A simple 3-D physical model has been developed to investigate the use of horizontal producer wells in in situ combustion processes. The semi-scaled 3-D model was a rectangular box with 40 cm by 40 cm by 10 cm dimensions. Dry in situ combustion experiments were conducted with three different well configurations: (1) a vertical injector and horizontal producer, (2) a vertical injector and two horizontal producers, and (3) injector and producer, both vertical. A matrix of 60 thermocouples was used to obtain temperature profile information, in the vertical and horizontal mid-planes. Most experiments were conducted with sandpacks containing a high saturation of heavy crude oil So(i) congruent-to 0.80. For each horizontal well configuration, the effect of oxygen flux and oxygen enrichment (21% and 3.5% oxygen) was investigated.