| Title | Organic petrography and scanning electron microscopy imaging of a thermal maturity series from the Montney tight-gas and hydrocarbon liquids fairway |
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| Author | Wood, J M; Sanei, H ; Ardakani, O H; Curtis, M E; Akai, T |
| Source | The Montney play of Western Canada: deposition to development; Bulletin of Canadian Petroleum Geology vol. 66, no. 2, 2018 p. 499-515 |
| Image |  |
| Year | 2018 |
| Alt Series | Natural Resources Canada, Contribution Series 20180003 |
| Publisher | Canadian Society of Petroleum Geologists |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Province | Alberta; British Columbia |
| NTS | 83M/03; 83M/04; 83M/05; 83M/06; 83M/11; 83M/12; 83M/13; 83M/14; 93P/01; 93P/02; 93P/07; 93P/08; 93P/09; 93P/10; 93P/15; 93P/16 |
| Lat/Long WENS | -121.0000 -119.0000 56.0000 55.0000 |
| Subjects | fossil fuels; petroleum resources; hydrocarbons; gas; oil; bitumen; asphalt; paraffin content; heavy oil; hydrocarbons, light; condensate; thermal maturation; thermal history; petrographic analyses;
scanning electron microscope analyses; drill core analyses; hydrocarbon migration; source rocks; bedrock geology; lithology; sedimentary rocks; siltstones; pressure-temperature conditions; organic residues; porosity; pore structure; wells; Montney
Formation; Western Canada Sedimentary Basin; Phanerozoic; Mesozoic; Triassic |
| Illustrations | location maps; geoscientific sketch maps; tables; photomicrographs; flow diagrams |
| Program | Geoscience for New Energy Supply (GNES) Shale Reservoir Characterization |
| Released | 2018 06 01 |
| Abstract | Organic petrography and field emission scanning electron microscopy (FESEM) images of drill-core samples from five wells comprising a thermal maturity series through the Montney Formation are used to
document and interpret the thermal evolution of migrated secondary organic matter (bitumen and oil) from the late oil window into the dry gas window. The present-day organic matter (OM) consists almost entirely of pore-filling secondary OM that
migrated into the organic-lean siltstones of the Montney Formation as liquid hydrocarbons. With increasing burial depth and changing temperature, pressure and compositional conditions, the originally introduced oil became unstable and dissociated
into different fractions. These dissociated hydrocarbon fractions underwent secondary cracking resulting in a range of solid and fluid hydrocarbon products including: natural gas, condensate, light oil, fluid-like hydrocarbon residue (FHR) and solid
bitumen and pyrobitumen. The solid to semi-solid secondary OM products have distinct characteristics in each of the late oil, wet gas and dry gas windows. The wide range of OM textures observed undoubtedly reflect a complex interplay of many organic
maturation mechanisms: however, petrographic observations in this study suggest important distinctions in how the different dissociated fractions of the original oil matured. The dissociated asphalt-rich fraction, which precipitated as globular or
granular aggregates in the central portions of large open pores, matured and consolidated into solid bitumen (oil and wet gas windows) and pyrobitumen (dry gas window). Solid bitumen/pyrobitumen accumulations have different degrees of organic
porosity that partially reflect the variable composition of the precursor asphalt fraction. The early paraffin-rich heavy oil fraction matured into paraffin wax (late oil window), FHR (wet gas window) and carbon residue (dry gas window) that coats
grain surfaces and fills the finer interstices of the original pore network. Differences in OM maturity operated at the micrometer scale such that, in the dry gas window, non-porous pyrobitumen in large pores is commonly observed next to highly
porous pyrobitumen associated with clays in smaller pores. |
| Summary | (Plain Language Summary, not published)
Organic petrography and field emission scanning electron microscopy (FESEM) images of drill-core samples from five wells of the Montney Formation are
used to document and interpret the thermal evolution of migrated secondary organic matter (bitumen and oil) from the late oil window into the dry gas window. |
| GEOSCAN ID | 308114 |
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