How Does HVFRs in High TDS Environment Enhance Reservoir Stimulation Volume

Improvement in hydrocarbon production from unconventional reservoirs, such as the Bakken Formation, is driven by drilling horizontal wells and multi-stage hydraulic fracturing. The main objective of a frac treatment is to create complex fracture geometry to increase well/reservoir contact area (i.e. large SRV; stimulated reservoir volume) by injecting larger fluid volume and high proppant concentration. The success of the treatment relies substantially on selecting appropriate fracturing fluids that transport the proppant particles deep enough into the fractures. This research is aimed at studying the capability of high-viscosity friction reducers (HVFRs) by examining the produced water from the Bakken Fm through an integral approach. The application of surfactant as an additive to the HVFRs was investigated in high TDS (total dissolved solids) conditions. To assess the current industry practice for hydraulic fracturing in the Williston Basin, these tasks were performed: a) rate trainset analysis (RTA) to evaluate the current completion in Bakken wells by estimatingfracture half-length and SRV properties, b) 2D/3D fracture simulation to study the impact of treatment fluids on fracture-network/SRV properties, and c) reservoir simulation to predict the estimated ultimate oil recovery (EUR) for identifyingoptimum hydraulic fracturing design. The results show that using a surfactant mixed with the frac fluids can lead to improved proppant transport, fracture conductivity profile, and thus higher effective fracture-half length compared tocurrent practice. It was found that such a frac fluid mixed with surfactant can result in improved EUR by as high as 15% compared with linear gel and HVFRs with produced water (HVFR-PR) due to larger SRVs. Reusing produced water, including formation and flow back water can be a wise decision to minimize environmental footprint and reduce operating costs. The findings from this research can be applied to other unconventional shale plays, such as Eagle Ford and Permian Basin for comparison and optimization purposes.