Oil Lost During Gas-Cap Migration Formula
Oil Lost During Gas-Cap Migration calculates oil lost during migration for reserves and recovery workflows in reservoir engineering.
How engineers use this formula
Use this formula when the listed inputs (A, h, phi, S_org, B_oa) are known and the assumptions behind the cited reserves and recovery relationship match the engineering case being checked.
Assumptions
- Input values are representative for the well, reservoir, fluid, or equipment case being evaluated.
- The declared units match the field-unit constants used in the formula.
- The cited formula applies to the selected petroleum engineering workflow.
Limitations
- The calculation does not replace a full engineering model or operating procedure.
- Accuracy depends on the source correlation, assumptions, input quality, and unit consistency.
Common mistakes
- Mixing unit systems without converting the inputs.
- Using default example values as field recommendations.
- Applying the formula outside the source assumptions.
Default example
Using the default inputs, O equals 253,898.181818 STB.
40
20
0.18
0.25
1.1
Inputs
A
acresAverage Cross-Sectional Area of the Gas-Oil Contact
h
ftAverage Change in Gas-Oil Contact Depth
phi
fractionPorosity
S_org
fractionResidual Oil Saturation in the Gas-Cap Shrinking Zone
B_oa
bbl/STBOil Formation Volume Factor at Abandonment
Outputs
O
Oil Lost During Migration
A
Average Cross-Sectional Area of the Gas-Oil Contact
h
Average Change in Gas-Oil Contact Depth
S_org
Residual Oil Saturation in the Gas-Cap Shrinking Zone
B_oa
Oil Formation Volume Factor at Abandonment
Source and review
reviewedAdvanced Reservoir Engineering, Ahmed, T., McKinney, P. D. (2005)
Ahmed, T. and McKinney, P. D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter 5, Page 333.
Source