Royalty Formula

I (and about 50 others) have mineral interest in New Mexico and have leased an 80 acre parcel. What I would like to know is the formula to calculate royalty payments. I assume it would be something like: # of BBLS X royalty % X price per BBL? + ?(gas or ?) and - ? (pooled interests, etc). Any info in regards to this would be greatly appreciated.

http://serc.osu.edu/extension/understanding-oil-and-gas-royalty-calculations

http://www.mineralrightsforum.com/group/eagle-ford-shale-karnes-county-tx/forum/topics/royalty-calculation

Vernon:

Google "Mantra Land Services"; click on "Resources" (top of page); click on "Oil & Gas Calculator" (left side of page); find "Gas" calculator on top and "Oil" calculator on bottom. Just plug in your figures.

http://www.mantralandservices.com/PageDisplay.asp?p1=3655