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How are reserve volumes estimated and how often do they change througout a fields life?
A basic introduction is very welcome, more details aswell...

thanks!

The process of estimating oil and gas reserves for a producing field generally continues throughout the life of the field. There is always uncertainty in making such estimates. The level of uncertainty is affected by the following factors:

1. Reservoir type,
2. Source of reservoir energy,
3. Assumptions adopted when making the estimate,
4. Available technology, and
5. Quantity and quality of the geological, engineering, and geophysical data,
6. Experience and knowledge of the evaluator.

All these factors need to be re-assessed as new data comes in during the life a of a field.
Therefore, the magnitude of uncertainty decreases with time until the economic limit is reached and the ultimate recovery is realized.

hope this helped

Initially you can calculate reserves using seismic interpretation in some software like Stratwork. using structure top and gridding it then using contact(OWC, OGC) and gridding it then subtracting both the grids. Method can be refined to meet the needs. Thanks