As you may be aware (from all the DWOPs and CWOPs that you and your company do with us here in Cairo), we run 13⅝” casing string in Nile Delta deepwater fields with centralizers subs and we perform these activities in the base before mobilizing the pipes to the rig.
We measure the pipe, drift it and make up centralizers with full joint, make up float shoe and float collar with full joints, etc.
We assemble or subassembly all small pieces of pipes together before sending them to the rig (e.g. hanger, float shoe, float collar, centralizers, etc. We send the backup items loose (not made up).
To reduce flat time casing running time we try to remove these activities from the rig and do them in town and or off-line.
I hope that helps
Dave, I've been involved in pre rig prep of tubulars on many occasions and each one can have challenges.
When running non weld style hinged centralisers it is best to install these offshore, preferably while the pipe is being run as they are relatively easy to fit, but we would regularly fit the stop collars on the beach as they are the time consuming part of the operation, especially ones with grub screws securing them to the casing. It's very important that these are fitted correctly to prevent slippage on the pipe.
With solid body slip on centralisers you can certainly have these fitted onshore but care must be taken when slinging the pipe into bundles as this can damage the centralisers, especially composite material ones. Steel bodied centralisers are less susceptible to damage when doing this.
If you are running centralizer subs then you have little option but to buck these onto the casing joints onshore as doing this on the rig would be extremely time consuming and probably be seen as unsafe. When we do these we always have wooden batons that sit slightly proud of the centralizer bows between each bow and these are held in place by plastic banding straps and can be removed just prior to make up on the rig floor.
We found that some centralisers slipped down the pipe when picked up off the v door as stop collars had not been correctly installed. Installing centralisers in town can be worthwhile but there should be an awareness on the rig of incorrect installation.
If a centraliser drops down the pipe when it's picked up, there is a danger of injury or damage.