This Well of the Week continues our series on the Resource Plays (basin-wide plays where hydrocarbons are the continuous phase) that have led the Canadian oil and gas industry. For the tenth WotW we traverse from the vicinity of the BC/NWT boundary and headway, way to the southeast to Viewfield Saskatchewan. Viewfield is the site of the first significant Canadian application of multi-stage fracturing in horizontal oil wells. Links to the previous posts are provided at the bottom of this article.
Resource Play: Bakken
Type Well: 191/01-23-008-09W2/00
Drilling/Completion Technology: Rotary/Horizontal/Multi-stage Hydraulically Fractured
Regional Geology
There has been Bakken oil production in Saskatchewan since 1956 but these pools were limited to salt solution and other structural features (Kohlruss, 2014) and weren’t at the forefront of industry activity. That all changes with the revolution in drilling and completion techniques at the beginning of the 21st century and the revitalization of the Bakken play in North Dakota.
Like a number of the other plays we have looked at (i. e.: Second White Specks, Canol, Cardium, CBM and Horn River), the North Dakota Bakken play is closely associated with the offsetting source rock (the Montney is a creature onto itself in this respect and is worth a separate article).
ND to SK Bakken Stratigraphic Cross Section, Cronkwright (2017)
The Viewfield Bakken is a different matter. The Bakken shales, while still kerogen rich, are immature north of the Can/USA border and did not significantly contribute to the resource endowment. With the McMurray oil sands (highlighted in the Bitumount post) the Saskatchewan Bakken is an accumulation of oil that migrated thousands of kilometres to their current location. There are some important differences from the other oil plays in this series although the general stratigraphic pattern from North Dakota to Saskatchewan is similar. These differences include the reservoir being normally pressured and at or above irreducible water saturation. Understanding reservoir variations and innovative ways to visualize these factors become even more important.
N-S Viewfield Stratigraphic Cross Section, Cronkwright (2017)
We are fortunate to be able to draw on the work of Enlighten geologist David Cronkwright in understanding these nuances. The N-S oriented stratigraphic cross-section A – A’ illustrates the stratigraphic changes across the pool. The Production, Water Cut and Phi*h maps, along with the Isopach Block diagram help explain the production variability across the pool and reinforce that the play is not the same everywhere you drill.
Facies Production and Phi*h maps, Cronkwright (2017)
If you need even more evidence of the importance of understanding the geology to economic success, the detailed cross-section illustrating the effect of cross a fault should make the point. Saskatchewan geology has flat layer cake geology indeed.
Variation in Water Cut with Production, Cronkwright (2017)
Block Diagram illustrating Isopach changes, Cronkwright (2017)
A few aspects stand out as we peruse this week’s discovery timeline. These include the continued predominance of resource plays and that the timeline is almost up to date with only room for one more play summary. This last play will be the subject of next week’s Well(s) of the Week and the series wrap-up.
Resource Play timeline up to the Bakken
References
Cronkwright, D. (2017). Integrating Sedimentology, Sequence Stratigraphy and Mineralogy to Evaluate Controls on Hydrocarbon Accumulation and Production in the Bakken Formation of Southeast Saskatchewan (Masters thesis, University of Calgary).
Kohlruss, D., 2014. Prospect Saskatchewan, The Hummingbird Bakken Pool. A Model for Salt Solution Induced Multi-zone Oil traps. Government of Saskatchewan. https://publications.saskatchewan.ca/api/v1/products/9962/formats/90083/download Accessed 10/13/2021.
Previous Posts
August 12, 2021 Well of the Week – The first gas well in Western Canada
August 19, 2021 Well of the Week – first oil well in Western Canada
August 26, 2021 Well of the Week – second oil discovery – second oil resource play
September 2. 2021 Well of the Week – Bitumount: The start of something big
September 9, 2021 Well of the Week – The first resource play with legs
September 16, 2021 Well of the Week – The Deep Basin era begins
September 23, 2021 Well of the Week – The beginning of Montney mania
September 30 – Well of the Week – And now for something completely different
October 7, 2021 – Well of the Week – Another resource play horns in