Abstract <p>Using horizontal, multilateral, and smart wells has become a standard practice in the oil and gas industry. However, modeling such wells is still a difficult task in many cases. Since, along with the geometric factors associated with their drilling in the reservoir, it is necessary to take into account the multiphase nature of the flow and such phenomena as pressure losses due to friction and when the liquid passes through the devices with which the wells are equipped. This paper presents a systematic derivation of well models for the control volume method on an unstructured grid. In the case of multisegment wells, pressure losses caused by gravity, friction, acceleration, and pressure losses during the passage of liquid through the flow control devices are taken into account.</p>