Esso operates fifteen reservoirs in the Pembina Nisku area, and of these, seven are being miscibly flooded (Vertical Hydrocarbon Miscible Floods). The miscible floods are now in an advanced stage of depletion. As the oil banks in these reservoirs continue to thin, solvent coning is becoming a concern and individual wells have to be choked back. The objective of drilling horizontal wells in these reservoirs is to allow us to maintain oil productivity without solvent coning and also to increase reserves by decreasing the sandwich loss.
The first horizontal well was drilled in the Pembina Nisku "K" pool in 1989. The well initially produced solvent but was successfully worked over and has now been producing at solution gas oil ratios for approximately one year. Since then, Esso Resources Canada Limited has drilled two more horizontal wells in the Pembina Nisku "M" and "Q" pools.