Development of a Coupled Compositional Wellbore/Reservoir Simulator for Modeling Pressure and Temperature Distribution in Horizontal Wells

Abstract

AbstractThe calculation of production parameters that address multiphase flow in wellbores is challenging. A great deal of research has been conducted to simulate fluid flow in horizontal wells. In most cases, only stand-alone wellbore models for black-oil have been used to simulate reservoir and well dynamics interactions. These models are based on simplified assumptions that lead to unrealistic estimation of pressure and temperature distributions in the well. In addition, most reservoir simulators use rough estimates of perforation pressure as boundary conditions between wellbore and reservoir, and neglect pressure drop in the horizontal wells. A steady-state, non-isothermal, fully-coupled compositional wellbore/reservoir simulator is developed to simulate fluid flow in horizontal wells in conjunction with vertical wells. This simulator is capable of handling concurrent flow of gas, oil and water in both horizontal and vertical wellbores. It can also accurately calculate pressure and temperature profiles, holdup, and component mass-flow rates in wellbores. Our simulation results can explain remarkable differences in flow rate between coupled wellbore/reservoir simulator and stand-alone reservoir simulator at the early stage of production. In this study, variation of liquid fraction along the well is also investigated. Liquid is unloaded in the horizontal well at the early stage of production and then loaded, starting from the upstream of flow, at the late stage of production.