Fractured Reservoirs

PART ONE: EXPLORATION APPROACHES AND CONSIDERATIONS

• CHAPTER 1: OVERVIEW AND SUMMARY STATISTICS
  • Introduction
  • Hydrocarbon reserves in fractured and tight reservoirs
  • History and method of fractured reservoir discoveries
  • Field size distribution
  • Tectonic setting
    • Bally-Snelson classification
    • Klemme classification
  • Reservoir age
  • Reservoir lithology
  • Burial depth
  • Fluid type

• CHAPTER 2: EXPLORING FOR FRACTURED RESERVOIRS
  • Introduction
  • Origin of natural fractures
    • Tectonic fractures
    • Regional fractures
    • Contractional fractures
    • Surface-related fractures
  • Fracture size, morphology and interconnectivity
    • Fracture size
    • Fracture morphology
      • Open fractures
      • Deformed fractures
      • Mineral-filled fractures
      • Vuggy fractures
    • Stylolites
  • Laboratory fracture experiment
  • Relationship of fractures to faults and folds
    • Fractures associated with faults
    • Fractures associated with folds
      • Fractures in folds produced by compressive stress
      • Fractures in folds produced by diapiric vertical uplift
    • Regional joints
  • Controls on fracture size and spacing
    • Lithologic controls on fracture spacing
    • Stratigraphic controls on fracture spacing
    • Bed curvature controls on fracture size
  • Classification of fractured reservoirs by production characteristics
  • Exploration strategies and techniques
    • Exploration strategies
      • Surface fracture maps
      • Fracture-facies maps
      • Fracture intensity index maps
      • Radius of curvature maps
      • Surface geochemical surveys
    • Exploration techniques
      • Drillers’ logs and mud logs
      • Well surveys
      • Wireline logs
      • Well tests
  • Petroleum systems in fractured reservoirs
    • General trends in source rocks
      • Total organic carbon (TOC) and kerogen type
      • Source rock age and lithology
      • Source rock depositional environment
    • General trend in seals
      • Seal lithology
      • Seal depositional environment
    • Trapping mechanism
      • Structural traps
      • Combination traps
      • Stratigraphic traps
  • Play classification
    • Fractures produced by extensional faulting and folding
    • Fractures produced by compressional faulting and folding
    • Fractures produced by wrench faulting and folding
    • Fractures produced by vertical basement uplift/salt movement
    • Fractures produced by regional fracturing and jointing
    • Fractures produced by subunconformity karstification

• CHAPTER 3: FRACTURED RESERVOIRS IN TECTONIC SETTINGS DOMINATED BY EXTENSIONAL FAULTING AND FOLDING
  • Introduction
  • Tectonic setting
    • Klemme classification
    • Bally-Snelson classification
  • Trapping configuration
  • Exploration histories
  • Reservoir characteristics
    • Reservoir lithology
    • Reservoir petrophysical characteristics
      • Carbonate reservoirs
      • Non-carbonate reservoirs
  • Fracture characteristics
    • Fracture porosity and permeability
    • Fracture origin
    • Fracture orientation, distribution and density
      • Fractures related to faulting
      • Fractures related to subunconformity karstification
      • Fractures related to cooling and hydrothermal activity
      • Fractuers created by hydraulic fracturing
  • Basics of petroleum systems
    • Lithologic and stratigraphic relationships
    • Tectonic relationships
  • Approaches and strategies

• CHAPTER 4: FRACTURED RESERVOIRS IN TECTONIC SETTINGS DOMINATED BY COMPRESSIONAL FAULTING AND FOLDING
  • Introduction
  • Tectonic setting
    • Klemme classification
    • Bally-Snelson classification
  • Trapping configuration
  • Exploration histories
  • Reservoir characteristics
    • Reservoir lithology
    • Reservoir petrophysical characteristics
      • Carbonate reservoirs
      • Non-carbonate reservoirs
  • Fracture characteristics
    • Fracture porosity and permeability
    • Fracture origin
    • Fracture orientation, distribution and density
      • Fractures on anticline related to simple folding
      • Fractures on anticline related to thrust/reverse faulting
      • Fractures related to subunconformity karstification
      • Fractures created by hydraulic fracturing
  • Basics of petroleum systems
    • Lithologic relationships
    • Tectonic relationships
  • Approaches and strategies

