Page 159 - Well Control for Completions and Interventions

Well Control Surface Equipment 151

Figure 4.6 Fixed diameter choke.

Figure 4.7 Adjustable needle and seat choke. Source: Image courtesy of Schlumberger.

regular adjustments are required to maintain a constant bottom hole pres-
sure (Fig. 4.6).

4.5.2 Manually adjustable choke
The manually adjustable chokes most commonly used on rig choke and
well test choke manifolds use a needle and seat to regulate flow. The
tapered stem and valve seat are easily replaced and made from hardened
material such as tungsten carbide (Fig. 4.7).

4.5.3 Remotely operated choke
If the choke manifold is equipped with a remotely operated choke, it will
be worked from a control panel. The panel draws the hydraulic pressure
needed to operate the choke from the BOP hydraulic supply. In addition
to the control leaver for the choke, the panel should have pressure gauges