Low-density Ceramic Proppants Research Articles

Reused green glass for the production of low-density ceramic proppants

The reuse of waste to promote manufacturing processes that are respectful of the environment is a fundamental requirement in circular economy practices. In this work, it is assessed the feasibility of manufacturing ceramic proppants from a commercial red clay, sodium and potassium feldspars, and significant amounts of green bottle glass recovered from urban wastes.Different ceramic mixtures were formulated, and the sintering conditions were defined considering optical dilatometric, differential thermal, and thermogravimetric analysis. The obtained granules were characterised following the international standard for proppants, and also using X-ray diffraction, scanning electron microscopy, and individual diametral compression tests.The results show that competitive proppants are obtained, due to their low-density (2.5 g/cm3) and good breakage ratio (7.8 % at 5000 psi, or 34.5 MPa), but also considering the involved low-cost processing route and raw materials.

Effect of feldspar milling on the properties of low-density ceramic proppants

ABSTRACT Low-density and high-strength ceramic proppants were successfully prepared from bauxite and feldspar. The addition of feldspar greatly reduced the sintering temperature (below 1300℃). The effects of the particle size of feldspar on the bulk density, apparent density and breakage ratio of the proppants were evaluated. The morphology and phase composition of the proppants was examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that the ball milling of feldspar can greatly improve the properties of ceramic proppants. The phases of the proppants obtained contain mullite and corundum. Bulk density, apparent density, and breakage resistance of the proppants sintered at 1280℃ increase with the prolongation of ball milling time of feldspar. When the feldspar are milled for 6 h, bulk density of the proppants is 1.46 g/cm3, apparent density is 2.70 g/cm3 and breakage ratio under 52 MPa closed pressure is 7.97%.

Effect of Sintering Temperature on Property of Low-Density Ceramic Proppant Adding Coal Gangue

Calcined flint clay (45.6 wt.% Al2O3) and solid waste coal gangue were used to prepare low-density ceramic proppant by solid state sintering method. The density and breakage ratio of the ceramic proppant were systematically investigated as a function of sintering temperature. The morphology and phase composition of the ceramic proppant were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that the ceramic proppant is composed of rod-like mullite and granular cristobalite. Bulk density and apparent density of the proppant first rise and then slightly decrease with increasing the sintering temperature, while breakage ratios under 35 MPa and 52 MPa pressure gradually decrease and then increase. As the sintering temperature increases up to 1400 °C, the ceramic proppant shows denser microstructure. The proppant sintered at 1400 °C have the best performance with 1.27 g/cm3 of bulk density, 2.79 g/cm3 of apparent density, 3.27 % of breakage ratio under 35 MPa closed pressure and 8.36 % of breakage ratio under 52 MPa closed pressure, which conform to the requirement of low-density ceramic proppant. The addition of solid waste can greatly reduce the preparation cost of the ceramic proppant.

Toughening effect of mullite whisker within low-density ceramic proppants

Main crystal phases of low-density ceramic proppants prepared by bauxite and feldspar are granular corundum and whisker-shaped mullite. Mullite whiskers are interlocked with one another and piled up inside the pores. High aspect ratio of mullite whiskers inside the pores can greatly enhance the fracture toughness. The dominant toughening mechanism for the proppants is attributed to crack bifurcation and deflection and pulling out and bridging effect of mullite whiskers.

Sintering mechanism of high-intensity and low-density ceramic proppants prepared by recycling of waste ceramic sands

ABSTRACTWaste ceramic sands were effectively used to prepare the high-intensity and low-density ceramic proppants, realising the recycling of the waste ceramic sands. The technology involved the pelletising in an intensive mixer, in which the waste ceramic sands and other starting materials were added, and followed by heat-treatment under different sintering conditions. The sintering temperature, holding time and heating rate were optimised by investigating the crystalline phase, microstructure, density and breakage ratio of the obtained proppants. The results showed that the proppants sintered at 1260°C for 2 h with a heating rate of 5°C min–1 under air atmosphere exhibited high crush resistance and low density, with the breakage ratio of 8.5% under 52 MPa closure pressure and bulk density of 1.65 g cm–3. The proppants prepared by bauxite, waste ceramic sands and sintering aids are promising candidates as high-intensity and low-density fracturing proppants in future applications.

Preparation and characterization of low-density ceramic proppant containing coal gangue additive

Low-density ceramic proppants were prepared from calcined flint clay and solid waste coal gangue by pelleting, drying, screening and sintering, namely solid state sintering method. The density and breakage ratio of the proppants were systematically investigated as a function of sintering temperature. The morphology and phase composition of the proppants were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that the ceramic proppants are composed of acicular mullite and granular cristobalite. Bulk density and apparent density of the proppants rise and thereafter down with increasing the sintering temperature. The proppants sintered at 1400 °C have the best performance with 1.28 g/cm3 of bulk density, 2.84 g/cm3 of apparent density and 7.89% of breakage ratio under 52 MPa closed pressure. The prepared ceramic proppants meet China industrial standard requirements SY/T5108-2014.

Sintering temperature dependence of low-cost, low-density ceramic proppant with high breakage resistance

The low-cost, low-density ceramic proppants with high breakage resistance were successfully prepared from low-grade bauxite (59.9wt%Al2O3) partially replaced by purple sand via solid state sintering method. The phase evolution and microstructure of the ceramic proppants sintered at different temperatures were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that with the increase of sintering temperature, the crystalline phases were transferred from sillimanite to mullite and corundum, and glass phase was generated. When sintered at the proper temperature of 1440°C, the close integration of mullite and corundum bonded by the proper liquid phase was observed, and the obtained proppant presents the apparent density of 2.98g/cm3, bulk density of 1.64g/cm3 and lowest breakage ratio of 7.8% under 52MPa closed pressure.

Erosion by Sand and Ceramic Proppants During Slurry Injection and Proppant Flowback

This article, written by Technology Editor Dennis Denney, contains highlights of paper SPE 90604, "Erosion by Proppant: A Comparison of the Erosivity of Sand and Ceramic Proppants During Slurry Injection and Flowback of Proppant," by M.C. Vincent, SPE, Carbo Ceramics Inc.; H.B. Miller, U. of Arizona; D. Milton-Tayler, SPE, FracTech Ltd.; and P.B. Kaufman, SPE, Carbo Ceramics Inc., prepared for the 2004 SPE Annual Technical Conference and Exhibition, Houston, 26-29 September. During fracture-stimulation treatments, particle-laden slurries may damage pumping equipment and have been shown to erode perforation tunnels. During subsequent flowback operations, minor to severe erosion of surface equipment may be observed if formation sand and/or proppants are produced. This paper compares the erosivity of sand-based and ceramic proppants. The erosion mechanisms are examined, and theoretical and laboratory measurements are in agreement that low-density ceramic proppants, because of roundness and sphericity, are less erosive than more-angular sand products. Introduction Impingement tests designed to simulate flowback conditions demonstrated that use of a spherical lightweight ceramic (LWC) may reduce wellhead or other impingement-surface erosion by up to 95% compared with an angular sand. Additional studies with intentionally crushed proppant (to increase angularity) demonstrate that proppant shape is a dominant factor in controlling erosion. Surprisingly, flowback testing has shown that resin coatings applied to proppant can increase erosion 15-fold. Erosivity and abrasiveness of all proppant types were shown to increase with prop-pant damage. Erosion in chokes was found to be three times greater with sand than with LWC. Several laboratory studies have demonstrated that spherical proppants are less likely to flow back from the fracture than more-angular products.