First let me qualify myself and say that I’m an ex-Reservoir Engineer, not a drilling engineer, so I defer to the more knowledgeable on this forum.
But I’ve been trying to think how drilling practises can be tightened up to enable business to carry on, so I’m just a sofa engineer thinking out loud (Res Eng’s are good at that).
There will be loads of new requirements for BOP’s, but many people suspect that the BOP wasn’t the real problem.
The cement job needed have a 100% probability of success on this well and it had a lot less probability than this. Because of the high pressures and the geology it really needed a 100% annular seal all the way from inside the last casing shoe to full depth. That, to my inexperienced eye, is what was needed - for me that is the simple criteria that needed to be applied. I’m thinking of ways you could get this.
Liner and Tieback is possibly better, I don’t know. Given you have a long string, wouldn’t a 2 stage cement job also do the job? Any other methods?