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Formation damage creation through core flood

  • 1.  Formation damage creation through core flood

    Posted 12-06-2024 10:32 PM

    Dear Friends,

    I am working on development of stimulation fluid like solvent-surfactant for the wells which have formation damage issues. During the process of development in the lab we do set of experiments in the lab for testing solubility of the collected crude oil or deposit sample, rheology experiments and Interfacial tension etc. We also try to do core flood experiments to see whether the developed formulation is able to remove the formation  plugs and thereby regain the original oil permeability. However, the problem we are facing currently is that we can not create enough damage in the cores by flooding with 3 to 5 PV of crude oil to mimic the phenomenon of deposition of organic deposits near well bore.

    Can any body suggest any suitable mean of creating enough damage (by organic deposits) inside the core through core flood experiments.

     



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    Abhishek Goswami
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  • 2.  RE: Formation damage creation through core flood

    Posted 12-07-2024 04:27 PM

    One option is to use bitumen or heavy oil in your core tests. Warm the bitumen to reduce its viscosity and inject into the core. Then inject 1 or 2 pore volumes of varsol. Soak at room temperature overnight. This should precipitate asphaltenes. You could also premix the bitumen and varsol to find an optimum ratio for maximum asphaltene precipitation. Then warm the liquid/solid mixture and inject that into the core. There are many permutations to try. You could use propane or butane instead of varsol, at various pressures, for example.



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    Ralph Jonasson Ph.D. (retired)
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  • 3.  RE: Formation damage creation through core flood

    Posted 12-07-2024 05:41 PM

    I am curious as to whether your damage us caused by condensed paraffins or ashaltenes?  I also am curious to know how many pore volumes of fluid production are needed to cause observed damage in the damaged zone in you well? Is the deposition primarily owing to pressure changes?  Or is there some effect of temperature changes, perhaps owing to injection of cold stimulation fluid?



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    Paul Leonard
    Fort WorthTX
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  • 4.  RE: Formation damage creation through core flood

    Posted 12-08-2024 04:23 AM
    Hi Abhishek,

    I am in the same camp as Paul. What is the root cause of the problem in the
    field? Have you checked for fill & taken bottom-hole samples?

    Recommend posting more information to the discussion boards of the FA TS &
    P&O Community about the pay zone; fluids; Temps, pressure, PGOR &/or WOR
    changes and progress in skin build-up rate versus cum. Prod & the above
    changes that your team is trying to address.

    Maybe, it may be a combination of organic and inorganic scaling and mobile
    fines accumulaion &/or residual completion damage.

    A sequence of different treatments or a cocktail of chemicals may be needed
    to liberate the damaging materials, so that the contaminated materials can
    be lifted to surface.

    Regards
    Bob




  • 5.  RE: Formation damage creation through core flood

    Posted 12-12-2024 03:18 AM

    Dear Pearson,

    The actual cause of formation damage varies on case to case basis. Here I am more concerned about the lab simulation of formation damage i.e. how to create a damage inside a core and establish effectiveness of the formulation through core flood experiment.  We select the formulation after screening a number of solvent combinations through experiments like solubility, rheology, wettability change and Interfacial Tension measurements. The selected formulation we try to validate in core flood experiment, however, in that stage the common problem we encounter is that we can not create enough damage in the core which can mimic actual field scenarios.

    Hope I could clarify your queries.




  • 6.  RE: Formation damage creation through core flood

    Posted 12-12-2024 04:45 AM
    Understood Abhishek,

    My point was that the mobile fines & the organic and inorganic scale
    components may be slowly moving into the wellbore area with the reservoir
    fluids, where they may become trapped by flow convergence.
    ...So, it seems to me that these components need to be part of the 3-4 PV
    flowing into the core sample.
    I am not a Production Chemist but I have been told that it is also
    difficult to properly simulate the behaviour of the resins.
    Strongly recommend taking your question to the FA TS.
    Regards
    Bob
    R. M. Pearson PEng
    Technical Director
    Glynn Resources Ltd.
    (+1) 5878946255




  • 7.  RE: Formation damage creation through core flood

    Posted 12-07-2024 06:07 PM

    ...some additional thoughts for you:

    How well-characterized are your reservoir fluids, especially with respect to pressure-dependent condensation effects?

    Are your cores acquired vertically, or, said differently, does your reservoir have strongly anisotropic permeability?



    ------------------------------
    Paul Leonard
    Fort WorthTX
    ------------------------------



  • 8.  RE: Formation damage creation through core flood

    Posted 12-07-2024 07:17 PM

    Sometimes we used actual core for experiments, but mostly we mixed our sand and bitumen and packed the vessels, or we would pack clean sand into pressure vessels and inject warm bitumen to prepare the core for testing.



    ------------------------------
    Ralph Jonasson, Ph.D. (retired)
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  • 9.  RE: Formation damage creation through core flood

    Posted 12-12-2024 02:37 AM

    Dear Jonason,

    Thank you so much. It sounds interesting we will try it in lab.




  • 10.  RE: Formation damage creation through core flood

    Posted 12-09-2024 01:30 AM

    Dear Abhishek,

    You may use an outcrop rock and saturated saturate it with Bitumen dissolved in Toluene or any other solvent then allow the solvent it evaporate at a suitable temperature, in this way the heavier components (Asphaltene and resins will reside inside the rock, and you can test your stimulation formulation. This would be more representative if you use the same organic deposit in your well in the solvent instead of bitumen.

    Thank you

    Khaled




  • 11.  RE: Formation damage creation through core flood

    Posted 12-12-2024 02:42 AM

    Dear Khaled,

    Agree. However, it is not always possible to get the representative deposit.

    Thanks a lot.