A Friction Reducer: Self-Cleaning to Enhance Conductivity for Hydraulic Fracturing

Abstract

Abstract Hydraulic fracturing often involves the injection of large amounts of water at high rates into the formation to create fractures. Typically, friction reducers (FRs) are added to the water to reduce pipe friction caused by turbulence, with polyacrylamide-based (PAM-based) polymers being the most common FRs. However, these polymers are difficult to break because of their high molecular weight and long polymer chains. As such, one common issue with the use of FRs for hydraulic fracturing is fracture and formation damages, which can significantly reduce production. A new technology featuring a self-cleaning FR has been developed to help minimize formation and propped fracture damage as well as enhance early and long-term flowback. This new FR exhibits a unique self-contraction property. With the addition of minimal to no breaker, its viscosity can decrease to water-like levels when exposed to high temperatures. Furthermore, the contracted polymer is small enough to pass through the pore throats, helping minimize formation and fracture damage. This paper presents laboratory data to illustrate this unique self-contraction property and its benefits. Formation and fracture damage of this new FR on tight sandstones/sandpack is investigated using the regained permeability and conductivity tests. Field trials were conducted successfully in the Marcellus shale. All results indicate that this new FR has superior cleanup and fracture conductivity; additionally, it causes less formation damage than traditional FRs.