In Situ Chemical Oxidation (ISCO) Injection

In-situ chemical oxidation (ISCO) injections are a proven way to rapidly break down harmful contaminants lurking in the soil and groundwater. However, during the design planning process, it is often discovered that on-site obstructions, such as buildings or roadways, prevent the necessary access to the contamination. Horizontal remediation wells not only provide access to these areas but inject more amendment volume in shorter time frames.

In-situ chemical oxidation (ISCO) injections are an excellent method for remediating groundwater contamination. It is a technique that involves injecting oxidizing chemicals directly into the contaminated area to break down the pollutants into less harmful substances.  The goal of an ISCO injection is to disperse significant volumes of the chosen amendment into the contaminated soil or groundwater. However, this treatment is rendered ineffective if the solution is not injected into the correct areas. Horizontal remediation wells provide an advanced vessel for ISCO remediation by accessing hard-to-reach areas and injecting more volume over a shorter period of time.

Horizontal wells allow the ability to reach contaminated zones that vertical wells cannot. In cases where ISCO injections are taking place, the contamination often resides beneath existing buildings, roads, or storage tanks where the source area originated. Vertical drill rigs must be set up directly on top of the target area, making it difficult or impossible to reach these contaminated zones.

During the drilling process of horizontal remediation wells, the bore path is tracked in real-time to ensure that the well screen will be expertly set within the target treatment zone. With several bit-locating techniques, even sites with high levels of potential interference can have horizontal wells installed beneath them, such as beneath busy highways or waterways.

When comparing a horizontal well system to a vertical well program, the horizontal option provides significantly more linear screen footage that the ISCO injection is distributed throughout. Simply put: more screen equals more success. One horizontal remediation well can place hundreds of feet of the screen in direct contact with the subsurface contamination. Oftentimes, one horizontal well can replace an entire system of vertical wells. Just a few horizontal remediation wells may be used to cover an entire site. With significantly more screen per well, more volume can be injected over a shorter period of time. Vertical wells can often struggle to inject the full ISCO amendment due to the limited screen sections per well.

When it comes to ISCO injections, the goal is to inject more volume in order to influence more subsurface contamination. Horizontal remediation wells are the preferred method for ISCO remediation in order to rapidly reduce contamination in both soil and groundwater.