1065 - OGP Surveying and Positioning Committee

Annex A______________________________________________________________________________________________________________Page A1Annex A - DTI Gazette Notice (in full)Co-ordinate Systems for UKCS Petroleum Exploration and Production LicencesIt has been drawn to the Department’s attention that there may be some uncertainty as topetroleum licence boundary co-ordinate description across the UKCS. This Notice sets outthe Department’s interpretation of licence boundary co-ordinates in existing licences andconfirms the position, until further notice, as to the co-ordinate systems that will apply in thecase of future awards of licences. These are to be determined in accordance with theprinciples set out below.Specific geographical co-ordinate systems are identified for use in various areas.Transformations between the relevant co-ordinate systems are defined. Through acombination of the declared co-ordinate systems and declared transformations, petroleumindustry users can unambiguously merge positional data throughout the UK and itscontinental shelf. The recommendations are made explicitly for petroleum licence boundaryco-ordinate description but are also suitable for use for petroleum data managementpurposes.The Oil and Gas Directorate of the Department of Trade and Industry advise that:1. To the east of 6 degrees West longitude, “European Datum” means the first adjustmentdated 1950, usually referred to as ED50. For UKCS petroleum exploration and productionpurposes ED50 is equivalent to ETRF89 with the “Common Offshore” transformationapplied.2. To the west of 6 degrees West longitude, the co-ordinate system for UKCS petroleumexploration is ETRF89. UKCS licence boundaries to the west of 6 degrees West longitudefollow a latitude and longitude graticule based on the ETRF89 system, except for licencesabutting 6 degrees West longitude on their eastern side where special provision isrequired to ensure exact adjacency to licences to the east based on ED50.3. The current practice of using the Ordnance Survey ( R ) GB National Grid as the coordinatesystems for petroleum exploration and production in landward areas of GreatBritain is maintained.4. The following geodetic transformations are recognised as defining the relationshipsbetween the various co-ordinate systems required for UKCS petroleum exploration andproduction purposes:4.1 the difference between the WGS 84 and ETRF89 co-ordinate systems is notsignificant and WGS 84 co-ordinate values can be assumed to be equivalent toETRF89. This is equivalent to the transformation between WGS 84 andETRF89 being taken to be zero.4.2 the recommended relationship between ED50 and WGS 84 or ETRF89 is the“Common Offshore” transformation. The Common Offshore transformation isan operation using the position vector transformation method and the followingspecified set of Helmert transformation parameters for changing co-ordinatesbetween the WGS 84 and ED50 co-ordinate systems on the UKCS. Forpetroleum exploration and production purposes the transformation can also beused between the ETRF89 and ED50 co-ordinate systems.____________________________________________________________________________________________UKOOA Guidance Notes on use of co-ordinate systems in data management on the UKCS - December 1999