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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 53 (1969)

Issue: 10. (October)

First Page: 2210

Last Page: 2210

Title: Middle Devonian Reef Production, Rainbow Area, Alberta: ABSTRACT

Author(s): Michael E. Hriskevich, John C. Rudolph

Article Type: Meeting abstract

Abstract:

The March 1965 discovery of oil by Banff Oil Ltd. in a Middle Devonian reef in the Rainbow area of northwestern Alberta, sparked a period of intensive exploratory effort which resulted in finding an estimated 1.5 billion bbl of oil and 1 Tcf of gas.(FOOTNOTE 1) The productive trend now referred to as the Rainbow-Zama trend, extends for 110 mi generally north-south and is 20 mi wide at its widest part. Additional discoveries have been made in the Slave Point Formation, Sulphur Point Formation, and Zama Member, all of which overlie the main producing formation--the Rainbow Member reef of the Keg River Formation.

Several unique events have occurred in the relatively short exploration and production history of the Rainbow part of the productive trend. The adaptation of common-depth-point seismic technique to the problem of finding carbonate reefs in an evaporite sequence represented a substantial advance in utilizing the seismic approach in exploration. The feasibility of carrying out overall operations (seismic and drilling) on a year-round basis in the muskeg environment of northwestern Alberta was illustrated.

In the field of reservoir engineering, detailed stratigraphic studies of reef cores were utilized extensively in providing the base for evaluation of secondary recovery schemes using one-, two-, and three-dimensional mathematical models which were constructed to simulate the productive formation and movement of contained fluids. Recovery factors of up to 88% have been accepted by the local regulatory body--the Alberta Oil and Gas Conservation Board. A program of sequential depletion of several separate pools, which have been approved, provides the most economic method of production and conservation.

Several important factors contributed to the drilling of the discovery well at Rainbow. The seismic data on which the location was based were obtained during 1953 to 1955, before the use of common-depth-point techniques in northern Alberta. Seismic interpretation was made difficult by the presence of a severe multiple problem. The selection of the location involved very close coordination between geologist and geophysicist. The availability of high risk capital for an area considered to have essentially sour gas prospects made it possible for the well to be drilled.

Subsequent developments in the field of reservoir engineering also gave rise to close coordination between geologists, reservoir engineer, and the electronic computer.

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Copyright 1997 American Association of Petroleum Geologists