Fahad Asks PERM:
Thanks for your assistance, my question is, how can we generate a relative permeability curve during laboratory core flooding tests. Suppose I want to see the effect of nanofluids in altering my core wettability, how can I generate the relative curves for both the base fluid (brine alone) and the nanofluids so that I can see this effect?
Dr. Jonathan Bryan from PERM Answers:
Basically relative permeability through unsteady state (USS) testing is obtained by flooding at a fixed rate or fixed pressure gradient and measuring the other parameter (DP or Q), along with oil and water cuts in the produced fluids. You also need to measure the end point saturations and end point effective permeability values, and then history match to get the relative permeability curves.
Your question on nano-fluids is particularly interesting because you need to know the effective viscosity of the nano-fluid in your porous medium. And that may or may not be the same as the viscosity of the bulk liquid phase. So the best thing to do is to do the following:
- Measure the bulk viscosity and concentration of nano-particles in your injection water.
- Measure the absolute permeability of a core that is 100% flooded by nano-fluids, and compare this to absolute permeability of the same core saturated 100% by water alone.
- Check the viscosity and nano-particle concentration in the produced fluids. If the values from Step 1 and Step 3 are unchanged, it means we don’t have filtration in the porous medium. Now you check your absolute permeability and see if it is changed compared to what. If it is, then the viscosity of the fluids in the porous medium are higher than the bulk viscosity.
At this point, you will have the background info you need to hopefully get the data required for relative permeability testing. And with everything else known, hopefully you can look at the shapes of your relative permeability curves to better understand wettability shifts.
Dr. Jonathan Bryan