Connecting Laboratory and Field Results for Gelant Treatments in Naturally Fractured Production Wells

Amaury Marin, Randy Seright, Maria Hernandez, Maria Espinoza, Fanny Mejias – 2002

Abstract

This paper demonstrates the connection between laboratory measurements and field results from gelant treatments in naturally fractured production wells at the Motatan field in Venezuela. HPAM with organic crosslinker corefloods established oil RRF of 20 and water RRF of 200 under reservoir conditions. At Well P-47, 1,000 bbl of this gel reduced water cut from 97% to 64% and increased oil production by 36%. Treatment success depends on gelant leakoff distance from the fracture face and in-situ RRF values in oil and water zones. Analyses using permeability, porosity, saturations, fluid properties, and pressure drops before/during/after placement determined these parameters. A methodology for optimizing gelant injection volume is presented.

Key Takeaways

  • Laboratory corefloods under reservoir conditions are essential for treatment design: establishing oil RRF of 20 and water RRF of 200 for the Motatan gel provided the DPR performance data needed to correctly size the field treatment.
  • At Motatan Well P-47, 1,000 bbl of lab-designed gel reduced water cut from 97% to 64% and increased oil production by 36% — a highly successful result directly traceable to laboratory characterization guiding the design.
  • Treatment success depends critically on gelant leakoff distance from the fracture face — too deep damages oil zones; too shallow provides insufficient water blockage — requiring quantitative penetration depth calculation in design.
  • Accurate pressure drop measurements before, during, and after gelant placement are the most important field data: errors propagate directly into errors in calculated penetration depth and RRF, which govern treatment sizing.
  • A quantitative methodology for optimizing gelant volume based on formation permeability, porosity, saturations, and fluid properties replaces empirical volume selection — directly addressing the root cause of erratic field success rates.
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