The crew of the Deepwater Horizon found pieces of seal because the methane was crystalizing them. There is a chance the same thing will happen with the relief wells. With the four risers operating and removing methane from the site where the relief well enters the well casing there is a 'chance' it might work. There is also a chance it may not and the only option is a subterranian explosion that will seal the well.
This well is a high content methane well and while it spews a large amount at the well head when it is not restrained, that doesn't mean it maintains the same status when the oil and gas are NOT moving. The only reason the well head doesn't freeze over without containment is because it is flowing to fast at a high pressure to create 'cohesive' ice 'masses,' only 'crystals.
I am dead serious about this.
The flange is leaking because the seal has either contracted due to freezing or crystalized as well.
The gauge is increasing its reading 'slowly' because the ice is increasing in the 'the stack.'
The vat is not diminished in its volume or capacity or pressure. Accurate readings of the vat are inhibited by the methane hydrates.
The risers to the surface can be closed slowly once the relief well is in place and ready to deliver the concrete. But, until that point the cap has to remain open and removing the methane from the well. The oil is secondary in concern, it is the methane that has made this well dangerous and continues to do so.