What is mean sea level in drilling?

The datum shall be mean sea level (MSL). On a side track or workover well depths shall be recorded in feet Below Drill Floor (BDF) but shall also be referenced to the “Original” rig drill floor elevation.

How is depth measured in drilling?

Driller’s depth is determined by summing the length of every joint of pipe in the drill string along with any bottomhole assembly (BHA) that is in the hole below the reference elevation of the well. The reference for the length of every joint of pipe run in the drill string is known as the driller’s tally.

What is true vertical depth in drilling?

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.

What is the difference between TVD and Tvdss?

True Vertical Depth (TVD), is the absolute vertical distance between a datum, such as the rotary table, and a point in the wellbore. True Vertical Depth Sub Sea (TVDSS), is the absolute vertical distance between mean sea level and a point in the wellbore.

What is the difference between MD and TVD?

True Vertical Depth (TVD) is measured vertically from the surface down to a certain target down hole. Measured Depth (MD) is the total length of the wellbore measured along the actual well path.

How do you calculate subsea elevation?

Calculating the subsea elevation: Subsea elevation = KB elevation – Measured depth. Do this calculation for each well showing your work at the bottom of each well log, and giving an example of this calculation in the space below.

What is MD and TVD?

What is drilling total depth?

(toʊtəl dɛpθ) or TD. (Extractive engineering: Field development, Drilling) Total depth is the downward length of a well, measured by the length of pipe which is needed to reach the bottom. Total depth of a well is the vertical distance from the rig floor to the bottom of the hole.

What is kelly bushing elevation?

Kelly Bushing Height (KB): The height of the drilling floor above the ground level. Many wellbore depth measurements are taken from the Kelly Bushing. The Kelly bushing elevation is calculated by adding the ground level to the Kelly bushing height. Rotary Table (RT): e.g. MDBRT or TVDBRT.

What does kelly bushing mean in drilling?

1. n. [Drilling] An adapter that serves to connect the rotary table to the kelly. The kelly bushing has an inside diameter profile that matches that of the kelly, usually square or hexagonal. It is connected to the rotary table by four large steel pins that fit into mating holes in the rotary table.

What is a kelly bushing?

What is subsea level?

The term “subsea” (SS) by itself should not be used, as it is ambiguous. It could mean: below sea floor or bottom, below mean sea level (MSL), below lowest astronomical tide (LAT), etc.