Toe-to-Heel Air Injection - Effect of Oil Layer Thickness

A simulation study of a full-section of the first THAI field pilot, conducted in the Athabasca Oil Sands of Alberta, Canada, has investigated the effect of different oil layer thicknesses:; namely,8, 25 and 40 metres. The physical model description was an idealised representation of the WHITESANDS Conklin field pilot, having an homogeneous oil layer and no bottom water, or interbedded shale features. For a 6-year operating period, the oil production showed an increasing trend with increasing oil layer thickness, up to 80 m3/day. However, for the 8 m thick reservoir, the oil production profile showed a continuous decline, with oxygen breakthrough occurring after 1350 days. A significant Steam Zone developed in all three cases, advancing fastest in the 8 m thick oil layer. This latter case was accompanied by an increase of gas channelling, in the direction of the production well end of the reservoir. Peak combustion temperatures were highest for the 25 m oil layer, and lowest for the 8 m thick case.