Oil and Gas Terms Beginning with “E” — Page 4

The wearing away of material, usually rock or steel, by the continuous abrasive action of a solids-laden slurry. For erosion to occur usually requires a high fluid velocity, on the order of hundreds of feet per second,… Read more →

A type of corrosion produced when easily removed scales (such as iron carbonate) that were initially protecting the metals in the pipe are eroded and the underlying metals are corroded.Erosion-corrosion is a common… Read more →

A type of corrosion produced when easily removed scales (such as iron carbonate) that were initially protecting the metals in the pipe are eroded and the underlying metals are corroded.Erosion-corrosion is a common… Read more →

The difference between a data value and the value predicted by a statistical distribution or other mathematical algorithm. Strictly, normal distributions apply only to random events, but they are often used to describe… Read more →

A steel cable attached to the rig derrick or mast near the work platform for the derrickman. This cable is anchored at surface level (on a vessel or the Earth) away from the mast in a loose catenary profile, and fitted… Read more →

The amount of oil and gas expected to be economically recovered from a reservoir or field by the end of its producing life. Estimated ultimate recovery can be referenced to a well, a field, or a basin. Read more →

A semi-enclosed coastal environment of deposition in which a river mouth permits freshwater to contact and mix with seawater. Read more →

Global sea level and its variations. Changes in sea level can result from movement of tectonic plates altering the volume of ocean basins, or when changes in climate affect the volume of water stored in glaciers and in… Read more →

Global sea level, which changes in response to changes in the volume of ocean water and the volume of ocean basins. Read more →

A hole dug to contain brine for disposal by evaporation. Some evaporation pits are lined with plastic or asphalt to keep water from filtering through and contaminating nearby free-water aquifers. Read more →

A class of sedimentary minerals and sedimentary rocks that form by precipitation from evaporating aqueous fluid. Common evaporite minerals are halite, gypsum and anhydrite, which can form as seawater evaporates, and the… Read more →

An appearance of seismic data as a diffraction, reflection, refraction or other similar feature produced by an arrival of seismic energy. An event can be a single wiggle within a trace, or a consistent lining up of… Read more →

That part of the effect of gas on the neutron porosity measurement that is not explained by differences in hydrogen index. By using the concept of hydrogen index, the only significant contributor to the neutron porosity… Read more →

The cementslurry remaining in the wellbore following a cement squeeze in which the objective is to squeeze slurry into the perforations and behind the casing or liner. The volume of slurry required to effect a… Read more →

The speed the drilling fluid attains when accelerated through bit nozzles. The exit velocity is typically in the low-hundreds of feet per second. It has been reported that in certain shaly formations, an impingement… Read more →

A cement system exhibiting a bulk volumetric increase after setting. Expanding cement is commonly used to eliminate or minimize the effects of microannuli. Read more →

A device or completion component designed to enable relative movement between two fixed assemblies in the event of thermal expansion or contraction. The forces generated by thermal expansion or contraction can be… Read more →

The results of extrapolating from a known data point to points away from measurements. In geostatistical modeling, generating expectation trends is a fundamental process that requires procedures to estimate geometric… Read more →

A perforating gun assembly that disintegrates upon firing, thereby reducing the volume and dimensions of retrieved components. Expendable guns are typically used where wellbore restrictions allow only limited access, as… Read more →

A temporary plug, inserted in the completion assembly before it is run, to enable pressure testing of the completed string. With the operation complete, the expendable plug can be pumped out of the assembly, thereby… Read more →

A computer system that uses a rule-based algorithm to provide expertise on a given subject. Many computer programs have been written for use in the oil field using rule-based approaches to provide expert systems. The… Read more →

The initial phase in petroleum operations that includes generation of a prospect or play or both, and drilling of an exploration well. Appraisal, development and production phases follow successful exploration. Read more →

(noun) A geologically defined concept comprising a specific combination of source rock, reservoir rock, seal, trap, and migration pathway in a particular area, which together create the conditions necessary for… Read more →

Surface seismic data acquired using an explosive energy source, such as dynamite. Read more →

(noun) A seismic acquisition geometry in which the distance between the source and the farthest receiver (offset) is increased beyond the standard spread length, providing longer-offset data that improves velocity… Read more →

A form of azimuthal anisotropy that occurs when fractures or microcracks are not horizontal. Waves that travel parallel to the fractures have a higher velocity than waves traveling perpendicular to fractures. Read more →

A downhole tool used to cut tubing or similar tubulars that have become stuck in the wellbore. The external cutter slips over the fish or tubing to be cut. Special hardened metal-cutters on the inside of the tool engage… Read more →

The continuous phase of an emulsion. The internal phase is the dispersed droplets of emulsified fluid. Read more →

A downhole tool used to pull or retrieve temporary plugs or similar equipment. The external pulling tool engages on the external surfaces of the item to be retrieved. Read more →

A type of tubing connection in which the external diameter of the tubing joint is larger adjacent to the tubing connection to provide the necessary strength. The internal tubing surface is flush to enable good… Read more →