Underexplored Plays IIGeophysics Applications in Risking (Intro)

Per Avseth (NTNU)

Force seminar, Stavanger 23-24. November 2016

The times they are a-changing

• Conventional seismic Broadband seismic

• Qualitative interpretation (post-stack) Quantitative interpretation (pre-stack)

• 3- and 4-way closures/structural highs Subtle traps with stratigraphiccomponents

• Geological concepts + Geophysical support Integrated workflows

• Best practices (old play models) Creative thinking (new play models, out-of-the-box)

How do we change/update our risking procedures accordingly?

A

Anomaly hunting vs. hydorcarbon prediction

DHI driven prospect: Screening Anomaly hunting Supporting geological concept

DHI supported prospect: Struct. Interpr. + conceptual model Geophysical support.

Geology-Geophysics integration: Iterative approach with alternative scenarios and model updates. (Falsification and devil’s advocate approach).

Avseth et al. (2016), AVO class III Brown (2012), AVO class IIp

Integrating geology and geophysics

Geology GeophysicsRock Physics

Bottle-neck Few observablesMany parameters

Ambiguities

QI prediction

Limitations/ResolutionUncertainties

Pit-fallsMore/Better data!More knowledge!

More integration!

ComplexityNoise/Artifacts

Variability

The road ahead…

Big data analysis: • Data volume increase + computer capacity improvement

• Statistical classification, pattern recognition, visualization

Don’t forget the physics!

Integrated QI workflows: • Geologically constrained inversions (Sequence stratigraphy, Depth trends)

• Rock physics/geophysics integrated with petr. syst. analysis, basin modeling, etc.

Mind the gap!

Improved technology and new innovations: • Broad-band technology and full wave-form inversion

• Joint inversions (seismic, CSEM, grav-mag)

• Co-visualizations and geobody extraction (e.g., AVO + spectral decomposition)

Think outside the box!

Geophysics applications used in risking: (Program)

• Rob Simm (Origo): Key note; Geophysics and risk – a sense check.

• Morten Blixt (Norsar): Assessing CSEM uncertainties during exploration.

• Ryan Williams (GeoTeric): Derisking the Gohta appraisalwell location using a Cognitive Interpretation workflow.

• Bill Shea (Sharp Reflections): Pre-stack seismic methods to identify new prospects and reduce exploration risk.