Laboratory flooding experiments with polymer solutions in sandstone cores are usually performed for studying the mechanisms of polymer flooding processes, and for measuring the properties which describe the process. A determination of the slug profile of the polymer solution allows the measurement of retention characteristics while taking into account the portion of the pore volume not in contact with the polymer solution.
By means of a simple tracer test with the use of inorganic salts, the inaccessible pore volume for a xanthan-type and a scleroglucan-type polymer in highly saline brine was measured. The amount of inaccessible pore volume had to be considered in the determination of retention isotherms for these polymers in core flooding experiments. An analytical simulation model according to immiscible displacement theory was applied for simulating linear displacement experiments effectively by considering inaccessible pore volume and retention characteristics.