• CHAPTER 5: FRACTURED RESERVOIRS IN TECTONIC SETTINGS DOMINATED BY WRENCH FAULTING AND FOLDING
  • Introduction
  • Tectonic setting
    • Klemme classification
    • Bally-Snelson classification
  • Trapping configuration
  • Exploration histories
  • Reservoir characteristics
    • Reservoir lithology
    • Reservoir petrophysical characteristics
  • Fracture characteristics
    • Fracture porosity and permeability
    • Fracture origin
    • Fracture orientation, distribution and density
      • Fractures directly caused by wrench faulting
      • Other fractures associated with wrench-faulted structures
      • Fractures related to subunconformity karstification
      • Fractures created by hydraulic fracturing
  • Basics of petroleum systems
    • Lithologic relationships
    • Tectonic relationships
  • Approaches and strategies

• CHAPTER 6: FRACTURED RESERVOIRS IN TECTONIC SETTINGS DOMINATED BY VERTICAL BASEMENT UPLIFT OR SALT MOVEMENT
  • Introduction
  • Tectonic setting
    • Klemme classification
    • Bally-Snelson classification
  • Trapping configuration
  • Exploration histories
  • Reservoir characteristics
    • Reservoir lithology
    • Reservoir petrophysical characteristics
    • Matrix porosity distribution
  • Fracture characteristics
    • Fracture porosity and permeability
    • Fracture origin
    • Fracture orientation, distribution and density
      • Fractures related to salt flow or diapirism
      • Fractures related to vertical basement uplift
      • Fractures related to subunconformity karstification
  • Basics of petroleum systems
    • Lithologic relationships
    • Tectonic relationships
  • Approaches and strategies

• CHAPTER 7: FRACTURED RESERVOIRS IN TECTONIC SETTINGS DOMINATED BY REGIONAL FRACTURING AND JOINTING
  • Introduction
  • Tectonic setting
    • Klemme classification
    • Bally-Snelson classification
  • Trapping configuration
  • Exploration histories
  • Reservoir characteristics
    • Reservoir lithology
    • Reservoir petrophysical characteristics
  • Fracture characteristics
    • Fracture porosity and permeability
    • Fracture origin
    • Fracture orientation, distribution and density
      • Reservoirs with good natural fractures
      • Reservoirs with natural plus hydraulically-induced fractures
      • Reservoirs in which natural fractures are limited or absent
      • Reservoirs with natural fractures plus karstic solution
  • Basics of petroleum systems
    • Lithologic relationships
    • Tectonic relationships
  • Approaches and strategies

• CHAPTER 8: RESERVOIRS WITH FRACTURES RELATED TO SUBUNCONFORMITY WEATHERING OR KARSTIFICATION
  • Introduction
  • Tectonic setting
    • Klemme classification
    • Bally-Snelson classification
  • Trapping configuration
  • Exploration histories
  • Reservoir characteristics
    • Reservoir lithology
    • Reservoir petrophysical characteristics
  • Fracture characteristics
    • Fracture porosity and permeability
    • Origin and timing of fracture vs karstification
    • Distribution of subunconformity karst porosity in fractured reservoirs
      • Solution-enhanced porosity in non-karstic carbonate reservoirs
      • Solution-enhanced porosity in karstic carbonate reservoirs
      • Solution-enhanced porosity in weathered-basement reservoirs
  • Basics of petroleum systems
    • Lithologic relationships
    • Tectonic relationships
  • Approaches and strategies

PART TWO: DEVELOPMENT APPROACHES AND CONSIDERATIONS

• CHAPTER 9: DEVELOPING AND PRODUCING FRACTURED RESERVOIRS
  • Introduction
  • Fracture versus matrix porosity and permeability
    • Porosity and permeability equations
    • Geometrical relationships between fracture and matrix blocks
  • Classification of fractured reservoirs by production characteristics
    • McNaughton and Gabb’s classification
    • Nelson’s classification
    • Other fractured reservoir classification
      • Saidi’s classification
      • Chawathe, Ertekin and Grader’s classification
  • Production tests in fractured reservoirs
    • Pressure transient analysis
    • Interference test
  • Drive mechanisms in fractured reservoirs
    • Overview
    • Drive mechanisms of reservoirs in the database
  • Enhanced oil recovery techniques
  • Recovery factor
    • Recovery factor by fluid type
    • Recovery factor by drive mechanism
    • Recovery factor by EOR technique
  • Reservoir classification based on performance and recovery
    • Type I – Fractured oil reservoir with little matrix porosity and permeability
    • Type II – Fractured oil reservoir with low to moderate matrix porosity and low matrix permeability
    • Type III – Fractured microporous oil reservoir with high matrix porosity and low matrix permeability
    • Type IV – Fractured macroporous oil reservoir with high matrix porosity and high matrix permeability
    • Type G – Fractured gas and gas-condensate reservoirs
  • Relative abundance and in-place reserves for each reservoir type
  • Recovery factors for each reservoir type

