Clay minerals in an oil-sand deposit and their effect on oil-bearing properties

The current research on the characteristics of clay minerals in oil-sand reservoirs of China is still in its infancy. The burial depth of oil sands in the western slope of the Songliao basin is relatively shallow, and the reservoir contains clay minerals. Scanning electron microscope observations and X-ray diffraction analysis were used to test the chemical composition and characteristics of clay minerals. Comprehensive analysis and further research found that the clay mineral content of the oil-sand reservoir was relatively low and the clay minerals belonged to the illite-montmorillonite mixed-layer, composed of montmorillonite and illite, with occasional kaolinite, but no chlorite. The oil-bearing property of the oil-sand reservoir was consistent with the type of clay mineral found. The reservoir containing a mixed layer of illite-montmorillonite has a relatively good oil-bearing potential, and the oil content ranged from 3.80% to 16.17%.