Principles of Applied Reservoir Simulation

John R. Fanchi, John R. Fanchi,

• Publisher: Gulf Professional Publishing
• Year: 2018
• eBook ISBN: 9780128155646
• Edition: 4
• Topic: Technology & Engineering
• Subtopic: Chemical & Biochemical Engineering
• Index: Technology & Engineering

Reservoir engineers today need to acquire more complex reservoir management and modeling skills. Principles of Applied Reservoir Simulation, Fourth Edition, continues to provide the fundamentals on these topics for both early and seasoned career engineers and researchers. Enhanced with more practicality and with a focus on more modern reservoir simulation workflows, this vital reference includes applications to not only traditional oil and gas reservoir problems but specialized applications in geomechanics, coal gas modelling, and unconventional resources. Strengthened with complementary software from the author to immediately apply to the engineer's projects, Principles of Applied Reservoir Simulation, Fourth Edition, delivers knowledge critical for today's basic and advanced reservoir and asset management.- Gives hands-on experience in working with reservoir simulators and links them to other petroleum engineering activities- Teaches on more specific reservoir simulation issues such as run control, tornado plot, linear displacement, fracture and cleat systems, and modern modelling workflows- Updates on more advanced simulation practices like EOR, petrophysics, geomechanics, and unconventional reservoirs

Chapter 1

Introduction to Reservoir Simulation

Abstract

Hydrocarbon reservoir management includes recovery of oil and gas resources using a variety of processes ranging from primary recovery to waterflooding, immiscible gas injection, and enhanced oil recovery (EOR). Many disciplines contribute to the reservoir management process. In the case of a hydrocarbon reservoir, successful reservoir management requires understanding the structure of the reservoir, the distribution of fluids within the reservoir, drilling and maintaining wells which can produce fluids from the reservoir, transport and processing of produced fluids, refining and marketing the fluids, safely abandoning the reservoir when it can no longer produce, and mitigating the environmental impact of operations throughout the life cycle of the reservoir. Reservoir simulation helps integrate information from all of the disciplines and provides quantitative reservoir performance forecasts.

Chapter 1 introduces the reader to the simulator IFLO that accompanies this book. Simulator applications using IFLO illustrate many chapter concepts throughout the text. Chapters 2 through 9 help you learn how to build a reservoir model and execute a flow simulator. Chapters 10 through 14 show how to conduct a flow model study.

Keywords

reservoir

management

oil

gas

simulator

modeling

Chapter Outline

1. 1.1 “Hands-on” Simulation
2. 1.2 Introduction to IFLO
3. 1.3 Input Data File
4. 1.4 Output Data Files
   • 1.4.1 Time Step Summary File: ITEMP.TSS
   • 1.4.2 Run Output File: ITEMP.ROF
   • 1.4.3 Well Output File: ITEMP.WEL
   • 1.4.4 Array File: ITEMP.ARR
   • 1.4.5 Material Balance Error File: ITEMP.MBE
5. 1.5 Activities
   • 1.5.1 Recommended Reading
   • 1.5.2 Exercises

A reservoir simulator is a computer program that is designed to model fluid flow in rock. Applied reservoir simulation is the use of these programs to solve reservoir flow problems and influence reservoir management decisions (Carlson, 2003; Gilman and Ozgen, 2013).

Reservoir simulation is an aspect of reservoir management. Modern reservoir management can be broadly defined as a continuous process that optimizes the interaction between data and decision-making during the life cycle of a field. This definition covers the management of a variety of reservoir systems, including hydrocarbon reservoirs, geothermal reservoirs, and reservoirs used for geological sequestration.

Hydrocarbon reservoir management includes recovery of oil and gas resources using a variety of processes ranging from primary recovery to waterflooding, immiscible gas injection, and enhanced oil recovery (EOR). Conventional hydrocarbon resources can be economically produced without stimulation treatments such as hydraulic fracturing, or special recovery processes and technologies. Other hydrocarbon resources are considered unconventional resources and include coal gas, tight gas, shale gas, gas hydrates, shale oil, and tar sands.

Reservoir management concepts, tools, and principles are applicable to subsurface resources other than oil and gas. For example, geothermal reservoirs and geological sequestration are reservoir management applications that can be analyzed using reservoir simulation. Geological sequestration is the capture, separation, and long-term storage of greenhouse gases or other gas pollutants in a subsurface environment. Carbon dioxide injection in a coal seam can be an enhanced gas recovery process and a geological sequestration process. If you would like to learn more about the role of energy in today’s society, see Energy in the 21st Century (Fanchi and Fanchi, 2017).

