Below is a list of relevant contracts and agreements. This list may not cover all contracts and agreements and it is best to confirm this with the appropriate OGA Area team contact. The operation was governed by an agreement between the British and Norwegian governments, called the Frigg Contract. The agreement may make part or all of the development of the development plan on the ground subject to the agreement of the parties. It is recommended that licensees request from the CIV, at an early stage, specific guidelines for any development proposal that may have cross-border effects. The authorisation period for cross-border areas depends on the degree of compliance required between the States concerned. The development and exploitation of fields beyond the borders of the UKCS or fields entirely located on either continental shelf requiring the development of new pipeline or drilling infrastructure and cross-border control arrangements require a formal agreement between the States concerned. The field was discovered in 1971 at a depth of 1,850 meters (6,070 ft) by the Petronord Group (Elf Aquitaine, Total Oil Marine Norsk and Norsk Hydro) and the Norwegian State with 25/1-1 drilling using the P 81 neptune semi-capable of blowing into 100 meters (330 ft) of water.  The well was located according to the interpretation of a grid of 15 km by 20 of reflection seismology lines dating from 1965.  A 5 km by 5 km seismic line grid was recorded in 1969, followed by a 1 km by 1 km grid in 1973, combined with four assessment drills that showed the field was 115 square kilometres (44 square miles), with a 170-metre (560 ft) gas column in lower sandstone forming an abyssal compartment in the Viking Structural Basin.  The structure of the fan appears on the seismic sections as a low relief anticline containing a flat point caused by the density contrast of the gas.  The two jackets that support the DP2 and QP tops weigh 8,800 tons and 4,210 tons respectively. The wreckage of the DP1 jacket, which weighs 6,900 tonnes and is unfished at the bottom of the sea after being damaged during installation, should also be removed.
Drill piles, pipes and umbines also remain in place. The only substantial change to the plan requested by the Norwegian government was the timetable for the withdrawal of the shutdown platforms, which is expected to be completed by 2013 and not by 2018, as proposed by the operator. For Oslo, this is the second version of the plan, which was published last November and is the legal document. Approval of the plan, with the exception of the GBS recommendation, is granted in Norway in the form of a Royal Decree. According to Amundsen, the seven tendered contractors and their concepts are as follows: the overall experience of the development phase is positive and shows that the seven concepts are technically feasible. Only one, Versatruss, has been built and commissioned so far, mainly in the Gulf of Mexico. All other concepts exist only on the drawing board, which means that owners need financial support to build their ships.. . . .