Production features of steam and gas push: Comparative analysis with steam assisted gravity drainage

Abstract

Using the numerical simulation method and the drafting software of Surfer, we charted the temperature fields and remaining oil saturation fields of steam assisted gravity drainage (SAGD) and steam and gas push (SAGP) in oil drainage periods, including beginning, peak stage and last stage of oil drainage. An intuitive and reliable comparative research was done about the formation and expanding process of steam chambers, the shape of steam chambers and flow features in different oil drainage periods. The recovery effectiveness of the two production methods was compared. The results show that: in the SAGP production process, the lateral expansion of the steam chamber is faster than that in SAGD and the vertical expansion slower than that in SAGD. By adding non-condensate gas in the steam of SAGD, it can reduce the amount of steam injection, increase thermal efficiency, improve the ratio of oil to steam, and ultimately improve the development effectiveness of SAGD. The case study indicates that SAGP can slow the decline of oil rate and extend the development time of heavy oil reservoir and improve the development effectiveness. Key words: heavy oil reservoir, flow feature, SAGD, SAGP, numerical simulation