添加铁粉制备低密度中强度陶粒支撑剂及性能研究

Preparation and Mechanisms of Light-weight Middle-strength Ceramisite Proppant by Iron Powder Additive

低密度中强度陶粒支撑剂的开发,既可以提高低渗透油气藏的开发效率又能显著降低油气开采成本。以Al2O3含量为63%的二级铝矾土为主要原料,以铁粉取代部分锰矿粉制备了低密度中强度陶粒支撑剂。结果表明:添加铁粉2%,锰矿粉3%、白云石1%时,在1 350℃下煅烧1h,有利于陶粒支撑剂中生成均匀分布的直径为0.3~1.0μm棒状莫来石晶相,棒状莫来石起到纤维增韧作用,提高支撑剂的强度,使其在52MPa的闭合压力下破碎率为5.29%,体积密度为1.63g/cm^3。随着铁粉添加量的增加,基体中液相大量增加,晶粒生长速度过快未能有效排除气孔,导致大量气孔包在晶粒之间,容易构成应力集中点而形成裂纹源,降低了支撑剂的密度和强度。

Light--weight middle--strength ceramisite proppant is beneficial to the improvement of productivity of low--per- meability oil and gas reservoir, and is able to reduce the cost of oil and gas production significantly. The light--weight mid- dle- strength ceramisite proppant was prepared from bauxite（ 63 wt% Al12O3 ） by adding manganese mineral, part of that was replace by iron powder. The results show that strength of ceramisite proppant was improved by rod--like mullite with the diameter of 0.3 ~1.0 μm, which playa remarkable role in the increment of fracture toughness, when iron powder con- tent is 3 wt%, and manganese mineral content is 2 wt%, and dolomite content is 1 wt% and sintering at 1 350 ℃ for 1 h. The breakage ratio is 5.29% and bulk density was 1.63 g/cm3 under 52 MPa closure pressure. In addition, as the iron pow- der increase, he liquid phase increase in the matrix, many intergranular closed pores were formed as a result of the grain growth which was too speedy to eliminate pores. It is easy to form the crack source and reduce the density and strength of eeramisite proppant.