Integrated Subsurface Description (Identify)

The Integrated Subsurface Description clarifies “what we know/do not know” with regards to the subsurface

At a minimum (Part A) the document provides a high-level overview of the range of subsurface realisations and the associated in-place and recoverable volume ranges (100%), supported by relevant analogues. It also highlights uncertainties, risks and mitigations associated with the subsurface.

In addition, Part B of the Integrated Subsurface Description can include supporting discipline work such as - geological setting (regional geological model, play concepts, detailed lead / prospect descriptions), detailed data analysis supporting estimates of reservoir properties (porosity, permeability, saturation, fluid type) and the related risking.

The Integrated subsurface Description should be updated with new data following a successful Exploration well, to include the improved subsurface understanding and updated volume ranges

The following Controls are captured in the Integrated Subsurface Description:

• 3.I.1 Appropriate range of geological subsurface scenarios described
• 3.I.2 Subsurface Risks & Recoverable Volume & Range quantified 

The Integrated Subsurface Description highlights the current understanding of subsurface volume ranges and the related realisations, uncertainties, risks and mitigations to support exploration, appraisal or development decision making.

In the event of a project pause or passage through a Decision Gate, the Integrated Subsurface Description records the understanding of the subsurface at that point, and hence functions as the red thread when there is a governance change, or a project is resumed.

The Integrated Subsurface Description provides the road map to discipline specific work.