• CHAPTER 10: TYPE I RESERVOIR OIL PRODUCTION – The matrix is non-porous and fractures provide all of the storage capacity and the fluid-flow pathways
  • Overview and summary statistics
  • Reservoir quality and heterogeneity
  • Reservoir performance and EOR technique
    • Water drive as the main producing mechanism
    • Solution gas drive as the main producing mechanism
    • Gravity drainage drive as the main producing mechanism
  • Recovery efficiency and successful reservoir management strategies

• CHAPTER 11: TYPE II RESERVOIR OIL PRODUCTION – Low porosity/low permeability matrix provides the storage capacity and fractures provide the fluid-flow pathways
  • Overview and summary statistics
  • Reservoir quality and heterogeneity
    • Carbonate reservoirs
    • Sandstone reservoirs
    • Volcanic and basement reservoirs
  • Reservoir performance and EOR technique
    • Water drive as the main producing mechanism
    • Solution gas drive as the main producing mechanism
    • Water drive in combination with other drive mechanisms
    • Other drive mechanisms
  • Recovery efficiency and successful reservoir management strategies

• CHAPTER 12: TYPE III RESERVOIR OIL PRODUCTION – High porosity/low permeability matrix provides the storage capacity and fractures provide the fluid-flow pathways
  • Overview and summary statistics
  • Reservoir quality and heterogeneity
    • Primary chalk reservoirs
    • Chalky limestone reservoirs
    • Chert/diatomite reservoirs
    • Dolomite reservoirs
    • Mixed limestone/dolomite reservoirs
  • Reservoir performance and EOR technique
    • Effect of fracture intensity/wettability on recovery efficiency
    • Solution gas drive as the main producing mechanism
    • Solution gas in combination with other drive mechanisms
    • Gravity drainage drive as the main producing mechanism
    • Other combination drive mechanisms
  • Recovery efficiency and successful reservoir management strategies

• CHAPTER 13: TYPE IV RESERVOIR OIL PRODUCTION – High porosity/high permeability matrix provides both the storage capacity and fluid-flow pathways and fractures merely enhance permeability
  • Overview and summary statistics
  • Reservoir quality and heterogeneity
    • Sandstone reservoirs
    • Carbonate reservoirs
  • Reservoir performance and EOR technique
    • Water drive as the main producing mechanism
    • Solution gas drive as the main producing mechanism
    • Gravity drainage drive as the main producing mechanism
    • Fluid expansion plus water combination drive mechanism
    • Water plus solution gas combination drive mechanism
  • Recovery efficiency and successful reservoir management strategies

• CHAPTER 14: TYPE G RESERVOIR GAS AND CONDENSATE PRODUCTION –
  • Overview and summary statistics
  • Reservoir quality and heterogeneity
    • Sandstone reservoirs
    • Carbonate reservoirs
    • Non-conventional reservoirs
      • Coal bed methane reservoirs
      • Fractured shale reservoirs
  • Reservoir performance and EOR technique
    • Conventional gas reservoirs
    • Non-conventional gas reservoirs
    • Gas condensate reservoirs
  • Recovery efficiency and successful reservoir management strategies

• BIBLIOGRAPHY

• ENCLOSURES
  • Enclosure 1.1 - Index of fractured and tight reservoirs with operators indicated
  • Enclosure 1.2 - Discovery year
  • Enclosure 1.3 - Bally basin classification
  • Enclosure 1.4 - Klemme basin classification
  • Enclosure 1.5 - Reservoir age
  • Enclosure 1.6 - Reservoir lithology
  • Enclosure 1.7 - Burial depth to OWC or GWC
  • Enclosure 1.8 - Fluid type and original in-place reserves
  • Enclosure 2.1 - Stratigraphic cross-section showing reservoirs, source rocks and seals
  • Enclosure 2.2 - Age and lithology of source rock
  • Enclosure 2.3 - Seal lithology
  • Enclosure 2.4 - Trap type
  • Enclosure 2.5 - Trapping mechanism
  • Enclosure 2.6 - Play type and fracture mechanism
  • Enclosure 9.1 - Drive mechanism
  • Enclosure 9.2 - Enhanced oil recovery (EOR) technique
  • Enclosure 9.3 - Fluid type and recovery factor
  • Enclosure 9.4 - Production reservoir type