Effect analysis of non-condensable gases on superheated steam flow in vertical single-tubing steam injection pipes based on the real gas equation of state and the transient heat transfer model in formation

Huge amount of efforts were done on saturated steam flow in wellbores with relatively little work on superheated multi-component thermal fluid (SMTF) flow in wellbores. In this paper, based on the continuity, energy and momentum balance equations, a flow model in the vertical wellbores is proposed. Then, coupled with the real gas model and transient heat flow model in formation, a comprehensive model is established for estimating thermophysical properties of SMTF in wellbores. Results show that (a) the effect of mass content of non-condensing gases on temperature profiles is negligible. The enthalpy of SMTF decreases rapidly with increasing of mass content of non-condensing gases. (b) When the injection rate is small, heat loss is the main factor on temperature drop, while when the injection rate is large enough, pressure drop becomes the dominant factor on temperature drop. (c) The two components of non-condensing gases and superheated steam in SMTF have a relatively independent mechanism of enhanced oil recovery, which should be selected based on the unique characteristics of each reservoir.