Archive of Texas PTTC Workshops

The PENCOR Division of Core Laboratories and The Petroleum Technology Transfer Council announce the third annual reservoir engineering symposium

Material Balance, Modeling and Simulation: Reservoir Engineering Tools.
Past, Present, and Future

Wednesday, June 29, 2005
Core Laboratories Corporate Headquarters, 6316 Windfern, Houston 77040

Presentation in PDF format Dr. John McMullan, Marathon Oil Company. “Material Balance: The Forgotten Reservoir Engineering Tool”
Material balance as a reservoir engineering tool has lost popularity in recent years with the widening use of reservoir simulation. Reservoir simulation is based upon the fundamental assumption of material balance, however. Is there a place for traditional material balance analysis in the reservoir engineering “tool kit”, or is it, as some have suggested, a “needless distraction” to the modern engineer?
Without question, material balance provides a much simpler tool for reservoir analysis than reservoir simulation. The data that must be collected for a material balance study is a subset of the data required for a simulation study. While material balance analysis is not always successful, it often is able to quantify the original volume of hydrocarbons in place and the drive mechanisms active in the reservoir. This understanding of the reservoir is critical in identifying un-drained hydrocarbon potential, well locations, and optimal completion and production strategies. With modern computer software, material balance analysis often requires only minutes. The vast majority of the time required is in the collection of the data…..this same data must also be collected for a reservoir simulation study. As such, material balance analysis should be considered a precursor to reservoir simulation, not a replacement. Material balance is quick, often straightforward, and can provide a valuable understanding of the reservoir. This understanding of the reservoir has the potential to accelerate the history matching phase in a reservoir simulation study. There is no logical reason not to consider material balance for reservoir analysis. This talk reviews the development and application of material balance, and uses several examples to illustrate its usefulness to the reservoir engineer.
Presentation in PDF format

Dr. Bill McCain, Texas A&M University. “Rapid ‘Tuning’ of Equations of State in Compositional Simulation”
A graduate school project over the last several years at Texas A. & M. University has worked to take some of the mystery out of ‘tuning’ equations of state for use in compositional simulation. A strategy has been proposed which appears to automatically work for any gas-condensate or near-critical/volatile oil. This strategy performs the tuning by altering the least accurately known properties of the fluid. The best technique for extending the lab measured composition of the plus fraction was determined. The best available correlations for assigning properties to the components of the extended composition were selected based on experimental results.
A major outcome of this work is an understanding that the method of the grouping the compositions of the multiple carbon number groups from the extended composition is dependent on the composition of the measured plus fraction of the original reservoir fluid. This presentation will provide a correlation for doing this grouping based on data from their study using 32 reservoir fluid studies.

Presentation in PDF format Dr. Chris White, Louisiana State University. “Emerging Uses of Reservoir Simulation: Insights, Planning, and Control”
The future of simulation will provide information never before available, but will also require more discipline, forethought and limitations. This presentation will discuss how new methods and hardware allow us to do sensitivity and history matching (insights), optimization and scenario modeling (planning), and eventually guide day-to-day decision making and operations (control). The presentation will focus not so much on theory, but rather on applications and operations.

Presentation in PowerPoint format

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Rob Sutton, Marathon Oil Company. “Variations in Modeling with PVT Correlations and Effects on Reservoir Performance Estimates”
At PTTC/Core Lab symposium of 2004, Dave Bergman presented a discussion of oil viscosity correlations, their accuracy and pitfalls if an unsuitable method is selected to represent a given crude oil. Ideally PVT properties are known; however, in situations where PVT is an unknown, correlations are utilized. The talk for 2005 has been expanded to discuss PVT methods for the calculation of the major oil properties of interest for engineers. In particular, these properties include bubble-point pressure, oil formation volume factor, isothermal compressibility, and viscosity. A number of correlations have been published over the years for these key properties and the range of answers derived from these methods can be quite variable. A conceptual black oil reservoir model was created to test these methods and access the impact of this variability on original oil in place, reservoir performance, oil recovery and project life. Oil properties over the range of 20-40 API and gas-oil ratios of 250-750 scf/STB at a reservoir temperature range of 125-250 °F were evaluated.
The talk provides an overview of oil PVT correlations and their variability. Results from the simulation studies will be presented to quantify the impact of correlation selection on reservoir performance and recovery.

For more information regarding the technical program, please contact Toddy Guidry with Pencor/Core Laboratories at 337-839-9060 ( email: )

About the Speakers

Dr. John McMullen received his B.S., M.S., and Ph.D. degrees in Petroleum Engineering from Louisiana State University. He has worked in a variety of locations for both independent and major oil companies. John has experience in many domestic and international producing areas, and taught reservoir engineering and reservoir simulation for several years at the L.S.U. Craft and Hawkins Department of Petroleum Engineering. He currently serves as a Senior Technical Consultant in the area of reservoir engineering for Marathon Oil Company in Houston. John is an active member of the Society of Petroleum Engineers and is a registered petroleum engineer in the states of Louisiana and Texas.

Dr. William D. (Bill) McCain, Jr. has been a Visiting Professor in the Harold Vance Department of Petroleum Engineering at Texas A&M University since 1991. McCain started his engineering career with Esso (now Exxon) Research Laboratories in 1956, where he assisted in research on surface processing of petroleum fluids. He was Professor and Head of the Petroleum Engineering Department at Mississippi State University from 1965 to 1976 and taught at Texas A&M University from 1984 through 1987. McCain was a consulting petroleum engineer with Cawley, Gillespie & Associates from 1987 until 1991. He was with S. A. Holditch & Associates from 1991 until 2000, retiring as Executive Vice President and Chief Engineer. He currently has his own consulting firm, McCain Engineering. He wrote two editions of the widely-used textbook, The Properties of Petroleum Fluids, holds U.S. Patents, and has numerous publications in the field of petroleum engineering. He holds a B.S. degree from Mississippi State University, and M.S. and Ph.D. degrees from the Georgia Institute of Technology, all in Chemical Engineering.

Dr. Christopher White, Associate Professor at Louisiana State University in the Craft & Hawkins Department of Petroleum Engineering, specializes in reservoir characterization topics including geostatistics, stratigraphy, petrophysics and integrated modeling. Before joining the faculty at LSU, Dr. White worked as a research scientist at the University of Texas at Austin and with Shell Development Company. Dr. White earned both his M.S. and Ph.D. from Stanford University in the field of Petroleum Engineering.

Rob Sutton graduated from Marietta College in May 1978. Following graduation, he was employed by Marathon Oil Company as a Production Engineer in the Lafayette Gulf Offshore District office. While working for Marathon in Lafayette, Rob took courses at the University of Southwestern Louisiana which led to an M.S. degree in Petroleum Engineering in December 1983. While in Lafayette, Rob had assignments in the Operations, Reservoir, and Production Coordination Departments. In June 1985, he transferred to Marathon’s Denver Research Center to work in the Reservoir Management Department where he was active in reser¬voir modeling, multiphase flow in pipe calculations, well performance analysis and training. He has worked temporary assignments in London and Aberdeen on Marathon’s North Sea assets. Rob wrote and maintains Marathon’s in-house multiphase flow computer program as well as programs to evaluate PVT properties, erosional velocity, well skin factor and gas well unloading velocity. Rob has authored SPE papers on multiphase flow calculations, oil PVT correlations, well performance analysis, and an improved method to calculate the com¬pressibility factors of gas-condensates. He recently wrote the chapter on oil PVT correlations for the SPE Petroleum Engineering Handbook.

For more information, please call Sigrid Clift at 512-471-0320.