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

The component of a tree that is extracted in the paper-manufacturing process and used as an additive in drilling fluids. Specifically, lignin is a highly polymerized, amorphous material that makes up the middle lamella… Read more →

The mineral leonardite, similar to brown coal. Lignite is found in surface deposits worldwide. Lignite is mined and put into piles where it can oxidize in the air before it is dried, ground and bagged for use in… Read more →

A highly anionic polymer used to deflocculateclay-based muds. Lignosulfonate is a byproduct of the sulfite method for manufacturing paper from wood pulp. Sometimes it is called sulfonated lignin. Lignosulfonate is a… Read more →

A type of water-base mud that is saturated with lime, Ca(OH)2, and has excess, undissolved lime solids maintained in reserve. Lime muds are classified according to excess lime content: (1) low-lime, 0.5 to 2 lbm/bbl,… Read more →

A carbonatesedimentaryrock predominantly composed of calcite of organic, chemical or detrital origin. Minor amounts of dolomite, chert and clay are common in limestones. Chalk is a form of fine-grained limestone. Read more →

A transform from raw log data chosen so that a log recorded in these units will give the correct porosity of the formation, providing the matrix is pure calcite and the pores are filled with fresh water. The unit, which… Read more →

Display ranges chosen for the density and neutron porosity logs such that the two curves will overlay at all porosity values providing the matrix is pure calcite and the pores are filled with fresh water. The most… Read more →

A completion with only a portion of the productive interval open to flow, either by design or as a result of damage. Limited-entry completions in vertical wells are designed to avoid unwanted fluid production, such as… Read more →

An injection pattern in which the injection wells are located in a straight line parallel to the production wells. In a line drive pattern, the injected fluid, which is normally water, steam or gas, creates a nearly… Read more →

The solution to differential equations treating the well as a vertical line through a porous medium. The solution is nearly identical to the finite-wellbore solution. At very early times, there is a notable difference… Read more →

A synthetic hydrocarbon liquid made by the polymerization of ethylene, H2C=CH2. LAOs and other synthetic fluids are used in synthetic-base drilling fluids and other applications in which refined oils might otherwise be… 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 →

Pertaining to an attraction for oil by a surface of a material or a molecule. This term is applied to the oil-wetting behavior of treatment chemicals for oil muds. Lipophilic oil-mud additives are required because most… Read more →

Natural gas, mainly methane and ethane, which has been liquefied at cryogenic temperatures. This process occurs at an extremely low temperature and a pressure near the atmospheric pressure. When a gas pipeline is not… Read more →

A sea vessel used to transport liquefied petroleum gas (LPG). The term is commonly abbreviated as LNGC Read more →

Gas mainly composed of propane and butane, which has been liquefied at low temperatures and moderate pressures. The gas is obtainable from refinery gases or after the cracking process of crude oil.Liquefied petroleum… 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 →

A phenomenon encountered during dry forward combustion in which an oil zone around the production well cannot be pushed forward by the heated oil. The fluid located in this zone is still at the original reservoir… Read more →

A hygroscopic liquid used to remove water and water vapor from a gas stream. Some liquid desiccants are glycols (diethylene, triethylene and tetraethylene), which are substances that can be regenerated. Regeneration… 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 →

A technique for measuring the pore volume of a core sample from the difference in its weight when dry and when saturated with a liquid. A clean, dry sample is weighed and then evacuated for several hours in a vacuum… Read more →

The electromagnetic force generated by a boundary between solutions of high salinity and low salinity. In a permeableformation, a liquid-junction potential is generated between the invaded zone and the undisturbed zone… Read more →

The process by which unconsolidated sediments become sedimentaryrock. Sediments typically are derived from preexisting rocks by weathering, transported and redeposited, and then buried and compacted by overlying… Read more →

A mappable subdivision of a stratigraphic unit that can be distinguished by its facies or lithology-the texture, mineralogy, grain size, and the depositional environment that produced it. Read more →

The surface that separates rock bodies of different lithologies, or rock types. A contact can be conformable or unconformable depending upon the types of rock, their relative ages and their attitudes. A fault surface… Read more →

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

The brittle outer layer of the Earth that includes the crust and uppermost mantle. It is made up of six major and several minor tectonic plates that move around on the softer asthenosphere. The lithosphere of the oceans… Read more →