Oil wells are drilled to reach hydrocarbon reservoirs for the purpose of oil and gas production. The exploration wells are drilled for exploration purposes in new areas while appraisal wells are drilled to assess the characteristics of existing reserves. Development wells are drilled for the production of oil and gas, and relief wells are drilled to stop the flow from a reservoir when a production well experiences a blowout. An injection well is made for injecting steam, carbon dioxide, and other substances to production units in order to maintain reservoir pressure or to lower the viscosity of oil.

Hydrochloric Acid mixed with water is used to aid in the removal of obstacles that form in wells during the drilling process by acidizing carbonate or limestone formations and removing contaminants such as scale, rust, and carbonite deposits. In addition, HCl is used in the recovery process of oil operations in the field.