Services

Kapexy’s experience covers PVT modeling of all types of petroleum reservoir fluids. Below are examples of the fluid modeling services offered.

Table of contents

 

Optimum Use of Fluid Samples

Selecting the right fluid samples for experimental PVT studies, planning and conducting PVT studies, and development of equation of state (EoS) models are crucial steps when planning the production from a new field. Kapexy can assist with

  • Selection of reservoir fluid samples for PVT studies
  • Planning of PVT studies
  • Equation of State (EoS) modeling
  • Generation of input tables for reservoir simulators

Not all fluid samples will necessarily be representative of the reservoir fluid. Samples may be contaminated with mud from drilling fluids, or they may be taken at a lower pressure than the saturation pressure and therefore be split into two phases at sampling conditions. Gas may have leaked from the sample cylinders during transfer to the PVT laboratory.

PVT measurements are performed to clarify how the fluid will behave during production and processing. If gas injection EOR is considered, it is essential with EOR PVT measurements, but the experimental program does not necessarily have to cover the full suite of possible, often expensive EOR PVT experiments.

The conducted EoS modeling may be for a single fluid, or it can be a common EoS model for multiple fluids.

To conclude the project, Kapexy will generate input tables for black oil and compositional reservoir simulators.

The entire project will be documented in a report.

 

 

Fieldwide EoS Modeling

Kapexy offers equation of state (EoS) modeling ranging from a single fluid EoS model to common EoS models for more than 100 fluids. Component lumping and model selection will be adapted to the customer’s end use. Carried out by consultants with 30+ years of experience, you are guaranteed a high-quality product. The EoS modeling service can optionally be combined with training of your engineers in the EoS modeling discipline to enable them to solve future EoS modeling tasks.

Asphaltene Screening & Modeling Studies

Asphaltene precipitation can occur in the reservoir, in the well or in the process equipment. Experimental asphaltene measurements are costly, and Kapexy offers, based on a compositional analysis and a SARA analysis, to determine whether there is a risk of asphaltene precipitation during production and possible gas injection. If this is the case, Kapexy can in collaboration with the laboratory plan an experimental program to provide the data necessary for Kapexy to subsequently develop a reliable asphaltene EoS model.

An asphaltene modeling project will, in addition to the asphaltene EoS model be delivered with a report with a complete asphaltene phase diagram that makes it easy to determine where in the production process to expect asphaltene precipitation. The effect of possible gas injection may also be covered.

Depth Gradient Modeling

Access to comprehensive data for the compositional variation with depth in petroleum reservoirs worldwide has enabled Kapexy to offer a highly specialized consulting service within depth gradient modeling. A compositional analysis and associated sampling data for a single fluid sample is all that is needed to obtain a reliable representation of compositional variation with depth. With fluid samples taken at different depths, the model can be adjusted to match the observed depth of a possible GOC and how the saturation pressure and GOR evolve with depth as well as the concentration profile of one or more components.

Thermodynamics Course for Reservoir Engineers

This 3-day thermodynamics course will refresh concepts from college studies and introduce the thermodynamic models that PVT packages and reservoir simulators use to calculate phase properties and phase compositions of reservoir fluids. The theory will be accompanied by practical examples that connect it to the PVT tasks faced by a reservoir engineer.

Day 1

  • Cubic equations of state
    • Van der Waals
    • SRK and PR
    • Volume correction
    • Classical mixing rules
  • Phase equilibria
    • Ideal and non-ideal mixtures
    • Henry’s constant
    • Fugacity
    • K-factors
    • Critical point
    • Saturation point calculations
    • PT Flash calculations

Day 2

  • Natural Gases
    • Corresponding states principle
    • GERG-2008 equation of state
  • Reservoir fluid characterization
    • Splitting of plus fraction
    • Equation of state parameters for C7+ components
    • Binary interaction parameters
  • Mixtures with water
    • What makes water special
    • Mathias-Copeman vapor pressure
    • Non-classical mixing rules
    • CPA model

Day 3

  • Thermal properties (H, S, Cp)
    • Enthalpy
    • Entropy
    • Heat capacity
  • Compositional grading
    • Gravity segregation
    • Gas-oil contact
    • Shift of phase type through criticality
    • Impact of temperature gradient
  • CO2 rich mixtures
    • Pure CO2
    • CO2 and hydrocarbons
    • CO2 and water
    • Chemical reactions with CO2

Course material: Book by Pedersen, K.S., Christensen, P.L., Azeem, J., Phase Behavior of Petroleum Reservoir Fluids, 3rd edition, Taylor & Francis, Boca Raton, US, 2024.

Lecturer: Karen Schou Pedersen

For more information, send e-mail to contact@kapexy.com