Slickwater hydraulic fracturing is commonly used to stimulate unconventional formations, including many shale reservoirs. Large volumes of water and additives are pumped downhole at high rates to propagate the fractures and delay proppant settling. At high flow velocities, proppants in friction reducer-based fluids can be very abrasive, leading to reduced service life for fracturing equipment. Slickwater fluids also often lead to poor proppant transport and placement, resulting in reduc ed stimulation efficiency. Traditionally, medium- to high-viscosity guar linear gels are used to mitigate these challenges, which may leave behind polymer damage and can also be affected by periods of guar shortages.
An alternative solution is presented here to deliver the desirable viscosity with a novel synthetic polymer system. The new polymer incorporates easily breakable linkages in its backbone, susceptible to conventional oilfield oxidizer breakers under downhole conditions. The system also shows fast hydration with almost instantaneous viscosity development, and thus allows rapid and easy adjustments of fluid viscosity and rapid switching between polymers when needed. Laboratory testing demonstrated that the polymer solution breaks in the presence of oxidizer breakers at elevated temperatures and leaves no formation or fracture damage. Many successful treatments using this system have been pumped and confirmed the above benefits, and significantly improved production of the trial wells over the offset wells has been observed. The new system greatly simplifies the overall process of hybrid hydraulic fracturing applications, making the new polymer an effective and economical option to address the ongoing guar availability and pricing challenges.
This paper will show the laboratory data, discuss several successful field applications of the new fluid system and present production data to demonstrate its real-world performance and effectiveness.