Allegro CD Directional Casing-While-Drilling Service | Schlumberger

Allegro CD

Directional casing-while-drilling service

Minimize NPT and risk of drilling in unstable formations

Our family of Allegro casing- and liner-while-drilling services improves well-construction efficiency and coordination to better deliver your well. This approach not only provides a way to reduce the risks associated with wellbore instability, but it also greatly increases performance through time savings—both on the drilling and flat time portions of the time-depth curve.

Maximize reliability and efficiency

Industry-first Allegro CD directional casing-while-drilling service has the ability to retrieve and reinstall BHAs multiple times while leaving casing at depth.

The service is compatible with any retrievable directional-drilling BHA when the interval requires logging while drilling or directional drilling. Conveyed on drill pipe, directional casing while drilling can be used to drill sections that involve multiple bit trips or for applications using rotary steerable systems and measurement- or logging-while-drilling tools.

Key capabilities include consistent casing rotation to break static friction, allowing even WOB bit; rotation and high-annular velocity to improve borehole cleaning; and the plastering effect (or smear effect) to maximize borehole strength and stability.

Allegro CD service also includes a drill lock assembly, which connects the BHA to the bottom of the casing shoe joint and enables applying torque and weight by the casing during drilling. The rig's top drive rotates the casing, and a downhole motor provides additional rotational speed and torque to the BHA and PDC bit.

Drillstring with Allegro CD system.
Allegro CD directional-casing-while-drilling service BHA.

Allegro CD service is the first directional-casing-while-drilling service and has the ability to retrieve and reinstall BHAs multiple times while leaving casing at depth.

View All

Share This