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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 66 (1982)

Issue: 5. (May)

First Page: 633

Last Page: 633

Title: Detection and Characterization of Reservoir Rock, Deep Basin Gas Area, Western Canada: ABSTRACT

Author(s): R. M. Sneider, H. R. King, H. E. Hawkes, T. B. Davis

Article Type: Meeting abstract

Abstract:

Major gas reserves have been discovered in the past 6 years in Cretaceous sandstones and conglomerates at depths of 3,000 to 10,000 ft (915 to 3,045 m) within Alberta and British Columbia, Canada. Discovery of these new reserves resulted from a joint geologic and petroleum engineering effort which used rock-fluid data from cuttings, cores, well logs, and drill-stem and production tests. A key element in the exploration search is the rapid detection and characterization of reservoir-rock properties from well cuttings, especially of the low-permeability rocks.

Rock studies of over 10,000 ft (3,045 m) of conventional cores integrated with petrophysical studies of well logs and core analyses, which were compared with drill-stem and production tests in over 200 wells, provide the basis for establishing reservoir-rock potential. Porous rocks are subdivided into three categories: type I, capable of gas production without natural and/or artificial fracturing (subdivided on basis of air permeability), type II, capable of gas production when interbedded with type I rocks or with natural and/or artificial fracturing, and type III, too tight to produce at commercial rates even with natural or artificial fracturing.

Criteria to identify a rock's reservoir potential from well cuttings or conventional and sidewall cores are based on examination of dry, freshly broken fragments with a binocular microscope. Estimates of the following parameters form the basis of establishing a rock's reservoir potential: (1) size, (2) volume and distribution of visible pores, (3) particle size and distribution, (4) type and amount of cements and pore-filling material, and (5) degree of consolidation. Geologists and engineers can make rapid, accurate estimates of reservoir-rock potential of unknown porous intervals with the help of several visual aids. These include plastic trays of cuttings-size rock chips crushed from conventional cores of known rock and pore types, porosity, and permeability; colored photographs of freshly broken rock surfaces; and thin-section microphotographs and scanning electron photomicrographs of rock chips and their pore casts.

The methods and procedures described continue to be used in Western Canada and the United States for delineation of exploration opportunities, identification of bypassed pays in old wells, for well-log interpretation, and in evaluating intervals for completion.

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Copyright 1997 American Association of Petroleum Geologists