Account for Stock
Calculate Stocks / Record Down-Grades / Record Internal Movements / Prepare Mass Balance
 Refinery Stocks represent the baseline between reporting periods, and they need to be accurately reported and maintained. OAS provides facilities to maintain information on refinery stocks held in tanks, pipelines and external sources such as depots, yards (e.g. bitumen), floating storage units, or even in transit.
Tank readings from an external source (e.g. Tank Gauging) can be automatically transferred to OAS, or can be input manually. Tank Stocks are calculated based on the strapping table and corrected for temperature (both liquid expansion and tank shell expansion), roof weight (floating roof only) and liquid in vapour (gas tanks only). Liquid expansion correction can be based on built-in ASTM formula, ASTM tables stored in the database or user-configured calculation methods. Nett and gross volumes are calculated based on free water, suspended water and base sediment when appropriate.
In the absence of a laboratory system, users can enter tank quality information such as density and BS&W. Integration with a lab system is common to make such information seamlessly available.
As well as movements across the refinery fence, OAS can be used to record internal movements and blends; an electronic pumping log is available for entry by pump house control rooms. Different refineries operate in different ways, but most will want to track the composition of crude tanks and will need to keep track of re-grades. All these can be entered into OAS either by the Offsites operator at the time or later by an Oil Accountant. Crude composition data is also very useful for other users such as Schedulers.
Mass Balance is of crucial importance to an Oil Accounting application. In OAS, the Mass Balance can be calculated for various time periods e.g. Daily, Weekly, Monthly, Quarterly. The cut-off time for each period is user definable. Periodic runs can be based on either actual data or previous, higher frequency, periodic mass balance data. The results can be analysed for imbalances, and the base data corrected as necessary.
The construction of the Mass Balance, and the data used by it, is configurable. |
Features
Tracks refinery stocks in tank, pipeline, depot or afloat, works in m3@15, and bbls@60, and tonnes and a site specific unit.
User configurable mass balance calculation with multi-level reporting and configurable periods
Handles movements ongoing over boundaries of mass balance period
User can AUTHORISE the closing of the books for an accounting period, preventing update of that periods data. Data integrity during final checking is assured by use of "Trial closing"
Adjustments to cover tank stocks, line contents, movement quantities, nomination quantities, material pool quantities can be input for “Closed” periods |
