Abstract

Esso Resources Canada Limited has embarked on a project to increase production from its Norman Wells Oilfield located 145 km south of the Arctic Circle, from 475 m3/D to 4000 m3/D of crude oil. This paper provides details on the development drilling portion of the project which is comprised of 150 wells to be drilled in 3 years utilizing 2 drilling rigs from July 1982 through September 1985. The majority of the wells will be directionally drilled from multiwell land pads and artificial islands to shallow reservoir targets underlying the Mackenzie River, a major river intersecting the field boundaries. Experience from the initial 27 wells completed is provided.

Introduction

Esso Resources Canada Ltd. undertook an evaluation of the feasibility of expanding the existing oilfield at Norman Wells, Northwest Territories (Figure 1) in the late 1970's. The current plans are to increase production from the oilfield by implementing a field wide waterflood scheme and developing the reservoir which lies partially under the Mackenzie River. The expansion program is expected to increase recoverable reserves from 17 to 43 percent of the 100 M m3 of oil in place. The expansion will develop the oilfield to a production rate of 4000 m3/D of crude oil from the current level of about 475 m3/D.

Aside from the logistical challenges that are presented by its geographical location near the Canadian Arctic, the presence of the major portion of the oilfield under the Mackenzie River, which at Norman Wells is five kilometers wide, presents unique challenges. Forty percent of the oil reserves are accessible from natural land features that overlay the reservoir, namely Goose Island, Bear Island and part of the mainland north shore of the Mackenzie River.

Scheduled project activity which commenced July of 1982, includes: construction of 6 artificial islands in the Mackenzie River and numerous land-based drilling and production pads; drilling and completion of 150 new wells, the majority of which are directional; construction and installation of a two-phase gathering system and gas lift and waterflood distribution system; construction and installation of a central processing facility on the mainland; and finally, the laying of a 305 mm, 866 km long buried crude oil and natural gas liquids pipeline from Norman Wells to connect with an existing pipeline at Zama, Alberta. Surface project field facilities are shown by Figure 2.

History

Located 145 km south of the Arctic Circle, the Norman Wells Oilfield has undergone numerous stages of development since discovery in 1920. Initially a source of fuel for river communities, refinery capacity from five wells grew to 133 m3/D in 1939 to support the demand of gold mining operations in the Northwest Territories. Triggered by United States involvement in the Second World War and the desire for a close source of oil to support her expanding military presence in Alaska, the period between 1942 and 1944 saw drilling activity increasing the number of wells to 62 and the laying of a 102 mm, 560 km long pipeline linking Norman Wells crude to a new refinery in Whitehorse, Yukon. Operating problems of the hastily constructed pipeline and refinery, coupled with reduced product demand in the Western Arctic coincident with peace time, resulted in closure of both facilities. Production operations at Norman Wells continued however, with refinery expansion in 1969 to present day capacity of 500 m3/D to meet regional market requirements.

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