Casing and tubing strings are the main parts of the well construction. All wells drilled for the purpose of oil or gas production (or injecting materials into underground formations) must be cased with material with sufficient strength and functionality.
Casing
Casing is the major structural component of a well. Casing is needed to:
Maintain borehole stability
Prevent contamination of water sands
Isolate water from producing formations
Control well pressures during drilling, production, and workover operations
Casing provides locations for the installation of:
API Casing
API developed srrcificatioms for casing that meet the major needs of the oil and and published in API specifications and bulletins.UJThese provide stan- dard dimensions. strength and performance properties, and the required thread-gauging practice to ensure com- plete interchangeability In addition to the API strength grades. the following
tables include information on higher-strength casing de- veloped to meet the needs or unusually deep wells.
Tubing
Tubing is the conduit through which oil and gas are brought from the producing formations to the field surface facilities for processing. Tubing must be adequately strong to resist loads and deformations associated with production and workovers. Further, tubing must be sized to support the expected rates of production of oil and gas. Clearly, tubing that is too small restricts production and subsequent economic performance of the well. Tubing that is too large, however, may have an economic impact beyond the cost of the tubing string itself, because the tubing size will influence the overall casing design of the well.
API Spec 5CT – Specification 5CT/ISO 11960, Specification for Casing and Tubing, Eighth Edition, Petroleum and natural gas industries-Steel pipes for use as casing or tubing for wells.
Standard: API SPEC 5CT
API 5CT pipe Size (mm):
Outer Dimensions: 6.0mm – 219.0mm
Wall Thickness: 1.0mm – 30 mm
Length: max 12000mm
Application: gas, water and oil transportation in both oil and natural gas .
The main steel grade of API 5CT:
API 5CT J55
API 5CT K55
API 5CT N80
API 5CT L80
API 5CT P110
Casing and tubing pipes in accordance with API 5CT
We offer casing and tubing pipes for the oil & gas industry.
Casing pipes in accordance with API 5CT:
| Type: | Seamless and welded |
| Dimensions: | 4-1/2″ – 20″ |
| Grade: | H-40 / J-55 / K-55 / N-80 / L-80 / C-90/ T-95 / P-110 / Q-125 |
| Connections: | STC (short threads)LTC (long threads)BTC (buttress threads)Premium gas-tight connectors |
Tubing pipes in accordance with API 5CT:
| Type: | Seamless and welded |
| Dimensions: | 1.050″ – 5-1/2″ |
| Grade: | H-40 / J-55 / K-55 / N-80 / L-80 / C-90/ T-95 / P-110 / Q-125 |
| Connections: | Non-upset ends (NUE);External upset ends (EUE);Premium gas-tight connectors |
Properties of casing and tubing
The American Petroleum Inst. (API) has formed standards for oil/gas casing that are accepted in most countries by oil and service companies. Casing is classified according to five properties:
The manner of manufacture
Steel grade
Type of joints
Length range
The wall thickness (unit weight)
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