Research

We are proud of our R&D effort and routinely publish our content in various journals, or through Master's and Doctorate theses.

2022

Publications

Passive learning to address nonstationarity in virtual flow metering applications

Hotvedt, M., Grimstad, B. & Imsland, L.S. Expert Systems With Applications

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On a hybrid approach to model learning applied to virtual flow metering

Hotvedt, M. Supervised by Imsland, L.S., Grimstad & B. Ljungquist, D. Ph.D. Thesis.

On gray-box modeling for virtual flow metering

Hotvedt, M., Grimstad, B. Ljungquist, D. & Imsland, L.S. Control Engineering Practice.

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2021

Publications

Multi-task learning for virtual flow metering

Sandnes, A.T., Grimstad, B. & Kolbjørnsen, O. Knowledge-Based Systems.

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Bayesian Neural Networks for Virtual Flow Metering: An Empirical Study

Grimstad, B., Hotvedt, M., Imsland, L.S., Kolbjørnsen. O. & Sandnes, A.T. Applied Soft Computing.

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Identifiability and physical interpretability of hybrid, gray-box models - a case study

Hotvedt, M., Grimstad, B. & Imsland, L.S. 16th IFAC Symposium on Advanced Control of Chemical Processes: Venice, Italy.

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MLOps - challenges with operationalizing machine learning systems

Kjetså, T.I.S., supervised by Grimstad, B. MSc thesis.

2020

Publications

Mathematical programming formulations for piecewise polynomial functions

Grimstad, B. & Knudsen, B.R. Journal of Global Optimization.

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Developing a Hybrid Data-Driven, Mechanistic Virtual Flow Meter - a Case Study

Hotvedt, M., Grimstad, B. & Imsland, L.S. Conference, 21st IFAC World Congress: Berlin, Germany.

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Real-Time Data-Driven and Hybrid Modeling of Two-Phase Flow in Oil and Gas Wells

Almås, I.V.A. & Sjulstad, C.F., supervised by Grimstad, B. MSc thesis.

A spatial branch-and-bound method for ReLU network-constrained problems

Masdal, E., supervised by Grimstad, B. MSc thesis.

Probabilistic deep learning with variational inference - Uncertainty quantification using variational inference for deep neural networks modelling oil and gas production

Hegnar, E., supervised by Grimstad, B. MSc thesis.

2019

Publications

Application of online learning to Bayesian neural networks for petroleum optimization

Baugstø, S.W., supervised by Grimstad, B. MSc thesis.

Integrating Machine Learning Techniques in Real-Time Production Optimization

Andreassen, R.S. & Westby, E.M., supervised by Grimstad, B. MSc thesis.

Slug Flow Root Cause Analysis A Data-Driven Approach

Sandnes. A.T., Uglane, V. & Grimstad, B. Offshore Technology Conference: Rio de Janeiro, Brazil.

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ReLU Networks as Surrogate Models in Mixed-Integer Linear Programs

Grimstad, B. & Andersson, H. Computers & Chemical Engineering.

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Dynamic Real-Time Optimisation of a CO2 Capture Facility

Hotvedt, M., Hauger, S.O., Gjertsen, F. & Imsland, L. Conference, 12th IFAC Symposium on Dynamics and Control of Process Systems, including Biosystems: Florianópolis, Brazil.

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2018

Publications

Data Driven Real-Time Petroleum Production Planning Using Optimization and Neural Networks

Malvik, A.G. & Witzøe, B., supervised by Grimstad, B. MSc thesis.

Petroleum production optimization – A static or dynamic problem

Foss, B.A., Knudsen, B.R. & Grimstad, B. Computers & Chemical Engineering.

A MIQCP formulation for B-spline constraints

Grimstad, B. Optimization Letters.

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2017

Publications

Predictive modeling with applications in decision support systems for oil and gas production

Cenar, U.A., supervised by Grimstad, B. MSc thesis.

2016

Publications

Data driven analysis in oil and gas operations

Nordmo, M., supervised by Grimstad, B. & Sandnes, A.T. MSc thesis.

Contributions to production optimization of oil reservoirs

Codas, A., supervised by Foss, B.A. & Gunnerud, V. PhD thesis.

Global optimization of multiphase flow networks using spline surrogate models

Grimstad, B. et al. Computers and Chemical Engineering.

