The Study Of Welltest Interpretation Method For Vertical Fracturing Well

Fracturing is the effective measures for development of low permeability which have been widely used in the oil field. After fracturing in low permeability reservoir vertical fractures and horizontal fractures formed,it is necessary to fully understand the impact of fractures on reservoir flow,and then combined with well testing data we can fully understand the nature of the reservior. In this paper,the Green function method and Newman product method are used to build the vertical fracture welltesting models in the infinite reservoir,closed boundary reservoir,constant pressure outer boundary reservoir,each case is divided into two cases,considering fracture aperture and without considering fracture aperture,the analytic solutions of bottom pressure is obtained and drawing the pressure and pressure derivative log-log type curves,analyse the influences of the fracture aperture,fracture symmetry and reservoir and fracture scale; Using the same method the horizontal fracture model in vertical well is built and obtain the analytic solution,drawing its pressure and pressure derivative log-log type curves,generally the horizontal fracture aperture is very small and its influence can be ignored,but the vertical position of horizontal fracture in the reservoir should be taken into consideration. Finally considering the actuating pressure gradient,the flow model for low permeability reservoir are built,the numerical solution of bottom-hole pressure is derived,it is found that the flow deviates from the Darcy flow because of the presence of actuating pressure gradient ,and the greater the actuating pressure gradient is ,the earlier the flow deviates from the linear flow and the greater deviation; analyse the influemces of fracture conductivity,hydraulic diffusivity,wellbore storage and wellbore storage for bottom hole pressure.