Sub-Surface Uncertainty Evaluation (SUE)

Course Description

INTRODUCTION TO SEISMIC UNCERTAINTY EVALUATION 1. Sources of Uncertainties (Data Acquisition, processing & Interpretation). 2. Validation with data examples on assessment/quantification & qualifications following standard industry practices. Introduction to new learning techniques/technology. 3. Value addition on how the course will benefit an interpreter, geologist, and a Reservoir Engineer. SEISMIC UNCERTAINTY ASSESSMENT 1. Geological factors influence on Velocities 2. Review and evaluate various types of velocity (Average, RMS, Stacking, Migration, Pseudo, P&S). SEISMIC UNCERTAINTY QUANTIFICATIONS 1. Construct geologically reasonable velocity models from the data (include synthetic seismograph creations and concept of geological/ geophysical well markers).Hard and soft approaches. 2. Map migration, structural modelling & stochastic depth conversion. 3. Advance WCT(Well Constrained Tomography) workflows to construct geologically plausible models. SEISMIC UNCERTAINTY QUALIFICATIONS 1. Quantifications to qualification stage: Blind well analysis, equiprobable model, multiple regression models.. 2. Update depth conversion models adaptable to local geology and test them through amplitude shut-offs and closure maps 3. Evaluate structural uncertainties by performing Monte Carlo simulation on best reference depth maps 4. Evaluate the products from the multiple realizations: Probability distribution maps, multi-seed structures, amplitude conformance

Course Objectives

Seismic Uncertainty Analysis is a three fold approach to support well planning: • Assessment, Quantification & Qualification • Data Analytics is a must to understand data leading to decision (Data2Decision) • Learn to qualify and quantify your seismic uncertainties: Determinsitic and Stochastic • Deploy Equiprobable models for Uncertainty assessments and qualifications • Monte Carlo regression engine provides a relatively optimum P10/ P50/P90 Volumetric ranges • Uncertainty reporting and well planning

Course Outline

Day 1 -4HRS SEISMIC UNCERTAINTIES ASSESSMENT • Standard practices to evaluate and estimate the Seismic Depth Uncertainties • Risk and Myths • Why Quantification & Qualification of seismic depth uncertainties is important in E&P? QUANTIFICATION OF UNCERTAINTIES (SEIS2WELLS) • Deterministic Depth Conversion– Hard And Soft Approaches • Probabilistic Depth Conversion – Variogram & uncertainty modelling • Additional Techniques : Map Migration, Equiprobable models ADVANCED RAY BASED DEPTH CALIBRATION (WELL TOMO) • Tomography Approach For Geological Plausible Velocity Models : Vertical Ray Tomography • Why it is better de-risking model? Predictions away from the hard data QUANTIFICATION TO QUALIFICATION • Blind Well Analysis to test the best technical cases • Multiple regression models • Equiprobable modelling Day 2 -4HRS QUALIFICATION OF UNCERTAINTIES: DRILL READY SEISMIC (DRS) • Structural Flexing To Compute Probabilistic Volumetrics • Spill Point Control And Amplitude Conformance Volumetrics • Single And Multi-Seed Closures • Probability And Iso-Probability Closure Maps • Stacked Reservoir Volumetrics DEPTH RISKING SCORECARD • Uncertainty Risking Scorecard • Depth Uncertainty Communication • Well Planning and Decision Making from the Uncertainty Cube • PITFALLS & GENERAL DISCUSSIONS • Case Studies • Q&A

Participants’ Profile

The course is designed for Geologist, Geophysicist, drilling Engineers and Reservoir Engineers.


Participants require a working knowledge on basic exploration cycle. Recommended reading • Integration of geology with depth conversion using Well-Constrained Tomography, EAGE April 2016 • Managing uncertainty to deliver complex development wells, AEGC September 2019 • Depth conversion and seismic inversion of the Scarborough gas field, ASEG December 2019

About the Instructor

Manish Agarwal is a senior reservoir geophysicist based in Perth with 25 years of experience in Oil&Gas exploration & field development. Areas of expertise include regional & field scale data integration, seismic and well data interpretation (Woodside operated fields: Pluto, Cimatti, Laverda, Browse, Scarborough, Myanmar & Senegal) & geophysical support for field development & drilling (Woodside operated fields: greater Enfield & greater Pluto). Full cycle of seismic data acquisition (6 years with Schlumberger & SVUL), seismic processing & Q.I. (11 years with CGG) & interpretation and field development (9 years with Woodside and Reliance). Active in support of field development plans, static& dynamic reservoir modelling & well planning. Experienced in new ventures & exploration, risk mitigation & data development. Involved in Q.C/Interpretation of 4D data from multiple Woodside producing assets (Brunello, Pluto, Laverda & Cimatti). Developed and integrated technical workflows for time to depth conversion using image ray tomography. Supported drilling and completion teams for geosteering long offset wells. Specialist in quantification of sub-surface depth uncertaintiesand subsequent probabilistic volumetric assessment.