Mackenzie Valley

Regional Geological & Geophysical Assessment Central Mackenzie Valley, NWT & Eagle Plain, YT

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Summary:
Location: 65 – 68 N and 139.5 – 125 W
Strata: Proterozoic – Tertiary
Year of Study: 2002

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Introduction

Historic exploration focus within the Mackenzie Valley north of latitude 64° was directed to the search for oil. The original discovery and development of the Norman Wells oil field was triggered in response to the needs of the allies in World War II. Later oil exploration was initiated, in large measure, as a reaction to the discovery of huge reserves in Alaska in the 1960’s. The resulting successes were modest; gas was found in the Colville Hills (but was uneconomic to produce) and modest amounts of oil and gas (also uneconomic) were discovered beneath the Eagle Plain.

The economics of gas production, having improved dramatically in the early part of the 21st Century, has created significant interest in bringing the large volumes of gas found below the Mackenzie Delta and southern Beaufort Sea (about 9 tcf, to date) to southern markets. South of Norman Wells, large gas reserves have recently been discovered, and brought on production, at Liard. Thus, the gas at Liard, beneath the Colville Hills, in the Mackenzie Delta, and below the Eagle Plains bracket the Mackenzie Valley between Latitudes 65° and 70° which is the area covered by the following evaluation (Figure 1.1).

Within the study area, the following data sets have been employed:

• 12000 kilometres of digitally scanned, two-dimensional seismic data;
• The logs, cores and test from 613 wells. This data set includes 4,731 metres of core and 685 tests;
• Publicly available data on measured outcrop sections, organic geochemistry, and petrographic samples.

From these data sets, PRCL has set out to answer the following questions:

1. What is the distribution and form of economically important strata?
2. What is the nature of the present structural configuration and what was the tectonic evolution of the region?
3. What were the depositional processes, paleoenvironments, and paleogeographic settings of key units?
4. What is the nature of preserved porosity and permeability and how did they form?
5. What is the nature and distribution of pressured fluids in the subsurface and how do these fluids relate to the locations of existing hydrocarbon accumulations?
6. Are there wells with bypassed hydrocarbons?
7. Based on an integration of the technical data, are there new play concepts that can be pursued that may result in the discovery of large additional producible resources? The following discussion attempts to answer these questions with reference to four successions deemed to be of the greatest economic interest: the Cambrian, Paleozoic Carbonates, Permo-Carboniferous, and Cretaceous.