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A Simple Data-Driven Approach to Production Estimation and Optimization

Grimstad, B., et. al. Conference, SPE Intelligent Energy International Conference and Exhibition: Aberdeen, Scotland, UK.

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Modelling and Optimization of Real-Time Petroleum Production Using robust regression, bootstrapping, moment matching, and two-stage stochastic optimization

Morken, M.L. & Sandberg, P.T., supervised by Grimstad, B. & Gunnerud, V. MSc thesis.

2015

Publications

Automatic detection of poorly calibrated models in state estimation applied to oil and gas production systems

Skibeli, H., supervised by Grimstad, B. MSc thesis.

Global optimization with spline constraints: a new branch-and-bound method based on B-splines

Grimstad, B. & Sandnes, A.T. Journal of Global Optimization.

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Designing shale-well proxy models for field development and production optimization problems

Knudsen, B.R. & Foss, B.A. Journal of Natural Gas Science and Engineering.

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Virtual flow metering using B-spline surrogate models

Grimstad, B., Robertson, P. & Foss, B.A. Conference, 2nd IFAC Workshop on Automatic Control in Offshore Oil and Gas Production: Florianópolis, Brazil.

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Daily production optimization for subsea production systems - methods based on mathematical programming and surrogate modelling

Grimstad, B. PhD thesis.

Production Optimization – Facilitated by Divide and Conquer Strategies

Foss, B.A., Grimstad, B. & Gunnerud, V. Conference, International Federation of Automatic Control, Florianopolis.

Towards an objective feasibility pump for convex MINLPs

Sharma, S., Knudsen, B.R. & Grimstad, B. Computational Optimization and Applications.

2014

Publications

A nonlinear, adaptive observer for gas-lift wells operating under slowly varying reservoir pressure

Grimstad, B. & Foss, B.A. Conference, 19th IFAC World Congress.

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Decision Support for Daily Production Optimization: In Genuine Real-Time

Gunnerud, V., Sandnes, A.T. & Ursin-Holm, S., et.al. Conference, SPE Intelligent Energy, Utrecht.

On Shut-In Based Production Optimization of Shale-Gas Systems

Knudsen, B.R., supervised by Foss, B.A. PhD thesis.

Dynamic estimation for controlling a subsea production system

Robertson, P., supervised by Foss, B.A. & Grimstad, B. MSc thesis.

2013

Publications

Routing and Scheduling of Platform Supply Vessels: Case from the Brazilian Petroleum Industry

Friedberg & Uglane, V. MSc thesis.

A Logic Branch and Bound Algorithm for Petroleum Production Opt. Based on Generalized Disjunctive Programming

Hansen-Tangen & Sangnes, supervised by Gunnerud, V. MSc thesis.

Mixed-Integer Nonlinear Programming Heuristics Applied to a Shale Gas Production Optimization Problem

Sharma, S., supervised by Grimstad, B. MSc thesis.

Subsea investments and well placements in the oil production industry

Haug, supervised by Gunnerud, V. MSc thesis.

Simulation based optimization of petroleum production problems

Shamlou, S. & Ursin-Holm, S. MSc thesis.

Solving a Network Flow Decision Problem with Sampled Nonlinearities

Sandnes, A.T. MSc thesis.

Advanced Optimization Techniques applied to a Petrobras Field

Gunnerud, V. Teixeira & Ursin-Holm, S. SPE Middle East Intelligent Energy Conference, Dubai.

Embedding structural information in simulation-based optimization

Conn, A., Foss, B.A. & Gunnerud, V. Computers and Chemical Engineering.

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Decision Analysis for Long-term and Short-term Production Optimization Applied to the Voador Field

Foss, B.A., Gunnerud, V., Hasan, Krogstad & Teixeria . SPE Res.Charac. & Sim.Conference, Abu Dhabi.

2012

Publications

Optimization of investment decisions and production planning in aging offshore petroleum fields

Storvold, supervised by Gunnerud, V. MSc thesis.

Optimization of Oil Production – Applied to the Marlim Field

Dzubur & Langvik, supervised by Gunnerud, V. MSc thesis.

A Study in MINLP-class Optimization Problems for Simulated Petroleum Production

Ausen, H., supervised by Grimstad, B. MSc thesis.

Production Optimization in a Cluster of Gas-Lift Wells

Binder, supervised by Gunnerud, V. MSc thesis.

