As it is in the nature of deep-ocean oil well blowouts to produce methane clathrate,

and it is one pursued from a position of considerable advantage

~ but it is also one which can disable efforts to collect the oil at the source ~

we are left with the task of trying to exclude nature from where, (and how), it wishes to be ;

or of crafting a system agreeable to its habits within the confines of our goals.

_

The 2,4 dome shown here, (in partial cutaway), uses a hyperbolic skirt within which's aperture the draw-pipe rotates ;

leaving clearance enough, (between the outer wall of the pipe and the inner of the aperture), to allow some material to escape .

Should the ice plug the aperture and begin to fill the chamber, the pipe can be raised or lowered allowing broader sections to break the ice free ;

and the leaf-like ice cutters at the base, (2 of 3 shown), to clear it from the skirt nearby .

The pipe is stabilized from above by a 6 point cradle, (4 shown), to which rings for lowering lines could be attached .

It has a reinforced band at the skirt bottom to which rings to anchors, (6, i imagine), could also be attached .

( the skirt and band walls are intended to be solid )