Schlumberger

AUTOCHOKE Drilling Choke

Overview Library

One-of-a-kind pressure-balanced drilling choke

The uniquely designed AUTOCHOKE pressure-balanced drilling choke is a one-of-a-kind technology from M-I SWACO that continues to set the standard for high-pressure drilling chokes. The 3K, 10K, and 15K AUTOCHOKE drilling chokes provide automatic, precise control and incorporate the best choke technology available for pressure intensive underbalanced drilling (UBD) and managed pressure drilling (MPD).

Regulating Casing Pressure Under All Conditions

The AUTOCHOKE drilling choke automatically regulates casing pressure under all conditions, including during mud pump start-up or shutdown and when making and breaking drillpipe connections. It automatically adjusts the orifice size to compensate as mud and gas flow alternatively through the unit.

Makes Stripping Pipe Simple and Safe

The AUTOCHOKE drilling choke is highly effective in hydrogen sulfide and abrasive fluid applications. With its ability to automatically maintain casing pressure, the AUTOCHOKE drilling choke makes stripping pipe simpler and safer. As drillpipe is lowered into the hole, an equal volume of fluid under pressure is automatically displaced through the high-performance choke.

Accurate Flow Control

The AUTOCHOKE drilling choke incorporates a sliding shuttle connected to a dynamic trim sleeve. Flow from the well passes through the inlet and is controlled by the action of the shuttle assembly. As it slides back and forth the shuttle assembly adjusts the position of the dynamic trim relative to the circular orifice of the matching static trim.

Adjustment Capabilities for Changing Pressures and Conditions

An increase in annulus pressure or a decrease in the hydraulic set point pressure will cause the shuttle assembly to move away from the static trim, increasing the orifice size. This allows fluid to flow from the well while decreasing casing pressure until it equals the set point pressure. A decrease in casing pressure or an increase in the set point pressure will cause the shuttle assembly to move toward the static trim. Through a decreased orifice size, fluid flow is reduced until casing pressure equals the set point pressure.

Applying Pressure Adjustments and Monitoring Conditions

The AUTOCHOKE drilling choke set point pressure applied to the backside of the shuttle assembly is adjusted by a pressure regulator and measured by the set point gauge located on the choke control panel. The annulus pressure is applied to the front side of the shuttle assembly.

Contact Us
M-I SWACO logo

Ensure Your Rig is Ready

Offshore Rig Technology 2014 Brochure
Equip your rig with best-in-class offshore rig technology and services. Download catalog

Drilling Chokes for the Most Challenging Conditions

Drilling Chokes Brochure tn
Advanced drilling chokes meet the challenges of well pressure control, managed pressure drilling, and underbalanced drilling even in hostile environments. Download brochure