Class II Injection Wells

The Preferred Way to Protect Water Sources and the Environment

Class II Injection Wells safely dispose of millions of gallons of water obtained during oil and natural gas production. They return water brought to the earth’s surface during drilling back to where it came from.


Why We Need Injection Wells

During oil and natural gas production, gallons of brine are brought to the earth’s surface.  Class II Injection Wells return this saltwater back into the earth where it can be safely kept and used to produce more natural resources.


What Injection Wells are Like

Injection Wells are drilled deep into the earth, below the lowest levels of groundwater, to ensure that drinking water is not contaminated.  Next, a surface pipe (called a steel casing) is placed to the bottom of the hole.  A very thick layer of cement is placed around the entire casing to add a second layer of protection.  The casing and layer of cement prevent fluids from mixing with each other or with injected fluids.


Drilling then continues below the casing down through the injection zone.  Once this is complete, a third layer of protection is created by adding another protective pipe (referred to as injection tubing) and firmly cementing it into place from top to bottom.  An injection packer, which is similar to a drain plug, is used near the bottom of the tubing to seal it against the casing.  This packer prevents water from entering the space between the tubing and casing when water is injected.


Regulators then conduct multiple tests to make sure that the injection well is operating properly and that the injected fluids are confined to the intended injection zone. to ensure the highest levels of safety are maintained.


What are injection zones like?

Injection zones are located in spongy rock beds made of sandstone or limestone deep in the earth. Rock beds like these are permeable and porous, absorbing injected wastewater so it doesn’t contaminate our drinking water.  


Injection zones are also covered by a thick and impenetrable layer of rock, such as shale.  This layer acts like a cap to further keep injected water safely in the porous rock bed.
Read more about Class II Injection Wells here.

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