Hydrogeological Services for Steam-Assisted Gravity Drainage (SAGD) Projects
Waterline’s Oil Sands Team is proficient in the turn-key completion of all required hydrogeological services during the baseline/EIA data collection and permitting process, as well as during the operational phases of the SAGD project(s). Waterline specializes in the following aspects of SAGD projects:
- Environmental Impact Assessments (EIAs);
- Source water development;
- Disposal capacity testing; and
- Regulatory requirements.
Environmental Impact Assessments (EIAs)
 Implementing a SAGD project requires that the local and regional hydrogeology, and linkages to related disciplines, such as surface water, be well understood. To achieve this, hydrogeology data is compiled during the baseline stage of the EIA process. Thereafter, the project is assessed in terms of its potential to impact the hydrogeologic setting, on a local and regional/cumulative basis. To be viewed as comprehensive, the impact analysis must consider linkages to related disciplines such as hydrology, groundwater – surface interaction, etc, as well as approved/existing projects in the area. Data gaps identified following the EIA submission are typically back-filled during the supplemental-information stage of the EIA application process.
Source Water Development
New SAGD Projects
SAGD projects cannot be implemented without a secure water source that meets the quality and quantity requirements of all project phases. Source water can be developed from surface water as obtained from a lake or river, or from groundwater using water wells. In terms of surface water, supplies are commonly obtained using a direct intake, or indirectly using an infiltration gallery completed adjacent to or under the surface water body. In terms of groundwater, water wells are constructed using engineered stainless steel wells screens or perforated intervals, and can include either soil or bedrock well completions. Respecting groundwater supplies, industry-standard testing methods are used to establish the long-term deliverability of the wells. Groundwater monitoring programs are implemented to prevent overexploitation of the resource and to minimize the potential for impact to existing users, as specified under the operating approval/permit for the project. Routine well maintenance programs are implemented to ensure uninterrupted source water delivery. Additional source water wells are added, as required, to ensure a redundant back-up water supply for the life of the project.
Existing SAGD Projects
To ensure an uninterrupted supply of source water, SAGD projects require that routine well maintenance is established and implemented. Redundancy of supply/delivery must also be maintained, through back-up well construction and testing. Wells must also be replaced from time to time. Area groundwater must also be monitored to ensure that water levels and quality remain within the range predicted in the EIA. Investigation is required where water quality or levels deviate from expected trends.
Disposal Capacity Testing
SAGD projects cannot be implemented without a secure disposal source that meets the disposal capacity of all phases of the project. Typically, disposal will not be authorized in potable water intervals, which consist of groundwater bearing intervals having a total dissolved solids (TDS) concentration of less than 4000 mg/L. Moreover, injection rates are limited to that that which should not result in fracturing of the bedrock. Step-injectivity tests, as detailed in ERCB Directive 051, are completed to determine the injection pressures that result in bedrock fracturing, for a given well/formation. Before completing step-injectivity tests, swabbing/pumping and groundwater quality sampling is usually completed on potential disposal intervals, as may exist between the McMurray Formation and the PreCambrian Shield/basement.
Regulatory Requirements
SAGD projects represent complex, multi-year endeavours that are subject to regulatory and permitting, respecting hydrogeology, on a variety of levels. Examples include potable groundwater testing, licensing and annual-returns reporting under the Water Act, surface water and groundwater quality monitoring programs associated with pilot and commercial plant approvals, groundwater – surface water monitoring programs specified in approvals respecting sensitive wetlands, etc. With increasing pressures on potable water resources in Alberta, with an increasingly knowledgeable public, and with a move to improve water use efficiency, SAGD regulatory reporting requirements are expected to increase in the future.
Waterline Resources Inc. | Groundwater Resource and Environmental Consultants | Calgary, AB, Victoria, B.C., Nanaimo, B.C.
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