Effect of Steam State on the Productivity of a Horizontal Well Pair During the Steam-Assisted-Gravity-Drainage Process: Physical Aspect Analysis

Abstract

Very limited studies were done on the superheated steam-assisted-gravity-drainage (SAGD) process. Besides, study of the effect of physical heating of steam at different state on the productivity during the SAGD process has not been reported. In this paper, a numerical model is proposed to reveal the effect of physical heating on the productivity of a horizontal well pair during the SAGD process. Results show that: (a) the temperature increase of superheated steam plays a weak influence on the productivity of a horizontal well pair during the SAGD process. (b) the heated area increases with the steam quality, while the increase of the heated area under superheated steam injection is not obvious compared with the heated area when the steam quality is equal to 1.0. (c) as the mobility of oil in the steam chamber increases, the fraction of oil produced from the steam chamber increases, and the pressure near the production well increases. (d) when the steam quality increases or becomes superheated steam, the mobility of the oil in the steam chamber increases, and the supply rate of oil near the production well gradually become larger than the decrease rate of oil in the same region induced by elastic energy. This study provides a The paper offers a comprehensive insight into the SAGD process, and helps petroleum engineers for SAGD project design in heavy oil reserves.