超低密高强度压裂支撑剂的制备及性能研究

发布时间：2018-05-31 23:07

  本文选题：铝矾土 + 煤系高岭土　； 参考：《太原理工大学》2017年硕士论文

【摘要】：由于社会发展与环境的压力,清洁能源在我国能源结构中的占比将逐步增大,常规性的天然气资源以及煤层气、页岩气等非常规性天然气资源将会成为未来的重要能源。这些能源的高效开采是目前亟须解决的一个问题。水力压裂技术作为石油开采过程中有效的增产和延长油井服役期的技术,在常规和非常规天然气的开采中发挥着重要的作用。由于地质结构的特殊性和环境保护的要求,超低密高强压裂支撑剂成为页岩气和煤层气等非常规天然气资源开采迫切需要开发的关键材料。本文以铝矾土和煤系高岭土为主要原料,分别辅以钾长石和工业氧化铝,并以白云石和V_2O_5作为添加剂,采用无压烧结技术制备了超低密高强度的压裂支撑剂。系统研究了烧成制度及添加剂对压裂支撑剂性能的影响,并采用XRD和SEM方法,分析了样品的物相组成和微观形貌。此外,借鉴多孔陶瓷的制备方法,探索了超低密压裂支撑剂的制备。研究结果表明:(1)原料中加入熔剂矿物钾长石后,所制备的压裂支撑剂的体积密度和视密度分别为1.30g/cm3和2.61 g/cm3,比未添加钾长石时降低了31.54%和8.77%。(2)烧结助剂白云石的加入一方面降低了烧成温度,另一方面在烧结过程中形成液相,促进了莫来石晶体的生长发育,提高了压裂支撑剂的强度。当白云石添加量为2wt%,且烧结温度为1330℃时,所制备的压裂支撑剂性能最好,52MPa闭合压力下的破碎率为4.51%。(3)以铝矾土、钾长石和白云石为原料,通过配方调制,在1300℃-1350℃下制备了符合行业标准SY/T 5108-2014的超低密高强度的压裂支撑剂。(4)V_2O_5对压裂支撑剂中莫来石晶须生长有显著的促进作用。加入V_2O_5后,可以使支撑剂颗粒在较低的温度下生成液相,促进了颗粒内反应组分的相互接触,有利于莫来石晶体的生长发育;同时V_2O_5能够促进莫来石晶体的定向生长,发育为针状的莫来石晶须,提高了支撑剂的强度。但V_2O_5加入量过多时会使得系统中的液相大量增加,反而对强度有不利的影响。(5)以煤系高岭土和工业氧化铝为原料,V_2O_5作为添加剂,通过弯曲强度试验获得制备压裂支撑剂的适宜烧结温度以及V_2O_5的最佳添加量:当烧结温度为1400℃,V_2O_5添加量为1wt%时,所制备的样品的弯曲强度达到了66.38MPa;以此条件制备的压裂支撑剂体积密度为1.25 g/cm3,52MPa闭合压力下的破碎率为5.23%,破碎等级达到了7.5K。(6)添加造孔剂能够降低支撑剂的密度,同时也引起支撑剂抗破碎能力下降。
[Abstract]:Due to the pressure of social development and environment, the proportion of clean energy in China's energy structure will gradually increase. The conventional natural gas resources, coal bed gas, shale gas and other unconventional natural gas resources will become an important energy in the future. The efficient exploitation of these energy sources is an urgent problem to be solved at present. Hydraulic fracturing, as an effective technique for increasing production and prolonging the service life of oil wells, plays an important role in the exploitation of conventional and unconventional natural gas. Due to the particularity of geological structure and the requirement of environmental protection, ultra-low density and high strength fracturing proppant has become the key material for exploitation of unconventional natural gas resources such as shale gas and coalbed gas. In this paper, the ultra-low density and high strength fracturing proppant was prepared by using bauxite and coal-series kaolin as main raw materials, potassium feldspar and industrial alumina respectively, and dolomite and V_2O_5 as additives. The effects of sintering conditions and additives on the properties of fracturing proppant were studied systematically. The phase composition and microstructure of the samples were analyzed by XRD and SEM methods. In addition, the preparation of ultra-low density fracturing proppant was explored by using the preparation method of porous ceramics. The results show that when the flux mineral potassium feldspar is added to the raw material, The bulk density and apparent density of the prepared fracturing proppant are 1.30g/cm3 and 2.61 g / cm ~ 3, respectively, which are 31.54% and 8.77% lower than those without potassium feldspar.) the addition of dolomite, a sintering promoter, decreases the sintering temperature on the one hand, and forms liquid phase during sintering on the other. It promotes the growth and development of mullite crystal and improves the strength of fracturing proppant. When the amount of dolomite is 2 wtlong and the sintering temperature is 1330 鈩，

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