The Jasmine Field was discovered in 2006 in block 30/06 in the UK Central North Sea. The main structure is a turtle-back faulted anticline located adjacent to the Joanne salt pillow on the J-Ridge. Two distinct structural domains have been interpreted; the steeply rotated West Limb fault block and the domino-style fault blocks of the Northern Terrace. The primary reservoir is Middle to Late Triassic in age and consists of moderate-high net to gross fluvial sandstones in the Joanne Member of the Skagerrak Formation.
In 2006 the discovery well 30/06-6 and follow-on geological sidetrack 30/06-6Z were drilled successfully within a challenging HPHT environment. A rich gas condensate fluid (CGR of 220 stb / mmscf) was discovered in a hydrocarbon column of 2300 ft and favourable DST flow rates were achieved. The discovery well confirmed a mapped independent structural closure of 1200 ft, and was followed by a downflank geological sidetrack, encountering a HWC some 1100 ft deeper than the mapped closure.
A number of development concepts were considered at this stage including multiple drilling centres to reach the entire prospective area. In order to reduce uncertainty in the reservoir extent, a three-well exploration/appraisal program was initiated in late 2007. The 30/06-7 mainbore exploration/appraisal well discovered a hydrocarbon column in the Northern Terrace. Two appraisal sidetracks were then drilled to test the northern extent of the Northern Terrace accumulation and to confirm the north western extension of the West Limb core area. This program also proved the existence of secondary reservoir sands in the Late Triassic and Jurassic intervals.
Development planning has included in-house seismic reprocessing and rigorous geocellular and dynamic simulation modelling. A thorough uncertainty analysis was performed, the results of which were used to determine optimal placement of the development wells. Phase 1 of the development will include up to 8 wells drilled from a 24 slot wellhead platform. The Jasmine wellhead platform will be bridge linked to a 38 bed accommodation platform. In addition, a riser platform will be installed at the Judy facility with arrival separation, metering and additional process equipment.
It is intended to acquire new 3D seismic data before the jacket arrives, in order to improve the quality of the seismic image and to refine placement of later development wells. Additional well-specific data acquisition is planned (for example LWD and wireline logging, coring, fluid sampling and pressure measurement and a walkabove VSP) to optimise the development of the field, fully characterise the primary and secondary reservoirs and mitigate against end member outcomes.
The Jasmine development is expected to be approved by all stakeholders by the end of 2010 with drilling due to commence in Q2 2011. First production is expected in Q4 2012.