Use of ``rock-typing`` to characterize carbonate reservoir heterogeneity. Final report
The objective of the project was to apply techniques of ``rock-typing`` and quantitative formation evaluation to borehole measurements in order to identify reservoir and non-reservoir rock-types and their properties within the ``C`` zone of the Ordovician Red River carbonates in the northeast Montana and northwest North Dakota areas of the Williston Basin. Rock-typing discriminates rock units according to their pore-size distribution. Formation evaluation estimates porosities and pore fluid saturation. Rock-types were discriminated using crossplots involving three rock-typing criteria: (1) linear relationship between bulk density and porosity, (2) linear relationship between acoustic interval transit-time and porosity, and (3) linear relationship between acoustic interval transit-time and bulk density. Each rock-type was quantitatively characterized by the slopes and intercepts established for different crossplots involving the above variables, as well as porosities and fluid saturations associated with the rock-types. All the existing production was confirmed through quantitative formation evaluation. Highly porous dolomites and anhydritic dolomites contribute most of the production, and constitute the best reservoir rock-types. The results of this study can be applied in field development and in-fill drilling. Potential targets would be areas of porosity pinchouts and those areas where highly porous zones are downdip from non-porous and tight dolomites. Such areas are abundant. In order to model reservoirs for enhanced oil recovery (EOR) operations, a more localized (e.g. field scale) study, expanded to involve other rock-typing criteria, is necessary.
- Research Organization:
- Ikwuakolam Energy Co., Denver, CO (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC22-91BC14655
- OSTI ID:
- 10143027
- Report Number(s):
- DOE/BC/14655-8; ON: DE94000118; BR: AC1510100
- Resource Relation:
- Other Information: DN: Plate accompanying this report is identified as DOE/BC/14655-8-Plate. Inquiries may be directed to: Office of Scientific and Technical Information, P. O. Box 62, Oak Ridge, TN 37831.; PBD: Mar 1994
- Country of Publication:
- United States
- Language:
- English
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