ISO/TC 67/SC 5/WG 2 - Casing and tubing connections and performance properties

This document specifies tests to perform in order to determine the galling tendency, sealing performance and structural integrity of casing and tubing connections. "Casing" and "tubing" apply to the service application and not to the diameter of the pipe. This document covers the testing of connections for the most commonly encountered well conditions. Not all possible service scenarios are included. For example, the presence of a corrosive fluid, which can influence the service performance of a connection, is not considered. This document supplements API RP 5C5:2017, the requirements of which are applicable with the exceptions specified in this document.

This document illustrates the formulae and templates necessary to calculate the various pipe properties given in International Standards, including — 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, and — critical dimensions of test samples. For formulae related to performance properties, extensive background information is also provided regarding their development and use. Formulae presented here are intended for use with pipe manufactured in accordance with ISO 11960 or API 5CT, ISO 11961 or API 5D, and ISO 3183 or API 5L, as applicable. These formulae and templates can be extended to other pipe with due caution. Pipe cold-worked during production is included in the scope of this document (e.g. cold rotary straightened pipe). Pipe modified by cold working after production, such as expandable tubulars and coiled tubing, is beyond the scope of this document. Application of performance property formulae in this document 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, etc., with the closest appropriate casing/tubing product. Similar caution is exercised when using the performance formulae for drill pipe. This document and the formulae contained herein relate the input pipe manufacturing parameters in ISO 11960 or API 5CT, ISO 11961 or API 5D, and ISO 3183 or API 5L to expected pipe performance. The design formulae in this document are not to be understood as a manufacturing warranty. Manufacturers are typically licensed to produce tubular products in accordance with manufacturing specifications which control the dimensions and physical properties of their product. Design formulae, 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 document is not a design code. It only provides formulae and templates for calculating the properties of tubulars intended for use in downhole applications. This document 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 formulae and listed values for performance properties in this document assume a benign environment and material properties conforming to ISO 11960 or API 5CT, ISO 11961 or API 5D and ISO 3183 or API 5L. Other environments can 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 document. Throughout this document tensile stresses are positive.

ISO/PAS 12835:2013 is intended for assessment of casing connections for those field applications in which the design of the casing-connection system is strain-based, and in which primary axial loading is on the casing-connection system driven by constrained thermal expansion, and in which that primary loading exceeds the casing-connection system's yield envelope. Consequently, ISO/PAS 12835:2013 should be considered as a protocol that is complementary to ISO 13679, which applies to classic elastic-design applications. ISO/PAS 12835:2013 describes the structure of the Thermal Well Casing Connection Evaluation Protocol (TWCCEP) and provides guidelines for its use by new or repeat TWCCEP users, whose familiarity with the TWCCEP provisions might vary. Clause 6 describes fundamental assumptions adopted in the TWCCEP.

ISO/TR 10400:2007 illustrates the equations and templates necessary to calculate the various pipe properties given in International Standards, including 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, and critical dimensions of test samples. For equations related to performance properties, extensive background information is also provided regarding their development and use. Equations presented in ISO/TR 10400:2007 are intended for use with pipe manufactured in accordance with ISO 11960 or API 5CT, ISO 11961 or API 5D, and ISO 3183 or API 5L, 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 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 ISO/TR 10400:2007 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, etc., with the closest appropriate casing/tubing product. Similar caution should be exercised when using the performance equations for drill pipe. ISO/TR 10400:2007 and the equations contained herein relate the input pipe manufacturing parameters in ISO 11960 or API 5CT, ISO 11961 or API 5, and ISO 3183 or API 5L to expected pipe performance. The design equations in ISO/TR 10400:2007 are not to be understood as a manufacturing warrantee. Manufacturers are typically licensed to produce tubular products in accordance with manufacturing specifications which 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. ISO/TR 10400:2007 is not a design code. It only provides equations and templates for calculating the properties of tubulars intended for use in downhole applications. ISO/TR 10400:2007 does not provide any guidance about loads that may 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 ISO/TR 10400:2007 assume a benign environment and material properties conforming to ISO 11960 or API 5CT, ISO 11961 or API 5D, and ISO 3183 or API 5L. 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 ISO/TR 10400:2007.

ISO 13679:2002 establishes minimum design verification testing procedures and acceptance criteria for casing and tubing connections for the oil and natural gas industries. These physical tests are part of a design verification process and provide objective evidence that the connection conforms to the manufacturer's claimed test load envelope and limit loads. It categorizes test severity into four test classes. It describes a system of identification codes for connections. ISO 13679:2002 does not provide the statistical basis for risk analysis. ISO 13679:2002 addresses only three of the five distinct types of primary loads to which casing and tubing strings are subjected in wells: fluid pressure (internal and/or external), axial force (tension or compression), bending (buckling and/or wellbore deviation), as well as make-up torsion. It does not address rotation torsion, non-axisymetric (area, line or point contact). ISO 13679:2002 specifies tests to be performed to determine the galling tendency, sealing performance and structural integrity of casing and tubing connections that apply to the service application and not to the diameter of the pipe.