Linear X-Ray Core Scanner
The Model 660 Linear X-Ray Core Scanner is used to measure the in situ fluid saturation in a core plug sample during relative permeability flow tests. Data obtained from relative permeability flow tests are used in reservoir performance prediction calculations. This method is most commonly applied to steady state relative permeability tests but it can also be applied to displacement flow tests. Fluid saturations (the fractional proportion of each phase within the pore space) are measured by dissolving an x-ray absorber in one of the phases. Then, by measuring the x-ray beam strength after it passes through the sample the saturations can be calculated. Typically the brine contains NaI as the monovalent ion. Iodine is a good x-ray absorber as it exhibits a critical K edge at about 35 kilovolts. The second phase (oil) contains no absorber. The difference in x-rays absorbed at the all brine and all oil saturation conditions is measured, and then by applying Beer's Law, using the measured scan values, the intermediate saturations can be calculated. At each equilibrium condition, the sample is scanned. The scan value is used to calculate the saturation value. Typical accuracy of the measured saturation values are within one pore space percent.