The Influence Of Size Effect On The Fracture Pressure Of Perforated Wells And The Starting Point Of Fractures

In this paper,numerical simulation of perforated well damage is carried out.Firstly,the elastic equilibrium equation is solved by using boundary element method to determine the stress-strain state of rock and perforation near the well surface.Secondly,the location of crack initiation is inferred based on the stress-strain state estimated by fracture criteria.Subsequently,under the assumption that there is no perforation effect on perforation,the numerical solutions and approximate analytical formulas of the elastic equilibrium equation are compared.Furthermore,in order to determine the initial pressure of fractures from perforated wells,the sensitivity of crack initiation to the standard parameters is analyzed by means of the size effect criterion,and the initial pressure calculated based on the maximum tensile stress criterion and the criterion considering the size effect are compared.The results of this study show that the criterion considering size effect must be used when the local strength of reservoir rocks is large.The work consists of 28 printed pages containing 26 pictures and a list of 14 sources.