Discussion Central

Expand all | Collapse all

Rag Layer

  • 1.  Rag Layer

    SENIOR MEMBER
    Posted 13 days ago
    A particular field is producing emulsion with an impenetrable rag layer resulting in significantly reduced crude treatment. Chemical and physical treatment have been ineffective so far. Anyone has experience with this? What should I be looking for?

    ------------------------------
    Renee English
    ------------------------------


  • 2.  RE: Rag Layer

    SENIOR MEMBER
    Posted 13 days ago

    Is this a field with enhanced recovery?  If it is, maybe there is something in the material they are injecting that is causing this -- is there a way you could check the water quality and what they're adding to it to see if anything is amiss?


    Every pound of solids going into the separator => about 10 pounds of emulsion.  In your case it sounds like something special is happening because regular solids just make more emulsion, they don't create an impenetrable rag layer.



    ------------------------------
    -Kirsten

    Kirsten Rosselot
    Process Profiles
    Calabasas, CA United States
    ------------------------------



  • 3.  RE: Rag Layer

    SENIOR MEMBER
    Posted 13 days ago
    This field is several kilometers away from any polymer flooding so we have ruled out that option. Additionally, there is no chemical treatment between the wellhead and the treatment facility. The strange "elastic" interface is observed in the well-head samples.

    I haven't been able to find much in literature so far. I've seen some mention of  (1) the high H2S content causes corrosion of CS piping and results in the formation of FeS which stabilizes the emulsion, or (2) Biodegradable crude.

    ------------------------------
    Renee English PMP
    Superintendent - Process & Flow Technology
    Staatsolie Maatschappij Suriname NV-Raffinaderij
    Paramaribo
    ------------------------------



  • 4.  RE: Rag Layer

    SENIOR MEMBER
    Posted 12 days ago
    Good day,

    Have you analyzed the incoming crude forboarsmeters such as salts, TSS and asphaltenes? I have came across a similar situation where the crude production from an offshore well increases ans with it, these parameters increased. The resultant effect was that the water drop out time increased significantly. You can try two things; inject a slugging chemical into the stream which will break these tough emulsions or pass the crude oil through a heater treated. The temperature will aid in  breaking these tight emulsions also. Hope this helps.

    ------------------------------
    Shantal Ramdeo PE
    Senior Process Engineer
    Heritage Petroleum Company Limited
    Princes Town
    ------------------------------



  • 5.  RE: Rag Layer

    SENIOR MEMBER
    Posted 12 days ago
    In the late 70s and early 80s, I was involved in enhanced oil recovery research (EOR) using surfactants.  We had one reservoir where the biological activity was so bad that production wells were being plugged in a short period of time.  The only treatment was using sodium hypochlorite, i.e. bleach, at an abnormally high concentration of a few per cent.  I believe it was somewhere between 2 and 4%.  An  expert said "That bug must have a thick skin!"

    Our biggest mistake was equating the treatment with using Clorox Bleach.  The foreman at the field went into the town and bought out the bleach supply from every grocery store.  It was as bad as the current toilet paper crisis due to the Covid-19 emergency.  Companies that performed work overs had their own bleach.  The treatment worked.

    My recommendation is to take samples and have them tested for biological activity.  Those tests should include the treatment options including biocides which may need to be injected to back flush the production wells.

    ------------------------------
    T. David Griffith, Ph.D.
    Blessing (Bay City), TX
    ------------------------------



  • 6.  RE: Rag Layer

    SENIOR MEMBER
    Posted 12 days ago
    Thank you for the feedback. We have sent the crude for testing so we can have a better idea of what it is we are dealing with.

    ------------------------------
    Renee English PMP
    Superintendent - Process & Flow Technology
    Staatsolie Maatschappij Suriname NV-Raffinaderij
    Paramaribo
    ------------------------------