<p> Modeling Heading in Gas-Lift Wells Using a Combined Dynamic Simulation / Gas-Lift Design Program</p><p>Perry T. Poradek EPS Americas, Inc.</p><p>One of the more common behaviors found in artificially lifted wells is that of heading, i.e. the instability of both wellhead flowing pressure and rate at the surface. This unstable situation creates several difficulties in modeling with conventional "steady-state" tools, which assume stable operating conditions. This paper outlines procedures to help with understanding this phenomenon and tries to solve the cause of this situation utilizing a dynamic simulator that reproduces the actual conditions. It also conceptually clarifies the gas lift injection process for engineers. </p>