Flow Assurance Technical Section

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  • 1.  Shear Rate Impact On Asphaltene Precipitation

    Posted 03-02-2024 03:36 AM

    Hello Network,

    I am inquiring about the influence of shear rate on asphaltene precipitation at the pore level.

    It is hypothesized that the shear rate has an impact on the precipitation of asphaltene within production tubings. Would it be feasible to explore this phenomenon at a laboratory scale using a small-length core measuring 7cm? And can the resultant effects be quantifiably discerned?

    Best regards!

    Abdelkader.



  • 2.  RE: Shear Rate Impact On Asphaltene Precipitation

    Posted 03-03-2024 01:36 PM

    Hi Abdelkader, I would have thought velocities within each pore would have been relatively low and 7cm seems awfully short.  Packed glass beads might be better than a real core. If you have a long length of pipe, however, this is a relatively easy measurement to make. We sell a device that attaches to the end of a tube and measures in real-time the amount of asphaltene passing by in real-time (the sum of dissolved+flocculated+precipiated). So if you can estimate [or measure] the percentage of asphaltene entering one end of the tube then you can measure the change at the other end as a function of flow-rate. Regards, John




  • 3.  RE: Shear Rate Impact On Asphaltene Precipitation

    Posted 03-04-2024 07:33 AM

    I agree with John, 7 cm is too short. He my ten cents... If reservoir core is not available you can use a synthetic core selected according to the reservoir properties (lithology and it is known wettability, permeability, pre size distribution, and porosity).



    ------------------------------
    Yani Carolina Araujo
    Global Manager SCAL and EOR Lab Services
    SGS Oil, Gas and Chemicals
    The Woodlands, Texas, USA
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    Original Message


  • 4.  RE: Shear Rate Impact On Asphaltene Precipitation

    Posted 03-05-2024 05:22 AM
    Edited by Zaki Ali 03-05-2024 05:25 AM

    Hi Abdelkader Ben Mansour,

    I agree with Yani Carolina Araujo suggestion to use a synthetic core which is quite insightful, especially when an actual reservoir core is not available. Synthetic cores can be excellent proxies for real cores, provided they are selected with careful consideration of the reservoir's properties. Here's how this approach can be effectively implemented:

    Selection of Synthetic Core

    1. Lithology Matching: The synthetic core should mimic the lithological characteristics of the reservoir. This includes the mineral composition and the textural features, ensuring that the synthetic core has a similar response to fluid flow and chemical interactions as the actual reservoir rock.

    2. Wettability Consideration: It's crucial that the synthetic core replicates the wettability of the reservoir rock, as this significantly influences fluid distribution, flow paths, and ultimately, the asphaltene precipitation dynamics.

    3. Permeability Alignment: The core must match the permeability of the reservoir to ensure that fluid flow rates and pressure drops are representative. This is vital for accurately assessing the impact of shear rate on asphaltene precipitation and deposition.

    4. Pore Size Distribution: Ensuring that the synthetic core has a similar pore size distribution as the reservoir rock is essential for accurate simulation of pore-scale flow dynamics and the subsequent asphaltene behavior.

    5. Porosity Consistency: The porosity of the synthetic core should be aligned with that of the reservoir to correctly simulate the storage and flow capacity of the porous medium.

    Advantages of Using Synthetic Cores

    1. Controlled Experiments: Synthetic cores offer a controlled environment where specific reservoir properties can be isolated and studied. This can help in understanding the precise impact of each property on asphaltene precipitation.

    2. Reproducibility: Experiments with synthetic cores can be more easily reproduced, as the cores can be manufactured to standard specifications, unlike natural cores that may have high variability.

    3. Availability: Synthetic cores can be more readily available than actual reservoir cores, especially for reservoirs that are difficult to core or for which coring is not economically feasible.

    4. Customization: They can be customized to study specific phenomena, allowing researchers to create scenarios that might be challenging to replicate with actual reservoir cores.

    Implementation Considerations

    • Experimental Design: Design experiments to ensure that flow rates, temperature, and pressure conditions accurately simulate the reservoir conditions, allowing for meaningful interpretation of the results.

    • Analytical Techniques: Utilize advanced analytical and imaging techniques to monitor asphaltene precipitation and deposition within the synthetic core, ensuring that the observations can be quantitatively and qualitatively analyzed.

    • Data Interpretation: Carefully interpret the data, considering the limitations and advantages of using synthetic cores, and validate the findings with theoretical models or available field data.

    In conclusion, utilizing a synthetic core selected according to the reservoir's lithology, wettability, permeability, pore size distribution, and porosity provides a viable alternative for studying the influence of shear rate on asphaltene precipitation, especially when reservoir cores are not available. This approach allows for tailored experiments that can yield valuable insights into the mechanisms governing asphaltene behavior in subsurface conditions.


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