Esso Resources Canada Limited is currently drilling development wells in Norman Wells as part of an expansion project to provide a field wide waterflood pattern and to increase the oil production from 475 m3/ day to 4000 rn3/day. Since the majority of the reservoir underlies the Mackenzie River at an average vertical depth of 450 m, optimum reservoir depletion requires the drilling of some 154 wells from the mainland, three natural islands and six artificial islands. The directional wells are mainly "S" type profiles with designed angle build rates of 8 °/30 m and angle drop rates of 4 °/30 m. Programmed target closures vary from 20 m to 750 m.
This drilling program presents challenges in directional programming, surveying, meeting target constraints, maintaining directional control and selecting bottom hole assemblies. These challenges have been effectively met while drilling thirty-nine wells since project initiation. Drilling program optimization is being achieved by reducing rig move times and improving drilling performance. The project to date has been highly successful in terms of time and cost reductions, achieving targets and successful well evaluation. Further time reductions and improved drilling performance are anticipated as the project progresses through improved applications of new and existing technology. This paper presents an overview of the project, the proposed drilling program, actual drilling performance and expected future improvements.
On July 2, 1982, Esso Resources Canada Limited spudded Esso Norman Wells G-28X which marked the beginning of a major oilfield development in the Northwest Territories. The Norman Wells oilfield (Figure 1) lies 145 km south of the Arctic Circle on the Mackenzie River. Although the Norman Wells discovery well was drilled in 1920, only minor development has taken place due to its geographic location and limited local markets. The current oil production is 475 m3/day from about 40 producing wells. Full scale development of this field, now in progress, will increase crude oil production to 4000 m3 /day. The increased production will reach southern markets via a 305 mm pipeline to be constructed from Norman wells to Zama, Alberta. The geographic location and the fact that the majority of the reservoir lies under the Mackenzie River present many logistical and drilling challenges in the Expansion Project.
Currently production comes from wells located on the mainland and two natural islands, namely Goose and Bear. Additional wells drilled from the mainland and natural islands will provide adequate depletion for 40% of the reservoir. To effectively develop the entire reservoir, directional wells will he drilled from six permanent artificial islands to be built in the Mackenzie River. These islands were designed using island building technology developed by Esso in its Beaufort Sea operations.
Approximately 154 wells, 123 of which are directional, are scheduled to be drilled from July 1982 to July 1985. These wells will allow a field wide waterflood pattern to be implemented increasing ultimate reserves recovery from 12% to about 40% of original oil in place.