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

The enlarged and threaded ends of joints of drillpipe. These components are fabricated separately from the pipe body and welded onto the pipe at a manufacturing facility. The tool joints provide high-strength,… Read more →

(noun) An assembly of multiple downhole tools connected end-to-end and run into the wellbore on wireline, coiled tubing, or drillpipe to perform a specific operation such as production logging, perforating, or fishing.… Read more →

The location supervisor for the drilling contractor. The toolpusher is usually a senior, experienced individual who has worked his way up through the ranks of the drilling crew positions. His job is largely… Read more →

An oil and gas lease wherein the bonus consideration is paid at the signing of the lease. However, this lease becomes effective only after the expiration or termination of an existing lease on the tract of land. Read more →

The top of the interval recorded on the log, or the shallowest point at which the log readings are valid. If the top of the log is at the casing shoe, the last valid reading of many logs will be a short distance below.… Read more →

What Is a Top Drive? A top drive suspends from the traveling block and rotates the drill string from the top of the stand using an electrically or hydraulically powered motor, eliminating the need for a kelly and rotary… Read more →

A contour map that displays the elevation of the Earth's surface. A topographic map is commonly used as the base map for surface geological mapping. Read more →

A plot representing the effect of invasion on resistivity measurements that have different depths of investigation. The plot assumes a step-profilemodel of invasion and determines true resistivity, flushed zone… Read more →

The connection between the wirelineloggingcable and the bridle. The torpedo consists of an outer mechanical connection enclosing electrical connections between the conductors. Read more →

A device for measuring in situ the velocity of fluid flow in a production or injection well based on the torque, or force, produced by the fluid on a stationary impeller. This torque can be related to the effective… Read more →

The bottom of a particular hole section, where drilling is stopped, logs are run and casing is cemented before starting the next, smaller diameter hole section. Read more →

A chemical analysis to measure the hardness ions in water-mud filtrates or in make-up water. Hardness is quantitatively determined by titration using standardized EDTA (versenate) reagent and ammonium hydroxide (weak)… Read more →

The concentration of organic material in source rocks as represented by the weight percent of organic carbon. A value of approximately 0.5% total organic carbon by weight percent is considered the minimum for an… Read more →

The total pore volume per unit volume of rock. It is measured in volume/volume, percent or porosity units.The total porosity is the total void space and as such includes isolated pores and the space occupied by… Read more →

A work shift of a drilling crew. Drilling operations usually occur around the clock because of the cost to rent a rig. As a result, there are usually two separate crews working twelve-hour tours to keep the operation… Read more →

The presentation on hard copy of log data from a single measurement versus depth. The term originated with the early optical recorders in which log data were recorded on film using an optical trace. Now the term curve… Read more →

A technique in which a tracer is injected into the flow stream of a production or injection well to determine fluid paths and velocities. Radioactive tracers have been used from the 1940s and are still common for… Read more →

(noun) A production logging technique in which a radioactive or chemical tracer is ejected from a tool into the wellbore fluid stream and detected by sensors positioned above or below the ejection point to determine the… Read more →

A method of determining injection-flow profiles by monitoring the reduction in tracer material as it moves down the well. A slug of radioactive tracer is added to the injection fluid. As the slug moves down the well,… Read more →

A vertical section of a log presentation over which one particular set of data is displayed. The track divides the presentation into different sections, each with a certain set of log curves or other data, such as depth… Read more →

A particular type of strike-slip fault that is a boundary of an oceanic tectonic plate. The actual movement of a transform fault is opposite to its apparent displacement because of the interplay of spreading and… Read more →

The migration of shoreline out of a basin and onto land during retrogradation. A transgression can result in sediments characteristic of shallow water being overlain by deeper water sediments. Read more →

A marine flooding surface separating the underlying lowstand systems tract from the overlying transgressivesystems tract. Typically, this is the first major flooding surface following the lowstand systems tract. Read more →

(noun) The radial distance from a wellbore to which a pressure disturbance has propagated during a well test before reaching a reservoir boundary or achieving pseudo-steady-state conditions. The transient drainage… Read more →

A variation of the electromagnetic method in which electric and magnetic fields are induced by transient pulses of electric current in coils or antennas instead of by continuous (sinusoidal) current. In the last two… Read more →

The change in pressure with time. In well testing, this refers to the pressure measured as a function of time after the test is initiated. Read more →

The pressure response resulting from changes in a well's production rate. This includes drawdown, in which the pressure falls in response to the production of fluids; buildups, in which the pressure rises after a well… Read more →

The pressure measurements recorded as a function of time, usually in the wellbore near the productive interval, after the flow rate of the well is changed. These form the basis for transient well-test analysis, and are… Read more →

The analysis of transient rate and pressure data taken while a well is flowing at variable rates. The analysis uses either deconvolution or convolution to correct for the flow-rate variations and can make drawdown data… Read more →

The duration of time for a P-wave to travel one foot, typically displayed on an acoustic log. The unit of microseconds per foot (or meter) is called the slowness, which is the inverse of velocity. Read more →