Dr Martin Preston, Marine Pollution Specialist and Honorary Research Fellow, comments on the Elgin gas release:
“The methane release represents a very significant explosion hazard, and of course methane is a potent greenhouse gas. The gas in this field is ‘sour gas’ i.e. it contains hydrogen sulphide which is very poisonous to humans and aquatic life – localised risks to marine life are likely. The hydrogen sulphide content of the current release is unclear at present. Localised fish kills cannot be ruled out.
“The associated gas condensates (low molecular weight hydrocarbons) may also represent a localised contamination issue. Reports of surface slicks indicate condensate release but these should evaporate/disperse fairly rapidly (hours/days) given warm weather and reasonable wind speeds.
“There are two technological solutions which may be considered – firstly, pumping heavy mud into the well. This would be a faster solution but riskier because of the explosion risk. It might fail anyway if the well structure has been damaged and gas is coming out over an area of sea floor.
“Drilling a relief well in a similar fashion to that used in the Gulf of Mexico spill is also a possibility. However the exercise should be quicker and easier in shallow water provided the explosion/H2S risks can be managed. However the process can be expected to take many weeks or months.
“The rate of gas escape should decrease as the reservoir pressure decreases but it is unclear at this stage how long this might take.”