| Title | Overpressure detection from geophysical, drilling and well testing data for petroleum exploration wells in the Beaufort-Mackenzie Basin, Yukon and Northwest Territories |
| Download | Downloads |
| |
| Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
| Author | Hu, K ; Issler, D
R; Chen, Z |
| Source | Geological Survey of Canada, Open File 6692, 2021, 37 pages, https://doi.org/10.4095/327948  Open Access |
| Image |  |
| Year | 2021 |
| Publisher | Natural Resources Canada |
| Document | open file |
| Lang. | English |
| Media | on-line; digital |
| File format | readme
|
| File format | pdf; rtf |
| Province | Northern offshore region; Northwest Territories; Yukon |
| NTS | 107; 117A; 117C; 117D |
| Area | Beaufort Sea; Mackenzie Bay; Mackenzie Delta; Richards Island; Tuktoyaktuk Peninsula; Anderson Plain |
| Lat/Long WENS | -142.0000 -128.0000 71.5000 68.0000 |
| Subjects | fossil fuels; geophysics; sedimentology; Science and Technology; Nature and Environment; petroleum exploration; exploration wells; oil wells; gas wells; geophysical surveys; seismic surveys; geophysical
logging; density logging; resistivity logging; drilling; boreholes; drilling mud analyses; formation pressures; geothermal temperatures; geothermal gradient; pore pressures; wireline logs; seismic velocities; porosity; rock stress analyses;
sedimentary basins; offshore areas; deltas; continental margins; continental shelf; deep sea drilling; bedrock geology; lithology; sedimentary rocks; shales; sandstones; Pleistocene; Neogene; Pliocene; Paleogene; Beaufort-Mackenzie Basin; Iperk
Sequence; Akpak Sequence; Mackenzie Bay Sequence; Kugmallit Sequence; Richards Sequence; Taglu Sequence; Aklak Sequence; Reindeer Formation; Methodology; Databases; Phanerozoic; Cenozoic; Quaternary; Tertiary |
| Illustrations | location maps; geoscientific sketch maps; stratigraphic charts; plots; tables; profiles; well logs |
| Program | GEM2: Geo-mapping for Energy and Minerals Western Arctic Project Management |
| Program | GEM: Geo-mapping for Energy and Minerals Mackenzie Delta and Corridor |
| Program | Geoscience for New Energy Supply (GNES) Frontier basin analysis |
| Program | Secure Canadian Energy Supply |
| Program | Northern Resources Development Program |
| Program | Program of Energy Research and Development (PERD) |
| Released | 2021 02 17 |
| Abstract | A comprehensive database consisting of geophysical data, drilling mud weights, and subsurface temperature, and formation pressure measurements was compiled and utilized to detect the depth to top of
overpressure for the petroleum exploration wells in the Beaufort-Mackenzie Basin. One hundred and fifty-two depths to the top of overpressure were determined for 112 wells by using geophysical methods, supplemented with drilling and geothermal data.
The majority of overpressure picks were confirmed using measured pore fluid pressure data. An additional 36 wells are believed to be too shallow to have penetrated an underlying overpressured zone. Composite plots for each well are presented
graphically with wireline logs, well seismic velocities, mud weights, and borehole temperatures to illustrate the geophysical, drilling and geothermal responses and their correlations with well testing data, thus providing multi-parameter evidence
for an integrated interpretation of overpressure distribution.
Overpressure interpretations were ranked based on the availability and quality of the various types of data, as well as the reliability of the different methods used. Among the
geophysical data that are good indicators of overpressure occurrences, shale sonic transit-time (and transformed porosity) and continuous sonic velocity are preferred because of the abundance of these data and the sensitivity of rock acoustic
properties to porosity and stress. Mud weights provide an upper estimate of in situ pore pressure because of the need to approximately balance formation pressures during drilling; interpretations based on mud weights are mostly consistent with the
results from geophysical data and measured fluid pressures from well tests. 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. Overpressure occurs predominantly within the Paleogene Aklak, Taglu, Richards, and Kugmallit sequences, but can reach the base of the Plio-Pleistocene Iperk Sequence in wells on the outer shelf in the deep-water region of the
Beaufort Sea. Our refined interpretations of overpressure occurrence in exploration wells provide key control points for more detailed mapping and modelling of overpressures in the basin. |
| Summary | (Plain Language Summary, not published)
This study presents detailed exploration well data, techniques and interpretations of overpressure detection for the Beaufort-Mackenzie Basin.
Geophysical, engineering and drilling data were utilized to detect the depth to top of overpressure for the petroleum exploration wells. One hundred and fifty-two depths to the top of overpressure were determined for 112 wells, and the reliability of
each pick was ranked according to a quality assessment scheme. 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. Overpressure occurs predominantly within the Paleogene Aklak, Taglu, Richards, and Kugmallit sequences, but can reach the base of the Plio-Pleistocene Iperk Sequence in wells on the outer shelf in the deep-water region of the Beaufort
Sea. |
| GEOSCAN ID | 327948 |
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