Footwall Uplift and Erosion During Jurassic Rifting: Scott and Telford Fields, UK Central North Sea

As producing fields enter late life, subsurface risk mitigation remains critical in order to justify continued infill well drilling. Despite >100 wells and modern 3D seismic in the Scott and Telford fields (UK Central North Sea), reservoir absence led to repeated development well failures. A new model now ascribes reservoir attenuation to Late Jurassic footwall uplift and erosion.

The 2015 Scott well J40 found a reduced Upper Jurassic reservoir section of Lower Scott sands only, with Upper Scott and Piper sands absent. Reinterpretation showed that missing reservoir sections reflected not fault cut-out as previously believed, but Late Jurassic footwall uplift and erosion. The failed 2016 Telford F6 well was shown to have drilled a thick Kimmeridge Clay hangingwall section north of the Telford Fault, rather than the southern footwall section targeted. Planning for the Scott J43 and four subsequent wells successfully mitigated reservoir risk while optimising reserves.

Scott and Piper sand distributions likely reflected early tectonic movements before the main Mid-Tithonian phase of NE-SW extensional faulting which saw Piper and Scott reservoirs locally reworked as Claymore sands. Later WNW-ESE faulting during opening of the Witch Ground Graben saw major crestal erosion at Telford while Scott footwall highs were partially downfaulted.