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

Referring to a type of conventional electrical log in which the current-emitting and the current-return electrodes (A and B) are placed close together on the sonde, with the measure electrode (M) several feet away and… Read more →

A colloidal suspension or emulsion of specific organic materials. Certain latices may be used as cement additives. Latex is used to provide gas-migration control, improve durability and improve bonding. It also offers… Read more →

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

A method of seismic inversion whereby the effects of rock layers having different seismic characteristics are removed from layers below. Read more →

A highly simplified description of a geological scenario. Although sometimes used for "quick and dirty" simulation models, this description is often not appropriate for detailed or accurate work. Generally, layer-cake… Read more →

An advanced testing technique using a combination of transient-rate and pressure measurements and stabilized flow profiles to determine permeability and skin for each of several layers commingled in a well. The… Read more →

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

The abbreviation for concentration in US oilfield units, pound per barrel. One lbm/bbl is the equivalent of one pound of additive in 42 US gallons of mud. The "m" is used to denote mass to avoid possible confusion with… Read more →

A test to detect hydrogen sulfide in a fluid by discoloration of a paper moistened with the lead acetate solution. It is important to determine the presence and amount of hydrogen sulfide because this gas is extremely… 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 →

The determination of the location of a leak in a pipeline. In onshore operations, this can be done by external detection or by using material balance leak-detection systems. In offshore operations, the task is more… Read more →

The magnitude of pressure exerted on a formation that causes fluid to be forced into the formation. The fluid may be flowing into the pore spaces of the rock or into cracks opened and propagated into the formation by… Read more →

The magnitude of pressure exerted on a formation that causes fluid to be forced into the formation. The fluid may be flowing into the pore spaces of the rock or into cracks opened and propagated into the formation by… Read more →

A test to determine the strength or fracturepressure of the open formation, usually conducted immediately after drilling below a new casing shoe. During the test, the well is shut in and fluid is pumped into the… Read more →

A type of acoustic energy that propagates in one direction while being confined in the other two directions, in this case by the borehole wall. Leaky modes can be considered as multiply reflected and constructively… Read more →

Residual gas, mainly methane and ethane, that remains after the heavier hydrocarbons have been condensed in the wellhead. When the lean gas is liquefied, it is called liquefied natural gas (LNG). Read more →

A gas condensate with low condensate formation in the reservoir (when the bottomhole pressure is reduced below the dewpoint pressure). Read more →

In a glycoldehydrator, glycol that has been boiled and no longer contains any water. When the glycol is lean, it can be pumped back to the absorber for reuse. Read more →

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

The contract that conveys the rights to explore and produce from the owner of the mineral rights (lessor) to a tenant (lessee), usually for a fee and with a specified duration. A lease usually includes a provision for… Read more →

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

A percentage share of production, or the value derived from production, which is granted to the lessor in the oil and gas lease, and which is free of the costs of drilling and producing. Read more →

The assembly on a coiled tubing reel that guides the tubing string onto the drum. Accurate spooling is necessary to avoid damaging the tubing and to ensure that the entire string can be run and retrieved without… Read more →

An occasion when a governmental body offers exploration acreage for leasing by exploration and production companies, typically in return for a fee and a performance or work obligation, such as acquisition of seismic… Read more →

The period of time during which economically sustainable production levels may be expected from a well. The anticipated well life and the characteristics of the reservoir fluid are the two main factors in specifying the… Read more →

A lifting device used when performing coiled tubing operations from a semisubmersiblerig or drillship. The coiled tubing injector and pressure-control equipment are positioned within the lifting frame, which is attached… Read more →

A short drillstring component that is temporarily connected to the top of a tool assembly that is to be lifted vertically, such as when running or retrieving a tool string. The external profile on the upper section of… Read more →

Crude oil that has a high APIgravity, usually more than 40o. Read more →

Hydrocarbons with low molecular weight such as methane, ethane, propane and butane. Read more →

An operating condition during a snubbing operation in which the wellheadpressure and buoyancy forces are greater than the force resulting from the weight of the pipe or tubing string. In the light-pipe condition the… Read more →