The worst case scenario for the Gulf Oil Disaster has always been the undermining of the wellhead, leading to total wellhead failure and an unchecked gusher of oil flowing directly from the sea floor.
On several occasions, industry analysts indicated that this may have occurred after the topkill efforts were suddenly suspended. Did the pressure increases of the topkill efforts force open a lateral seam in the well below the blow out preventer? Did the sudden decrease in pressure lead to the sudden suspension of the topkill?
The government oversight of the topkill operations knows full well if there was a sudden pressure loss or if a lateral blowout below the blow out preventer has occurred.
The direct questions that need to be asked are these:
How certain are you that the integrity of the well has not failed and oil is not leaking out directly from the sea floor?
and
Are you making ongoing efforts to to survey the sea floor surrounding the blow out preventer to ensure that well integrity failure has not occurred?
This is what it looks like while they are collecting 15,000 barrels of oil per day.
There is a significant amount of oil leaking from the blow out preventer. The real worst-case scenario is what normally happens when a blow out preventer fails. The material pushing out of the well erodes the wellhead below the cement cap holding the blow out preventer in place. Eventually this oil/gas mixture forces its way up out of the sea floor in an uncontrolled volcano spewing in multiple locations directly from the sea floor.
realize this now: for an unchecked gusher lasting this long, a failure of the surrounding rock matrix leading to a gusher directly from the area surrounding the wellhead ALWAYS HAPPENS.
eventually the surrounding well area always fails.
to see how this process happens, watch this video at time 1:20
how do we know that oil and gas is not flowing out of the sea floor surround the well head?
This is the normal process of an uncontrolled well blowout. This degradation of the well always happens eventually.
An interesting analysis from Michael Williams, a survivor of the deepwater rig explosion, he had to jump to safety from the burning rig.
Michael P. Williams - May 13, 2010
Your analogy to some sort of Promethean ‘Pandora’s box’ is completely inapropos to the loss of control on BP’s Macondo Prospect well. There is no need for a declaration of allegorical Force Majeure to understand the genesis of this disaster.
The proximate cause of this incident is almost certainly a failed primary cementation that resulted in direct and fairly unrestricted hydraulic communication of reservoir fluids (gas and oil) to the uncemented production casing annulus. Zonal isolation is the principal function of a primary cementation, and BP deliberately chose not to evaluate the integrity of that isolation (possibly against the advice of cementing contractor Halliburton), by means of widely-used wireline acoustic logging methods, before commencing to prepare the Macondo well for temporary plugging and abandonment.
Even if BP drilling management believed that this operation, and any remedial ‘squeeze’ cementing that indications of poor isolation might require, could be more economically left to the later re-entry of the well for completion, it is difficult to understand how confirmation of zonal isolation could not have been seen as essential and safety-critical — vis-à-vis ruling out the possibility of reservoir communication to the production casing backside at the wellhead — before displacing the riser to seawater, an operation that brought the differential pressure between an overpressured gas-charged production casing annulus and production casing bore, and across the production casing seal assembly, to a maximum, precipitating the catastrophic breach in mechanical well integrity — either in the wellhead seal assembly, or by gross failure or leak-to-failure of a near-wellhead production casing connection — that gave rise to loss of well control.
BP’s claims of limited involvement in the actual drilling of the Macondo Prospect well are so disingenuous and incongruent with the facts that they would be laughable if they were not so cynically absurd. All aspects of Macondo well design and drilling program execution came under BP’s direct control, supervision, approval and authority, and for BP to suggest that they simply were not significantly involved in the conduct of day-to-day well operations, including those on 20 April, is to turn the world upside down and expect no one to notice.
When the incident investigation is complete, it may well be found that near-wellhead casing connection failure, due to combined high tension and collapse loads, allowed the topmost several ‘joints’ of production casing, along with casing hanger and seal assembly (for which the lock-down ring, a safeguard against upward displacement, was purposefully not installed), to be hydraulically displaced upward in to the blowout preventer bore. Questions of blowout preventer operability and malfunction aside, the shearing blind rams on even a deepwater blowout preventer stack were not designed to reliably sever high-strength, heavy wall production casing.
BP’s decision to defer the setting of a cement plug in the the production casing until after riser displacement to seawater ought to receive serious scrutiny, but the outcome (viz., sudden and catastrophic loss of well control) would not have been materially different if they had set a cement plug first in as much as the well is almost certainly flowing up the production casing annulus.
Getting back to BP’s failure to evaluate the integrity of zonal isolation afforded by primary cementation of the production casing before commencing to prepare a subsea well cased in to a confirmed high-pressure oil and gas reservoir for temporary abandonment, the industry needs to revisit the wisdom of this practice, commonplace as it may (or may not) be. As low as the actuarial probability of this catastrophic loss of well integrity and control may have been, the consequential costs for this failure are beyond extraordinary, making the overall risk — probability of occurrence times consequential costs — of sufficient magnitude to merit a more circumspect approach to preparing and vetting subsea production wells for temporary post-drilling suspension pending completion.
In the end, Transocean, Halliburton and Cameron (the BOP manufacturer) will be found neither grossly negligent nor principally responsible for this disaster — culpability will rest entirely with BP, as perpetrators of one of the most colossal and avoidable risk management failures in offshore drilling history.
what he is saying is that the nature of the failure looks like this:
this means that well pressure is leaking out between the inner and outer casing of the wellhead. In between the production casing and the intermediate casing.
continued exposure to well pressure surges caused by gas moving up the wellhead will lead to total failure of the rock matrix surrounding the wellhead.
We need to know if this has happened yet.