Study On The Mathematical Model Solution Of Unsteady Seepage Flow With Dual Porosity Media Under Elastic Boundary

In view of the large limitations of the dual-porosity media seepage model established in the early study in the process of describing the unstable seepage,elastic external boundary condition is introduced in this paper,which can treats the idealized assumption(external boundary with constant pressure,closed and infinite)in the traditional model as a special case.The influences of well-bore storage and skin factors on reservoir pressure are considered to establish two unsteady seepage models(the one is wellbore storage and skin effects normally considered and the other one is effective bore sizes introduced).in dual-porosity media under the elastic boundary.The Laplace space solution of seepage model is obtained by using Laplace transform and similar structure theory in turn.Subsequently,Numerical experiments were carried out by using Stehfest inversion transformation and the corresponding mapping software,the type curves are drawn,and the impacts of the variation of the main parameters on them are analyzed.All of the two results indicate that in the case of elastic boundary,the characteristic curves determined by wellbore reservoir and skin coefficient with different values are asymptotically close to one curve respectively.The elastic coefficient influences the asymptotic trajectory of the characteristic curves determined by different well storage coefficients and the asymptotic rate of the characteristic curves determined by different skin coefficients,and the elastic coefficient is negatively correlated with the asymptotic rate.The last but not least,the model established in this paper and the corresponding data analysis provide a more solid theoretical basis for the scientific analysis of the influence of reservoir parameters on reservoir pressure,and provide a new idea for the design and improvement of related well testing software.