This is the 11th and penultimate post in our series detailing how resource plays (basin-wide plays where hydrocarbons are the continuous phase) have often driven the Canadian oil and gas industry throughout its history. Links to the previous posts are provided at the bottom of this article.
Resource Play: East and West Shale Basin Duvernay
Type Wells: See discussion below.
Drilling/Completion Technology: rotary/horizontal/multi-stage hydraulically fractured
Before diving into a look at the Duvernay, it is worth noting that some resource plays we previously looked at were significant contributors to industry activity before horizontal wells completed with multi-stage hydraulic fracturing revitalized these plays (e. g.: Cardium and Montney). The Horn River, in contrast, was developed horizontally from the outset. The Duvernay was a bit more like the Bakken in that there were some halting attempts to kick start the play with vertical wells. And then there were some initial horizontal wells which led the way to much more impressive results.
The previous posts were chock full of beautiful maps. These may not have been overly appealing to any engineers reading so, in a nod to their sensibilities, this week the story is being told with the assistance of equally interesting graphs.
Identifying the wells that kicked off the Duvernay play is an interesting challenge. The Duvernay is at least two different plays, the West Shale Basin Duvernay (WSBD) is dominated by liquids rich gas targets while the East Shale Basin Duvernay (ESBD) is almost exclusively an oil mature region. As a “Splitter”, I can see there being 3 distinct sub-basins/plays in the ESBD. The stratigraphy, sedimentology and reservoir phase of each is somewhat different.
Production forecast for 100/07-33-068-21W5/00 – courtesy of Subsurface Dynamics
And should the Type Well for each basin be designated based on the vertical wells that provided initial evidence of the productive potential of this prolific source rock for the WSBD and ESBD (100/07-33-068-21W5/00 and 102/10-18-031-25W4/00 respectively)?
Or should it be based on the first horizontal wells that hinted that this technological advance could make these plays viable? (i. e.: 100/01-20-038-28W4/00 for the ESBD and 102/13-20-060-17W5/02 for the WSBD). Even if these wells were not exactly blockbusters?
Production forecast for 100/10-18-031-25W4/00 – courtesy of Subsurface Dynamics
Map created with data from Petro Ninja and Switzer et al., 1994. Or perhaps we should focus on the wells that indicate the improvements possible by tweaking the well design. with the best cumulative oil or gas production in (i. e.: 100/14-12-065-19W5/00 – best overall cumulative oil production, 102/14-06-032-24W4/00 – best ESBD cumulative oil production and 100/13-30-056-18W5/00 best overall gas production).
To those who have stuck through this and the preceding missives. Thank you for your continued interest. As this week’s timeline illustrates, we have reached the end of the timeline of significant discoveries in the WCSB. Next week – an attempt to put this history into a cohesive context.
Discovery timeline up to the Duvernay
References Switzer, S. B., Holland, W. G., Christie, D. S., Graf, G. C., Hedinger, A. S., McAuley, R. J., Wierzbicki, R. A. and Packard, J. J. (1994): Devonian Woodbend-Winterburn Strata of the Western Canada Sedimentary Basin; in Geological Atlas of the Western Canada Sedimentary Basin, G.D. Mossop and I. Shetsen (comp.), Canadian Society of Petroleum Geologists and Alberta Research Council, URL https://ags.aer.ca/publications/chapter-12-devonian-woodbend-winterburn-strata.html, [04/26/2020].