Characterization of foam assisted SAGD process

Key words:  heavy oil reservoir  steam assisted gravity drainage  foam  numerical simulation  steam chamber

Abstract:

Steam assisted gravity drainage (SAGD) and foam assisted SAGD (FA-SAGD) are effective processes for heavy oil recovery. The temperature distributions in these processes were studied for both homogeneous and heterogeneous reservoirs using a numerical simulation method in order to reveal the expansion of the steam chambers and compare the effectiveness of the two production methods. The results show that, in the FA-SAGD production process, the lateral expansion of the steam chamber is faster than that in the SAGD process, and the vertical expansion is slower than that in the SAGD. The steam chamber of the FA-SAGD is mainly developed in the middle part of the reservoir, and its contact area with cap rocks is small, which can reduce the heat loss of the cap rock. When the SAGD process is applied in a heterogeneous reservoir, steam tends to flow through mainly in high permeable layers, and the expansion of the steam chamber along the horizontal well bore is not uniform. While in the FA-SAGD process, the expansion of the steam chamber in the reservoir is uniform due to the blocking effect of foam in high permeable layers, which can increase the sweeping efficiency of foam and reduce heat loss. Subsequently, the application of the FA-SAGD can improve the ratio of oil to steam and increase oil recovery.