Due to its reduced environmental impact, Horizontal Directional Drilling (HDD) has become an increasingly popular method for installing pipes, cables, and other underground infrastructure. It allows for quicker job completion relative to traditional open-trench methods. This makes the practice suitable for a wide range of applications, including complex water crossings, urban areas, and environmentally sensitive sites such as wetlands. Despite this increased efficiency and lowered environmental impact, working in environmentally sensitive areas still caries carries significant risks. The largest risk is inadvertent returns or “frac-outs.” With an HDD project, the goal is 0 inadvertent returns, but that cannot always be met. If an inadvertent return happens on a project, it presents a variety of problems, including environmental damage, cost overruns, and project delays.
Proper Polymer Management
Drilling fluids are essential to HDD success and preventing inadvertent returns. Polymers are commonly used in HDD for stabilization, lubrication, and preventing fluid loss downhole. It’s no secret that polymer chemistries are complex. Add too much, and you’re losing money; add too little, and the borehole’s integrity is compromised, increasing your risk of inadvertent returns. It’s key to find the sweet spot. On top of this, you must always have someone on site, slowly and steadily mixing. This person must ensure that the costly specialty polymers are fully solubilized and added in the correct order and dosage concentration. Overall, polymers require proper management to maximize efficiency and minimize downtime, which can be difficult to sustain manually.
Automated Direct Injection Unit
Sentinel’s Patented Automated Direct Injection Unit is a containerized polymer injection unit plumbed between the fluid reclaimer and the downhole pump to ensure constant chemistry injection. This eliminates the need for 24-hour monitoring during dynamic drilling environments. With the Automated Direct Injection Unit, mixing expensive polymers becomes a “set-it-and-forget-it” task, allowing on-site drilling personnel to focus on the task at hand. The Direct Injection Unit is equipped with touchscreen software to set the exact measured dosage required for a specific drilling environment.
Polymers only work if there’s enough available water to solubilize. This system mixes fresh water and polymers directly, minimizing polymer fisheyes and supporting full solubilization. The automation of this unit eliminates the need for estimation, providing consistent delivery across changing formations.
Automated Response to Inadvertent Returns
A large HDD client was installing pipe in an environmentally sensitive area – a wetland. The inevitable happened – inadvertent returns. They faced two choices. They could either use more specialty fluid materials, which would lead to higher costs, or bring in Sentinel’s Automated Direct Injection Unit. They chose Sentinel’s solution.
Using Sentinel’s Direct Injection Unit, the client was able to drill effectively while minimizing material consumption. Sentinel provided a full response plan, equipment, and materials for consumption. The unit reduced material consumption by over 50%. This reduced the need for constant manual oversight and provided consistent performance across formation changes.
Managing Inadvertent Returns Unafraid
In sensitive areas, inadvertent returns are high risk. Traditionally, you had to respond with more material and more monitoring, increasing time and costs. With this unit, you now have faster responses, tighter control, and less overcorrection in critical areas, helping manage and reduce the risk of inadvertent returns. Sentinel Solutions’ patented Automated Direct Injection Unit provides precision that reduces both waste and risk.