Modeling techniques for simulating well behavior

Abstract

This thesis is a catalog of modeling techniques useful in simulating well behavior in certain types of reservoirs that are often encountered in petroleum reservoirs. Emphasis has been placed on techniques that can be used with any conventional reservoir simulator. The catalog includes models for wells in homogeneous-acting reservoirs, wells containing vertical hydraulic fractures, wells producing from naturally fractured reservoirs, and wells producing from commingled layers. New relations to model the combined effect of wellbore storage and skin in pressure-transient test are developed. These relations enable this effect to be modeled in any conventional reservoir simulator without the need to modify the existing program. Alternative grid construction to be used to model behavior of wells containing vertical hydraulic fractures is presented. This grid system reduces the complexity of grid construction near the fracture trip while retaining the accuracy of the pressure solutions obtained from the numerical model. We also investigate the early-time numerical error caused by the discretization of finite-difference in both radial and linear flow. Relations are presented to be used as guidelines for when the effect of numerical error ends so that reliable pressure-transient test analysis can be performed.