Formation Evaluation
Background
Geological Controls on Rock Properties
- Mineralogy
- Sediment Texture (Grain Size and Sorting)
- Compaction and Cementation
- Evaluation Techniques (thin-section, SEM, XRD)
Introduction to the Logging Tools
- Logging While Drilling
- Open Hole Wireline Logging
- Cased Hole Logging
Idealised Workflow
Based on a clastic sequence. Ideally conducted on one dataset (wireline, CCA and SCAL). Calculations performed in Excel to allow quick and easy experimentation with input parameters.
Quicklook Log Interpretation - Operations
- Quality Control
- Identifying the Reservoir
- Identifying the fluid type and contacts
- Calculating Porosity
- Calculating Hydrocarbon Saturation
- Pressure / Fluid Sampling
- Permeability Determination
- Presenting the Results
Conventional and Special Core Analysis
- Cores and Cuttings
- Cuttings Analysis
- Porosity and Permeability
- Fluid Saturations (Extraction and Capillary Pressure)
- Reservoir Conditions
Final Interpretation
- Net Sand Definition
- Porosity Calculation
- Archie Saturation
- Permeability
Further Studies - Single Wells
Advanced Log Interpretation
Situations beyond the simple clastic example outlined above.
- Shaly Sand Analysis
- Carbonates - Fractures
- Multi-Mineral / Statistical Models
- NMR Logging
- Thin Beds
- Thermal Decay Neutron Interpretation
Integration with Seismic
Showing how the formation evaluation is calibrated to the seismic and extended beyond the well.
- Synthetic Seismograms
- Fluid replacement modelling
- Acoustic / Elastic Impedance Modelling
Reservoir Engineering
Summary of the input of engineering parameters to the formation evaluation process.
- Behaviour of Gases
- Behaviour of Oil / Wet Gas Reservoirs
- Material Balance
- Darcy's Law
- Well Testing (Drill Stem, RFT, Leak-Off, Interference etc)
Rock Properties Distribution
Consideration of how the key formation evaluation rock properties might be extended beyond the well control.
- Porosity (2D interpolation, seismic data integration, 3D modelling)
- Water Saturation (direct mapping, water saturation / porosity relationship, capillary pressure functions, 3D water saturations)
- Net Pay (2D, seismic integration, 3D)
- Permeability (2D and 3D modelling)
