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 →

The distance between analogous points in a wave train, measured perpendicular to the wavefront. In seismic data, the wavelength is the seismic velocity divided by frequency. It can be expressed mathematically as: Read more →

A one-dimensional pulse, usually the basic response from a single reflector. Its key attributes are its amplitude, frequency and phase. The wavelet originates as a packet of energy from the source point, having a… 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 piece of steel cable placed inside a logginghead that is designed to break at a predetermined tension. If the logging tool becomes stuck in the borehole, there is a danger that the logging cable will break at surface,… Read more →

A near-surface, possibly unconsolidated layer of low seismicvelocity. The base of the weathered layer commonly coincides with the water table and a sharp increase in seismic velocity. The weathered layer typically has… Read more →

The physical, chemical and biological processes that decompose rock at and below the surface of the Earth through low pressures and temperatures and the presence of air and water. Weathering includes processes such as… Read more →

A method of compensating for delays in seismicreflection or refraction times induced by low-velocity layers such as the weathered layer near the Earth's surface. It is a type of static correction. Read more →

A new, completely inexperienced member of the drilling crew. Such a crewmember is stereotyped as prone to making mistakes and being injured, and typically endures pranks played on him by the drilling crew. While the… Read more →

A device or system used to measure, display and record the weight of a tubing string, slickline string or coiled tubing string in the wellbore. The weight indicator is the principal means by which the equipment operator… Read more →

A mud that contains commercial weighting material such as barite or hematite. The economic difference in weighted and unweighted muds is the cost of replacing weighting material according to the solids control practices… Read more →

A high-specific gravity and finely divided solid material used to increase density of a drilling fluid. (Dissolved salts that increase fluid density, such as calcium bromide in brines, are not called weighting… Read more →

That period when drilling debris and fluids are still coming out of the formation and perforations. During this time, the skin effect is changing and any well-test results may reflect temporary obstruction to flow that… 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 →

Activities associated with drilling a wellbore to intercept one of more specified locations. The term usually is used in reference to directional or horizontal wells that are oriented to maximize contact with the most… Read more →

The description of a proposed wellbore, including the shape, orientation, depth, completion, and evaluation. Well plans might be relatively simple for vertical wellbores. Directional or horizontal wellbores require more… Read more →

The flow rate at which a well is theoretically capable of producing. This is usually defined by a mathematical formula related to Darcy's law, often at maximum theoreticalpressure drawdown. These theoretical rates were,… Read more →

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

The maintenance procedures performed on an oil or gas well after the well has been completed and production from the reservoir has begun. Well service activities are generally conducted to maintain or enhance the well… 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 →

Any restriction to flow from near-well reductions in flow capacity. This damage is thought to result from reductions in near-well permeability caused by perforating debris or from the solids or mud filtrateinvasion… Read more →

A schematic diagram that identifies the main completion components installed in a wellbore. The information included in the wellbore diagram relates to the principal dimensions of the components and the depth at which… Read more →

Following a surface shut-in, the flow into a well caused by the compressibility of the fluids in the wellbore. Most of the flow occurs from compression of gas in the wellbore. The practical result is that the sandface… 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 →