Analysis of Oil and Gas Production Performance

Steven W. Poston is a retired professor emeritus from Texas A&M University, with more than 18 years of teaching experience at the graduate and undergraduate levels in applied reservoir engineering analysis and subsurface description of petroleum reservoirs both in the United States and internationally. His industry experience includes more than 14 years in a variety of subsurface engineering, geological, and managerial roles for Gulf Oil Exploration and Production Company in Nigeria, Pennsylvania, Louisiana, and Texas. Poston has coauthored numerous industry technical papers, has served on a number of SPE committees, and was coauthor of the SPE books Overpressured Gas Reservoirs and Analysis of Production Decline Curves.

Marcelo Laprea-Bigott is professor of engineering practice at the Harold Vance Department of Petroleum Engineering at Texas A&M University and has more than 45 years of consulting experience and an extensive background in developing and delivering technical training courses in the field of reservoir engineering for a variety of national oil companies and international clients. He joined Texas A&M University in 2006 after 20 years with Schlumberger Data and Consulting Services, having been an advisor in their Network of Excellence in Training (NExT). Laprea-Bigott’s other private sector industry experience includes more than 13 years as founder, principal owner, and president of Simupet, C.A., a petroleum engineering consulting firm; Consorcio Lamar C.A., an integrated oilfield tubulars management company; and president of S. A. Holditch and Associates–Venezuela. Additionally, he was a professor at Universidad de Oriente–Venezuela, a visiting adjunct professor at Texas A&M University, a visiting adjunct professor at the University of Tulsa, and the former assistant director of the Energy Institute at Texas A&M University. Laprea-Bigott holds a PhD degree from Texas A&M University.

Bobby D. Poe Jr. is a production and reservoir engineer with more than 30 years of industrial experience in all levels of well stimulation, well performance, and reservoir-engineering analyses. His most recent engineering position is as the production interpretation advisor at Schlumberger in Houston. Poe holds a PhD degree in petroleum engineering from Texas A&M University. He has served on a number of SPE Reprint Series and editorial committees, has authored or coauthored numerous technical articles related to production analyses, and coauthored the SPE book Analysis of Production Decline Curves. Poe holds more than a dozen US and international patents related to production-engineering analyses and interpretation techniques.

Preface vii
About the Authors ix

Chapter 1 – Introduction to Decline Curves 1
Introduction to Decline Curves 1
Physical Considerations 2
Arps Equations 4
Transient Boundary-Dominated Conditions 12

Chapter 2 – Effects of Field Conditions 19
Field Examples 20
Production Segments 21
Correcting for Well Downtime 23
Informational Plots 24
Multiplot Analysis 26

Chapter 3 – Smoothing Variable Production 31
Production Histories 31
Pseudo Production Time 31
Normalizing Production 34
The Quadratic Model 35

Chapter 4 – Well and Reservoir Models 47
Geological Considerations 48
Unfractured Vertical Wellbore Models 48
Horizontal-Unfractured-Well Case 51
Horizontal Well Example 52
Fractured Vertical Wellbore Case 55

Chapter 5 – Fractured Horizontal Wells 67
Geological Setting 67
Depletion Model 71
Shale Well Examples 74
Regional Analysis Example 78

Chapter 6 – Type Curves 85
Introduction 85
The Problem 86
Fetkovich Method 87
The Blasingame et al. Type Curve Method 97
Poe and Poston Type Curves 102

Chapter 7 – Two Phase Flow 115
Geological Influences 116
The Waterflood Event 117
Performance History—Provost Field 122
Estimating Reserves and Predicting Performance 123
Analysis Procedure 124
Analysis Procedure 126
Results of Analyses 126
Relative Permeability 127
Multiple Performance Plots 135
Well Diagnostics Plots 142

Nomenclature 155
References 159
Index 163