Preparation of geopolymer-based porous filter using the quartz sand compact method

With the increasing of high temperature oil wells and steam ones, the traditional sands control filter cannot be used in those wells. Therefore, based on the conditions, using particle compact method, round quartz sands with a certain particle size and an inorganic polymer (geopolymer) material with good heat resistance is selected to prepare a heat-resistant filter with suitable pore diameter. By adjusting the contents of water-glass, water, sand and thickening agent of the geopolymer-based sand control filters, open space structure is built by low-cost geopolymer slurry and sand. When the size of quartz sand is mainly of 450-600 mu m, and the volume ratio of quartz sand to slurry is 4.3:1, the compressive strength and permeability of this sand control filter reach 10.33 MPa and 18 D, respectively. Thermal gravimetry and calcination experiments show heat-resistance up to 736 degrees C. Scanning electron microscopy shows that the sand particles are wrapped by the geopolymer slurry and that pore sizes of 170-210 mu m are present between the particles. Mercury intrusion porosimetry measurement finds the pore size distribution to be close to 150-280 mu m. Measurement of sand retaining precision indicates that the filter can intercept particles larger than 45 mu m and allow clay particles to pass through. Deformation measurements confirm no significant deformation occurred for up to 210 days and durability of the filter. In measurement of chemical resistance, the compressive strength decreases in the acid solution, and no significant changes in the compressive strength are observed in air, water, diesel oil and salt solutions. Therefore, compared to the approach of improving the heat-resistance of a resin sand control filter, the use of the geopolymer-based sand control filter should be a better choice in many cases due to its heat resistance, ease of preparation and minor deformation.