As part of their HOD development project in Norway, AkerBP decided to test several circulation subs to ensure they could pass the heavy concentrations of LCM that may be used while drilling the 8 1/2″ hole section. Xrig was chosen as the test facility and OBM was mixed with high concentrations of LCM consisting of CaCo3 with a D50 of 1.2mm up to a D90 of 1.9mm mixed with fibres and other solids up to a concentration of 400kg/m3. The AVS passed all the tests and was selected for the HOD B5 well.