Negative Equipment LL with Wellesley

Songesand (35/4-2) – Reservoir section

What happened:

Noticed several times that “slugs” of cuttings would reach the shakers for no good reason.

What was planned:

Circulate through 20″ casing with 5 1/2″ DP

What was learned:

There is large annular space for 10 m between inside of 20″ extension joint, and the outside 5 1/2″ DP. The low flowrate of only 800 lpm and very thin mud (3 RPM reading @ 50 deg C of only 4-5), hole cleaning was poor in this area. Could be that cuttings accumulated inside the 20″ extension joint and caused high ECD-

What actions are required:

For future wells with similar flowrates, it would be smart to install some kind of “inner liner” inside the joint making the ID similar to the ID of the 9 5/8″ casing.