What are Water Disposal Wells

The Need for Salt Water Disposal Wells

The porous underground reservoirs, where Oil and Natural gas is found, also contain water in different proportions.  Due to natural gravity, oil floats on this water and can mostly be extracted separately.  However, when oil or gas extracted, some of this salt water is also extracted along with it.  This natural salt water which comes along with targeted source is called produced water.  Water which is used for hydraulic fracturing to extract oil or gas also sometimes comes to the surface along with extracted materials. 

The purpose of water disposal wells is to return this extracted water to the deep sub terrain rock formations from which oil was extracted.  Such wells are also used for returning flow-back volumes from work-overs, which may include the water ejected from slick water-fracture.  This is the water or frack-fluid which is used for hydraulic fracturing of rock formations to release gas.

This type of water or fluid disposal needs to meet certain criteria, which is determined by the charecterstics of the rock formation.  The regulations for disposal of extracted water or fluids are administered by the Commission which is meant to protect the surface and underground water sources.  The method for disposal would depend on the various properties of the underground formations. The injection pressure and other methods are reviewed from time to time.

The permission for salt water disposal is granted by the Commission empowered by the Ministry of Environment.  This permission is issued after a thorough review of the application to ensure that the fluid migration to other areas from the injection zone is minimized.  It is necessary that the company has the right for extraction of petroleum and gas in the rock formation where the water disposal is done.  The Commission also issues an effluent permit for the composition of disposed water or fluid.  A monthly disposal or injection statement also has to be submitted to the Commission along with details such as average wellhead pressure and volume of disposed fluid.

Once the formalities are completed, the Commission, on behalf of Ministry of Environment, issues the approval for water disposal under the relevant Oil and Gas Activities Act.