Cement top up: Nemo Field

THE PROBLEM
Earlier wells in the vicinity of the Nemo 7/4-2 well (Offshore Norway) required remedial cementing. The requirement to minimise lateral deflection of the riser/conductor system to limit the load gave a requirement for a cement top up system to ensure that the 30 inch conductor is fully cemented to the seabed.

THE SOLUTION
Claxton was asked to provide technical advice and guidance for the design, specification and manufacture of a cement top up system. A secondary cementing system was designed to be installed at the same time as the conductor to enable cement filling of possible voids in the annulus between the conductor and 36” well hole.

Due to the well depth the cement top up system was fixed to the 30 inch conductor prior to installation and run through the 36 inch hole section to a depth of approx. 30m below the mud line. The system was connected to the cementing unit topside by means of a 1 ½ inch nominal bore (NB) grouting hose deployed on a powered umbilical reel. An ROV disconnect was used to connect the hose subsea.

THE RESULT
The Claxton Cement Top Up system enabled the customer to perform a secondary cement job offline saving a significant amount of rig time and ensuring a good cement job. This gave the customer a better solution to months of cementing difficulties.