Elgin: The Explosion and Environmental Impact

0


Humans have been exploring and exploiting oil and natural gas for over 5000 years so you would expect after all these years of experience, especially after the Deepwater Oil Horizon Disaster in the Gulf of Mexico in 2010, if another leak occurred somewhere else we would now know how to deal with it quickly and efficiently minimising the threats to both the natural environment and man.

After 14 hours battling with the leak on Sunday, Total evacuated the rig of its 238 personnel and workers from a nearby platform owned by Shell were also evacuated as a precaution.

The leaks source is thought to be from a rock above the gas reservoir at around 4,000m. The rig which supplies gas for camping stoves and gas hobs was shut down although controversially the flare was left burning. Total have said it would be difficult to estimate the amount that is leaking although images seem to suggest that there is a sheen of oil about 9 nautical miles long (aka 16.65km and 333 lengths in an Olympic size pool) and could contain anything between 2 and 23 tonnes of gas condensate.

The site is currently being monitored by planes to monitor where it is spreading. Air and sea exclusion zones have also been put into place to minimise risk to human health.

If this gas beneath the platform came into contact with the flare situated on top of the rig it would cause a huge explosion and create £6 billion worth of damage but fortunately the weather conditions so far have been favourable blowing the gas cloud away from the flare.

Potentially Total will be able to drill a relief well as they did in the Deepwater Oil horizon but this could take many months and cost up to £1.6 billion, in the meantime the gas will still leak.

There has been criticism from many over the flare, which is required to avoid pressure build up and dispose of larger less combustible products, which remained lit even though emergency procedures were followed. Total defends this decision and claimed the main priority was to prevent loss of life, but many believe that whilst employees where turning off the power from the rest of the rig to reduce the risk of ignition leaving a burning flare just above a cloud of gas condensate seems contradictory. Currently it is too unsafe for the flare to be extinguished.

The leak contains not only gas but dissolved hydrogen sulphide, methane and carbon dioxide. Hydrogen sulphide is known to be poisonous and the others are green house gases. Despite this the Scottish Environmental Secretary Richard Lochhead has stated he expects the gas condensate to disperse naturally and cause minimal environmental risk with only acute localised damage but he concedes inevitably there will be some deaths.

Another solution is known as dynamic kill. Large amounts of mud are pumped into the well to try and stop the flow of gas, although this causes pressure build up and dredging the mud has environmental implications.

Ideally the gas leak would stop of its own accord, which may happen as the gas field is towards the end of its life.

Unfortunately there seems to be no instant resolution to this issue and only time will tell as to how much damage has actually been done.

avatar

Leave A Reply