Other Planning LL with Wellesley

Hemispheres (36/1-4) – Top hole

What happened:

Tool used successfully but Schlumberger should be told what our requirements are at the planning stage so the crew come on board knowing what we want.

What was planned:

ECD tool planned for drilling 17 1/2″ hole with RMR.

What was learned:

Schlumberger have two methods they routinely offer customers for measuring ECD – see attached Methodology procedure. The ECD measurement tool is essentially a pressure sensor. The tool can be calibrated to express ECD as a gradient from depth back to seabed or Mean Sea Level. It can also be referred back to Rig Floor, whatever we choose.

What actions are required:

We should decide how we want to use the data the tool can provide and specify in the DOP. Also attached is the Pore Pressure / Fracture Gradient / Hydrostatic Pressure prediction for the well. It refers back to rig floor to calculate pore, hydrostatic, dynamic and fracture gradients with depth – in other words accounting for the seawater and air gap.
While drilling ahead the most useful mode for the ECD tool is from seabed down. The value generated can be directly compared to the mud weight in use.