What is MD in drilling?

In the oil industry measured depth (commonly referred to as MD, or just the depth), is the length of the borehole. In conventional vertical wells, this coincides with the true vertical depth, but in directional or horizontal wells, especially those using extended reach drilling, the two can deviate greatly.

What does ECD mean in drilling?

equivalent circulating density
1. n. [Drilling Fluids] The ECD is an important parameter in avoiding kicks and losses, particularly in wells that have a narrow window between the fracture gradient and pore-pressure gradient. Alternate Form: equivalent circulating density. © 2022 Schlumberger Limited.

What is ECD and ESD drilling?

The equivalent Static Density (ESD) is an expression of the hydrostatic pressure exerted by a static column of fluid. Equivalent Circulating Density (ECD) is the sum of the ESD of the drilling fluid and pressure loss in the annulus due to fluid flow.

How do you calculate ECD?

The ECD is calculated as: d + P/(0.052*D), where d is the mud weight (ppg), P is the pressure drop in the annulus between depth D and surface (psi), and D is the true vertical depth (feet).

What is 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.

What is kelly bushing in drilling rig?

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 the full form of ECD?

Early childhood development (ECD)

Why ECD is important in drilling?

ECD is a key parameter during drilling through formations where the margin between the pore pressure and the fracture pressure (FP) is narrow. In these critical formations, the ECD is used to control the formation pressure and prevent kicks.

What affects ECD drilling?

Major Components That Affect ECD Value In Drilling. In summary, ECD is the combination of raw mud density plus other influences on wellbore annular pressure. mud hydrostatic pressure and drilled solids.

What affects ECD in drilling?

Mud rheology The viscosity of the mud is a measure of the frictional pressure losses the mud experiences when it is being pumped. The frictional pressure losses in the annulus are measured as the annular pressure loss. Thus changes in mud viscosity affect the Drilling Equivalent Circulating Density ECD.

How is TVD drilling calculated?

That length becomes the hypotenuse of a right triangle. As the angle of deviation increases, the less True Vertical Depth is. TVD = . 940 x 1000 = 940 feet.

What does ECD stand for in drilling?

Equivalent circulating density (ECD) Equivalent circulating density is felt when the pumps are on and drilling fluid is circulating out of the hole. ECD (equivalent circulating density) is the dynamic density exerted by a circulating mud at any point in the borehole.

What is ECD in a borehole?

Equivalent circulating density (ECD) ECD (equivalent circulating density) is the dynamic density exerted by a circulating mud at any point in the borehole. The equivalent circulating density or dynamic density at any time during fluid flow is always greater than the static mud density when flow is stopped.

What is the equivalent circulating density of drilling mud?

This pressure loss is absorbed by the formation. So the equivalent circulating density (ECD) is the sum of this pressure loss (converted to density) and the original mud density of the drilling mud under static conditions.

Why does the ECD of a well crack under flow conditions?

This is because under flow conditions the ECD (dynamic density) could exert a higher pressure which is greater than the pressure needed to induce formation fracture. The ECD could induce a higher pressure that fractures weak formations. Fluids could rush into the wellbore through these fractures causing a kick