WorldWide Drilling Resource

A Better Way for Site Remediation? Adapted form Information by Directional Technologies Inc. Drilling projects can often encounter environmental challenges. In one such case, traditional methods of remediation presented a number of issues for drilling professionals and a local business, so a different method was chosen. The site contained a small, active gasoline station impacted with petroleum hydrocarbons in the subsurface. The contaminant plume was located in a high-traffic area, beneath a canopy, and adjacent to active underground storage tanks. Using traditional methods and vertical wells at the site would not only have made access for remediation difficult, but it would have been intrusive to everyday activities around the site. Traditional methods would have required extensive trenching around the building to connect remediation wells to the system com- pound. It would have required saw cutting when trenching through paved surfaces, which presents dangers to shallow subsurface utility lines and requires dust control measures. During installation trench plates, safety cones, caution tape, and barri- cades would have been necessary to protect the trenching - all of which are unat- tractive features at an active site, especially one with an open busi- ness trying to attract customers. Completion of trenches would have required fill material, compaction, rebar, and concrete resurfacing - all at great cost to the project budg- et. Once completed, paving scars could create permanent eyesores for the site owner, potentially reducing the property value. The solution? Horizontal Remediation Wells (HRWs) were installed by experi- enced environmental directional drilling professionals. HRWs have been utilized in the environmental industry for 25 years, and are a proven method for site remedi- ation. Whether the remedial method is extraction or injection, HRWs can be installed anywhere beneath a site from a single entry point located near the reme- diation system compound. The HRWs extend directly from the remediation system into the petroleum contaminant plume. Typically, one HRW can provide the same radius of influence as multiple vertical remediation wells. Therefore, HRWs are cost effective when compared to traditional vertical well system installations, and routinely outperform vertical wells. Installing HRWs with directional drilling does not interrupt site activities, leaves no paving scars, and is safer for site per- sonnel. For this site, the use of directional drilling to install HRWs avoided hundreds of feet of trenching around the building, which would have resulted in major site disruptions. Lesley Griffiths said, “Our ambition is for our nation to be a world leader in pioneer- ing low-carbon energy. This is a cutting-edge model of generating a clean source of renewable energy, drawing on the legacy of our coal mining heritage.” Test drilling for a feasibility study was carried out at the Old Brewers site in Caerau, and the mining void was full of water to a depth of 750 feet. The British Geological Survey has been involved in testing the temperature, chemistry, and volume of the water. Temperatures are expected to be warm enough for the project to be a success. The project is modeled after a similar one in the Netherlands, where the world’s first mine water power station was opened in 2008. However, the Caerau model promises to be the first ever large-scale mine water energy project in the UK. It would attract further investment to the area and address fuel poverty by cutting energy bills. While the initial heat network will involve 150 properties, a school, and church, there may be potential to warm up to 1000 homes. Additional funding for the project, which is a demonstrator project for the UK Government-led Smart System and Heat Programme, will be made up by the UK Government, Energy Systems Catapult, and Bridgend County Borough Council. Construction is expected to start in 2020, with the first 150 homes being heated by winter 2021. Professor Hywel Thomas, Cardiff University’s pro vice-chancellor for research, innovation, and engagement said, “This is proving to be a fas- cinating research project that is deepening our understanding of subsur- face geometry and the hydraulics of mine workings. This innovative, low carbon source of heat energy could help Bridgend County Borough Council meet government targets of reducing UK carbon emissions by 80% by 2050.” 48 MAY 2018 WorldWide Drilling Resource ® UK’s First cont’d from page 43. DIR