The Upper Devonian Big Valley Formation has been touted as a potential unconventional light oil play in southern Alberta. This occurred as the result of several investment houses (ie: Zaitlin et al. 2011; Bryden 2011) applying the informal term " Alberta Bakken" to the Bakken age equivalent Exshaw Shale. The use of the " Alberta Bakken" term suggests prolific production of liquid hydrocarbons from an unconventional reservoir analogous to the Bakken Shale of the Williston Basin. However, this is not the case in southern Alberta where production of liquid hydrocarbons is mainly generated from carbonates of the underlying Big Valley Formation. The Big Valley Formation is in part equivalent to the prolific oil producing interval in the Three Forks Group of the Williston Basin (Figure 1). Currently, the Three Forks has an estimated 2 Bbbl of recoverable oil (Sonnenberg et al, 2011).
The study area encompasses Township 4 to Township 11, from Range 22 to Range 26 west of the Fourth Meridian inclusive (Figure 2). Data for this study is based on 21 cores and 84 geophysical logs that penetrate through the Big Valley Formation. Cores along with wireline logs were used to interpret stratigraphic and depositional trends of the Big Valley Formation presented herein.
The Big Valley Formation is an emerging light oil play in southern Alberta which currently produces at depths greater than 2000 m in the study area. At present, the most prolific vertical producer has yielded 250, 0000 barrels of oil. This highly productive vertical well exhibits anomalously thick Exshaw (~17 m) and Big Valley formations (~25 m), which contrasts with regional thickness trends of 7 and 10 m respectively (Figure 3,4). The Big Valley Formation in southern Alberta is in the early stages of exploration with further development of the play dependent on accurately predicting stratigraphic thickness trends as well as sedimentological and diagenetic controls on the hydrocarbon rich facies.