2 replies to this topic

[ADITYA.DUBEY]

Dear Members

 

We are facing currently problem with water slug in our Oil and gas processing plant.

Let me start with the beginning.

 

Our onshore terminal receives oil+water emulsion from the offshore via a 35 Km long sub-sea pipeline.It gets collected into a slugcatcher(operating at 7 barg and 30 Deg C).Afterwards oil+water emulsion is heated in a heater upto 80 Deg C and fed to the horizontal separators for separating oil and water. We used to dose demulsifier in the heater inlet and were getting fine result with the required water and oil separation.

 

After increased water cut from the offshore wells,demulsifier dosing seemed ineffective in terms of seperation,so after much brain storming ,demulsifier dosing was started from offshore also in the subsea pipeline.

 

Now we are facing problem with water slug in the slugcatcher.It seems that because of longer subsea pipeline length,high residence time is creating water separation and resulting in water slug. Demulsifier dosing is already reduced to minimum possible from offshore.

 

Can we dilute demulsifier with diesel and then dose into subsea pipeline?Will reducing demulsifier concentration be effective same as in terms of reducing residence time?

 

Regards

Aditya

[Bobby Strain]

What you may be experiencing could be that the dispersed phase is not what it was before. So you may need to use a different demulsifier that you can inject at the heater inlet. You might also need to draw a water phase from your slug catcher.

 

Bobby

[P.K.Rao]

Demulsifiers are two types, 1) Water soluble and 2) Oil soluble. Water soluble demuldifier may not work well if you use diesel..  Oil soluble demulsifers can be tried. I suggest study first in your laboratory for finding  the best effective demulsifier. Pleasei refer to my article on "Evaluation of Demulsifers"  A book was published by Amazon which contain this evaluation also along with other articles. The name of the book is "RTOL Test Methods by P.K.Rao"