The following question was asked by Anne McNeill (Nexen) at the Best
Practices Forum on Tuesday 17th January:
"Who uses flexjoint wearbushings, who doesn't and what experiences
has anybody had?"
What is the industry opinion?
Dear Business Associates
I have seen more than once a riser leak as the drill string cut
through the ball joint lower flange + BOP upper flange to the point
of cutting the API ring gasket.
So for me, ball joint/flex joint wear bushing is a must.
The only decisions are:
1. if I should opt for a 'Full Bore' style - i.e. in line with the
drift diameter of the BOP/wellhead [to allow unhindered access to
the subsea head] or a Reduced Bore style, which we have to trip
often to get access to the wellhead below.
2. If the wear bushing should be retrievable thru the riser or with
Most of the original ball joints - eg Regan - did have a wear
My preference is afor a full bore style with an ID equivalent to the
drift diameter of the items below. If possible, have a two-layer
inlay with a metallic inner layer of a contrasting color, acting as
a tell-tale to indicate the need for replacement.