Experimental Study on Preventing Formation Damage Due to Clay Swelling Caused by Water Based Drilling Fluid Using Aluminum Ion Based Clay Inhibitor

Document Type : Research Note


1 Petroleum university of technonology

2 Petroleum University of Technology



Formation damage is an unfavorable challenge that occurs during drilling. The present study reports applicability of aluminum complex (AC, the combination between Al ion of aluminum sulfate (AS) and ethylenediaminetetraacetic (EDTA)) as a permanent clay swelling inhibitor in water-based drilling fluids. That used to reduce formation damage in the near wellbore. This complex is an environmentally friendly and inexpensive additive in water-based drilling fluids (WBDFs) as a clay swelling inhibitor. Some experiments were performed in this study including free swelling test, bentonite sedimentation test, compatibility test, and core flood analysis. The results showed that AC solution can act properly as a clay swelling inhibitor at optimal concentration of AC around 5.4%wt. More than, compatibility test indicated that AC additive is compatible with other common additives in WBDF. The results show adding 8.1 wt.% of AC solution have lowest permeability reduction compared to other concentrations. More than, core flooding results showed AC solution can act as permanent clay inhibitor compared to KCl that is a temporary inhibitor. The AC solution performance was not much sensitive to salinity.