Calculation of the relative permeability of carbonate rocks using the unsteady-state core flooding method

Measurements of relative permeability, considered the most critical component in reservoir injection and production performance, are the subject of a significant amount of researchers’ attention. The goal of coring and core analysis is to provide data typical of reservoir conditions to minimize ambiguity in reservoir appraisal. Relative permeability data are required to understand the flow of fluid in porous media and reservoir modeling. These data are often collected using steady-state flow or unsteady-state flow techniques. Researchers used the unsteady-state technique, which takes fluid viscosity and saturation averages at a breakthrough into account while conducting their studies. Core flooding experiments were conducted using three core plugs from limestone formation in one of the southern Iraqi fields. The petrophysical parameters for the plugs varied and the residual oil saturation varied from one plug to another despite these plugs from the same produced unit. Johnson, BossIer, and Naumann correlation, Corey correlation, and Pirson’s correlation were used to test and compare relative permeability to oil and water. Pirson’s correlation yielded higher relative permeabilities to oil and water than Johnson, Bossler, and Naumann’s correlation and Corey’s correlation, respectively. Water breakthrough has been shown to rise somewhat when core plug permeability increases.