Peter Tybjerg

Manager & Principal Consultant

Calsep Copenhagen

Phone: +45 45 97 08 17

Consulting Services, examples

EoS Modeling Study for 7 Reservoir Fluids
The study included QC of 7 reservoir fluid compositions and associated PVT data. Subsequently an investigation of reservoir zone communication between 7 reservoir fluids was conducted. This was followed by a development of 7 EOS models calibrated against routine (Separator Test, CME, and Differential Depletion) and EOR (Swelling Test, Equilibrium Contact, Multi Contact, Slim Tube, MMP) PVT data. Finally, the EOS models were exported to Eclipse Compositional and VIP Compositional.

EoS Modeling of 5 Reservoir Fluids
Five reservoir fluids and accompanying PVT data were quality checked and a fluid column analysis performed for two of the fluids, which were sampled in different depths in the same well. Depth gradient simulations revealed that fluid communication did exist. A common EOS model was developed for all five fluids and used for generation of Eclipse Compositional input files.

Wax Deposition in a Well
The fluid was characterized to match measured wax content of the crude and wax appearance temperatures. Eighteen different production scenarios were evaluated with varying GOR, water cuts and oil production rates. Wax deposition in the well was observed in 5 out of the 18 scenarios.

Corrosion in Wells
The purpose of the study was to quantify the H2S and CO2 in concentrations in wells in an oil field. A QC was initially performed to decide which fluid compositions were of a satisfactory quality for use in the EOS modeling. Verification of the developed EOS models was done by simulating the separator test and differential depletion experiments. The simulated content of CO2 and H2S in the liberated gases was then compared with the reported compositions to validate the developed EOS model with respect to CO2 and H2S distribution between gas and liquid. Finally, the EOS models were exported to Prosper.


Tybjerg P., Kontogeorgis G.M, Michelsen M.L, Stenby E.H,
Phase equilibria modeling of methanol-containing systems with the CPA and sPC-SAFT equations of state
Fluid Phase Equilibria, Volume 288, Issues 1-2, 25 January 2010, Pages 128-138

Al-Ajmi, M. F., Tybjerg, P., Rasmussen, C. P., Azeem,
Modeling for Two Major Kuwaiti Oil Reservoir
J., SPE 141241-PP, MEOS, Bahrain, 26–28 September, 2011

Lindeloff, N.L., Mogensen, K., Pedersen, K.S., Tybjerg, P., Noman, R.,
Investigation of Miscibility Behavior of CO2 rich Hydrocarbon Systems – With Application for Gas Injection EOR
SPE 166270-MS, SPE Annual Technical Conference and Exhibition, New Orleans, LA, USA, 30 September – 2 October 2013

Bartolome, P., Tybjerg, P.,
Wax Deposition in North Sea Reservoir Wells: Field Observations and Simulations
17th International Conference on Multiphase Technology, Cannes, France, 10-12 June 2015

Tybjerg, P., Pedersen, K.S. and Krejbjerg, K.,
Reservoir Fluid Characterization Procedure for PC-SAFT Equation of State
SPE 187170-MS, SPE ATCE, San Antonio, Texas, 9-11 October 2017.


2011-2015 Graduate Diploma in Business Administration, Copenhagen Business School,    Copenhagen, Denmark
2002-2008 2008 M. Sc. in chemical engineering from the Technical University of Denmark, Kgs. Lyngby, Denmark.
2006 Ph.D. course in molecular dynamics: Computer Modeling in Chemistry. Technical University of Denmark, Kgs. Lyngby, Denmark.
2005 Ph.D course in Thermodynamic models: Fundamental and Computational Aspects. Technical University of Denmark, Kgs. Lyngby, Denmark.



2008 –      Calsep A/S


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Middle East


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