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TVD Cast
TVD may refer to: * True Vertical Depth, the vertical depth of the drill bit, used while directional drilling, especially when horizontal. *Total variation diminishing *''The Vampire Diaries'', an American television series which began airing in 2009. *ISO 4217 code for Tuvaluan dollar {{disambig it:TVD ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
True Vertical Depth
True vertical depth'is the measurement of a straight line perpendicularly downwards from a horizontal plane. In the petroleum industry, true vertical depth, abbreviated as TVD, is the measurement from the surface to the bottom of the borehole (or anywhere along its length) in a straight perpendicular line represented by line (a) in the image. Line (b) is the actual borehole and its length would be considered the "measured depth" in oil industry terminology. The TVD is ''always'' equal to or less than (≤) the ''measured depth''. If you imagine line (b) were a piece of string and pull it straight down, you would see that it would be longer than line (a). This example oil well would be considered a directional well because it deviates from a straight vertical line. See also * Depth in a well * Driller's depth The original depth recorded while drilling an oil or gas well is known as the driller's depth. The problem Since there is not a single reference or measurement system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Directional Drilling
Directional drilling (or slant drilling) is the practice of drilling non-vertical bores. It can be broken down into four main groups: oilfield directional drilling, utility installation directional drilling, directional boring (horizontal directional drilling - HDD), and surface in seam (SIS), which horizontally intersects a vertical bore target to extract coal bed methane. History Many prerequisites enabled this suite of technologies to become productive. Probably, the first requirement was the realization that oil wells, or water wells, do not necessarily need to be vertical. This realization was quite slow, and did not really grasp the attention of the oil industry until the late 1920s when there were several lawsuits alleging that wells drilled from a rig on one property had crossed the boundary and were penetrating a reservoir on an adjacent property. Initially, proxy evidence such as production changes in other wells was accepted, but such cases fueled the development of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Total Variation Diminishing
In numerical methods, total variation diminishing (TVD) is a property of certain discretization schemes used to solve hyperbolic partial differential equations. The most notable application of this method is in computational fluid dynamics. The concept of TVD was introduced by Ami Harten. Model equation In systems described by partial differential equations, such as the following hyperbolic advection equation, :\frac + a\frac = 0, the total variation (TV) is given by :TV(u(\cdot,t)) = \int \left, \frac \ \mathrmx , and the total variation for the discrete case is, :TV(u^n) = TV(u(\cdot,t^n)) = \sum_j \left, u_^n - u_j^n \ . where u_^n=u(x_,t^n). A numerical method is said to be total variation diminishing (TVD) if, :TV \left( u^\right) \leq TV \left( u^\right) . Characteristics A numerical scheme is said to be monotonicity preserving if the following properties are maintained: *If u^ is monotonically increasing (or decreasing) in space, then so is u^. proved the follow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Vampire Diaries
''The Vampire Diaries'' is an American supernatural fiction, supernatural teen drama television series developed by Kevin Williamson (screenwriter), Kevin Williamson and Julie Plec, based on the The Vampire Diaries (novel series), book series of the same name written by L. J. Smith (author), L. J. Smith. The series premiered on The CW on September 10, 2009, and concluded on March 10, 2017, having aired 171 episodes over eight seasons. The Pilot (The Vampire Diaries), pilot episode attracted the largest audience for The CW of any series premiere since the network began in 2006; the The Vampire Diaries (season 1), first season averaged 3.60 million viewers. It became the most-watched series on the network before being supplanted by ''Arrow (TV series), Arrow''. The show has received numerous award nominations, winning four People's Choice Awards and many Teen Choice Awards. In April 2015, lead actress Nina Dobrev, who played Elena Gilbert, confirmed that she would be leavin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tuvaluan Dollar
The Tuvaluan dollar is the currency of Tuvalu, whose unofficial international currency code is TVD. Tuvalu has never had banknotes of its own, and has been issuing coins since 1976. However, the Tuvaluan dollar is used as a unit of account, and is pegged to the Australian dollar at parity. From 1966 to 1976, Tuvalu officially used the Australian dollar. In 1976, Tuvalu began issuing its own coins, which continue to circulate alongside Australian coins. Tuvalu continues to use Australian banknotes. Tuvaluan coins are not legal tender in Australia. Similar to the Faroese króna's relationship to the Danish krone and the Panamanian balboa's relationship to the United States dollar, the Tuvaluan dollar is not an independent currency, but a variation of the Australian dollar. Tuvalu does not have a monetary authority or central bank, and the National Bank of Tuvalu, the only bank in Tuvalu, performs some monetary functions for the government, including the holding of government accoun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
