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Statistical de-risking of faults associated with picking strategies: Implications for assessing fault seal for CO2 storage in the Northern Horda Platform

Introduction

Smeaheia is a potential CO2 storage site, located approximately 40 km Northwest of the Kollsnes processing plant, 20 km East of Troll East, in the Northern Horda Platform. The feasibility of this storage site relies on a strong sealing and low reactivity potential of a basement-involved half-graben bounding fault zone, named the Vette Fault Zone.

The methodology for fault interpretation and analysis (such as displacement, fault seal and reactivation) is widely accepted and used within academia and industry:

  1. Fault segments are interpreted and correlated to generate a triangulated surface,
  2. Fault polygons (intersections between horizon and fault) are generated and QC’d,
  3. Fault throw is computed, VShale is draped onto the fault, which is used along with the throw to compute the shale gouge ratio (SGR) or shale smear factor (SSF). 

However, there is missing information regarding the precise techniques for improved accuracy that should be used when interpreting both faults segments and fault polygons.  This is a crucial step and will influence fault growth analysis, fault stability analysis and fault seal analysis. 

This project will form part of an ongoing research project known as FRISK, a spin-off project from NCCS, researching into methods for de-risking faults for CO2 storage.


Aims

Improve our knowledge of the best practice for fault interpretation, and show how different picking strategies will influence the fault growth interpretation, fault reactivation analysis and fault seal potential.


Objectives

  • Interpret several faults within the footwall of the Vette fault using several picking techniques
  • Generate fault polygons, again using several picking techniques
  • Examine fault Throw – Distance plots depending on picking technique
  • Examine how fault stability and fault seal vary with picking technique
  • Use statistics to assess best practice for fault interpretation

Data

This project will use a high-resolution 3D seismic survey (GN1101) that covers part of the Smeaheia storage site. Additional 3D and 2D seismic datasets are also available should the student wish to expand the area. Well log data from Smeaheia and Troll are available for fault seal analysis. Documented in situ stress state is used for fault reactivation potential.  Previously interpreted horizons can be used for generation of fault polygons (although the student can also interpret horizons if they wish).
 

Tools and Method

The student will use Petrel, Move, and/or T7 (TrapTester) to create fault framework models, which will be used to analyse how attributes vary with picking strategy.  Faults will be picked using different line spacing, to generate different triangulated fault surfaces.  Fault polygons will be generated, again using different line spacing. Fault growth analysis, fault seal analysis and fault reactivation analysis will be performed. How the fault surface and polygons vary with picking strategy will be assessed.
 

Learning Outcomes

Proficiency using Petrel E&P Software Platform, Midland Valley Move and/or Badleys T7.  Statistical analysis of fault attributes (such as displacement and fault stability) depending on picking strategy. Independent research, academic writing and presentation skills.

 

Contact Details

For further information or to register interest in projects, please contact Emma Michie (e.m.haines@geo.uio.no).

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Tags: Structural geology, seismic interpretation, fault analysis, fault reactivation, CCS
Published Sep. 10, 2020 1:49 PM - Last modified Oct. 22, 2020 10:56 AM

Supervisor(s)

Scope (credits)

60