In perfectly vertical wells, the TVD equals the MD; otherwise, the TVD is less than the MD measured from the same datum. Common datums used are ground level (GL), drilling rig floor (DF), Rotary table (RT), kelly bushing (KB or RKB) and mean sea level (MSL).

The vertical distance from a point in the well (usually the current or final depth) to a point at the surface, usually the elevation of the rotary kelly bushing (RKB). This is one of two primary depth measurements used by the drillers, the other being measured depth.

2017年11月25日 · The top of the rig kelly bushing is also used as a datum for depth measurement. In this case, the depths are referred to as depths below rotary kelly bushing (RKB). The depth of any point in the well path can be expressed in terms of the Along Hole Depth (AHD) and the True Vertical Depth (TVD) of the point below the reference datum.

2019年1月22日 · TVD：Ture Vertical Depth，垂深。 MD：Messure Depth，测量深度。 SSTVD：Sub-surface Ture Vertical Depth，海面以下垂深。 这几者之间的关系，图中一目了然。 我们在钻井作业期间采取的井深值称为“钻井深度”。 现场钻机采用钻杆钻进的深度叫做“钻杆深度”，岩心深度以及来自钻孔的岩心/泥浆和其他材料的所有分析都在“钻井深度”中测量。 如果是来自电缆记录器操作的深度值被称为“测井深度”。 电缆记录仪深度通常被认为比钻机深度更可靠。 …

TVD：True Vertical Depth，垂直深度。 从方钻杆补心（KB）开始，井眼的真实垂向深度（图2）！ 老外很严谨，为什么要加一个“True”啊，因为对应MD不“True”。 直井MD和TVD是一样的，斜井，水平井就不同了，MD更多的体现了“长度”的概念，TVD才是True的“垂向深度”。

2009年7月23日 · TVDSS (true vertical depth sub sea) in vertical well will be exactly the same values as TVD but usually written in negative signs (-), so: TVDSS = (-) TVD below datum (MSL) MD (Measured Depth) is the entire depth of well measured from the ground surface. In directional or deviated well, MD can be calculated or obtained by trajectory data.

TVD，就是从钻台面到井底的垂直深度MD，就是测井时从钻台面到井底的测量长度TD，完钻后井下所有钻具总长和方钻杆方入的长度若是直井，理论上TVD

2020年9月23日 · The acronym TVDSS is commonly used in the oil industry to represent TVD minus the elevation above mean sea level of the depth reference point of the well. The depth reference point is the kelly bushing in the United States and a few other nations, but is the drill floor in most places.

2023年5月21日 · The acronym TVDSS is commonly used in the oil industry to represent TVD minus the elevation above mean sea level of the depth reference point of the well. The depth reference point is the kelly bushing in the United States and a few other nations, but is the drill floor in most places.

相对于水平井而言,大位移井的水平位移更大,能较大范围地控制含油面积,开发相同面积的油田可以大量减少钻井的数量,尤其在陆地上开采近海油田的油气资 源,可以大量节省海上钻井平.