Utilizing Indigenous Pakistani Bentonite for Subsurface Water Jellification: A Multidisciplinary Approach to Reducing Water Cut in Oil Fields

This study investigates the potential of indigenous Pakistani bentonite for subsurface water jellification as a means to control excessive water production and improve oil recovery. Laboratory tests assessed gelation efficiency, permeability reduction, rheological performance, and chemical compatibility under reservoir-like conditions. At a concentration of 4% by weight, the bentonite formed stable gels within 30 minutes and reached a gel strength of about 350 Pa after 24 hours. Permeability experiments showed a marked improvement in water control, with sandstone cores exhibiting a 95% reduction in permeability (from 100 mD to 5 mD) and a sharp decrease in water flow, while carbonate cores achieved an 88% reduction despite their more complex pore structures. Rheological evaluations confirmed that the gels maintained viscosity in the range of 230–250 cP when exposed to temperatures between 25 and 90°C, demonstrating good thermal stability. Furthermore, Chemical testing revealed that the gels remained stable in brines with salinity up to 25,000 ppm, though a modest 10% decline in gel strength was recorded at ultra-high salinities above 30,000 ppm. Overall, the findings indicate that indigenous bentonite, although requiring a slightly higher dosage compared to imported materials, offers competitive performance and distinct advantages at lower thermal thresholds and typical reservoir salinity levels. The ability to cut down water flow of Indigenous bentonite while staying chemically stable within the reservoir and along reservoir fluids points to its value as a low-cost local solution. Henceforth, future studies should focus on initiating pilot field testing. Moreover, refining the gel structure is also required, as it can withstand the harsher environments of highly saline or high-temperature reservoirs.