Clay Swelling Mitigation During Fracturing Operations Using Novel Magnetic Surfactants

Abstract

Abstract In unconventional tight sandstone formations, due to the presence of clays, the fracturing operations may not be effective because of the clay swelling. The fracturing stimulation is the most used treatment method to produce from such kinds of reservoirs. The swelling of clays caused additional pressure to drop. Prior knowledge about the clay swelling behavior of the rocks with the fracturing fluid can reduce the risk associated with productivity issues. If swelling occurs at the rock's surface, it adversely affects the conductivity of the fractures. This study proposed novel synthesized magnetic surfactants as a solution for the swelling of clay in hydraulic fracturing treatment. Several coreflooding tests were run using sandstone cores containing a significant proportion of the swelling clays. The permeability was assessed earlier and afterward the coreflooding tests. A scanning electron microscope (SEM) was run before and after the coreflooding experiments. The performances of magnetic surfactants were matched with the well-known clay stabilizing agents including NaCl and KCl. Permeability measurement after coreflooding experiments revealed 90% permeability lost for the samples mixed with conventional clay stabilizer when post-treated with Deionized Water. On the other hand, the fracturing fluid containing magnetic surfactant solutions as clay swelling stabilizers reserved the initial permeability even post-flooded with DW. It was observed that the conventional clay stabilizers do not provide long-term stabilization of the swelling, while magnetic surfactants retain the permeability for long hours even being interacting with fresh water. Magnetic surfactants have not been used as swelling inhibitors in fracturing fluids. This is the first study that reports the use of magnetic surfactant in clay swelling inhibition.