I'm not sure I follow you
@justinmetals was there an announcement that they let the cement solidify as you say? I don't think so, it sounds like you've made an assumption and believe it to be true. The last announcement was quite clear that there was a significant amount of cement displaced into the annulus and that the wiper (top one that is) was found at the 2400m depth marker. That would mean 2400m of 5-1/2" pipe cement fill was displaced and 1800m remained in the pipe, giving around 60% fill.
As far as I know about the technique, the top wiper is pushed under pressure and the operation is monitored for pressure spikes that would indicate excess friction, which would likely be when the problem was identified.
Another possibility that hasn't been discussed is that the bottom wiper was hung up and the seal was broken, allowing the cement through. This may still have caused a jam in the line from the top wiper. Who knows, but NWE announcement did say that it was remedial works now and seal checks once the rig was mobilised.
