Recently, interest in using produced water for hydraulic stimulation processes has greatly increased within the oilfield services industry. However, successful hydraulic fracturing operations using produced water have yet to reach their full potential. This is largely because of wide variance in water quality from such sources as bacterial content, suspended solids, scale, and precipitate potential. Among these, suspended solids are a major issue. Their presence can create severe problems by plugging the proppant's pore space. In this paper, the effects of total suspended solids (TSS) on proppant permeability using a novel benchtop device (Ye et al. 2009) are discussed. This apparatus imposes a controlled strain on the proppant pack while continually measuring its permeability up to a compressive stress of 7,100 psi. Another unique feature of this apparatus is the direct visualization of the proppant pack through a polycarbonate window. Images taken have been analyzed, which provides quantitative information about the relationship between relative permeability and fine particles invasion. Results using produced water samples revealed that electrocoagulation (EC) treatment would increase the permeability up to 40%, depending on the proppant and produced water source. Extensive data analyses and flow visualizations are presented, demonstrating the effects of TSS on the permeability of proppant packs.

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