Research On The Preparation And Properties Of Low-density High-strength Ceramic Proppants

With the world economy developing, the demand for oil and gas is also increasing. Hydraulic fracturing technology is the first choice for the exploitation of low permeability reservoir. In this technology, proppants play an important role, which will affect the oil and gas production and the service life of the well.This paper systematically analyzed the research status and existing problems of fracturing proppants. Currently, the resource of high-grade bauxite is rare. For the phenomenon, the low-density and high-strength ceramic proppants were prepared using bauxite(59.9 wt.%Al2O3) and purple sand as the raw materials, manganese ore powder and dolomite as the additives. The influences of different contents of additives and sintering temperature on the properties, crystalline phases and microstructure of ceramic proppants were obtained. Moreover, this paper is based on the accumulation phenomenon of waste ceramic sands, for the first time, using them and bauxite for the preparation of ceramic proppants. The effects of different sintering system on the properties crystalline phases and microstructure were obtained. And the phase evolution and microstructure of the ceramic proppants were investigated by X-ray diffraction(XRD) and scanning electron microscopy(SEM). The paper obtains these main conclusions, as following:(1) The ceramic proppants were prepared using bauxite(89 wt.%) and purple sand(11 wt.%) as the raw materials at 1560 ?.(2) Manganese ore powder was introduced as additive in the formulation,which can reduce the sintering temperature. When the content of manganese powder is 4 wt.%, the mullite-corundum ceramic proppants with the better performance can be prepared at 1420 ?. With the content of manganese powder increase, the grain phase of proppants samples is turned from needle into columnar, the grain size becomes larger and the peak intensity of corundum phase increases.(3) The appropriate amount of manganese and dolomite used as composite additives can play a better cooling effect. The low-density and high-strength ceramic proppants can be prepared by the composite additives sintered at1310 ?. The obtained proppants presents the apparent density of 2.993 g/cm3,bulk density of 1.65 g/cm3 and the lower breakage ratio of 8.97 % under 52 MPa closed pressure. At the temperature, the right amount of liquid phase is attributed to the introduction of composite additives, which makes the key capacity enhanced between mullite and corundum. Therefore, the strength of ceramic proppants is improved.(4) The low-density and high-strength ceramic proppants sintered 1260 ?were prepared using bauxite as the main raw, manganese powder and dolomite as additives, with the waste ceramic proppants(10 wt.%), which achieves re-use of waste ceramic sand.(5) Sintering temperature, holding time and heating rate also have effects on the structure and properties of ceramic proppants in varying degrees. Suitable heating rate can help exhaust the pores and improve the compactness. When the sintering temperature is reached, holding for some time contributes to a better crystal growth.