| Title | Overpressure detection in the Beaufort-Mackenzie Basin, northern Canada, using an integrated approach |
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| Author | Hu, K ; Issler, D
R; Chen, Z; Dietrich, J R; Dixon, J |
| Source | 2022, 1 sheet |
| Image |  |
| Year | 2022 |
| Alt Series | Natural Resources Canada, Contribution Series 20220002 |
| Meeting | GeoConvention; Calgary; CA; June 20-22, 2022 |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Province | Northwest Territories; Yukon |
| Area | Beaufort Sea; Mackenzie Bay; Canada |
| Lat/Long WENS | -142.0000 -128.0000 71.5000 68.0000 |
| Subjects | tectonics; Science and Technology; Beaufort-Mackenzie Basin; Cenozoic; Cretaceous |
| Illustrations | location maps; cross-sections; cross-plots; diagrams |
| Program | GEM: Geo-mapping for Energy and Minerals Mackenzie Delta and Corridor |
| Released | 2022 06 20 |
| Abstract | (Summary)
The Beaufort-Mackenzie Basin (BMB) is a late Cretaceous-Cenozoic post-rift basin that is composed of a series of normally pressured and overpressured, folded and faulted deltaic
complexes. It extends northward from the onshore Mackenzie Delta to the outer shelf and slope beneath the Beaufort Sea in Arctic Canada. Overpressure is associated with rapid sediment accumulation, undercompacted shale, shale diapirism, and major
fault systems (Hitchon et al., 1990; Issler, 1992; Issler et al., 2002; Chen et al., 2010). More than 280 wells have been drilled in the basin (Fig. 1) and studies by the GSC demonstrate the strong association between overpressure and shale porosity
trends within Cenozoic strata (Fig. 2) that are detectable using multiple well logs (Issler, 1992; Katsube and Issler, 1993; Issler and Katsube, 1994; Katsube et al., 1995, 1996, 2011; Issler et al., (2002). Previously, Issler et al. (2011) mapped
the distribution of overpressure at well locations using fluid pressure and shale log data. This study focuses on overpressure detection in the Beaufort-Mackenzie Basin by employing an integrated approach that combines geophysical, drilling, and well
testing data from petroleum exploration wells. It not only presents detailed documentation of the large comprehensive datasets and refined interpretations for the top of the overpressure zone in exploration wells (Hu et al., 2021), but it also
presents stratigraphic frameworks to illustrate the distributions of the detected overpressure along schematic stratigraphic cross sections throughout the basin. One hundred and fifty-two depths to the top of overpressure were determined for 112
wells based on the integrated analysis of the proposed multiparameter data (well logs, well seismic interval velocity, mud weight, and pressure test), most of which were confirmed by formation pressure tests, and the overpressure interpretations were
ranked according to a quality assessment scheme. Overall, well logs and log-derived formation properties in shale sections are good indicators of overpressure. However, the most reliable and consistent geophysical parameters for detecting
overpressure are shale sonic transit-time (and its porosity) and continuous sonic velocity because of the abundance of these data and the sensitivity of rock acoustic properties to porosity and stress. In general, mud pressure trends calculated from
drilling mud weight data are mostly consistent with overpressure interpretations from geophysical data and fluid pressure measurements. The interpreted depth to the top of overpressure varies from <1000 to over 4500 m (GL/SL) and is largely confined
to undercompacted sediments in the central-northern delta and offshore areas. The top of overpressure is predominantly restricted to the Paleocene-Eocene Aklak, Taglu and Richards sequences on Richards Island, and occurs in progressively younger
strata northward in the offshore toward the outer shelf. In the central shelf region, the top of overpressure is mainly within the Richards and Kugmallit sequences, while it rises above the base of the thick Pliocene-Pleistocene Iperk Sequence in the
outer shelf. |
| Summary | (Plain Language Summary, not published)
This study focuses on overpressure detection in the Beaufort-Mackenzie Basin by employing an integrated approach that combines geophysical, drilling, and
well testing data from petroleum exploration wells. It not only presents detailed documentation of the large comprehensive datasets and refined interpretations for the top of the overpressure zone in exploration wells, but it also presents
stratigraphic frameworks to illustrate the distributions of the detected overpressure along schematic stratigraphic cross sections throughout the basin. |
| GEOSCAN ID | 329897 |
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