Olivier Dubrule

Olivier Dubrule

PhD	Petroleum Geostatistics
PhD university	Ecole des Mines de Paris

Olivier Dubrule obtained a PhD Degree in Petroleum Geostatistics at Ecole des Mines de Paris in 1981. He then worked for Sohio Petroleum Company in the USA (1982–1986), Shell International in The Netherlands (1986–1991) and, since 1991, he has been with Elf and TotalFinaElf, working in France and in the UK. During his career, he has held a variety of staff and management positions where he developed and applied new techniques for reservoir characterisation, earth modelling, risk analysis and uncertainty quantification. After leading the Earth Modelling and Uncertainty Quantification group at TotalFinaElf, Dr. Dubrule recently became manager of Geoscience Training and Communication.

Dubrule has authored more than 20 papers in the field of geostatistics and earth modelling. In 1991, he received the President's prize of the International Association of Mathematical Geology, for Outstanding Contribution to Mathematical Geology by an individual 35 years or younger. In the last decade, he organized and chaired a number of events organised by SPE, EAGE, SEG, or AAPG. Dubrule is the author of AAPG Course Notes Series #38 Geostatistics in Petroleum Geology, and editor (with E. Damsleth) of Petroleum Geostatistics a Special Issue of EAGE's Petroleum Geoscience Journal, published in 2001.

2003 SEG/EAGE Distinguished Instructor Short Course

Geostatistics for Seismic Data Integration in Earth Models

In recent years, the use of geostatistics has spread from the world of reservoir characterisation to that of velocity analysis, time-to-depth conversion, seismic inversion, uncertainty quantification, and more generally to that of seismic data integration in earth models. Nevertheless, many geoscientists still regard geostatistics as little more than a statistical black-box. By explaining the concepts and applications, the goal of this course is to clarify the benefits of geostatistics and help spread its use.

The course will cover the use of geostatistics for interpolation (kriging…), heterogeneity modelling, uncertainty quantification (simulation…), and data integration (cokriging, external drift, geostatistical inversion…). A variety of applications and examples will be presented, including velocity mapping, time-to-depth conversion, heterogeneity modelling, and seismic data integration in stochastic earth models. The relationships between geostatistics and approaches more familiar to geophysicists, such as filtering or bayesian methods, will also be discussed, without entering into mathematical details. A number of case studies will be presented, covering examples from various parts of the world. This will be a lively course, illustrated by examples, exercises and discussion sessions.

The short-course presentation, limited to one-day, will provide an overview of basic concepts and applications. The course document will provide a support to the course, and further extend some of the more technical considerations.

As a result of following this course, geoscientists, and more specifically geophysicists will better understand how geostatistics fits into their workflow, what tools and techniques they should use depending on the problem at hand, and what added-value may result from its use.

O. Dubrule has significant teaching experience, through his AAPG sponsored course "Geostatistics in Petroleum Geology" and through courses he has given internally at TotalFinaElf, at the Geological Society (through Japec) and at academic institutions such as Imperial College (London) and Ecole des Mines (France).

This course comes at a time when the use of geostatistics is spreading in geophysics, as shown by the increase in the number of geostatistics papers submitted to Geophysics or Geophysical Prospecting. It should raise significant interest among both SEG and EAGE members.

Course Outline

Introduction

• Earth modelling, the meeting point for data integration.
• The role of geostatistics at different steps of the Earth modelling workflow
• Basics of statistics

The Covariance and the Variogramm

• Stationarity vs. non-stationarity, what does this mean practically ?
• Variogram and covariance. Interpreting the sill, the range, the nugget effect.
• How to compute a variogram
• Various variogram and covariance models, how to fit them, their relation with fractals

Interpolation

• Kriging, for property interpolation in 2D or 3D
• Error cokriging and factorial kriging for velocity analysis and mapping
• Time-to-depth conversion using the External Drift method
• Collocated cokriging, for integration of seismic attributes information in reservoir models
• How Kriging relates to other deterministic interpolation techniques (multiquadrics, splines…)

Conditional Simulation for Heterogeneity Modelling and Uncertainty Quantification

• Conditional simulation, what is it, and when should it be applied?
• Conditional simulation for 3D geological facies modelling
• Stochastic Earth modelling integrating all subsurface uncertainties
• Geostatistical inversion
• Geostatistical inversion, for acoustic impedance inversion at reservoir scale
• Geostatistical inversion versus other geophysical inversion techniques

Conclusion

• Geostatistical websites and software
• The do's and dont's of geostatistics
• The current and future role of geostatistics in the reservoir modelling workflow

Additional Resource

The accompanying textbook is available for purchase.

External links

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