We’ve all been watching the BP Oil spill in the Gulf of Mexico caused by the explosion and collapse of the Deepwater Horizon oil rig. And we all have a response. There are those who are horrified about the environmental catastrophe, others who wonder about the technology and engineering expertise necessary at those depths and obviously there are those who consider the inevitable safety issues. There will even be those who are wondering about the future impact on the offshore oil and gas industry. At the end of this newsletter, you will find a complimentary 15 page write-up on Risk Management, which relates to this topic.
What actually happened and what is BP doing about it?
In essence, the action of the oil leakage is happening a mile under the ocean. At this level we are looking at a huge 150 atmospheres of pressure which dramatically changes the standard ways we operate.
For example a week or so ago, icy methane hydrates formed when natural gas got mixed up with the freezing water at those high pressures. This clogged the pipes and lifted a 125 tonne coffer dam (lowered over the leak) right off the sea bed. Something not anticipated.
Oil is actually leaking through two points – one at each end of the well’s riser pipe (at its connection to the blowout preventer – sitting on top of the actual oil well, and at the end of the riser where it was connected to the ill fated oil platform). The one end of the riser pipe (originally going up to the platform) is lying on the sea bed. A clever insertion device here is currently sucking up the oil (at the rate of 2000 barrels per day) from the end of the riser pipe (where it is located on the sea bed). The debate now is how much oil is leaking into the Gulf. Estimates vary from 5000 barrels per day (an angry, but optimistic US government estimate, perhaps) to 50,000 barrels per day (something a well could theoretically produce). It is probably something in between these extremes.
The approach to block the flow with drilling mud (water and clay minerals) hasn’t worked. The next trick after this was supposed to be a “junk shot” with rubber and plastic goodies to gum things up in the blow out preventer; but this has seemingly been discarded after the drilling mud tactic failed. The third trick is putting a new blowout preventer on top of the old one (this current strategy will unfold over the next few days). But it means that the existing riser needs to be chopped off (this will result in the loss of the current siphon -through the insertion device to the riser – which is bringing some oil up to a barge). So the risks are high here; as failure will mean another 2000 barrels of oil per day will leak out.
Relief wells are also being drilled to get to the point 4000 m below the sea bed. Here they will intersect with the existing wells and a deadweight of drilling fluid pumped down to stop the flow. This, however, still has a long way to go…although the technical risks are perhaps lower.
The other big issue with the operation is the spraying of chemical dispersants. They break up the oil into smaller droplets which disperse widely and are hopefully broken down by bacteria. Unfortunately, the dispersants used are toxic so whilst this is working to an extent, it conveys mixed blessings.
The other rather grim prediction is that a considerable amount of the oil flowing into the Gulf will create an underwater death zone and an environmental catastrophe for sea creatures.
The million dollar question on my mind is of course: what particular approach is going to work? There is some optimism about placing a new blow out preventer on top of the current one. We will know in the next few days.
So what can we gain from this nightmare?
Oil is definitely going to be in increasingly short supply in the years to come. Thus the requirement to operate at these extreme depths and conditions is steadily growing in intensity. This presents an incredible opportunity to go where no one has gone before – to tailor one’s current services and goods to servicing an ‘extreme environment with safety and security. Extreme risks, but with extreme rewards.
With these disasters and pioneering endeavours, we have to realize that we are stretching our engineering to the limits – well outside of our comfort zones and this quote illustrates this point:
A ship in harbor is safe – but that is not what ships are built for (John A. Shedd).
Yours in engineering learning