Monitoring liquid Dropout for Investigating Liquid Loading in Gas Wells

摘要

This paper presents a dynamic simulation approach to monitoring liquid dropout in gas wells forinvestigating liquid loading of a fluid flowing in mist flow regime. It involves incorporating an event locationproperty into an ODE solver that runs a dynamic mist flow model. The dynamic mist flow model was developedby coupling thermodynamic and hydrodynamic models as well as constitutive equations using Matlab programsthat incorporate the Peng-Robinson equation of state and the convex hull algorithm. The event locationproperty is integrated in such a way that at arbitrary positions in the wellbore, the event parameter informs thesolver in the ODE file to return appropriate event function information. This is so because during flow, phaseand compositional changes occur at different segments of the wellbore that would trigger the Event locationproperty. In this instance, it returns temperature, pressure and composition at specific depths. Phase change isbeing monitored by changes in the color as the phase proportions vary. Using appropriate color coding, theliquid and vapor phases are monitored along the wellbore, and the amount of condensable liquid is beingtracked by the changes in the color of the fluid composition at a given temperature and pressure. Hence, atspecific depths in the wellbore, the composition of the fluid is determined which gives a clue of the amount ofliquid dropout. The calculated phase compositions were validated using data obtained from commercialsoftware, NIST RefProp and the results show good agreement. This procedure can provide substantial benefitsin adequately investigating how liquids dropout during flow in gas wells.