April 13, 2012
In the framework of the Elgin gas leak monitoring, Total contacted the NCAS* (National Centre for Atmospheric Science). This scientific organization is a world leader in atmospheric science and in trace gas measurements. NCAS were undertaking scientific flights in and around the Elgin gas plume on March 30th and April 3rd and it soon became clear that these could be of assistance to Total. NCAS have made the data from these flights available to Total. The flights crossed the gas plume at several distances from the leak point, between 5 and 25 nautical miles. A flight pass upwind of the platform was carried out to determine the background methane content.
It was found to be approximately 0.00019 %, in line with normal atmospheric measurements. Then, several passes were undertaken in the plume. The methane content from these measurements were in all cases found to be lower than 0.00028 %. The concentration data provided to us by NCAS confirm a very strong dilution of the effluents outside the Elgin platform exclusion zone.
The data from NCAS confirmed also a decrease of the leak flowrate between March 30 and April 3rd, in line with platform observations via infra-red and normal camera pictures. TotalEnergies intends to pursue the cooperation with NCAS through the support of an additional flight in the coming days, to continue its environmental data gathering.
* NCAS is part of the UK Natural Environment Research Council. One of its roles is to manage the UK Facility for Airborne Atmospheric Measurements, in cooperation with the Met Office.