Oil and Gas Terms Beginning with “L” — Page 2

Late-time transient data in pressure transient analysis is the portion of the wellbore pressure response recorded after the radial flow period has ended and the pressure disturbance from the wellbore has propagated far… Read more →

A lateral in petroleum well drilling refers to the horizontal or near-horizontal section of a directionally drilled well that extends through a target reservoir after the wellbore has been turned from near-vertical to… Read more →

Latex in oil and gas drilling and well completion operations refers to natural or synthetic rubber latex compounds (colloidal dispersions of polymer particles in water) used as additives to drilling fluids, cement… Read more →

A slab of reservoirrock bounded above and below by another layer in vertical hydraulic communication. Read more →

Layer stripping is a seismic inversion strategy that solves for the subsurface one rock layer at a time, working from the shallowest interval downward, so that each layer is determined only after every layer above it… Read more →

Layer-cake geometry describes a depositional architecture in which stratigraphic units are arranged in laterally continuous, horizontally stacked layers that maintain approximately uniform thickness and properties over… Read more →

Layered reservoir testing (also called commingled zone testing, selective interval testing, or multilayer well testing) is a set of well testing methodologies applied to wells that produce from multiple distinct… Read more →

A commonly used (but strictly speaking, incorrect) version of lbm/bbl. Read more →

lbm/bbl is the abbreviation for "pound per barrel," the standard concentration unit used in US oilfield operations to express the concentration of additives, weighting materials, and other solid or liquid components… Read more →

The lead acetate test is a rapid colorimetric field test used to detect the presence of hydrogen sulfide (H2S) in drilling mud, formation fluids, gas streams, or any wellbore fluid by exposing a strip of paper or fabric… Read more →

(noun) The first cement slurry pumped during a primary cementing operation, designed with lower density and extended volume to fill the upper portion of the casing-borehole annulus. Lead cement is typically lighter than… Read more →

Leak detection in oil and gas refers to the systems, technologies, and procedures used to identify and locate unintended releases of hydrocarbons, produced water, or other substances from pipelines, vessels, wellbores,… Read more →

A leak-off test (LOT) is a wellbore pressure integrity test performed immediately after drilling below a new casing shoe and cementing, in which the drilled formation below the shoe is pressurized by pumping a measured… Read more →

In hydraulic fracturing, leakoff is the continuous loss of fracturing fluid from the propagating fracture into the surrounding formation matrix through the fracture walls during pumping, governed by the formation's… Read more →

What Is a Leakoff Test? Leakoff test (abbreviated LOT) is a pressure integrity test performed immediately after drilling out a casing shoe cement plug, in which the formation directly below the shoe is pressured up with… Read more →

What Is a Leaky Mode? A leaky mode is a type of guided acoustic wave that propagates along a borehole in a formation where the borehole fluid wave velocity is greater than the shear wave velocity of the surrounding… Read more →

Lean gas is natural gas that is composed almost entirely of methane and a small fraction of ethane, with the heavier hydrocarbons, propane, butanes, and the pentanes-plus condensate range, largely removed. It is the… Read more →

A lean gas condensate is a single-phase gaseous reservoir fluid that, when its pressure is drawn down below the dewpoint at reservoir temperature, drops out only a small volume of liquid hydrocarbons, conventionally… Read more →

Lean glycol is triethylene glycol (TEG) that has been heated in a reboiler to drive off the water it absorbed in the contactor, returning it to a low-water-content state ready to be pumped back to the top of the… Read more →

Liquid hydrocarbon utilized to remove heavier components from the gas stream in a gas processing plant. Read more →

What Is an Oil and Gas Lease? An oil and gas lease is a private contract that lets one party drill for, produce, and sell hydrocarbons from underneath land owned by another party. The owner of the underground minerals,… Read more →

The fastest route that a seismic ray can travel between two points, generally dictated by Fermat's principle. Read more →

What Is a Lessor Royalty? Lessor royalty (also called landowner royalty or mineral royalty) is the share of gross production revenue paid to the mineral rights owner (lessor) by the oil and gas operator (lessee) under… Read more →

A levelwind (also written level-wind or level wind) is a mechanical device that guides wire rope, cable, or coiled tubing onto a reel or drum in an orderly, evenly spaced pattern during winding and unwinding operations,… Read more →

What Is a Licensing Round? Licensing round is a competitive bidding process organized by a national government or regulatory authority through which exploration and production rights over defined acreage blocks are… Read more →

The life of the well is the total span of time, usually measured in years, during which a well is expected to produce hydrocarbons in commercially worthwhile amounts. It begins when the well is brought on production… Read more →

A lifting frame is a structural steel assembly engineered to distribute and transfer the load from a crane or overhead hoist attachment point to multiple pick points on a large, heavy, or geometrically irregular load —… Read more →

A lifting sub is a short threaded adapter or crossover tool used in drilling, completion, and workover operations to provide a connection point between the drill string or casing string and the elevators or traveling… Read more →

What Is Light Crude Oil? Light crude oil is crude oil with an API gravity greater than 31.1 degrees, corresponding to a density below approximately 870 kg/m 3 (0.870 g/cm 3 ), that flows freely at surface conditions… Read more →

What Are Light Hydrocarbons? Light hydrocarbons (also called light ends or low-molecular-weight hydrocarbons) are hydrocarbon compounds with carbon numbers ranging from C 1 through C 6 , encompassing methane, ethane,… Read more →