Deep Groundwater Exploration and Characterization in Alberta, Canada

Alberta contains the bulk of the Western Canadian Sedimentary Basin, which is host to the Athabasca Oil Sands in the northeast and several tight gas targets, including the Montney and Duvernay Formations, closer to the Rocky Mountain front in the northwest. These unconventional projects have intensive water requirements. Steam Assisted Gravity Drainage is used for extracting in-situ oil sands and slick-water hydraulic fracturing for tight gas resources. Alberta’s Water Allocation and Allocation Guideline for Oilfield Injection requires operators to investigate saline water sources prior to making an application to use fresh water for an industrial project. In Alberta, saline groundwater is defined as >4000 TDS mg/L by the provincial Water Act. The base of groundwater protection (BGWP) is the depth at which groundwater exceeding 4000 TDS mg/L is encountered. Across the province, the BGWP exceeds 1000 m (3300 ft) near the Rocky Mountains to as shallow as 300 m (1000 ft) at the updip part of the basin where the oil sands occur. This regulatory framework and geologic setting requires hydrogeologists working in Alberta to be well versed in deep groundwater exploration methods. Fortunately, Alberta is data-rich in terms of data sets to use for these purposes. All oil and gas wells drilled in the province must be geophysically logged, including running a gamma ray and neutron-porosity tool to ground surface through casing. These logs, along with water chemistry and pressure data (i.e., drill stem tests), must be submitted to the Alberta Energy Regulator and made public after a confidentiality period. Various mapping software has been developed to streamline access to these datasets. We will discuss how this data is used to explore for deep groundwater, using some examples from projects that Matrix has been involved with.