Oil Recovery Calculator

Understanding the Oil Recovery Factor (ORF)

The Oil Recovery Factor (ORF) is a critical metric in reservoir engineering and petroleum geology. It represents the percentage or fraction of initial petroleum in place (EIPO) that can be realistically extracted or recovered from an oil reservoir (ERO).

Typically, a reservoir's recovery factor depends on the geology, the type of drive mechanisms present, and the recovery techniques applied (primary, secondary, or enhanced tertiary oil recovery).

Reservoir Engineering Formulas

The relationship between Oil Recovery Factor ($ORF$), Estimated Recoverable Oil ($ERO$), and Estimated Initial Petroleum in Place ($EIPO$) is defined by the following simple equations:

• Oil Recovery Factor ($ORF$): The percentage of oil that is extractable: $$ORF = \frac{ERO}{EIPO} \times 100\%$$
• Estimated Recoverable Oil ($ERO$): The total volume of oil that can be extracted: $$ERO = \frac{ORF \times EIPO}{100}$$
• Estimated Initial Petroleum in Place ($EIPO$): The total volume of oil originally present in the reservoir before any extraction: $$EIPO = \frac{ERO}{ORF} \times 100$$

Typical Oil Recovery Factors

Depending on the extraction phase, typical recovery factors fall within these ranges:

• Primary Recovery: Natural reservoir pressure pushes oil to the surface, typically recovering 5% to 15% of the initial oil.
• Secondary Recovery: Water or gas injection is used to maintain pressure, increasing the cumulative recovery to 30% to 40%.
• Enhanced Oil Recovery (EOR): Thermal, chemical, or miscible gas injection alters the oil properties to ease extraction, enabling recovery factors of 50% to 60% or higher.

How to Use the Oil Recovery Calculator

1. Select the variable you want to solve for (ORF, ERO, or EIPO) using the dropdown menu.
2. Select the volume unit (Barrels or Cubic Meters) for consistency.
3. Enter the two known values in their respective input fields.
4. The calculator instantly updates the third value and displays the full engineering breakdown in the output section.