A major operator has used a novel approach to improve the performance of stimulation fluids in high-permeability, deepwater completions. A concentrated breaker solution is pumped into the formation before the introduction of crosslinked gel. This breaker solution improves cleanup of fractured and non-fractured perforations during high-permeability fracturing operations. This technique was developed because laboratory testing indicated that conventional breakers can be consumed by sediments, resulting in less than optimal gel breaks. This observation, when combined with the knowledge that whole crosslinked gel leakoff occurs in high-permeability formations, makes it necessary to pre-treat the near-wellbore region with a sacrificial concentrated breaker.

This paper includes studies on core materials with specific mineral compositions to determine the effectiveness of the concentrated breaker technique. Interaction between fracturing-fluid breakers and formation materials has been investigated at temperatures between 120° and 225°F. Core-flow experiments measuring the amount of active breaker present in the fluid exiting the core have also been performed with both enzyme and oxidizing breakers, and retained breaker activity of enzyme and conventional oxidizing breakers was compared.

Enzyme stability is affected by the presence of minerals as well as the formulation of the stimulation fluid. A comparative study performed at 175°F showed that breaker activity decreases as temperature increases for both a conventional oxidizing breaker as well as a stable, high-temperature oxidizing breaker. However, at 225°F the stable, high-temperature oxidizing breaker maintained some activity upon exiting the core.

This paper highlights three successful applications of the concentrated breaker solution in the Gulf of Mexico (GOM). These successes are compared to performance from offset wells, providing a benchmark for identifying the benefits of this new process.

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