My very limited understanding of the situation agrees with your more expert one. There are a couple of POSSIBLE complicating factors:
1. The flow MAY be from the annulus (outside the casing).
AND,
2. If it IS then it MAY be flowing through the “Casing Hanger Packoff.”
3. IF this is true, it will be very difficult to “flow” mud or cement back down that “Packoff,” because ot held positive pressure in testing (it tested poorly under negative pressure).
4. If the mud goes past the leak (under the assumption that the leak is through the casing hanger packoff) it will go down the casing.
5. I believe the casing has a mechanical plug near the bottom. If so, and if the pressure of the mud pushes it out, that COULD add to the flow/pressure from the annulus.
That is a lot of POSSIBLES, and MAYBEs, and I hope they can cope with them if they should happen.
DG
Your “very limited” understanding is right on my FRiend! There are a great many things that could still go wrong with this.
The flow very likely IS behind the pipe (outside the casing) but IS entering the well at some point (very likely through a liner lap). If that point is far enough down it doesn’t matter but if it isn’t that is really bad news!
Secondly, they must be careful in pumping so as to not overpressure and fracture the formation as that would also be very bad.
And thirdly, Even if the current operation is completely successful the relief wells will still have to be completed in order for this thing to be made safe.