Formation brine in Marcellus Shale typically contains high concentration of barium as indicated by flowback/produced water quality. When injection fluid used for hydraulic fracturing is rich in dissolved sulfate, BaSO4 will precipitate in the subsurface and may be transported back to the surface during the flowback period. The attachment of barium sulfate to the proppant that is injected with hydraulic fracturing fluid to enhance the productivity of a gas well will influence the permeability of the proppant pack and well productivity. This study is designed to evaluate the fate and transport of BaSO4 particles under the conditions that are relevant for gas extraction in Marcellus Shale. It was found that the mobility of barite particles through proppant is very limited at high ionic strength typical of deep brines, which is due to the agglomeration of barite particles and reduced electrostatic repulsion between barite and sand. Breakthrough of barite though the sand column is much faster in the presence of sulfonated polymeric phosphine carboxylic acid (SPPCA) even at high salinity conditions. Such behavior is most likely due to the reduction in size and/or surface charge (zeta) potential of barite particle that would precipitate in the presence of SPPCA. SEM images of barite particles illustrates that the presence of scaling inhibitors result in the decrease in particle size and more spherical morphology. Particle size shown in the SEM image is consistent with the particle size distribution measured by light scattering. The findings of this study indicated that it is possible to control potential reduction in well permeability in the case when high sulfate fluid is used for hydraulic fracturing in Marcellus Shale.

Mobility of antiscalant-modified BaSO4 particles through saturated proppant pack

249th National Meeting (2015)

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