Oil and gas production accounting records how much oil and gas each well produced each month and where every barrel was sent. A barrel is the standard measure of oil, about 159 litres. It is a part of oil and gas accounting software. It is used mainly in North America. In India, oil output is reported in tonnes and gas in cubic metres, and the producer reports it to the government, which charges a royalty on it.
A well's output is measured at the wellhead and at the points where it is sold. Meters and tank gauges give these readings. Many wells share one tank or pipeline. So the software must allocate, which means working out how much of the tank's total came from each well. Then it records where each barrel went: sold to a buyer, kept in storage, used on site or lost. The totals must match, and an employee checks any difference. This check is reconciliation.
Consider two wells in North Dakota that pump into one tank. A test on well A shows 1,000 barrels in the month and a test on well B shows 3,000. But the tank's meter, at the point where the oil is sold, shows only 3,800 barrels, because tests are estimates and a little oil is lost in handling. The sale meter is the exact figure, so the software scales the tests down to fit it: both wells are credited at 95% of their tested volume. Well A gets 950 barrels and well B gets 2,850. Each well's owners are then paid on that figure. The box follows one well through a month.
The meter readings come from SCADA, the control system that reads field equipment, and from a process historian, which stores such readings over time. The sales value then goes to revenue distribution, which pays the owners.