Overview

Multistage chokes are used to control cavitation during water injection and noise/velocity control in high-pressure gas applications. In water injection, the choke faces a number of changes that are distinct from those seen during production. Water undergoes a sudden and substantial pressure drop during its passage through the choke trim and induces cavitation. The solution is to manage the pressure reduction as a series of consecutive pressure drops.

Cameron offers three multistage choke solutions:

  • MS33 cage-in-cage style for clean fluid applications
  • DBA with benefits of debris tolerance and resistance to blockage
  • Silencer labyrinth-style trim for enhanced controllability, velocity control, and cavitation prevention in extreme pressure drop applications

Within water Injection, the choke faces a number of specific changes that are distinct from those seen during production. The main issue occurs as the water undergoes a sudden and substantial pressure drop during its passage through the choke trim. This induces an undesirable and highly damaging phenomenon known as cavitation.  With a sudden pressure reduction in a single stage choke, water becomes vaporized, and the term ‘cavitation’ is used to describe the subsequent ‘implosion’ of the vapor bubbles back into liquid form. It is particularly damaging when cavitation occurs adjacent to the internal components of the choke, as it essentially eats away these parts in a somewhat similar way to sand erosion.

Therefore, the solution to this issue is to manage the pressure reduction as a series of consecutive pressure drops, which is the role of a multi-stage choke.

To successfully avoid the troubles of cavitation, Cameron can offer the most appropriate multi-stage choke solution to best accommodate the job at hand.