scope:

GENERAL

This technical report defines the methodology and test procedures necessary for the evaluation of polymeric materials suitable for use as the internal pressure sheath of an unbonded flexible pipes in high temperature applications. It describes the processes by which the critical material properties, both static and dynamic, can be measured and evaluated against relevant performance criteria.

This document relates primarily to the properties necessary for an internal pressure sheath required for oil and gas production. These are most relevant to high temperature applications. Only thermoplastic materials are considered for the internal pressure sheath. Elastomeric materials, which are used in bonded flexible pipes, are not considered in this document.

This document has the following format:

Section 1 Scope

Section 2 Referenced Documents

Section 3 Definitions and Acronyms

Section 4 Service Application - Background to selection of material tests used in the evaluation programme

Section 5 Evaluation Overview - The overall methodology employed in the evaluation of a candidate material

Section 6 Evaluation Test Programme - Presents, in detail, each of the material tests which form the material evaluation test programme

Section 7 Material Evaluation - Presents the criteria against which material test results should be compared and gives guidance on the interpretation of results.

Section 8 Bibliography

The following two applications of the Evaluation Standard are considered:

a. the evaluation of a candidate polymer for HT flexible pipe service,

b. the evaluation of a candidate polymer to determine its generic performance envelope/limits.

SIGNIFICANCE

This Evaluation Standard provides a procedure for determining whether candidate polymeric materials have the property levels necessary for successful use as the internal pressure sheath of an unbonded flexible pipe in high temperature high pressure applications.

For the purposes of this document, high temperatures are defined as those between 130 and 200°C. High pressure is considered to be at least 34.5 MPa (5000 psi).

This Evaluation Standard also provides a means for comparing the performance attributes of several potential pressure sheath materials for high temperature applications.

CURRENT STANDARDS

The current standards which relate to the evaluation of polymers for internal pressure sheath applications are:

i) API Specification 17J, "Specification for Unbonded Flexible Pipe," First Edition [1],

ii) API Recommended Practice 17B "Recommended Practice for Flexible Pipe," Second Edition [2].

These documents address all aspects of unbonded flexible pipe technology relevant to current levels of high temperature service; that is, to 130°C.

UNITS

Système International (SI) units are used in this evaluation standard. Imperial units may be given in brackets after the SI units.

SAFETY

The procedures described in this evaluation standard include materials tests requiring the use of high temperature and high pressure conditions, often with hostile chemicals. It is the responsibility of individuals or organisations using the standard to ensure that all appropriate safety procedures are implemented to prevent injuries to personnel and/or damage to equipment or facilities.