Life After SAGD – 20 Years Later

Abstract

Abstract I presented a paper "Is There Life After SAGD?" at the 1996 Western Regional Meeting1. The paper was published and elicited some 20 discussions. Today, SAGD - Steam-Assisted Gravity Drainage - is a commercially successful recovery method in Canada, if the price of oil is right. The subject of this paper is what we have learned in the past 20 years, and what is the future of SAGD in oil (tar) sands and heavy oil exploitation. At last count there were 18 SAGD projects in Alberta, and none anywhere. Bitumen production by SAGD is about 800,000 B/D. There have been failures also - in Alberta, California, Venezuela, etc. The oil recovery factor can be as high as 60%, depending on how one defines it, and as low as 10-20%. The steam-oil ratio varies from 1.6 Bbl steam/Bbl oil, to 8 Bbl/Bbl. (Note that these are based on 95% downhole steam quality and are to be multiplied by ~1.3 to compare with typical steam injection SOR's). There are large variations even within the same project. The heat production can be as much as 50% of that injected. The desired downhole steam quality is 100%. Thus SAGD is a unique recovery method, but its application requires great caution. Some of the assertions of 20 years ago still apply. A few new aspects of SAGD have come to the fore. Many variations of the basic process have been proposed and tested. Many have failed. In some of the less successful projects, solvents and other additives are being injected with steam to improve performance. The attractive features of SAGD are described, and application guidelines are offered, based on failures. SAGD is here to stay, but what are the limits to application? This is the focus of the paper.