API TR 5C3
Calculating Performance Properties of Pipe Used as Casing or Tubing
|Publication Date:||1 June 2018|
This technical report illustrates the equations and templates necessary to calculate the various pipe properties, including the following:
- pipe performance properties, such as axial strength, internal pressure resistance, and collapse resistance;
- minimum physical properties;
- product assembly force (torque);
- product test pressures;
- critical product dimensions related to testing criteria;
- critical dimensions of testing equipment;
- critical dimensions of test samples.
For equations related to performance properties, extensive background information is also provided regarding their development and use.
Equations presented here are intended for use with pipe manufactured in accordance with API 5CT or ISO 11960, API 5DP or ISO 11961, and API 5L or ISO 3183, as applicable. These equations and templates may be extended to other pipe with due caution. Pipe cold-worked during production is included in the scope of this technical report (e.g. cold rotary straightened [CRS] pipe). Pipe modified by cold working after production, such as expandable tubulars and coiled tubing, is beyond the scope of this technical report.
Application of performance property equations in this technical report to line pipe and other pipe is restricted to their use as casing/tubing in a well or laboratory test, and requires due caution to match the heat-treat process, straightening process, yield strength, and so forth, with the closest appropriate casing/tubing product. Similar caution should be exercised when using the performance equations for drill pipe.
This technical report and the equations contained herein relate the input pipe manufacturing parameters in API 5CT or ISO 11960, API 5DP or ISO 11961, and API 5L or ISO 3183 to expected pipe performance. The design equations in this technical report are not to be understood as a manufacturing warrantee. Manufacturers are typically licensed to produce tubular products in accordance with manufacturing specifications that control the dimensions and physical properties of their product. Design equations, on the other hand, are a reference point for users to characterize tubular performance and begin their own well design or research of pipe input properties.
This technical report is not a design code. It only provides equations and templates for calculating the properties of tubulars intended for use in downhole applications. This technical report does not provide any guidance about loads that can be encountered by tubulars or about safety margins needed for acceptable design. Users are responsible for defining appropriate design loads and selecting adequate safety factors to develop safe and efficient designs. The design loads and safety factors will likely be selected based on historical practice, local regulatory requirements, and specific well conditions.
All equations and listed values for performance properties in this technical report assume a benign environment and material properties conforming to API 5CT or ISO 11960, API 5DP or ISO 11961, and API 5L or ISO 3183. Other environments may require additional analyses, such as that outlined in Annex D. Pipe performance properties under dynamic loads and pipe connection sealing resistance are excluded from the scope of this technical report.
Throughout this technical report tensile stresses are positive.