Definition - What does Hydraulic Snubber mean?
A Hydraulic Snubber is a device that is used to hold or grip the drill string when it is inserted into a wellbore. The primary function of the device is to restrain or control the movement of the drill string during abnormal dynamic conditions created inside the wellbore due to sudden pressure surges, shock wave generations, earthquakes or accidental rupture of piping, etc. Hydraulic snubbers also help in suppressing the effect of pressure surges and pressure pulse from the medium in the wellbore.
Petropedia explains Hydraulic Snubber
Snubbers grab drill strings during snubbing operations. These devices are designed to withstand temperatures and pressure of up to 120 degrees Celsius and 400 bars respectively. Snubbers are useful during abnormal dynamic conditions generated in the wellbore and are used to push pipes and other related equipment into the well against the pressure generated by the medium in the wellbore.
Snubbers can be either hydraulically operated or mechanically operated. Hydraulically operated snubbers are known as hydraulic snubbers. They consist of two cylinders (either concentrically or parallel aligned) along with their respective pistons that can move up and down. These pistons are operated with the help of pressurized hydraulic fluid circulated into the cylinders to provide the necessary force to push the drill string and other tools into the wellbore during abnormal working conditions, i.e., when high pressure is mounted. There are pressure relief valves on the cylinders that make sure that the necessary force should be maintained to push the equipment down the hole and these valves also open and close automatically to adjust the back force on the piston. This mechanism allows pipe deflection and restrains movements during abnormal work conditions.