Clay stabilizers are means to prevent fines migration and clay swelling, which are caused by the contact of formation with low salinity or high pH brines. Previous clay stabilizers including: Al and Zr compounds and cationic polymers have several drawbacks. Al and Zr compounds can be removed by acids. Cationic polymers can cause formation damage in some cases, and their environmental impact is questionable. There is a need to develop new clay stabilizers that can work following acid treatment and are environmentally acceptable.

Laboratory studies were conducted on newly developed Al compound. Zeta potential and particle size measurements were used to determine surface charge of four types of clays: kaolinite, illite, montmorillonite, and chlorite; and to optimize clay stabilizer concentration. Coreflood experiments were conducted on Berea sandstone cores (1.5 in. diameter and 6.0 in. length) to assess the effectiveness of the new compound and determine the impact of acids on its performance. Atomic absorption was used to measure the concentrations of Al, Mg, Ca, and Fe in the core flood effluent.

The new clay stabilizer was very effective in mitigating fines migration. Zeta potential indicated that the isoelectric point at which complete shields of surface charge of clay particles was achieved at a stabilizer concentration of 0.2 wt%. Coreflood tests showed that this new chemical was effective, and unlike previous Al compounds, it did not dissolve in acids. In addition it is environmentally friendly compound, and also worked very well at 200°F. The behavior of the new stabilizer was much better when it was prepared in DI water than in brine.

You can access this article if you purchase or spend a download.