Methane Hydrates, page-17

I don't believe the hydrates explanation can be relevant here simply because the 10 June ann stated that the 13 3/8ths csg had been set prior to the rig undergoing unscheduled maint. When casing is set it is cemented to the surrounding formations and an integrity test run to check that the cementing job has no discernable flaws. As part of this process a cement floor is placed in the well (casing shoe). This means the well had been totally isolated from the surrounding formations and not subject to inflow of any combination of methane, water, or any other fluids. Any comment about hydrates could still be relevant but they would relate to sea floor conditions imo. Occasionally, rig anchors or placement of the surface conductor can disturb the sea floor in such a way that methane hydrates can spontaneously dissociate and methane bubbles to the surface. This is of course a major safety hazard for the rig.

Hydrates have in recent times been recognised as being present in many deep sea settings and normally confined to the upper 50m or so of seafloor sediments where temperatures are close to zero and the right pressure conditions exist. I'm pretty sure that problems with hydrates WITHIN a well only occur when the well is left open to formation fluids for an extended period. That really only happens when there is some kind of problem with the wellbore, or equipment in the wellbore, or blockages, ruptures, casing failures, etc. The problems reported have been clearly stated as being rig-related not wellbore. Faulty BOP issues could well fit this, but I haven't seen anything official to suggest this is the problem either. However, I have been moving house so have not paid close attention to all announcements by all my tickers. Hope this helps.