North Sea Central Graben Pressure Study Phase 2

Table Of Contents

Introduction
Benefits and Deliverables

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.

North Sea Central Graben Pressure Study Phase 2

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