{[(X + Y - W)/Z1] * Z2} + X = A,
Where:
A = calculated end of month inventory;
W = first inventory measurement;
X = second inventory measurement;
Y = gross sales volume between the first and second inventory;
Z1 = number of actual days produced between the first and second inventory; and
Z2 = number of actual days produced between the second inventory and end of calendar month for which the OGOR report is due.
For example: If the first inventory measurement performed on January 12 is 125 bbl, the second inventory measurement performed on February 10 is 150 bbl, the gross sales volume between the first and second inventory is 198 bbl, and February is the calendar month for which the report is due. For purposes of this example, we assume February had 28 days and that the well was non-producing for two of those days.
{[(150 bbl + 198 bbl - 125 bbl)/29 days] * 16 days} + 150 bbl = 273 bbl for the February end-of-month inventory.
43 C.F.R. §3173.9