Reservoir management is fundamental to the efficient and responsible means of extracting hydrocarbons, and maximising the economic benefit to the operator, licence holders and central government. All stakeholders have a social responsibility to protect the local population and environment. The process of managing an oil or gas reservoir begins after discovery and continues through appraisal, development, production and abandonment; there is cost associated with each phase and a series of decision gates should be in place to ensure that an economic benefit exists before progress is made. To correctly establish potential value at each stage it is necessary to acquire and analyse data from the subsurface, the planned surface facilities and the contractual obligations to the end-user of the hydrocarbons produced. This is especially true of any improved recovery methods proposed or plans to extend field life. To achieve all the above requires a multi-skilled team of professionals working together with a clear set of objectives and associated rewards. The team's make-up will change over time, as different skills are required, as will the management of the team, with geoscientists, engineers and commercial analysts needed to address the issues as they arise.
This book is designed as a guide for non-specialists involved in the process of reservoir management, which is often treated as a task for reservoir engineers alone: it is a task for all the disciplines involved in turning a exploration success into a commercial asset. Most explorers earn their bonus based on the initial estimates of in-place hydrocarbons, regardless of the ultimate cost of production; the explorers have usually moved on to a new basin before the first oil or gas is produced! This book is not a deeply academic tome, rather the description of a process enlivened by a number of stories and case studies from the author's forty years of experience in the oil-patch.
Table of Contents
Preface xi
List of Abbreviations xiii
1 Introduction 1
1.1 The Basics 3
1.2 Field Appraisal 5
1.3 Volumetrics 7
1.4 Drive Mechanism 8
1.5 Field Development 9
1.6 Reservoir Simulation 11
1.7 Field Production 12
1.8 Reservoir Monitoring and Surveillance 13
1.9 Improved Hydrocarbon Recovery 14
1.10 Cessation of Production: Field Abandonment 15
1.11 Summary 15
2 Reservoir Management Process 17
2.1 Field Appraisal 19
2.2 Field Development 22
2.3 Field Production 27
2.4 An Integrated Team Structure for Reservoir Management 30
2.5 Summary 34
3 Reservoir Description 35
3.1 Multi-scale Data 36
3.2 Reservoir Structure 37
3.3 Reservoir Framework 44
3.4 Depositional Environment 46
3.5 Static Reservoir Properties 47
3.6 Dynamic Reservoir Properties 53
3.7 Reservoir Hydrocarbon Fluids 59
3.8 Summary 63
4 Building an Integrated Reservoir Model 65
4.1 Simulation Model Design 67
4.2 Designing the Modeling Grid 73
4.3 Facies Modeling 87
4.4 Property Modeling 97
4.5 Upscaling 108
4.6 Model Analysis and Uncertainty 109
4.7 Summary 110
5 Performance, Monitoring, and Forecasting 111
5.1 Natural Drive Mechanisms 112
5.2 Reservoir Monitoring 120
5.3 Production System 122
5.4 Resource and Reserves Estimation 126
5.5 Petroleum Resources Management System (PRMS) 136
5.6 Summary 141
6 Improving Hydrocarbon Recovery 143
6.1 Primary Recovery 145
6.2 Secondary Recovery 148
6.3 Tertiary Oil Recovery 153
6.4 Summary 158
7 Development Economics 159
7.1 Key Economic Criteria 160
7.2 Risk and Uncertainty 165
7.3 Summary 171
8 Tales of the Unexpected 173
8.1 Laggan and Tormore, Flett Basin, West of Shetland, UKCS 173
8.2 Dación Field, Maturín Basin, Venezuela 176
8.3 As-Sarah Field, East Sirt Basin, Libya 177
8.4 Ceiba Field, Rio Muni Basin, Equatorial Guinea 178
8.5 Glenn Pool Field, Cherokee Basin, Oklahoma, USA 181
8.6 Schiehallion Field, Faroe-Shetland Basin, West of Shetland 184
8.7 North Burbank Field, Cherokee Basin, Oklahoma, USA 187
8.8 Nakhla Field, Hameimat Trough, East Sirt Basin, Libya 192
8.9 Forties Field, Central North Sea, UKCS 196
8.10 Leman Field, Southern North Sea, UKCS 201
8.11 Summary 204
Appendix 1 Guide to Reservoir Simulation 205
A.1 Phases of a Reservoir Simulation Study 206
A.2 Data Gathering 209
A.3 Upscaling 229
A.4 History Matching 243
A.5 Summary 251
References 253
Bibliography 261
Index 263
