Because Directional Technologies has a thorough understanding of horizontal wells, from well placement to operations and maintenance, the company is able to provide very specific solutions for each project. The use of sophisticated, state-of-the-art well screen design software, that is not limited to certain lengths of the well, ensures that each horizontal well delivers maximum production. The following case study describes how Directional Technologies delivered a precise, segmented horizontal well injection design underneath an occupied building.
Precise, Segmented Injections with Horizontal Remediation Wells
by Seth Croy
Taking advantage of custom designed horizontal wells with segmented screen sections, isolated remedial injections were targeted to deliver treatment in precise locations and concentrations. Directional Technologies, Inc. recently provided hands-on design support and experienced field crews to install 10 horizontal injection and extraction wells. Analyzing assessment and monitoring data, the horizontal wells were strategically located under an occupied building to target the zone of treatment. As part of an aggressive and successful in-situ chemical oxidation plan, the segmented wells were pumped extracting groundwater. The extracted groundwater was treated with sodium persulfate and then re-injected into the adjacent wells, creating a circulation effect between the wells and individual zones.
Groundwater impacts were significantly reduced beneath the building. Also, the extracted groundwater changed considerably during the injection events from observed oil sheens to no sheen and no “fuel oil” odor. No further remediation was necessary, and the site is proceeding ahead to closure status.
To meet remedial objectives, the horizontal well screens were engineered for injection and extraction with the following design considerations:
- Provide more treatment in known zones of higher concentrations using segments in the well screen that consisted of 20-foot sections.
- Properly account for the well riser, conveyance lines, elevation changes, hydraulic head and hydraulic conductivity of the formation in the design of the horizontal well screens.
- Most effective placement of the horizontal wells by reviewing assessment data, such as the direction of groundwater flow.
- Optimize the development of the natural filter pack in the soil formation surrounding the horizontal well screens.
Directional Technologies’ 24 years of expertise in installing horizontal remediation wells ensure optimal placement and performance to meet remedial goals.