Eagle Ford / Austin Chalk – Multi-Client PVT Study

Eagle Ford / Austin Chalk – Sample Overview

Last updated: 15 August 2022

Eagle Ford / Austin Chalk – Multi-Client Study

The Eagle Ford / Austin Chalk multi-client project was first initiated in 2016. The main objective of the study was to create one, field-wide equation of state (EOS) model for the entire Eagle Ford / Austin Chalk. Since then more data has been incorporated into the model, resulting in a more robust thermodynamic description. But what is a field-wide EOS model? In simple terms, you can think of it as a field-wide “PVT correlation” applicable for all fluids in a given basin (black oils | volatile oils | near-critical fluids | gas condensates | wet gases | dry gases). The model is tuned/adjusted to measured PVT laboratory data available in that particular basin, and can be used to consistently predict PVT data such as saturation pressures, formation volume factors (FVF), solution GORs/CGRs, densities, compressibilities and viscosities across a field.. Here are some key information about the study.

Number of PVT Samples

In this study, 97 PVT samples from 92 different well locations were included in the EOS model development work. Of the 97 samples, 83 are from the Eagle Ford, while 14 are from the Austin Chalk. The Eagle Ford and Austin Chalk samples are thermodynamically consistent, even though the compositions tend to vary, meaning that one EOS model is sufficient for both. In general, compositionally, Austin Chalk samples tend to be richer (lower GOR / higher CGR) then the Eagle Ford samples in the same area / pad. There are 28 considered as bubblepoints samples, 65 dewpoints and 4 dry gas samples. The C7+ component is ranging from 0 mol% to 45 mol%.

Participating Companies

New companies are joining the study every single year.

  • Devon Energy
  • EP Energy
  • Lewis Petro
  • Magnolia
  • Marathon Oil Company
  • Murphy Oil
  • Ranger Oil
  • Repsol
  • SM Energy
  • (Penn Virginia)
  • (Lone Star)
  • (Equinor)

Experimental Overview

Experiments #
Separator test17
Oil viscosity17

Table above summarize PVT experiments performed on all samples.

Unconventional Fluids Systems

Unconventional fluid systems demonstrate strong field-wide PVT consistency although the reservoir fluid (i.e. composition) varies significantly. Reservoir fluid differences are dominantly determined by thermal maturity, which is the main reason behind the consistent fluid characteristics over large areas. What this means in practice, is that we can use one fluid model (i.e. EOS model) for the entire field, but what changes from area-to-area/well-to-well is the GOR (i.e. composition). This has been one of the key findings in all our studies.

Which Unconventional Basins Have We Conducted This Type of Work?

Consortium Budget

The participation budget is 40,000 USD per company.

Want to know more? Send an e-mail to carlsen@whitson.com


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whitson supports energy companies, oil services companies, investors and government organizations with expertise and expansive analysis within PVT, gas condensate reservoirs and gas-based EOR. Our coverage ranges from R&D based industry studies to detailed due diligence, transaction or court case projects. We help our clients find the best possible answers to complex questions and assist them in the successful decision-making on technical challenges. We do this through a continuous, transparent dialog with our clients – before, during and after our engagement. The company was founded by Dr. Curtis Hays Whitson in 1988 and is a Norwegian corporation located in Trondheim, Norway, with local presence in USA, Middle East, India and Indonesia