Development And Performance Evaluation Of Low Density Proppants

Proppants, one of the most important fracturing technique materials in reservoir stimulation, are utilized to prop up the fracturing surfaces after the fracturing operations and thus enhance the fluids flowing ability through the formation. At present, there are some shortcomings in current proppants such as high relative density, which requires high performance of fracturing fluids and gives rise to low transport performance. The properties of prppants exert a profound influence on the fracturing effect. Therefore, it's significant to develop low density proppants with excellent and expected properties.To begin with, research status quo of proppants at home and abroad has been present and discussed, and then studies regarding proppants have been done and so has their functional test performed based on these researches. Through selecting materials and preparation technology, proppants with hollow or porous structure have came into being in order to reduce the density of proppants. Additionally, hollow proppants consist of two layers of material before sintering, which refers to internal core material and the external package material. During sintering of proppant, the reaction of internal core material leads to disintegration and thus produce gas. As a result of venting these gas through the external package material., the hollow structure are formed.Two different types of proppants, via this method, are development. One is low density proppants with hollow ceramic, and another is low density proppants with porous resin.During the development of low density proppants with hollow ceramic, on the basis of several spherical shell materials and core pore forming materials selection, samples have been sintered after granulation and the evaluated the properties. Urea as the internal pore forming agent and silica as the combination of external package material ceramsite hollow low-density proppants have been elected for the present, whose apparent density can reach 1.82g/cm3 and the crushing rate is less than 6.19% under the 27.6MPa. So as to improve performance of urea/silica hollow low-density proppant, the sintering process has undergone further optimization, thermogravimetric analysis has been carried out on the urea and urea's main decomposition temperature point have been ascertained. On account of the extension of urea's main decomposition temperature point, the apparent density can reach 1.69g/cm3 and under the 27.6MPa, the crushing rate is less than 4.71%.In the process of the development of low density proppants with porous resin curing agent, the foaming agent and reinforcing agent are added to the resin powder, and hence the apparent density can reach 1.03g/cm, which could be in a position to be suspended in the water, and under the 27.6MPa, the crushing rate is less than 3.36%.In the end, these two types of proppants'properties, compared with the ones of other three conventional and traditional low-density proppant, perform better during evaluation and comparison. In consequence, both low density proppants with hollow ceramic and low density proppants with porous resin have an edge.