How it works
To create a horizontal well, you first drill down vertically to a depth above the gas-bearing rock formation. Then you use special tools to curve the well so that the hole is drilled horizontally within the rock for up to several thousand feet.
The benefits of horizontal drilling include:
- Maximum contact with the gas-bearing rock formation, producing more gas from a single well
- Multiple horizontal wells can be drilled laterally from the same surface location, which disturbs less ground surface than vertical wells would to produce the same amount of gas
Horizontal drilling follows the same protocols for aquifer protection, fluid containment, and waste handling as vertical drilling.
Hydraulic fracturing involves pumping a fluid and a propping material (such as sand) down the well under high pressure to create fractures in the gas-bearing rock. The propping material (called a “proppant”) holds the fractures open, allowing more gas to flow into the well than would naturally. There is no blast or explosion.
Hydraulic fracturing requires large volumes of water to fracture the rocks and produce the gas; each well may use more than one million gallons of water. Compounds are often added to the water to make the fracturing process more effective. These may include:
- Friction reducers
- Biocides to prevent the growth of bacteria that could damage the piping or clog fractures
- Gel to carry the proppant into the fractures
- Other agents to make sure the proppant stays in the fractures and prevent pipe corrosion
The DEC assesses the chemical makeup of these additives and ensures that all necessary safeguards and best practices are followed. And of course, the fluid removed from the wells must legally be handled, transported, and disposed of properly.
The opportunity in Marcellus Shale
Why the interest in the Marcellus Shale formation? It’s thought to be the second largest natural gas field in the world, according to the Marcellus Shale Coalition. Geologists estimate that the entire formation may contain up to 489 trillion cubic feet of natural gas (New York State uses about 1.1 trillion cubic feet of natural gas annually). Production is currently focused on five states: Pennsylvania, Ohio, West Virginia, Maryland, and New York.
The Marcellus formation is about a mile below the surface and it’s very tight, which has made exploration and extraction difficult and expensive. Recent enhancements in gas well technology and the increasing demand for natural gas in the Northeast have sparked interest in exploration here in New York. This includes the construction of the Millennium Pipeline that runs through the Southern Tier.