Reservoir system analysis
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It has been suggested that this article be merged with [[::Reservoir system|Reservoir system]]. (Discuss) |
| Exploring for Oil and Gas Traps | |
| |
| Series | Treatise in Petroleum Geology |
|---|---|
| Part | Predicting the occurrence of oil and gas traps |
| Chapter | Predicting reservoir system quality and performance |
| Author | Dan J. Hartmann, Edward A. Beaumont |
| Link | Web page |
| Store | AAPG Store |
Reservoir performance
The fundamental goal of the explorationist is to predict the performance that a reservoir will have over the production life of the field. Reservoir performance affects the economic viability of a play or prospect and is a function of reservoir system quality. Performance is expressed by
- Initial production rate and production rate decline over time
- The percentage of hydrocarbon recovered from the hydrocarbon originally in place (recovery factor)
Reservoir system quality
Reservoir system quality is the capacity of a reservoir to store and transmit oil or gas. The quality of a reservoir system is determined by its
- Pore throat size distribution and pore geometry (including natural fractures; see also Pore and pore throat sizes)
- Pore volume
- Permeability to hydrocarbon
- Water saturation (hydrocarbon pore volume)
- Lateral continuity, number, and position of flow units and containers
- Reservoir pressure and drive mechanism
Procedure for reservoir system analysis
Below is a suggested procedure for reservoir system analysis:
- Select a key well(s) for detailed petrophysical analysis (see Petrophysical analysis of lithofacies).
- Subdivide the reservoir in the key well(s) into flow units (see Flow units for reservoir characterization).
- Determine pore type for each flow unit in the key well using core descriptions, thin section and scanning electron microscopy analysis, porosity/permeability–r35 analysis, Water saturation –depth plot, Buckles plot, etc.
- Construct stratigraphic strike and dip cross sections that include the key well. Use a region/fieldwide time marker at the top of the reservoir as the datum.
- Subdivide the reservoir interval of each well into flow units.
- Correlate flow units between wells and subdivide the reservoir into containers by determining which flow units interact during drainage.
- Determine hydrocarbon volume by computing the volume of pay by flow unit for each container.
- Predict performance in terms of recovery amount and time by incorporating the above analysis with expected fluid properties and drive mechanism (see Drive mechanisms and recovery). Predictions should compare well with performance of analog reservoir systems.
Selecting a key well
The key well is most representative of the reservoir and has the best data. In some cases, such as in complex reservoirs, more than one key well may be necessary. A detailed petrophysical analysis of the key well can be compared to and calibrated with other wells in the reservoir that have less data.
See also
- Reservoir system
- Defining flow units and containers
- Reservoir drive mechanisms
- Predicting reservoir drive mechanism
External links
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