Relative Permeability and Flow Intermittency Measurements Using X-Ray Micro-tomography in a Complex Microporous Carbonate

We imaged the steady-state flow of brine and decane at different fractional flows during dual injection in a micro-porous limestone using X-ray micro-tomography. We applied differential imaging on Estaillades carbonate to (a) distinguish micro-porous regions from macro-pores, and (b) determine fluid phase pore occupancy and relative permeability at a capillary number, Ca = 7.3×10-6. The sample porosity was approximately 28 %, with 7% in macro-pores and 21% in pores that could not be directly resolved (micro-porosity). We find that, in addition to brine and decane, a fraction of the macroscopic pore space contains an intermittent phase, which is occupied either by brine or oil during the hour-long scan time. Furthermore, fluid occupancy in micro-porosity was classified into three sub-phases: micro-pore space with oil, micro-pore space with brine, and micro pores partially filled with oil and brine.