INVESTIGATION OF CLAY STABILIZER POTENTIAL FOR HIGH CLAY CONTENT FORMATION

Abstract

Clay swelling has been studied for decades due to its damaging problem in the reservoir. It has caused permeability impairment due to blockage at the pore throat and reduction of the available pore spaces in the reservoir. The past few decades have seen rapid development of clay stabilizers to treat clay minerals near-wellbore region areas. However, there a limited study investigating the potential of clay stabilizers to prevent clay swelling throughout the reservoir. The present study aimed to investigate the potential of potassium chloride (KCl) and Poly-diallyldimethylammonium chloride (PolyDADMAC) as cationic clay stabilizers to mitigate the clay swelling phenomenon throughout the reservoir. This study conducted a series of free swelling tests on bentonite with varying brine salinity and clay stabilizer concentration. In addition, the rheological properties of KCl and PolyDADMAC were measured at 24°C and 98°C and at a 7.34 s–1 shear rate to determine its flow potential throughout the reservoir. The results showed that 0.3 wt.% to 1.5 wt.% of KCl and PolyDADMAC were able to control the expansion of bentonite immersed in an aqueous solution, with PolyDADMAC has shown excellent performance, whereas the bentonite expansion in PolyDADMAC solution is significantly lower than KCl. This result is driven by the fact that PolyDADMAC has greater amounts of cationic charges to neutralize abundant negative charges on clay mineral surfaces. Furthermore, the viscosity of 0.3 wt.% to 1.5 wt.% of KCl and PolyDADMAC at 24°C and 98°C recorded is low, which is 0.25 cP to 1.45 cP and 0.83 cP to 2.32 cP respectively. This low value proves its potential to be penetrated throughout the reservoir, not limited to near the wellbore region only.
 Keywords: Cationic clay stabilizer, salinity, bentonite swelling, viscosity