Geir Evensen

Geir Evensen
The man behind EnKF joins IRIS

Chief Scientist Geir Evensen joined IRIS energy on April 1st. Evensen has extensive experience with data assimilation in ocean and weather models as well as ensemble-based history matching within petroleum reservoir models. At IRIS he is part of the Reservoir group at the Bergen office.

Research Director Randi Valestrand is very pleased to have Evensen on the team.

- IRIS and Evensen share a long history on data-assimilation and assisted history matching. He invented the Ensemble Kalman Filter when he was at the Nansen Center and IRIS picked it up early 2000 and brought it into solving the history matching petroleum problem. After 13 years in the oil industry Evensen has now returned to research here at IRIS, so you can say that the loop has been closed in a way.

Among other things, Evensen will participate in projects on ensemble based methods, with extra focus of including 4D seismic data in assisted history matching.

- He will also initiate new projects directed at Fast Model Update, which relates very well with most of the research we do in the Reservoir group. We are impressed by how fast the Fast Model Update workflow has been widely implemented in Statoil, it is one of the few things taken from research and broadly implemented at Statoil the last 10 years, she says.

In 1989 Evensen started as a researcher at Nansen Environmental and Remote Sensing Center (NERSC), where he completed a PhD and Postdoc within applied mathematics, both related to data-assimilation methods for use in oceanography and meteorology. While at the Nansen Center he developed new ensemble-based data-assimilation methods, e.g. Ensemble Kalman Filter (EnKF), which is now used operationally in all large international weather services, and Ensemble Smoother (ES), which has become very popular as a method for history matching oil-reservoir models.

From 2003 to 2016 he worked at Norsk Hydro and Statoil, where he has managed the development and implementation of the Fast-Model-Update technology. Fast Model Update is an ensemble-based tool for multidisciplinary and multi-realization reservoir modelling and management that is now established as Statoil’s preferred modelling technology.

He also holds a secondary position as Research Director at the Nansen Center. This position opens new possibilities for collaboration that he hopes will result in joint projects in the future.

What made you join IRIS?
- I knew several of the people working in IRIS Bergen well before starting, both from studying with them and from working closely with IRIS in different projects during my time in Hydro and Statoil. The most important reason for coming to IRIS is that my background in data-assimilation fits well with the ongoing research activities here. 
- After just having completed the Fast Model Update implementation in Statoil I wished to work with more fundamental research and with uncertain times in the industry, this was a good time and opportunity to switch jobs.

What will you be working on at IRIS?
- I am interested in ensemble-based modelling and data assimilation, which has a great potential for applications in a wide range of research areas. Thus, in addition to continuing the development of ensemble methods for use in Fast Model Update, I also see possibilities for introducing multi-realization modelling and data assimilation in other research areas.

What is your impression of IRIS so far?
- I really like the working environment. It’s informal and quite busy at the same time. That suits me well. The office is also a short walk from where I live, which is also nice. I’ve spent the first weeks getting to know my colleagues and new routines. I’ve also started to plan new projects for my further research.

Cand. Scient. (Master) in Applied Mathematics (plasma dynamics) at the Department of Mathematics, University in Bergen, 1989.
Dr. Scient. (Ph.D.) in Applied Mathematics (PhD thesis on data assimilation methods for nonlinear dynamical systems) at the Department of Mathematics, University in Bergen, 1992.

2004 – present: Professor II at the Nansen Center. Supervision of PhD students and supporting the development and execution of new projects.
2003 – 2016: Leader Fast Model Updating, Statoil. Leader of a technology implementation project on integrated reservoir modeling.
1995 – 2003: Research Director. The Nansen Center. Management of the Modelling and Data Assimilation group and management of a project portfolio on ocean and data assimilation research.
1996 – 2002: Professor II at the Department of Mathematics, University of Bergen. Supervised a number of Master and PhD students.
2000: Appointed « Professeur associé de 2ième catégorie » at L’École Nationale Supérieure des Mines de Paris.
1993- 1995: Postdoc at the Nansen Center. Post Doc on data assimilation funded by Norwegian Research Council.
1989 – 2003: Researcher (PhD and postdoc) at the Nansen Center. Worked with data-assimilation methods for use in oceanography and meteorology. Worked as department and project manager. Appointed Board Director in Ocean Numerics Ltc., (a joint venture between NERSC and UK-based Fugro Geos Ltd), where the ocean-modelling system was commercialized.