An Integrated Horizontal- and Vertical-Flow Simulation With Application to Wax Precipitation

Abstract

Summary There is a lack of comprehensive simulation tools that (a) accommodate the complexities of advanced completions together with near-wellbore behavior and that (b) have reliable wax-precipitation models for production planning. In this work, these issues are tackled by combining three specific models. First, a steady-state, three-phase, nonisothermal flow model in advanced horizontal completions was implemented to run fluid-specific simulations, thereby calculating field-specific flow conditions. This is useful in situations when fluid-specific temperature calculations are important, such as wax crystallization. Second, a nonisothermal, vertical flow model was developed by combining Hagedorn and Brown's multiphase-flow correlation with Ramey's multiphase-temperature model by solving them in sequence (iteratively). The advanced horizontal-well model and vertical flow model were coupled iteratively at the bottom hole where the two models meet. Third, two different analytical wax-crystallization models were incorporated in the aforementioned coupled flow simulator to calculate the location of wax precipitation along the vertical section of the well. These three simulation models, individually and in combination, were tested and found to be in par with theory, expectations, and published results. In addition, a significant difference was noted between Ramey's analytical temperature profile (which is a widely used approximation) and the complete Ramey's model integrated with the simulator developed in this work.