The Devonian of western Canada -- aspects of a petroleum system: Introduction

Weissenberger, John A.W.

doi:10.2113/gscpgbull.49.1.1

Cited by 18 publications

(5 citation statements)

References 2 publications

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“…The Upper Devonian (Frasnian) Duvernay Formation (Woodbend Group) is composed of multicyclic units of black organic‐rich shale and bituminous carbonates [ Weissenberger and Potma , ], ranging between 25 and 60 m in thickness [ Davis and Karlen , ] and extends throughout most of central Alberta. The Duvernay Formation overlies the Cooking Lake Formation platform in the East Shale Basin, west of the Leduc Rimbey Meadowbrook reefal trend, and the Majeau Lake Formation in western central Alberta [ Stoakes , ].…”

Section: The Duvernay Formationmentioning

confidence: 99%

A seismological overview of the induced earthquakes in the Duvernay play near Fox Creek, Alberta

Schultz¹,

et al. 2017

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This paper summarizes the current state of understanding regarding the induced seismicity in connection with hydraulic fracturing operations targeting the Duvernay Formation in central Alberta, near the town of Fox Creek. We demonstrate that earthquakes in this region cluster into distinct sequences in time, space, and focal mechanism using (i) cross‐correlation detection methods to delineate transient temporal relationships, (ii) double‐difference relocations to confirm spatial clustering, and (iii) moment tensor solutions to assess fault motion consistency. The spatiotemporal clustering of the earthquake sequences is strongly related to the nearby hydraulic fracturing operations. In addition, we identify a preference for strike‐slip motions on subvertical faults with an approximate 45° P axis orientation, consistent with expectation from the ambient stress field. The hypocentral geometries for two of the largest‐magnitude (M ~4) sequences that are robustly constrained by local array data provide compelling evidence for planar features starting at Duvernay Formation depths and extending into the shallow Precambrian basement. We interpret these lineaments as subvertical faults orientated approximately north‐south, consistent with the regional moment tensor solutions. Finally, we conclude that the sequences were triggered by pore pressure increases in response to hydraulic fracturing stimulations along previously existing faults.

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Section: The Duvernay Formationmentioning

confidence: 99%

A seismological overview of the induced earthquakes in the Duvernay play near Fox Creek, Alberta

Schultz¹,

et al. 2017

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“…Hydraulic fracturing in this region is focused on the Late Devonian Duvernay Formation (Fig. 2), which is composed of multicyclic units of organic-rich shales and fine-grained carbonates ( 30 ). Precambrian basement is inferred to be located ~400 m below the reservoir ( 27 ), while immediately above the Duvernay is the Ireton Formation, which is primarily composed of clays alternated with fine-grained carbonates ( 31 ).…”

Section: Introductionmentioning

confidence: 99%

The role of aseismic slip in hydraulic fracturing–induced seismicity

et al. 2019

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Models for hydraulic fracturing–induced earthquakes in shales typically ascribe fault activation to elevated pore pressure or increased shear stress; however, these mechanisms are incompatible with experiments and rate-state frictional models, which predict stable sliding (aseismic slip) on faults that penetrate rocks with high clay or total organic carbon. Recent studies further indicate that the earthquakes tend to nucleate over relatively short injection time scales and sufficiently far from the injection zone that triggering by either poroelastic stress changes or pore pressure diffusion is unlikely. Here, we invoke an alternative model based on recent laboratory and in situ experiments, wherein distal, unstable regions of a fault are progressively loaded by aseismic slip on proximal, stable regions stimulated by hydraulic fracturing. This model predicts that dynamic rupture initiates when the creep front impinges on a fault region where rock composition favors dynamic and slip rate weakening behavior.

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“…During the Late Devonian, the WCSB is thought to have been located just south of the paleoequator in a zone of high aridity and predominantly east-northeasterly winds ( Figure 2) (Witzke and Heckel, 1988;Wendte, 1992a;Potma et al, 2001). The middle Frasnian paleogeography of the Alberta part of the WCSB consists of both large-and small-scale rimmed shelf complexes (e.g., Wimborne-Bashaw, Fairholme, and Grosmont) and isolated shelves (e.g., Golden Spike and Leduc) and adjacent deeper water basinal areas enriched in shale ( Figure 2) (Potma et al, 2001;Weissenberger and Potma, 2001). Innisfail field is located in south-central Alberta and is developed on a northerly trending Leduc Formation promontory that extends from the western side of the Wimborne-Bashaw shelf complex ( Figure 2).…”

Section: Geologic Settingmentioning

confidence: 99%