Oil and Gas

Oil and Gas | Reservoir Engineering

PVT Equation of State Applications to Hydrocarbon Fluids

Course Code: N982
Instructors:  Ronald LangAaron Zick
Course Outline:  Download
Format and Duration
4 days


This practical course will provide attendees with a working knowledge of Pressure Volume Temperature Equation of State (PVT EOS) theory and its applications, following a path from field sampling, to the lab and on to the examination of common practices and analyses used in classical and simulated reservoir engineering. It will also address black oil and compositional modeling for simulation.

Duration and Training Method

This is a four-day classroom-based course that includes theory, worked examples, and a field trip to a reservoir fluid lab.

Course Overview

Participants will learn to:

  1. Evaluate fluid types and phase behavior.
  2. Explain why and how the Equation of State (EOS) was developed.
  3. Select methods of sampling.
  4. Assess and quality control PVT lab reports including DLE, CCE, CVD.
  5. Set up PVT simulators to tune an EOS to PVT lab report.
  6. Manage compositional modeling including vaporization/condensation processes.
  7. Construct black oil and compositional simulation models.
  8. Assess viscosity and construct tables for simulation.
  9. Assess uncertainties in measurements.

Three and a half days of classroom work will be followed by a half-day field excursion.

1. Basic Thermodynamics
a. Gibb’s phase rule
b. Reservoir fluid types and the phase diagram
-Black oil
-Volatile oil
-Near-Critical oil
-Retrograde condensates: lean-rich; low-high dropouts
-Wet and dry gas
c. Single components and development of equation of state (EOS)
d. Two-component systems and binary interaction parameters (BIP)
e. Multi-component systems and ternary-quaternary diagrams

2. Equation of State Phase Behavior Modeling
a. Software applications
b. Data requirements for fluid characterization
c. Experimental data for tuning EOS to fluid characterization
d. Gamma distribution fitting
e. Plus fraction characterization and gamma splitting
f. Pseudoization and component lumping

3. PVT Experiments for Petroleum Fluids
a. Traditional black oil experiments including DLE, CCE, CVD
b. Building black oil tables from directly from PVT data
c. Compositional experiments including:
-Equilibrium phase compositions
-Swelling experiments
-Multi-contact vaporization experiments
-Slim tube displacements

4. EOS Characterization Tuning
a. General guidelines for tuning
b. Initializing the characterization
c. Inputting measured data
d. Guidelines for choosing regression variables
e. Trial and error including:
-Modifying the data weighting
-Modifying the choice of regression variables
-Learning to recognize data outliers and discrepancies
-Learning to recognize good matches from poor matches

5. Estimating Reservoir Fluid Compositions
a. “Equilibrium Contact Mixing” method
b. Mathematical decontamination
c. Gravity induced thermodynamic segregation

6. Using Black Oil Properties from a Tuned EOS
a. Run your own laboratory experiments
b. Simulate depletion experiments
c. Generate results for multi-stage surface conditions
d. Translate results in reservoir simulator format

7. Minimum Miscibility Pressures and Enrichments
a. Mechanisms
-Condensing gas drive
-Vaporizing gas drive
-Condensing/vaporizing gas drive
b. EOS predictions
-Slim tube simulations
-Multi-cell, multi-contact mixing simulations
-Predictions by the method of characteristics

8. Reservoir Fluid Lab Visit
a. How PVT experiments are conducted
b. Understanding limitations and uncertainties

This course is designed for engineers assigned with the responsibility of determining reservoir hydrocarbons originally in place and forecasting produced oil and gas volumes during depletion. Understanding phase behavior and PVT laboratory experiments are essential to the reservoir engineer engaged in primary, secondary and enhanced oil recovery (EOR) operations. Simulation engineers will gain confidence in characterizing reservoir fluids for history matching and predictions. Process and chemical engineers will also benefit from the course.

Ronald Lang

Ronald (Ron) Lang is a senior staff reservoir engineer and serves as a team lead with RPS Knowledge Reservoir in Houston, Texas. He has over 40 years of experience in all aspects of reservoir engineering including classical and simulation applications. He is actively involved as a consultant in domestic and international studies requiring application of PVT equation of state (EOS) principles. He participates in association with geosciences teams in field development strategies including primary, secondary, and enhanced oil recovery (EOR) projects.

His career began with Amoco Production Company in Houston and transitioned to consulting firms engaged in exploration and development; acquisition and divestment transaction advisory; and petroleum engineering technical evaluations. He is a licensed professional engineer in the state of Texas.

As an experienced simulation engineer, Mr. Lang learned the importance of correctly applying PVT (EOS) to properly characterize reservoir fluids and accurately predict fluid behaviour and its ultimate impact on reservoir performance. He has studied EOS under the guidance of leading experts in the oil and gas industry. In the development of conventional and unconventional oil and gas resources, it is crucial for engineers to understand the differences among the various classes of reservoir fluids. In particular, reserves and their value can be lost rapidly if engineers do not properly define near-critical fluids, and their behaviour, such as in the volatile oils and retrograde gases.

Affiliations and Accreditation
BSc  Texas Tech University - Petroleum Engineering

Courses Taught
N982:  PVT Equation of State Applications to Hydrocarbon Fluids

Aaron Zick

Dr. Aaron Zick has specialized in reservoir fluid phase behavior and phase behavior modelling for the past 30 years. Founder and operator of Zick Technologies since 1993, Aaron has provided the petroleum industry throughout the world with expertise in equation-of-state software programming, phase behavior modeling and fluid characterization.

Prior to forming his consulting firm, Dr Zick was the Director of Research at Reservoir Simulation Research Corporation (1991–1993), where he was responsible for the research and development of more efficient, accurate, and reliable techniques for modeling reservoir fluid phase behavior. Dr Zick was also the Senior Principal Research Engineer at ARCO Oil and Gas Company (1983–1991) in charge of research and development of technology and software for oil and gas recovery.

Dr. Zick has published several articles in respected academic journals and received the ARCO President’s Award for “Advancing and Applying Compositional Technology.”, the ARCO Vice President’s Award for “Limited-Compositional Reservoir Simulator Development.”, and the ARCO Special Achievement Award for “Development of the State-of-the-Art EOSPHASE Phase Behavior Program.”

Affiliations and Accreditation
PhD Stanford University - Chemical Engineering
MSc Stanford University - Chemical Engineering
BSc Stanford University - Chemical Engineering

Courses Taught
N982: PVT Equation of State Applications to Hydrocarbons Fluids

CEU: 3.2 Continuing Education Units
PDH: 32 Professional Development Hours
Certificate: Certificate Issued Upon Completion
RPS is accredited by the International Association for Continuing Education and Training (IACET) and is authorized to issue the IACET CEU. We comply with the ANSI/IACET Standard, which is recognised internationally as a standard of excellence in instructional practices.
We issue a Certificate of Attendance which verifies the number of training hours attended. Our courses are generally accepted by most professional licensing boards/associations towards continuing education credits. Please check with your licensing board to determine if the courses and certificate of attendance meet their specific criteria.