A CRITICAL TASK

When it comes to the construction of storage ponds, an often overlooked step of the project is proper site selection. Site selection includes measuring the needs of a new project against the merits of potential locations. In our experience, a thorough and comprehensive site selection phase almost always results in a better end product: cheaper, more effective Produced and Fresh Water storage ponds.

Because of the benefits, we strongly recommend that the site selection process includes someone knowledgeable and experienced with the continually evolving regulatory landscape for water storage across Western Canada. With these types of developments, there are several key factors to consider when siting your project, the most important being:

• Proximity to existing infrastructure
• Topography
• Geotechnical conditions, i.e. Soil type, water table elevation, depth of bedrock
• Vegetation cover, which may indicate underlying soil conditions.
• Historical imagery
• Experience in the area

In Alberta, containment ponds are currently regulated under AER’s Directive 055: Storage Requirements for Upstream Petroleum Industry, while in British Columbia containment ponds are expected to comply with the OGC Management of Saline Fluid for Hydraulic Fracturing Guideline.

In situations where produced water ponds are required, a risk assessment and cost analysis are required to determine if a lined containment pond or temporary above-grade storage unit should be utilized. Various technical components influence the risk factor profile, with the most essential items being time and cost. If water is only required for a short period of time, or there is an abundance of easily sourced fresh water in the area, most would choose to install a temporary unit or truck the water in. Conversely, if the water source will be utilized for years to come, it is often worth the investment to construct a permanent pond. It is important to note, the risk assessment process is unique to each project with critical considerations and ultimately comes down to the client’s preference.

Benefit vs Risk Highlights for Produced Pond or Temporary Above-Grade Storage:

• Produced Pond: Cost per m³ to construct, operate, and remediate is extremely attractive compared to the cost of building secondary containment and rental/acquisition/salvage of above-grade tanks. The exact economics widely vary based on volume, length, proximity to pipelines, etc. It’s also important to note, the construction of adequate secondary containment is a significant, and often overlooked, cost when building a tank farm.
• Produced Pond: Potential for groundwater contamination through a leak in a below grade pond (However, this is addressed with added layers of containment and multiple leak detection mechanisms).
• AWSS: Above-grade tanks are portable, therefore if you do not need them for a long duration, you can return the rental or move to another site. It is a much easier reclamation to move it assuming there are no spills (which do happen often for above-grade tanks).
• AWSS: It is easier to manage tanks that are above-grade, both in terms of bird deterrent and size. If your project has a variable frac schedule, you are able to rent 3 at once or if you build the space, 10 at once, then scale back down to 3 when needed.
• AWSS: Above-grade tanks often require more surface space, but also are less reliant on sub-grade materials

RECENT CASE STUDY:

• HGC supported a client with their frac and flowback water strategy, when deciding between a lined containment pond or temporary above-grade C-Ring storage for 75,000 m³ of production fluid. The optimum site from a proximity to existing infrastructure perspective posed several technical challenges including a congested and smallish site, a shallow clayey-gravelly seam, high groundwater table and large topographic changes across the site creating a challenge to minimize berm heights while maintaining a material balance. Utilizing a bow-tie risk assessment and lifecycle cost analysis, we ensured the most economical solution also fit the risk profile for the client. Ultimately, through the implementation of several risk mitigation solutions, a 75,000 m³ lined containment pond was designed, approved, and constructed in 2019. Our scope incorporated irregular geometry, a customized pump-out system, additional containment liner, and a leak detection system.

The site selection process for produced water storage sites involves a cooperative effort between Environmental, Regulatory, Civil, and Geotechnical Engineering disciplines. With a core suite of services and experts spanning all four divisions, HGC is strategically positioned to ensure reliable, pragmatic and responsible development. Whether your project is urban development, renewable energy, or remote Oil and Gas development, our extensive experience on a broad array of site layouts enables our delivery of the preliminary stages of site selection by comparing numerous sites for economical, design-driven decisions. Through teamwork, planning, and innovative design, HGC has overcome numerous siting challenges. We would be happy to discuss any site selection questions you may have and how it can benefit your program.