Although planimetering of contour maps to determine reservoir volumes is widely-accepted, it can be shown mathematically that planimetering always is less rigorous than numerical integration when integrating net volume, net porous volume or hydrocarbon pore volume. This is true whether a) individual variables (such as porosity and thickness) are contoured, planimetered and multiplied, or b) combined variables (such as porosity * thickness) are contoured and planimetered. Numerical integration is shown to be the most mathematically rigorous method of determining reservoir volumes.

You can access this article if you purchase or spend a download.