The Lower Cretaceous McMurray Formation in western Canada has over 1.8 trillion barrels of bitumen resource in place. Due to the bitumen in its natural state having a very low API (6-12°) and corresponding high viscosity, traditional primary (pump jacks) and secondary (water flood) recovery techniques cannot be used. Instead, economic extraction of the bitumen occurs via surface mining and subsurface steam-assisted gravity drainage (SAGD). Using the Pike and Jackfish oil sands project areas as a case study, it will be shown that successful SAGD operations requires a thorough understanding of the depositional fabric and stratigraphic architecture of the reservoir.
Within the study area, reservoir intervals in the form of cross-bedded sandstones and sandy inclined heterolithic strata (IHS) are present within both the middle and upper McMurray. Overlying the middle McMurray are upper McMurray parasequence cycles reflective of brackish bays and deltaic embayment deposits. In many areas, however, these parasequences are absent and instead substituted by fluvial channels with brackish water overprint. The facies within these fluvial channels are very similar in character to the those seen within the middle McMurray. To help progress our understanding of baffles and barriers to flow within these aforementioned reservoir facies, dip meter and seismic data are presented as data that can be used. From this, a better understanding of the complex interplay of facies and stratigraphic relationships can be made. More importantly, clearer insights into SAGD performance (pre- and post-steam) can also be achieved.
Using the McMurray Formation as an underpinning, the wider implications of understanding fluvial sedimentation will be addressed by using reservoirs from the Middle East as examples. For example, many siliciclastic reservoirs in locations such as Kuwait (Wara Formation) and Iraq (Zubair Formation) are also influenced to a large degree by fluvial sedimentation. Not unlike SAGD, any successful secondary recovery techniques applied within these reservoirs will also require a detailed characterization of the channel stacking patterns and channel orientations prior to implementation.
Steam Assisted Gravity Drainage (SAGD) producer wells in the McMurray formation require sand control technologies that will limit sand production while minimizing production constraints caused by high pressure drops and liner plugging. Previous publications around sand control selection and sizing for SAGD producers have provided varied and often conflicting design recommendations based on the expected formation sand particle size distribution. Small scale lab testing of sand control medium is often challenged with inconsistent results and uncertainty around the appropriate normalization for test comparison and scaling up to real-world applications. Devon Canada designed and constructed an in-house large scale liner testing apparatus to evaluate sand control technologies and determine the optimal aperture or filter size for sand types expected in the McMurray formation of the future Pike 1 SAGD project. The large scale liner testing results are presented in this paper along with the final recommendation for sand control on Pike SAGD producer wells. A brief review of the Pike McMurray sand typing and small scale liner testing is also presented.
Minimizing and mitigating the environmental impacts of our developments and operations is a very important business driver for Devon Canada Corporation (Devon). Devon takes this responsibility seriously, and believes in maintaining social license to operate, respecting stakeholder interests, and not just meeting, but exceeding, regulatory requirements where it makes sense to do so. Our commitment to the environment is reflected in our corporate policies, which include a Biodiversity and Land Stewardship Policy that provides overarching top-level direction to wildlife, biodiversity and land issues. Wildlife and biodiversity are among the most tangible concerns for stakeholders in Alberta's oil sands region. In 2002, very little was known about wildlife responses to in situ oil sands development. Acknowledging this information deficiency, and recognizing that in situ oil sands development was a long term and incremental commitment, Devon initiated what would become an ongoing In Situ Wildlife Mitigation and Monitoring Program to monitor wildlife populations, conduct research to fill key data gaps, and mitigate negative impacts to wildlife and biodiversity in and around our project areas. To achieve our vision of minimizing impacts to wildlife in the oil sands region, we have made biologically sound commitments, collaborated with peers and other resource sectors, developed strategic research partnerships, and engaged employees at every level throughout the company in implementation. In its current state, the Program has now been endorsed by regulators as the best-in-industry for such initiatives, and has been recognized with numerous awards for its comprehensiveness, innovation and corporate commitment.
Matt Abram and Graham Cain, Devon Canada Summary The unconsolidated sands of the Lower Cretaceous McMurray formation are the primary host of the Athabasca oil-sands deposit in Alberta, Canada. Alberta has one of the world's largest nonconventional hydrocarbon resources with an estimated 1.8 trillion bbl of heavy oil (ERCB ST98-2013). The Pike 1 Project is a jointventure between Devon Canada Corporation (operator) and BP Canada Energy Group ULC. The Pike 1 Project is currently under a multiyear appraisal program to evaluate the McMurray bitumen resources that are amenable to steam-assisted gravity drainage (SAGD). In the Pike 1 Project area, the particle-size distribution (PSD) of the middle McMurray reservoir sands is highly variable because of the complex nature of the depositional environment. In order to understand the McMurray reservoir sands, Devon has exercised rigorous laboratory sampling and quality-control procedures to confirm the comprehensiveness of the PSD data set. By use of an unsupervised hierarchical classification technique, a dynamically growing self-organizing tree algorithm was used to cluster all of the PSD histograms from within the bitumen net-pay zone into one of four sand classes on the basis of similarity. Each sand class has a distinct PSD and permeability range. Using the sand classes, Devon extracted select intervals of core that closely matched the PSD histogram of each class to provide physical samples, termed "sandprints," to fulfill sand-control-testing objectives. Further work included integrating the sand classes within the Pike 1 geological model, 3D permeability mapping, and upscaled sand-class volumes for SAGD well-pad optimization. This paper describes the process by which Devon has evaluated and classified the Pike 1 PSD data set into distinct sand classes within the unconsolidated middle McMurray reservoir. Devon's methodology of acquiring these sands, necessary for sand-control testing, is also discussed in detail, emphasizing the overall effectiveness of the process. By use of this innovative PSD classification process as a supporting tool to reservoir characterization, Devon intends to realize the following benefits: - SAGD horizontal-well-pair placement optimization - A more methodical approach to laboratory testing of horizontal-liner technology for SAGD producers and injectors - Improved reservoir management Introduction Pike is a multistage, joint-venture project, owned 50% each by Devon Canada (operator) and BP Canada Energy Group ULC (Figure 1). The first commercial scheme applied for on the Pike lease is the Pike 1 Project, and it is currently under review by the Alberta Energy Regulator and Alberta Environment.
Li, Pingke (Sunshine Oil Sands Limited) | Stroich, Al (Grizzly Oil Sands ULC) | Vink, Andrew (Devon Canada Corporation) | Nespor, Kristian (Devon Canada Corporation) | Bhadauria, Swapnil (Devon Canada Corporation) | McCormack, Mike (Fractical Solutions)