Flow Assurance Technical Section

 View Only

  • 1.  Experience with downhole heating for flow assurance purpose

    Posted 02-27-2015 08:40 AM
    This message has been cross posted to the following Discussions: Flow Assurance Technical Section and Production .
    -------------------------------------------

    We are working on a oil field having a high paraffin content. The reservoir temperature (~48 deg) is above the wax appearance temperature (~45deg at max) and hence inflow is not an issue. However, there is severe wax deposition in tubing and flowline. Our current operating philosophy relies heavily on regular pigging & scraping (almost every other day for each well and flowline) which besides being resource intensive, is extremely hard to optimize and stabilize production due to dynamics of ambient temperature, flow rate, choke changes, gas coning, BSW variation etc.

    One of the common solutions (DHCI) has been deployed for the ongoing drilling campaign. However, the PPD injection isn't much helpful as the fluid already cools below WAT at the chemical injection point. It slightly helps reducing scraping frequency and somewhat stabilizing flowline pressure drop fluctuations.

    I am exploring alternatives like downhole electrical heating for flow assurance purpose in an attempt to minimize (possibly eliminate?) scraping and minimize pigging (long flowlines of 2 to 7 km will cool the fluid to ambient even if heated at wellhead). Would appreciate feedback on this technology (not for EOR, only for flow assurance in tubing section)

    Regards,
    ------------------------------
    Amol Agrawal
    Production Technologist
    Shell Gabon
    ------------------------------



  • 2.  RE: Experience with downhole heating for flow assurance purpose

    Posted 02-28-2015 09:43 PM
    Amol, Yes, I have heard that downhole electrical heating cables have been used successfully in Turkmenistan during the Nineties to control wax deposition. What made it economic was the existing power lines infrastructure and low cost of electricity at the time. Consider it in combination with VIT to balance capex of tubing and opex of power. ------------------------------ Regards, Taras Makogon HoustonTX ------------------------------
    Original Message


  • 3.  RE: Experience with downhole heating for flow assurance purpose

    Posted 03-03-2015 04:36 PM

    Amol,

    I would like to expand on the comments so far.

    I also know of projects where heaters have been used successfully. You will need to contact the vendors to find out which kind is best suited for your project. 

    As Taras suggests below, heaters in combination with VIT might help you get the flowing temperatures you need. In addition you might look into using a thermally insulating packer fluid instead of or in addition to the VIT for your wellbore insulation.

    A combination of downhole heating, heat preservation technologies and/or DHCI might help you get your wells flowing with minimal or no remedial work required.

    On surface insulation along with heating, or high enough surface arrival temperature, may be a solution.

    There are a lot of good suggestions in this thread, so I would suggest you get som flow modeling done to investigate the options and come up with the best solution for your well network.

    Best regards,

    ------------------------------
    Kjetil Eriksen
    Product Champion Insulating Packer Fluids
    M-I L.L.C.
    HoustonTX
    ------------------------------


    Original Message


  • 4.  RE: Experience with downhole heating for flow assurance purpose

    Posted 03-01-2015 03:37 AM

    Hello,

    I too have heard that downhole electrical heating is a possibility, but I'm not an expert on this, best talk to some vendors. I know that the flowlines can be electrically heated and insulated to avoid wax deposition. All these would require some significant capex.

    One other option would be to utilise downhole hot water recycling. Again significant capex to provide and install hot water supply to wellhead, but this may  help if you have an emulsion problem and could also provide additional lift if you use a downhole jet pump.

    ------------------------------
    Simon Richards
    Andover
    ------------------------------




  • 5.  RE: Experience with downhole heating for flow assurance purpose

    Posted 03-02-2015 03:07 AM

    Hi,

    In the past, I've seen the following options, sometimes combined:

    -periodically circulating hot water through annulus.

    -DHCI, the deeper the better.

    -Electrical heating (tracing): very effective but expensive

    -Insulating lines

    Also, I'm currently using an electrical system called "clearwell" (you can google it) by WTF, which is quite simple and it's supposed to reduce scaling and wax problems. I still haven't seen or read enough of it as to guarantee it's efficiency.

    Regards,
    ------------------------------
    Marcelo Stainoh
    Reservoir Engineer
    ------------------------------


    Original Message