Abstract
Abstract Damage to proppant packs is known to negatively impact well productivity. The damage is often the result of inadequate degradation of the polymers used to viscosify fracturing fluids. Gel breakers are used to degrade the polymer by cleaving the macro-molecule into smaller fragments, ideally to a size which can easily be produced during load recovery. Fluid viscosity reduction is commonly used to gauge polymer degradation. However, although viscosity reduction indicates polymer degradation, it is misleading to conclude that this reduced viscosity equates to improved fracture conductivity. Polymer fragments which are desolublized from the gelled fluid no longer contribute to fluid viscosity but do, unfortunately contribute significantly to proppant pack damage. Several new breaker technologies have been introduced in efforts to improve polymer degradation, and hence, improve fracture conductivity and ultimately well productivity. Many production case histories have been offered as evidence of the utility of the new technologies to improve well productivity. However, the facility to quantitatively determine the polymer degrading efficiency of the breakers has heretofore been lacking. Laboratory procedures, both wet chemical and instrumental, have recently been developed to address characterization of the relative degrading efficiency of the various breakers and breaking mechanisms. The analysis of the combined data provide both a qualitative size distribution, as well as a quantitative profile of the polymer fragments. Extensive studies were conducted employing the new procedures to compare the degrading efficiency of various oxidative and enzymatic breakers. Detailed analysis of the results are provided.
Published Version
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