Figure 1 - Skekilie top -down combustion. (Shekilie High Pressure Air Injection Pilot Project Progress Report No. 2, 1993)

Shekilie (Alberta)

From 1993 to 1998, Petro-Canada conducted an experimental project in the keg River C2C Pinnacle Reef pool in Alberta. This 37.3 ^oAPI oil pool had a single vertical producer and a weak water-drive that gave a recovery factor of 30% on primary.

The vertical producer was converted to an air injector by cementing-back most of the well interval across the pay section and a horizontal well was drilled at the original oil-water contact for production. Air injection was implemented as a top-down combustion process (see Figure 1).

The injection well was ignited and the combustion front was successfully propagated downward. An important addition to the knowledge base is that the injection well remained intact while the combustion zone progressed downward around it.

Although the horizontal well completely traversed the reef, only 60 m of the lateral section remained opened due to wellbore collapse that occurred during the well completion. This collapse was likely induced by fluid-loss into reservoir fractures.

A production test showed severe downward gas-coning into the restricted open section. However, there was a considerable (prorated) increase in the oil production rate. Also noteworthy was the absence of any chemical alteration of the oil or the formation of emulsions.