ABSTRACT
A case study has been conducted on over 90 gas wells in West Texas to optimize fracture conductivity and well profitability. This study provides direct comparisons evaluating the effectiveness of treatments incorporating various designs and breaker systems. The wells stimulated with new designs focusing on methods to improve fracture conductivity have shown significant increases in production rates. These same wells have also shown improved clean-up properties, as compared to surrounding wells, by eliminating swabbing time and returning higher volumes of fracturing fluid.
Recent laboratory studies have demonstrated that realistic in-situ fracture conductivity values are significantly lower than previously thought. New testing procedures have concluded that proppant permeability values are greatly reduced when exposed to long term tests. Additionally, fluid damage and polymer concentration further impair these permeability numbers. When breaker concentrations are increased to a level to effectively degrade the concentrated polymer the rheology of the fluid will be adversely affected, thus sacrificing the execution of the treatment.
New designs have evolved placing emphasis on proper fluid selection, increasing proppant volumes and concentrations, and improved breaker scheduling. Encapsulation techniques have been developed allowing a controlled delay of breaker activation until after the proppant is placed. Extremely high breaker concentrations are now obtainable without adversely effecting the rheological properties of the fracturing fluids.
