West of Shetland Rock Physics Study Phase 1
Introduction
Phase 2 of this study was completed in 2011, and it enhances the North Sea Central Graben Pressure Study Phase 1 by integrating full 3D seismic coverage to supply:
- Better definition of pressure compartments
- Evidence for fluid escape in and around breached traps
- Structural definition relative to well position and the location of seal failure
The maps in this study are based on data released up to 2009, and include:
- An effective stress map to show areas of potential seal breach
- New definition of Jurassic/Triassic pressure compartments
Phase 2 is a complementary study and does not replicate the five case studies of Phase 1.

Benefits and Deliverables
Benefits
- Integration of well and seismic data for strengthened confidence in the resulting model
- Improved knowledge of sub-Chalk compartments and pressures
- Predictive algorithms for fracture gradients and overburden for the entire basin
- Improved definition of seal breach risk
Deliverables
- Maps from Phase 1 updated with an additional 300 E&A wells provided by IHS
- Integration of seismic data supplied by PGS in the form of a comprehensive overpressure compartment map for Jurassic and Triassic intervals
- A risking strategy for seal breach (hydraulic top-seal failure) using structural crestal depths derived from seismic data Effective stress maps at Base Chalk and Base Cretaceous and an assessment of seal breach in undrilled areas
- Discussion of vertical fluid flow and leakage above traps/faults
- A reassessment of stratigraphic position for pressure data in the Palaeocene
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Liza Yellott
Jul 13, 2026 9:27:27 AM
Jul 13, 2026 9:27:27 AM