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

The edge of an advancing wave, which includes adjacent points that have the same phase. Read more →

Wavelength is the distance between two analogous points in a wave train, such as crest to crest or trough to trough, measured perpendicular to the wavefront. In reflection seismology, where acoustic energy propagates… Read more →

What Is a Wavelet in Seismic Interpretation? A wavelet in seismic exploration is the source signature — the time-varying pressure pulse generated by a seismic source and embedded in the recorded seismic trace — whose… Read more →

What Is Wavelet Extraction? Wavelet extraction is the process of estimating the seismic wavelet — the characteristic pulse that the earth's reflectivity is convolved with to produce a recorded seismic trace — from… Read more →

The reciprocal of wavelength, so the number of wave cycles per unit of distance, abbreviated as k. Read more →

A weak point in wireline logging operations is a piece of steel cable installed inside the logging head (the connection between the wireline cable and the logging tool) that has been specifically engineered to break at… Read more →

What Is the Weathered Layer? The weathered layer is the shallow, loose, low-velocity ground that seismic energy crosses before it reaches deeper rock. It may include soil, glacial till, muskeg, dry sand, broken bedrock,… Read more →

Weathering in geology is the suite of physical, chemical, and biological processes that decompose, disintegrate, and alter rock at and near the Earth's surface under the low-pressure, low-temperature conditions (in the… Read more →

A weathering correction is a static time adjustment applied to seismic reflection or refraction data to remove the travel-time delays introduced by the low-velocity layer, the loose, dry, weathered material that… Read more →

In the petroleum drilling industry, "weevil" (also spelled "wevil" or "weeble" in regional usage) is oilfield slang for a new, inexperienced worker on a drilling rig — specifically a roughneck or roustabout who is… Read more →

The weight indicator is a surface instrument on a drilling rig that measures and displays the hook load — the total weight supported by the traveling block and hook assembly, which includes the weight of the drill… Read more →

A weighted mud is a drilling fluid system that contains commercial weighting material (most commonly barite, BaSO4, with specific gravity 4.20; or hematite, Fe2O3, with specific gravity 5.00 to 5.50) added to increase… Read more →

Weighting material is a dense solid additive blended into drilling fluid to increase mud density above the base fluid density in order to generate sufficient hydrostatic pressure to control formation pore pressure and… Read more →

Well cleanup (also called cleanup period or cleanup flow) is the transient period following the initial completion or workover of a well during which drilling and completion debris (drill cuttings, drilling mud… Read more →

What Is Well Control? Well control maintains the balance between formation pressure and wellbore pressure during drilling, completion, workover, and intervention operations, preventing uncontrolled flow of oil, gas, or… Read more →

The well production or injection rate. Read more →

The change in pressure at one well caused by production from one or more other wells. Read more →

(noun) A continuous record of measurements made as a function of depth in a wellbore, acquired by lowering electronic instruments on a wireline, drillpipe, or coiled tubing through the borehole. Well logs measure… Read more →

Well placement is the integrated set of activities and technologies used to drill a wellbore to intercept one or more specified subsurface targets — defined by geological, geomechanical, and reservoir engineering… Read more →

A well plan in petroleum engineering is the comprehensive technical document that defines the proposed wellbore design before drilling commences — specifying the wellbore trajectory (vertical, directional, or… Read more →

Well potential is the maximum rate at which a well can produce oil, gas, or water under a specified set of conditions (wellhead pressure, choke size, artificial lift settings, or bottomhole flowing pressure),… Read more →

The volume of produced fluid per unit of time. Read more →

Well servicing is the maintenance and intervention procedures performed on an oil or gas well after the well has been completed and production from the reservoir has begun — providing the operational management that… Read more →

(noun) Any treatment performed on a well to restore or enhance its productivity or injectivity beyond the natural capacity of the formation. Well stimulation techniques include hydraulic fracturing, matrix acidising,… Read more →

(noun) A multi-well pressure transient test in which fluid is produced from or injected into one well while pressure changes are monitored at one or more offset observation wells. The test provides information about… Read more →

Wellbore damage (also called formation damage or near-wellbore damage) is any reduction in the natural ability of a reservoir to flow fluids into the well. The damage occurs in a thin zone immediately surrounding the… Read more →

A wellbore diagram is a schematic representation that identifies the main completion components installed in a wellbore — providing the comprehensive visual reference for the well's mechanical configuration that… Read more →

Wellbore fill-up in oil and gas operations refers to the volume of fluid required to fill the wellbore from a reference depth to the surface (or from one depth to another), a calculation that arises in multiple… Read more →

What Is Wellbore Storage? Wellbore storage (also called wellbore unloading, afterflow, or the wellbore storage effect) is the distortion of early pressure transient data during a well test caused by the compressibility… Read more →

What Is a Wellhead? A wellhead is the steel pressure-containing assembly installed at the surface of a completed well that seals the annular space between casing strings, supports the entire weight of suspended casing… Read more →