Casing

{
  "id": "MLC-T-ENV-004301",
  "term": "Casing",
  "field": "Environment",
  "definition": "1. The pipe material placed inside a drilled hole to prevent the hole from collapsing. The two types of casing in most injection wells are surface casing, the outer most casing that extends from the surface to the base of the lowermost USDW, and long-string casing, which extends from the surface to or through the injection zone.\n\n2. This term refers to the steel pipe with which the well is constructed. Generally, there are at least two and sometimes three casing strings, one inside the other concentrically. They are cemented to the rock or unconsolidated material to prevent the movement of fluid into or between underground sources of drinking water (USDWs)\n\n3. Pipe cemented in the well to seal off formation fluids and to keep the hole from caving in.\n\n4. Casing is pipe usually larger in diameter and longer than drill pipe and is used to line the hole.\n\n5. Pipe or tubing of appropriate material, of varying diameter and weight, lowered into a borehole during or after drilling in order to support the sides of the hole and thus prevent the walls from caving, to prevent loss of drilling mud into porous ground whereby a cement slurry is pumped into a drilled hole and/or forced behind the casing.\n\n6. The tubular lining of a well. Also a steel or plastic pipe installed during construction to prevent collapse of the well hole.",
  "subject": "Water",
  "references": [
    "Underground Injection Control Glossary",
    "Underground Injection Control Terms",
    "Glossary: Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources",
    "DOL Occupational Health and Safety Administration Oil and Gas Well Drilling and Servicing eTool at http://www.osha.gov/SLTC/etools/oilandgas",
    "40 CFR 146.3 (CFR 2018)",
    "Private Wells Glossary"
  ],
  "url": "https://mlchart.com/terminology/environment/casing/"
}