Thomas Welton - Residue-Free Fracturing Fluid Provides Superior Cleanup and Exceptional Proppant Transport

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      Publication Details (including relevant citation   information):

      Schultheiss, Nathan, Fontenelle, Lucas, Welton, Thomas -

      Abstract: Abstract Currently, guar-based fluid   systems are the preferred choice for hydraulic fracturing   operations, primarily because the fluid formulations can be   widely varied depending on reservoir conditions and operational   needs. However, fluids prepared with guar are inherently dirty   and contain water-insoluble residues, which can significantly   reduce the permeability of the proppant pack when flowing back   and producing the well. This can result in a possible reduction   in overall hydrocarbon production. Herein, a new, residue-free,   hydraulic fracturing fluid system has been developed that   provides excellent performance during the fracturing process and   includes superior cleanup characteristics. The "res-free?? fluid   is a premium fracturing fluid with comparable, or improved,   properties compared to a typical guar/borate crosslinked system.   First, because the fluid does not generate insoluble residue on   breaking, excellent regained conductivity and core permeability   can be achieved, which has been demonstrated both in laboratory   testing and in the field by measuring well productivity. Second,   the fluid is robust, allowing for precise viscosity and breaker   control. Third, the fluid is salt tolerant and is usable up to   temperatures of 275 F. Finally, it is capable of providing   excellent proppant-carrying characteristics. The   proppant-transport characteristics of this fluid are comparable   to other fluids in use, as measured by a slurry viscometer. This   paper highlights regained conductivity and core permeability,   rheological performance, and proppant-transport characteristics   of the new fluid and provides comparative guar-based fluid data.   This new, residue-free fluid is applicable to fracturing a wide   variety of reservoirs, including unconventional reservoirs, and   has been used successfully in over 180 wells (>2,250   stages/zones) at temperatures up to 300 F bottomhole static   temperature (BHST). Future papers will present case studies of   jobs and will provide production and well performance results.   Introduction Water viscosifying agents, such as guar and its   derivatives, have been relied on within the oil and gas industry   for many years (Beckwith 2012). These polymers provide viscosity,   which supports and carries proppant as well as creates fracture   length/width during the hydraulic fracturing process. To   accomplish this function, the fluid viscosity is increased   exponentially to a value that has been determined to be required   for efficient transport of proppant into the hydraulically   generated fractures. Furthermore, the fluid also provides   fluid-loss and leakoff control. Once the fracturing treatment is   complete, reducing the viscosity of the fluid is essential for   promoting the flowback of the fracturing fluid so that minimal   obstruction occurs as the hydrocarbons move from the formation to   the wellbore. Additionally, on breaking the fluid, obtaining the   highest degree of proppant pack conductivity and permeability   ensures that maximum return will be achieved once the well is   placed on production. It is widely accepted that reducing gel   damage to the proppant pack and formation leads to minimal flow   restrictions, which directly impacts the return of oil and gas to   the wellbore (Almond 1984). Thus, reducing insoluble residue   within the proppant pack can be advantageous, whether from the   gel breaking or from the polymer manufacturing process.

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