Historically, guar-borate fluids have been the most commonly used crosslinked gel system in fracturing applications. Low cost, shear tolerance, and operational ease of guar-borate fluids often makes them the preferred candidates compared to other fluid systems for viscous fluid applications of fracturing services. However, residue generated in broken guar-borate fluids can have a negative impact on the conductivity of the fractures placed into the reservoir and the permeability of the proppant pack. This paper focuses on evaluating residue generated from guar-based fracturing fluids in the presence of various ions using extensive laboratory methods.
Hydraulic fracturing is a technique used for improving hydrocarbon production from conventional and unconventional reservoirs. The process sometimes involves pumping a high viscosity, proppant laden fluid into the reservoir to create the desired fracture geometry. Crosslinkers are often used to amplify the fluid viscosity of the base polymer to create wider fractures and to support proppant transport into and within the fractures. Breakers then reduce fluid viscosity before and during cleanup to ease flowback of the broken polymer gel. Both cleanup and flowback are crucial steps that can directly impact production of hydrocarbon from the fractured reservoir.
Laboratory results have shown that some ions, when present in the water source, can significantly impact the amount of residue generated from guar-based fracturing fluid. This paper presents a systematic study on the effect of ions, such as potassium, calcium, and magnesium, on guar and guar derivative residue and their hydration properties.
Residue generated after breaking guar-based fluids can have negative impact on the conductivity of the reservoir and the permeability of the proppant pack, which can significantly lower hydrocarbon production. Understanding the impact of various ions on cleanup properties of fracturing fluid can improve fluid design and therefore improve the conductivity of the proppant pack and formation.