Oil and Gas Terms Beginning with “T” — Page 4

Three-component seismic data (3C seismic) refers to seismic acquisition using receiver stations that each record three independent channels of particle motion — one vertical component (measuring up-down ground motion)… Read more →

What Is 3D Seismic Data? 3D seismic data is a densely sampled, three-dimensional volumetric image of the subsurface created by recording seismic reflections from a closely spaced grid of source and receiver positions at… Read more →

A three-dimensional survey (3D survey) in petroleum geophysics is a seismic data acquisition program that records reflected acoustic energy over a surface area rather than along a single line — generating a volumetric… Read more →

The simultaneous flow of oil, free gas and water into a wellbore. Stratified flow is the rule rather than the exception. Read more →

A three-phase separator in oil and gas production is a pressure vessel that simultaneously separates produced wellstream fluids into three distinct phases — gas, crude oil, and produced water — using gravity settling,… Read more →

Threshold velocity in spinner flowmeter measurements is the theoretical minimum fluid velocity required to initiate spinner rotation, calculated under the simplifying assumption that the spinner response is perfectly… Read more →

Through-flowline (TFL) servicing is a riserless subsea well-intervention method in which tool strings, treatment fluids, and pump-down devices such as plugs, darts, and pump-down locomotives are circulated to and from a… Read more →

Through-tubing in oil and gas well operations refers to any downhole operation, tool, or equipment run through the existing production tubing string that is already installed in the well, without pulling the production… Read more →

A through-tubing gun (TTG) is a perforating gun assembly designed with an outer diameter small enough to be run through the bore of the existing production tubing string into the casing below, allowing new perforations… Read more →

A thrust fault is a reverse fault (a compressional fault in which the hanging wall has moved upward relative to the footwall) with a low angle of dip (typically less than 30 degrees from horizontal, and often 10-20… Read more →

In petroleum geology and well log analysis, a tick mark is a small annotation symbol placed on a stratigraphic column, core description, or well log display at a specific depth to indicate a geological feature, a sample… Read more →

In petroleum geology and well log interpretation, a tie (also called a log tie, seismic tie, or well tie) is the process of matching and correlating specific marker horizons, formation tops, or stratigraphic features… Read more →

A tie line in petroleum engineering and physical chemistry is a line segment drawn on a ternary phase diagram connecting the compositions of two distinct phases that are in thermodynamic equilibrium with each other at a… Read more →

A tie-back liner is a casing or liner string run inside a previously set liner to extend the cemented casing string back up to the surface or to a higher point in the wellbore, connecting the top of a deep liner to the… Read more →

A tie-back packer is a sealing device used in well completions to connect a new section of casing or tubing back to a section already in place. The most common application is reconnecting an upper casing string to a… Read more →

(noun) A section of casing or liner run from the top of a previously hung liner back up to the wellhead, creating a continuous casing string from surface to the liner setting depth. Tie-back strings are used to provide… Read more →

Tight in petroleum industry usage carries two distinct and context-dependent meanings: first, in the operational and business sense, it describes the state of secrecy or confidentiality that operators maintain over… Read more →

An emulsion with small and closely distributed droplets. A tight emulsion can be difficult to break. Read more →

What Is Tight Gas? Tight gas is natural gas trapped in low-permeability sandstone, carbonate, or coal formations that cannot produce at economic flow rates without stimulation — principally hydraulic fracturing. The US… Read more →

A tight hole is a well that the operator requires to be kept as secret as possible, particularly with respect to the geological and petrophysical information obtained during drilling (formation tops, lithology,… Read more →

Time after bit (TAB) in logging while drilling (LWD) and measurement while drilling (MWD) refers to the elapsed time between the moment the drill bit penetrates a specific depth of formation and the moment that depth is… Read more →

The time domain is the representation of a signal or measurement as a function of time, where the horizontal axis is elapsed time and the vertical axis is the quantity being measured, such as the ground-velocity or… Read more →

Time migration is a seismic data processing technique that corrects for the geometric distortion of seismic reflection events caused by dipping reflectors, diffractions from fault tips and formation edges, and lateral… Read more →

A time slice is a horizontal display cut through a 3D seismic data volume at a constant two-way travel time. Instead of showing how seismic amplitude varies with depth along a vertical profile (as a conventional seismic… Read more →

Time-lapse logging refers to logging techniques in which the same measurement is acquired at different times in the life of a reservoir to characterize changes that occur between the measurement times — typically used… Read more →

Time-lapse seismic data, also called 4D seismic data, consists of two or more seismic surveys acquired over the same area at different times during the producing life of a field, with the surveys processed and analyzed… Read more →

Timed slug analysis is a well testing and inflow performance evaluation technique in which a known volume of fluid (the slug) is suddenly introduced into or removed from the wellbore, and the subsequent pressure… Read more →

Titration in oil and gas laboratory analysis is a quantitative analytical chemistry technique in which a solution of known concentration (the titrant) is added incrementally to a sample solution until the chemical… Read more →

Toe-to-heel air injection (THAI) is an in-situ combustion enhanced oil recovery process for heavy oil and oil sands reservoirs in which air is injected into a well near the "toe" of a horizontal producer well, igniting… Read more →

What Is Tomography in Oil and Gas Exploration? Tomography in oil and gas is a computational imaging technique that reconstructs the spatial distribution of a physical property — most commonly seismic P-wave velocity,… Read more →