Oil and Gas Terms Beginning with “T” — Page 3

A temperature survey (also called a temperature log or geothermal survey) is a wellbore measurement in which a calibrated thermometer or thermistor sensor is run on slickline, wireline, coiled tubing, or as part of a… Read more →

The force per unit cross-sectional area required to pull a substance apart. Read more →

A tension-set packer is a downhole mechanical sealing device used in oil and gas well completions and workovers that is set in tension (by picking up the tubing string and maintaining an upward pull force on the tool… Read more →

Tensor methods are the family of mathematical techniques that represent directionally dependent reservoir properties as rank-two tensors rather than as single scalar values, allowing geologists and reservoir engineers… Read more →

A term lease is an oil and gas lease that expires automatically after a stated period of time, regardless of whether oil, gas, or other minerals are being produced from the lands when that period ends. It stands in… Read more →

A ternary diagram (also called a triangular diagram or ternary plot) is a graphical tool used across many disciplines in petroleum engineering, geochemistry, petrology, and fluid phase behavior to represent the… Read more →

Terrain correction (also called topographic correction) in gravity surveying is a mathematical adjustment applied to raw gravimeter measurements to remove the gravitational effect of the irregular terrain surrounding… Read more →

Pertaining to sediments or depositional environments on land or above the level of high tide. Read more →

Tertiary recovery refers to the third stage of hydrocarbon production from a reservoir — the suite of enhanced oil recovery (EOR) methods applied after primary recovery (natural reservoir energy drive) and secondary… Read more →

A test separator is a process vessel used to separate and meter relatively small quantities of produced oil, gas, and water for the purpose of evaluating individual well production performance — distinguished from… Read more →

In petroleum engineering, the word "theoretical" describes an equation or a model that was derived from the basic laws of physics, chemistry, or mathematics, rather than from fitting curves to experimental data. A… Read more →

Thermal diffusion length (Ld) is a parameter used in nuclear physics and neutron logging to characterize thermal neutron interactions in bulk materials — defined as the characteristic distance between the point at which… Read more →

The thermal gradient, also called the geothermal gradient, is the rate at which temperature increases with depth in the Earth, normally expressed in degrees Celsius per kilometre or degrees Fahrenheit per thousand feet.… Read more →

Thermal maturity is the degree to which a source rock has been heated over geologic time during the process of transforming solid kerogen into liquid and gaseous hydrocarbons. It is the single most important variable… Read more →

A thermal neutron absorber is an element or mineral with an exceptionally high cross-section for capturing thermal neutrons (neutrons that have been slowed by elastic scattering interactions with surrounding matter to… Read more →

Thermal neutron porosity measurement is a nuclear well logging technique that emits fast neutrons from a chemical source (americium-beryllium) or electronic neutron generator into the formation and measures the flux of… Read more →

What Is Thermal Recovery? Thermal recovery is a category of enhanced oil recovery (EOR) that uses heat — delivered by steam injection, combustion, or electrical heating — to reduce the viscosity of heavy oil and bitumen… Read more →

Thermal simulation is a reservoir simulation technique that explicitly models the flow of heat through the reservoir rock and fluids simultaneously with the flow of oil, gas, and water — required for accurate prediction… Read more →

A thermally activated mud emulsion is a water-based drilling fluid that uses cloud-point glycol as a shale inhibitor. Cloud-point glycol is a water-soluble polymer that dissolves clearly in water at surface temperatures… Read more →

Thickening time is the measured duration from the initiation of a cement slurry mixing to the point at which the slurry's consistency reaches 100 Bearden units of consistency (Bc), the threshold at which the slurry is… Read more →

A thief is a sampling device lowered into a tank on a line to capture a volume of fluid or sediment from a chosen depth, so that the sample can be analyzed to determine the crude oil's gravity and its basic sediment and… Read more →

An opening in the top of the stock tank. The thiefhatch allows tank access for a thief or other level measuring devices. Read more →

A formation encountered during drilling into which circulating fluids can be lost. Read more →

Thixotropic describes a fluid that builds gel strength over time when it is left undisturbed and then thins and flows freely again once it is agitated or sheared, a reversible structural change that is central to how… Read more →

Thixotropy in drilling fluid engineering is the property of a fluid — particularly water-based and oil-based drilling muds — to form a semi-rigid gel structure when left undisturbed and to revert to a flowing liquid… Read more →

What Is Thorium in Well Log Interpretation? Thorium (Th) in well log analysis is a naturally occurring radioactive element measured by the spectral gamma ray logging tool, where its concentration (in parts per million,… Read more →

A common measure for volume of gas. Standard conditions are normally set at 60oF and 14.7 psia, abbreviated Mscf/d. Read more →

A thread protector is a sleeve or cap made up onto the threaded end of a tubular good, casing, tubing, drill pipe, line pipe, or a downhole tool, to shield the connection during transport, handling, and storage. The… Read more →

A pocket-size thread gauge used in field operations to correctly identify or confirm the thread type and size of tubular goods. Read more →

A threadform in oilfield tubular connections refers to the specific geometric profile of the threaded connection between two tubular components — defined by the thread's cross-sectional shape (the shape of the… Read more →