Stack model and cap. appr. to invst. inte. oper. across dif. Ind. Sect., O&G vs aviation, military and medicine

Bjørkvoll, Gibson, Gunnerud, V. & Larsen, M., et.al. SPE Intelligent Energy Conference, Utrecht.

Decision Support in Long Term Planning of Petroleum Production Fields

Dueñas Díez, M., Erlingsen, Gunnerud, V., Nygreen, B. & Strat. SPE Intelligent Energy Conference, Utrecht.

Oil production optimization solved by piecewise linearization in a Branch & Price framework

Foss, B.A., Gunnerud, V., McKinnon, K.I.M. & Nygreen, B. Computers and Operations Research.

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Integrated production optimization of oil fields with pressure and routing constraints: The Urucu field

Codas, A. & Gunnerud, V., et.al. Computers and Chemical Engineering.

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Optimization of a Simulated Well Cluster using Surrogate Models

Grimstad, B., et.al. Conference, IFAC WS on Automatic Control in Offshore Oil and Gas Production.

Optimization of petroleum production networks – Through proxy models and structural constraints

Shamlou, S., et.al. Conference, International symposium on Advanced control of chemical processes.

2011

Publications

Optimization of offshore natural gas field development

Johansen, supervised by Gunnerud, V. MSc thesis.

Real Option Valuation of Offshore Petroleum Field Tie-ins

Fleten, Gunnerud, V., Hem & Svendsen. Journal of Real Options.

Parallel Dantzig–Wolfe decomposition of petroleum production allocation problems

Foss, B.A., Gunnerud, V. Hagem, E., Rönnqvist, M. & Torgnes, E., Journal of the Operational Research Society.

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On decomposition and piecewise linearization in petroleum production optimization

Gunnerud, V. PhD thesis.

Life of field tool for optimal subsea design, condition monitoring, virtual metering, and flow assurance advice using a common field model

Bakken, A., Grimstad, B. & Larsen, M. Conference, Society for Underwater Technology.

The Option to Switch from Oil to Natural Gas in Active Offshore Petroleum Fields

Fleten, Gunnerud, V., Hem & Svendsen. International conference on real options theory meets practice.

2010

Publications

Real option analysis of strategic decisions in offshore petroleum production

Hem & Svendsen, supervised by Gunnerud, V. MSc thesis.

Simultaneous Methods for the Optimization of Water Flooding in Reservoir Engineering Applications

Heirung, T.A., supervised by Foss, B.A. MSc thesis.

Production Optimization in Shale Gas Reservoirs

Knudsen, B.R., supervised by Foss, B.A. MSc thesis.

Strategic optimization models for off-shore oil and gas production

Erlingsen & Strat, supervised by Gunnerud, V. MSc thesis.

Parallel Dantzig–Wolfe decomposition for real-time optimization—Applied to a complex oil field

Foss, B.A., Gunnerud, V. & Torgnes, E. Journal of process control.

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Oil production optimization—A piecewise linear model, solved with two decomposition strategies

Gunnerud, V. & Foss, B.A. Computers & Chemical engineering.

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2009

Publications

Optimization Algorithms for Short-Term Production Planning

Hanssen, supervised by Foss, B.A. MSc thesis.

Optimization of Petroleum Production under Uncertainty - Applied to the Troll C Field

Glæserud & Syrdalen, supervised by Gunnerud, V. MSc thesis.

Petroleum Production Planning Optimization - Applied to the StatoilHydro Offshore Oil and Gas Field Troll West

Hagem & Torgnes, supervised by Gunnerud, V. MSc thesis.

Lagrangian Decomposition of Oil Production Optimization Applied to the Troll West Oil Rim

Dueñas Díez, M., Foss, B.A. & Gunnerud, V. SPE Journal.

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Dantzig-Wolfe decomposition for real-time optimization - applied to the Troll west oil rim

Gunnerud, V., et.al. Conference, International symposium on Advanced control of chemical processes.

2008

Publications

Decomposition of optimization problems in petroleum production - applied to the Troll Oil field

Vestbø, & Walberg, supervised by Gunnerud, V. MSc thesis.

Distributed optimization and control of offshore oil production: the intelligent platform

Gunnerud, V. & Wartmann, et.al. Conference, Foundations of Computer Aided Process Operations.

2007

Publications

Production planning optimization for the Troll C field

Gunnerud, V. MSc thesis.