Research On Ceramic Fracturing Proppant With Low Density And High Strength

As an effective technique for increasing output applied to the oil and gas industry,the hydraulic fracturing technology has become one of the important technologies directly related to the energy development of our country.Proppants are a kind of spherical ceramic particles which can support the rock fracture and improve the permeability of oil and gas.They are very vital for the hydraulic fracturing.The performance of proppant concerns the effect of hydraulic fracturing and the service life of the oil and gas wells,so it is of great significance to research on high-performance proppants.Currently,the research on high strength fracturing proppant is based on high quality bauxite that the content of Al₂O₃ is greater than 75% as the raw material,and the utilization of low grade bauxite is limited.In order to develop the application field of low grade bauxite and produce the high value-added production,in this paper,high strength ceramic proppant which can meet the requirements of industrial production was prepared with starting materials of low grade bauxite that the content of Al₂O₃ is 67.48% and additives of manganese ore powder;For reducing the density and preparing the proppant that meets the requirements of hydraulic fracturing applied in the unconventional low permeability oil and gas reservoirs,in this paper,firstly,the low density and high strength corundum-mullite based ceramic proppant was prepared with the materials of secondary bauxite,Kfeldspar and dolomite.Next the reinforced ceramic proppant with mullite whisker was prepared using kaolinite-coal-gangue as the raw materials and V₂O₅ powder as the additive.The effect of V₂O₅ powder on the properties of proppant with mullite whisker was systematically investigated.The conclusions are divided into the following several parts.?1?The ceramic fracturing proppant was prepared with secondary bauxite as the main raw material,but the sintering temperature was higher.When the calcination temperature was 1500?,the breaking rate could be reduced to below 9%.Therefore,it is difficult to prepare proppants with broken grade of 7.5K at a relatively low temperature.?2?The addition of manganese ore powder can effectively reduces the sintering temperature,enhance the bulk density and improve the strength of the bauxite-based fracturing proppant.When the content of manganese ore powder is 3%,the sample exhibited the optimal properties.The broken grade of samples sintering from 1350? to 1500? all reach 7.5K.Among them,the sample sintering at 1400? shows a lowest breakage ratio of 3.7%.The fracturing proppant meets the requirements of deep oil and gas wells which can be applied to industrial production.?3?Lightly calcined bauxite can improve the sintering properties of ceramic products.The results show that the ceramic proppant sample has a best performance when the ratio of lightly calcined bauxite to bauxite is 1:4.The samples of ceramic proppant sintering from 1350 ? to 1500 ? respectively exhibits the broken grade of 7.5K.Compared with the proppants prepared with bauxite raw material powder,the sintering range of these proppants doped with 20% lightly calcined bauxite is relatively wide and the producing process is easily controlled.?4?The content of Al₂O₃ contained in raw material can be decrease by adding K-feldspar,at the same time,the density of samples also decreases;By adding a moderate amount of dolomite,the strength of samples can improve,because more corundum and mullite are forming in the samples;while the content of dolomite is 2%,the sample sintering at 1340? shows the best performance with the bulk density of 1.31 g/cm3,apparent density of 2.62 g/cm3 and the broken grade of 7.5K.?5?The reinforced ceramic proppant with mullite whisker was prepared at 1400? with kaolinite-coal-gangue as the raw materials and V₂O₅ powder as the additive.With the improving of V₂O₅ powder content,the main crystalline phase of ceramic proppant gradually generated mullite whisker;Morever,the sample with 1wt% V₂O₅ powder exhibited the optimal properities with the bulk density of 1.25 g/cm3,apparent density of 2.69 g/cm3,and the broken grade of 7.5K.