Research

2024

Publications

Bayesian machine learning for virtual flow metering: Anders T. Sandnes. PhD thesis
A deep latent variable model for semi-supervised multi-unit soft sensing in industrial processes: Bjarne Grimstad, Kristian Løvland, Lars S. Imsland, Vidar Gunnerud
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2023

Publications

Multi-unit soft sensing permits few-shot learning: Bjarne Grimstad, Kristian Løvland, Lars S. Imsland
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Flow Fusion, Exploiting Measurement Redundancy for Smarter Allocation: Christine Foss Sjulstad, Danielle Monteiro, Bjarne Grimstad. 41st Global Flow Measurement Workshop
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Multi-task neural networks by learned contextual inputs: Anders T. Sandnes, Bjarne Grimstad, Odd Kolbjørnsen
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Sequential Monte Carlo applied to virtual flow meter calibration: Anders T. Sandnes, Bjarne Grimstad, Odd Kolbjørnsen
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Deep Latent Variable Models for Well Modeling: Camilla Dybdal. MSc thesis, NTNU
A Temporal Multi-Task Learning Approach to Virtual Flow Metering: Eskil Ould-Saada. MSc thesis, NTNU
Bayesian Analysis of Carbon Dioxide Production in Land-based Atlantic Salmon using Latent Gaussian Statespace Modeling: Sivert Laukli. MSc thesis, NTNU
White Paper: AI Flow Solutions: Christine Foss Sjulstad, Mathilde Wekre
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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.
When is gray-box modeling advantageous for virtual flow metering?: Hotvedt, M., Grimstad, B. Ljungquist, D. & Imsland, L.S. IFAC-PapersOnLine.
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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

Global optimization of multiphase flow networks using spline surrogate models: Grimstad, B. et al. Computers and Chemical Engineering.
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Iterative optimization of flow networks by local data driven sensitivity models: Authors: Vidar Gunnerud, Bjarne Foss
Publication Date: 14 Feb 2016 - Norway
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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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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.
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.