Enter the force at the wellhead, the friction force, and the buoyed weight of string into the calculator to determine the snub force.

## Snub Force Formula

The following equation is used to calculate the Snub Force.

SF = WF +FF -BW
• Where SF is the snubbing force
• WF is the force at wellhead
• FF is the frictional force
• BW is the buoyed weight of string

To calculate the snub force, add the force at the wellhead to the frictional force, then subtract the buoyancy weight of the string.

## What is a Snub Force?

Definition:

Snubbing is a method of maintaining control over an oil or natural gas well. It is also known as “snubbing unit” or “Snub Force.”

In drilling and completion operations, a snubbing unit is a heavy-duty truck used to operate a wellhead at pressures up to 15,000 psi. The snubbing unit consists of a mast and substructure that supports the hydraulic cylinder. A hydraulic pump powers the ram and slips.

The unit can be used to pull and run casing, tubing, drill pipe, and other tools required in drilling operations, including the installation of packers and bridge plugs.

## How to Calculate Snub Force?

Example Problem:

The following example outlines the steps and information needed to calculate Snub Force.

First, determine the force at the wellhead. In this example, the wellhead force is 500N.

Next, determine the frictional force. For this problem, the frictional force is 100N.

Next, determine the buoyed weight of the string. In this case, the weight is 50N.

Finally, calculate the snub force using the formula above:

SF = WF +FF -BW

SF = 500 +100 -50

SF = 550N