Preparation And Performance Study Of Low-density Fracturing Proppants

Acting as key role in oil and gas production process,Proppant determined the level of oil and gas collection rates.High-strength proppants maintained the reservoir effectively and fractured channel.However,high-strength proppant always mean high density which was difficult for pumping.How to prepare low density proppant was the researched in this paper.Using SiO2 ceramic powder,bauxite as spherical shell coating materials,the templates was prepared by a hollow structure with a single hollow proppant.The thermal character of pyrolysis was analyzed by porogen simultaneous thermal analyzer.Optical microscope and SEM was taken to observe the profile and the structure of the proppant respectively.Single proppant compressive strength and isostatic broken rate tested the strength of the hollow ceramic proppant.Moreover,the effect of curvature of proppant on the mechanical performance was calculated,and an formula was established which mainly bridged the connection of curvature and single particle compression.With the study on preparation and properties of proppant,several conclusions were drawn as follow:1)The result showed that the performance of hollow proppant made from urea was much better than the ones made from PS ball,starch,phenolic resin.The single hollow structure proppant was made from urea and SiO2 ceramic powder which was accustomed to blanking plastic processing and sintering at 1200 ?.The prepared proppant was consisted of ?-quartz phase,no ?-cristobalite existed.Meanwhile few quartz glass phase in quartz phase benefited improving the spherical profile.Proppants distributed detached to each other and no obvious adhesion between each proppant.So seldom crackers and holes in the shell that proppant had high strength.2)Preprocessing the low-grade bauxite raw material contributed to densify the bauxite proppant within sintering process and improved strength of proppants either.Taking urea as hole template,the hollow bauxite ceramic proppant were prepared referring to debinding quartz hollow proppant.This kind of hollow proppant had a complex single inner hollow structure and few crackers in the shell which were less than 10?m.The compressive strength of bauxite hollow proppant prepared by low-grade bauxite was much better than the same kind of particle size quartz hollow proppant.3)The thickness of the proppant shell ranged from 200 ?m to 450 ?m while the radius of proppant was about 350?m to 1200?m.As the curvature ?(?=t/r)varied from 0.5 to 3,the function of radius(r)and shell thickness(t)was followed:F = f(r)·g(t)=1.7695×10-4(r-0.1903 +1)·t24153?F = f(r).g(t)=9.6430×10-5(r-0.158 +1)·t2 2695 Formulation above indicated that the influence of shell thickness on the compressive resistance was more than that of hollow radius.4)The hollow quartz proppant with 200?m hollow radius and 200?m shell thickness was better than the natural quartz sand.This kind of proppant could stand 100 MPa isostatic compressive and no particle broken,even no cracker on the surface of spherical particle.This type of proppant was adoptable in shallow oil reservoir.