Hydraulic fracturing has been extensively used as an efficient method to enhance the hydrocarbon production, especially in tight formations. However, this technique has been associated with long-lasting formation damage challenge due to fracturing fluid filtrate leakoff. According to Laplace equation, this fluid leakoff results in a phenomenon called water blockage due to capillary forces. Recent studies have shown that surfactants can be used as an additive to fracturing fluids and they will reduce the required pressure to displace the injected fracturing fluids. In this study, the performance of two new nano-emulsion surfactants has been investigated.

Nano-emulsion surfactant mixtures were prepared at different concentrations ranging from 0.5 to 5 gpt using field mixing water. Mixing water and representative field condensate samples were used to conduct both the surface tension and contact angle measurements at temperature range of 77-325°F. Laplace equation was used to calculate capillary pressure values based on surface tension and contact angle values.

The results based on this study have illustrated the effectiveness of nano-emulsion surfactants to recover the fracturing fluid filtrate during flowback. The performance of these surfactants was investigated as a function of several parameters such as surfactant concentration, soaking time, and temperature. In addition, this paper explored the adsorption behavior of these surfactants on formation rock and the effect of nano-emulsion surfactants on the rock wettability. Optimal design parameters of these nano-emulsion surfactants to achieve significant enhancement in injected fracturing fluid recovery are also discussed.

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