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

Light pipe in snubbing and well intervention operations describes the condition that exists when the combined upward forces acting on a tubular string being run into a pressurized wellbore (primarily the wellhead… Read more →

Lignin, as used in drilling fluids, refers to natural polyphenolic polymers derived from wood pulp processing that function as deflocculants (thinners) in water-based mud systems by adsorbing onto the positively charged… Read more →

What Is Lignite? Lignite is a low-rank, brownish-black coal with a carbon content of 25-35% and a high moisture content of 20-45%, representing the earliest stage of coalification from peat and characterised by visible… Read more →

What Is Lignosulfonate? Lignosulfonate (also called lignin sulfonate or sulfite lignin) is a water-soluble anionic polymer derived from lignin, the structural biopolymer that binds cellulose fibers in wood, through the… Read more →

What Is a Lime Mud? A lime mud is a water-based drilling fluid that uses hydrated lime (calcium hydroxide, Ca(OH)2) as both a pH buffer and a source of soluble calcium to inhibit reactive clay swelling and provide a… Read more →

What Is Limestone? Limestone (chemical formula CaCO 3 , composed principally of the mineral calcite) is a sedimentary carbonate rock that forms one of the world's most prolific hydrocarbon reservoir lithologies. Major… Read more →

A limestone porosity unit (also written as limestone units or pu-ls) is a calibration convention for neutron porosity logs in which the tool's response is scaled to read apparent porosity directly in a pure limestone… Read more →

Limestone-compatible scale refers to a mineral scale deposit that forms preferentially on or within limestone (calcite-based) reservoir rock, wellbore surfaces, or production equipment when the produced water chemistry… Read more →

What Is Limited Entry? Limited entry (also called limited-entry perforation or limited-entry fracturing) is a hydraulic fracturing completion technique in which the number of perforation clusters and shots per cluster… Read more →

What Is a Line Drive? Line drive (also called line-drive flooding or line-drive waterflood pattern) is a secondary recovery injection strategy in which rows of injection wells are arranged parallel to rows of production… Read more →

The line source solution is the analytical solution to the radial diffusivity equation that describes pressure transient behavior in a porous medium around a vertical wellbore that is modeled as an infinitely thin line… Read more →

A linear alpha-olefin (LAO) is a synthetic hydrocarbon liquid produced by the catalytic polymerization (oligomerization) of ethylene (H2C=CH2) — typically through ethylene oligomerization processes that produce a range… Read more →

What Is Linear Flow? Linear flow is a flow regime in which reservoir fluids move in parallel, straight-line paths toward the wellbore or fracture — as opposed to radial flow, where fluid converges from all directions… Read more →

What Is a Liner? A liner is a string of casing that does not extend to the surface but instead anchors to and hangs from the inside of the previous casing string, covering open wellbore from a point inside the host… Read more →

What Is a Liner Hanger? A liner hanger is a downhole mechanical device that anchors a liner string at the bottom of the previously run casing string, transferring the combined weight of the liner and cement slurry from… Read more →

Lipophilic in oil and gas chemistry describes a substance or molecular region that has a physical or chemical affinity for oils, fats, and nonpolar organic solvents, tending to dissolve in, mix with, or adsorb onto… Read more →

What Is Liquefied Natural Gas? Liquefied natural gas (LNG) (also called cryogenic natural gas or super-cooled methane) is natural gas, composed predominantly of methane (CH 4 ), that has been purified and cooled to… Read more →

What Is a Liquefied Natural Gas Carrier? Liquefied natural gas carrier (also called an LNG carrier, LNG tanker, or LNG vessel) is a specialized cryogenic ocean-going ship designed to transport liquefied natural gas at… Read more →

What Is Liquefied Petroleum Gas? Liquefied petroleum gas (LPG) (also called autogas, bottled gas, or propane-butane mix) is a mixture of light hydrocarbon gases, primarily propane (C 3 H 8 ) and butane (C 4 H 10 ), that… Read more →

A material used in a liquid form to modify the properties of cement for use in oil- or gas-well cementing. Read more →

Liquid blocking (also called liquid loading in production engineering, or water blocking and condensate blocking when specified by the blocking fluid type) is the accumulation of liquid water, condensate, or liquid… Read more →

What Is a Liquid Desiccant? Liquid desiccant (also called glycol dehydration fluid or hygroscopic absorption liquid) is a water-absorbing (hygroscopic) liquid used in gas dehydration systems to remove water vapor from… Read more →

Liquid compounds such as propanes, butanes, pentanes and heavier products extracted from the gas flowstream. Read more →

The depth at which the first liquid is found in a well. Read more →

The liquid saturation method (also called the liquid resaturation or immersion technique) in core analysis is a procedure for measuring pore volume, grain volume, and bulk volume of a core plug or whole core sample by… Read more →

Liquid-junction potential is the electrical potential difference that develops at the interface between two aqueous solutions of different ionic composition or concentration — such as the boundary between drilling mud… Read more →

Lithification is the diagenetic process by which loose, unconsolidated sediment (such as sand, mud, or carbonate grains deposited in a marine, fluvial, or aeolian environment) is converted into a hard, coherent… Read more →

What Is a Lithofacies? Lithofacies (also called a rock facies or sedimentary facies) is a body of rock characterized by a distinctive combination of lithology, texture, sedimentary structures, fossil content, and color… Read more →

A lithologic contact is the surface in the rock record where one rock type meets another. The rocks on either side of the contact have different lithologies (rock types), reflecting different depositional environments,… Read more →

The macroscopic nature of the mineral content, grain size, texture and color of rocks. Read more →