Application of a Novel Clay Stabilizer to Mitigate Formation Damage due to Clay Swelling

Abstract

Clay swelling and fines migration can cause formation damage of hydrocarbon bearing zones and prevent economic realization of oil/gas wells. Identification and management of clay particles in the formation is a necessary component of production and drilling engineers’ responsibilities.

This research focuses on the application of a cationic inorganic Al/Zr-based polymer clay stabilizer to prevent swelling of smectite particles in a sandstone matrix. Previous work has focused on mitigating fines migration; swelling mitigation is tested here. Berea sandstone cores were injected with a montmorillonite slurry to supplement the very low concentration of naturally occurring swelling clays. The modified Berea cores were subjected to a unique aluminum/zirconium-based clay stabilizer, via coreflood, to determine the effect of the stabilizer as a clay control mechanism. Pressure differential across the core and analysis of the coreflood effluent were used to measure the effectiveness of the treatment.

The Al/Zr stabilizer performed well as a means to prevent clay swelling. When compared to an untreated core, permeability loss due to clay swelling and fines migration was negligible. Performance of the stabilizer at different concentrations suggests that an increase in stabilizer concentration does not correlate directly with permeability maintenance.