An on-line linear X-ray apparatus has been used to examine deep bed filtration during water injection in Bentheimer sandstone core samples. The aim of this project was to investigate the effect of residual oil saturation on the deposition profile of suspended solids in the injected water, and to compare that with a previous study at fully brine saturated cores. Hematite particles were used as suspended solids in the brine. The X-ray apparatus was used to estimate the amount of deposited material at any time and distance along the core sample. Permeability decline as determined by the pressure change and chemical analysis of hematite concentration were used to confirm the X-ray analysis.

The effect of residual oil saturation was seen in most of the samples. The presence of oil caused greater apparent damage (reduction of permeability). It was also observed that there is rather deeper invasion at residual oil saturation than at fully brine saturation, and it was inferred from the X-ray measurements that the external filter cake is thicker.

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