The Two Models Predict Similar Leakoff Rates

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  3. Reservoir Sweep Improvement
  4. New Filter Cake Model
  5. Where The Conventional Model Fails And The New Model Succeeds
  6. Models Predict Similar Leakoff Rates
Fig. 1 Summary of leakoff data at 41°C.

Leakoff predictions from the new model are shown by the solid red line in the above figure. Leakoff predictions from the conventional filter cake model are shown by the green line. Both predictions match the experimental data quite well for a Cr(III)-acetate-HPAM gel. The aqueous gel used in these experiments contained 0.5% Alcoflood 935 HPAM (molecular weight: ~5 million Daltons; degree of hydrolysis: 5-10%), 0.0417% Cr(III)-acetate, 1% NaCl, and 0.1%CaCl2 aged for 1 day or 5 times the gelation time at 41°C. During extrusion of this formed gel through fractured Berea sandstone cores, gel dehydration and water leakoff were quantified for a significant range of conditions, including fracture widths from 0.02 to 0.16 in., fracture lengths from 0.5 to 32 ft, fracture heights from 1.5 to 12 in., and injection fluxes from 129 to 66,200 ft/d.