Proper demulsifier dose

[rainoil]

Hi every body,
I have a question about demulsifier dose.
How to calculate approximately dose to breaking water-oil emulsion effective (avoid under and over dose).
Because my boss asked me that question, and said it base on oil flow.
But I think it have to base on the total fluid (exactly the volume of emulsion).
Im not sure about that.
Can every help me to solve this problem?
Thanks.

[gusgon]

As every crude oil and emulsion are different nad as emulsifiers vary from oil field to oil filed, there is not a rule for finding the "right dose". You have to perform a Bottle Test, as a matter of fact yo have to do it at least twice a year in order to adjust the dose and the demulsifier brand. The Bottle Test not only allows you to select the brand and dose, but the right temperature.

As a rule of thumb for 1st Stage and Test Separator the dose might be 25 ppm. For Desalter or Coalescer inlets it could be 5 ppm.

[rainoil]

Thanks gusgon very much,
I totally argee with you, it's very hard to find out the right dose.
But Bottle Test not exactly, because it is 'steady condition', not 'dynamic' at the condition of the 3phase Separator
Actually this is a very common problem that Control room engineer have to deal with.
The total fluid and the water cut from wells alway change time to time.
And we have to face with the problem Oil in water overboad high, it can be over dose.
In my field, fist we used demusifier of BakerHugh, after that we change to use Nalco.
As experience, we decided adjust demusifier base on amount of emulsion go to Electrostatic Treater.
If large, we will slowly increase a little bit and continuous monitoring to have right action ;and opposite.