any chromium compounds. Read more →

What Is Chrome Lignite? Chrome lignite (also called chrome-treated lignite or CTL) is a drilling fluid filtration control additive prepared by treating natural leonardite or sub-bituminous coal (lignite) with chromic… Read more →