# Simple Material Balance

In this module, recovery factors for both oil (\(RF_{oil}\)) and gas (\(RF_{gas}\)) can be calculated with readily available data. The data required for calculating recovery factors is:

- Fluid definition
- Initial reservoir fluid composition (generated with any of the available methods)
- Surface process associated to the well (used to generate the black oil table)

- Initial reservoir pressure
- Reservoir temperature
- Abandonment pressure (\(p_{a}\))
- Cumulative produced GOR (\(\frac{G_p}{N_p}\))

## How is cumulative produced GOR (\(\frac{G_p}{N_p}\)) estimated?

From type curves, numerical simulation or guessing.

## Recovery Factors

Recovery factor for oil (\(RF_{oil}\)) is defined as produced surface volume of oil (N) divided by original oil in place (N), i.e. \(RF_{oil} = \frac{N_p}{N}\). Recovery factor for gas \(RF_{gas}\) is defined as produced surface volume of gas (G) divided by original gas in place (G), i.e. \(RF_{gas} = \frac{G_p}{G}\).