A New Analytic Solution for Finite Conductivity Vertical Fractures With Real Time and Laplace Space Parameter Estimation

Publisher Website
Google Scholar
Abstract
A new analytic solution, based on a trilinear flow model, is developed to study the transient behavior of a well intercepted by a finite-conductivity vertical fracture. The solution takes into account the effects of skin, wellbore storage, and fracture diffusivity. Both constant pressure and constant rate cases are considered. The solution is simple and reliable for short time analysis of the system of interest. Combining this solution with the well-known semi-log asymptotic solution provides a reliable tool for formation evaluation of fractured wells. We have also demonstrated that the optimization technique is a convenient means of reservoir parameter estimation in real time and Laplace spaces. For the problem examined in this paper, real time parameter estimation is found to be more convenient than Laplace space parameter estimation. A set of early-time asymptotic solutions is also presented. Our results indicate that if the wellbore storage effect is absent but a skin exists, then the fracture diffusivity will influence the early time data. Also if both the skin and storage effects are present, then the early time data alone cannot provide a unique determination of skin and other reservoir parameters.