We have all heard of the debate on hydraulic fracturing and the concerns about groundwater contamination. The availability to and consumption by the oil industry of water resources during the course of developing unconventional resource plays is another important issue for the industry, regulatory authorities, and the society in general. The joint industry project mentioned here starts to tackle this issue by identifying the shallow and deepwater sources in the deep basin study area.
The West-Central Alberta Water Project is a prime example of a Petroleum Technology Alliance of Canada (PTAC) project that demonstrates broad benefits by working together to identify and address current challenges related to water management. PTAC’s mission is to facilitate innovation, collaborative research and technology development, demonstration, and deployment for a responsible Canadian hydrocarbon energy industry. PTAC has facilitated the Alberta Upstream Petroleum Research Fund (AUPRF) for more than 10 years.
Soheil Asgarpour, PhD, P. Eng
The Integrated Assessment of Water Resources for Unconventional Oil and Gas Plays, West-Central Alberta Project (known as the West-Central Alberta Water Project) is cofunded by AUPRF and a partnership of 11 oil and gas companies. The project is being conducted by integrated water resources (IWR), a team of three consulting companies. The 2-year project was initiated in June 2012, and Year 1 results are now available. The project will be completed by 30 June 2014.
With the development of horizontal drilling, multistage hydraulic fracturing, and multiwell pad technologies, industry is developing unconventional oil and natural gas resources (Alberta’s Montney and Duvernay plays are two prime examples in the heart of the project area). Significant volumes of water will be required to sustain these activities. The science-based information provided by this project is required for appropriate planning and associated resource management decisions.
The project aligns with other water-related initiatives, including Alberta’s Water for Life Strategy, and the Alberta Water Council recommendations for enhancement of baseline groundwater information and enhancement of analysis, interpretation, and reporting tools. It focuses on water sources and fluid disposal that are within the broader water and fluid-management cycle for unconventional activities. In addition, the project supports the Canadian Association of Petroleum Producers’ (CAPP) guiding principles for hydraulic fracturing and the hydraulic-fracturing Operating Practice 5: Water Sourcing, Measurement, and Reuse.
The key goal of the project is to assess and integrate information on all potential water sources, including: (1) surface waters; (2) shallow aquifers in unconsolidated materials and bedrock; and, (3) deep saline aquifers. The deep aquifers are also being assessed as potential deep disposal zones for flowback and produced fluids. The project is not evaluating fluid recycling or fluid treatments.
Project Area Description. The project includes an extensive area of oil and natural gas resources and activity. It covers more than 142 000 km2 of surface terrain and 91 000 km2 of subsurface area (Fig. 1). The surface project area includes parts of the Peace/Smoky, Athabasca, North Saskatchewan, and Red Deer River watersheds.
Glacial sediments dominate the landscape, with vast expanses of morainal and glaciolacustrine material deposited in a relatively thin cover (<10 m) over the uppermost bedrock units.
Precipitation is relatively evenly distributed throughout the year, with summer temperatures cooling with increasing elevation towards the Rocky Mountains. The quantity and timing of precipitation varies substantially across the project area and plays an important role in surface water resources.
Geological Setting. The subsurface portion of the project area lies on the western flank of the Western Canadian Sedimentary Basin, where the sedimentary succession measures more than 4000 m thick. Strata are relatively undeformed, and dip uniformly southwestward toward the Rocky Mountain foothills. This setting hosts an extensive basin-centred hydrocarbon regime (the Deep Basin), containing numerous unconventional oil and gas plays in shale, tight sandstone, and tight carbonate.
The project encompasses the Montney and/or Duvernay plays (Fig. 1). However, other plays are now being accessed using horizontal, multistage hydraulic-fractured wellbores; including Swan Hills, Glauconite/Bluesky/Wilrich, Falher/Notikewin, Cardium, and other tight sandstones (e.g., the Rock Creek, basal Belly River, and Dunvegan).
|Fig. 1—The project area showing delineation of surface and subsurface
project areas in west-central Alberta.
|Fig. 2—Summary image depicting deep saline aquifer distribution across the project area.