Study On Mechanical Properties And Fracture Law Of Conglomerate Reservoir

Conglomerate is one of the most important reservoir in China.Compared with conventional sandstone reservoir,the glutenite oil and gas is of high gravel content and strong heterogeneity.When used in hydraulic fracturing reservoir,it shows big interwall operation pressure,strong fluctuation and poor regularity.The understanding of the Mechanical properties of conglomeratic reservoir and rock failure rule is of great significance to improve reservoir effect.This article chooses the acoustic wave velocity test,AE test and simulation of rupture and numerical simulation of Thick Wall to study the effects of particle size and gravel content on wave velocity,elastic modulus,Poisson's ratio and uniaxial compressive strength were analyzed.The heterogeneity coefficient was proposed by gray correlation method to characterize the heterogeneity of conglomerates.The relationship between the heterogeneity coefficient and the mechanical properties of conglomerates is analyzed.The fracture characteristics of simulated conglomerate samples were studied by uniaxial loading acoustic emission monitoring and thick-wall tube rupture experiments.The total number of acoustic emission events,post-peak b value and thick-wall tube fracture and fractal dimension and the heterogeneity coefficient,the results show that with the increase of the congenital heterogeneity coefficient,the tortuosity of the single crack increases,and the complexity of the fracture is reduced.Using the discrete element software PFC to simulate the rupture of the conglomerate,the rupture complexity of the conglomerate seam is reduced with the increase of the heterogeneity coefficient,which indicates that the inhomogeneity of the conglomerate reservoir is stronger and the difficulty of forming the seam the bigger ones.Having analyzed the conglomerate reservoir rock mechanics and its structural characterization of heterogeneity in Mahu region and the characteristic of heterogeneity of reservoir fracturing operation,the engineering advice is given.The result is of important guided-significance to the design of field fracturing optimization and construction.