Many disciplines contribute to the reservoir management process (Fanchi, 2016; Fanchi and Christiansen, 2017). In the case of a hydrocarbon reservoir, successful reservoir management requires understanding the structure of the reservoir, the distribution of fluids within the reservoir, drilling, and maintaining wells which can produce fluids from the reservoir, transport, and processing of produced fluids, refining and marketing the fluids, safely abandoning the reservoir when it can no longer produce, and mitigating the environmental impact of operations throughout the life cycle of the reservoir. Properly constituted asset management teams include personnel—often specialists—with the expertise needed to accomplish all of these tasks. They must be able to communicate with one another and work together toward a common objective. Reservoir simulation helps integrate information from all of the disciplines and provides quantitative reservoir performance forecasts.

Reservoir simulation studies are important when significant choices must be made. The choices can range from “business as usual” to major changes in investment strategy. By studying a range of scenarios, modelers can provide information to decision makers that can help them decide how to commit limited resources to activities that can achieve management objectives. These objectives may refer to the planning of a single well, or the development of a world-class size reservoir.

Reservoir flow modeling is the most sophisticated methodology available for generating production profiles. A production profile presents fluid production as a function of time. By combining production profiles with hydrocarbon price forecasts, it is possible to create cash flow projections. The combination of production profile from flow modeling and price forecast from economic modeling yields economic forecasts that can be used by decision makers to compare the economic value of competing reservoir management concepts.

Reservoir management is most effective when as much relevant data as possible from all sources is collected and integrated into a reservoir-management study. This requires the acquisition and management of data that can be expensive to acquire. As a consequence, the cost of acquiring data needs to be evaluated in relation to the benefits that would result from its acquisition. They are involved in decisions that prioritize data needs based on project objectives, relevance, cost, and impact.

One of the critical tasks of reservoir management is the acquisition and maintenance of an up-to-date database. The reservoir simulation process can help coordinate activities for an asset management team by gathering the resources that are needed to determine the optimum plan for operating a field. Collecting data for a reservoir flow model is a good way to ensure that every important technical variable is considered as data is collected from the many disciplines that contribute to reservoir management. If model performance is especially sensitive to a particular parameter, then a plan should be made to reduce uncertainty in the parameter.

Chapters 2 through 9 help you learn how to build a reservoir model and execute a flow simulator. Chapters 10 through 14 show how to conduct a flow model study. The rest of Chapter 1 introduces you to the simulator that accompanies this book.

1.1. “Hands-on” Simulation

The best way to learn how to apply reservoir flow simulators is to get some “hands-on” experience with a real reservoir flow simulator. Consequently, let us consider applying a reservoir flow simulator known as IFLO. Many of the terms used in this section to describe IFLO are discussed in more detail in subsequent chapters.

The integrated flow model IFLO is a pseudomiscible, multicomponent, multidimensional fluid flow simulator (Fanchi, 2000). It is called an integrated flow model because it integrates a petrophysical model into a traditional flow simulator. This integration makes it possible to integrate data from such disciplines as geology, geophysics, petrophysics, and petroleum engineering in a single software package.

IFLO can be used to model isothermal, Darcy flow in up to three dimensions. It assumes that reservoir fluids can be described by up to three fluid phases (oil, gas, and water) with physical properties that depend on pressure and, to an extent, composition. Natural gas and injected solvent are allowed to dissolve in both the oil and water phases. IFLO includes a petrophysical algorithm that allows the calculation of reservoir geophysical attributes that make it possible to track changes in seismic variables as a function of time, and to perform geomechanical calculations. A coal gas desorption option is available for modeling coalbed methane production.

A variety of useful geoscience, geomechanical, and reservoir engineering features are available when using IFLO. Well modeling features include the representation of horizontal or deviated wells, a well index calculation option, and a stress-dependent permeability model for improving the calculation of well and reservoir flow performance. Petrophysical features include im...

Table of contents

• Cover
• Title page
• Table of Contents
• Copyright
• Dedication
• About the Author
• Preface to the Fourth Edition
• Acknowledgments
• Website – Software
• Chapter 1: Introduction to Reservoir Simulation
• Chapter 2: Geological Modeling
• Chapter 3: Rock Properties
• Chapter 4: Petroelastic Modeling and Geomechanical Modeling
• Chapter 5: Rock–Fluid Interaction
• Chapter 6: Fluid Properties and Model Initialization
• Chapter 7: Multiphase Fluid Flow Equations
• Chapter 8: Wells
• Chapter 9: Fundamentals of Reservoir Simulation
• Chapter 10: Overview of the Modeling Process
• Chapter 11: Traditional Model Study
• Chapter 12: Modern Flow Modeling Workflows
• Chapter 13: Fracture and Shale Systems
• Chapter 14: Enhanced Recovery and Coal Gas Modeling
• Appendix A1: Initialization Data
• Appendix A2: Recurrent Data
• Appendix B: Example IFLO Input Data Set
• Appendix C: Unit Conversion Factors
• References
• Index