From cubic metre to standard cubic metre 1

[Ifakiz]

We transfer 400000bbl of crude oil into a storage tank at 40deg centigrade and API of 37.5.after one day, the tank temp was 35 deg centigrade and the API was 37.1.
we needs to know the actual vol of the crude
Can anyone help?

 

[25362]

As I understood your question you wish to know what was the volume contraction upon cooling.

From the definition of ^oAPI, the volume contraction would be:

100 (37.5-37.1) [÷] (37.5+131.5) = 0.2367 %​

 

[mrspcs]

The closest I can think to "actual volume of crude" is the Net Standard Volume (NSV) which is the volume at standard temp. condition (60 deg. F) and corrected for API, water and sediment.

(Where did the 400 Mbbls figure came from ? Transfered from a "certified" tank ? measured by flow meter ?).

Assuming that the tank was not drained (water) and that sediment content is the same, if you calc. "standard volume" starting from either condition, you should arrive at the same result.

That is:
1) tank level (and convert to vol. with the tank's callibration tables)
2)tank temp. reading (and use tables for temp. correction for vol. and API gravity)
3)water and sediment (% from lab result of a sample, convert % to bbls and deduct from gross volume)

With these, calculate NSV (net standard volume)

A word of WARNING about conversion of LEVEL to BARRELS.
We were measuring Tank Level with RADAR gauges in metric units (callibrated in -milimeters-)
The Tank Callibration Tables however where in Imperial units (inches) with an appreciation of 1/16".
The application calculating tank volumes (for the inventory and mass balances of the tank farm) was taking the tank level readings direct from the radar readings (mm), it would then ROUND THE FIGURE to the nearest 1/16" to be able to use the tank callibration tables and calculate the volume (bbls).
This rounding process over time would accumulate sufficient error to get the operation of the tank farm off-spec. (accuracy limits for inventory / custody transfer mass balances etc.).

Hope this helps.
MS



MS

http://www.3rps.com

 

[MortenA]

It seems unlikely to me that a "shrinkage factor" has not allready been determined if this volume measurement is for fiscal reference.

This knowledge would at least be withoin your company contract department. Dont try to guess this or deduct it from your current data. Its (most likely) a contract issue.

Best regards

Morten