Skip to content or main menu


Thermal Well Casing Connection Evaluation Protocol (TWCCEP) was published as ISO Publicly Available Specification (PAS) 12835 on

TWCCEP provides procedures for assessing the suitability of threaded connections for service in production casing strings of thermal recovery wells (e.g. SAGD or CSS wells). TWCCEP is intended for connection assessments for strain-based design applications. It is not intended for elastic-design applications addressed by ISO 13679 and API 5C5.

ISO publication brings a successful conclusion to a two-year standardization effort, in which industry experts from member countries of ISO Technical Committee 67 Sub Committee 5 worked on a TWCCEP draft previously submitted to ISO.

The original TWCCEP draft was developed through a multi-client project coordinated by Noetic Engineering and sponsored by eleven industry participants: Cenovus Energy, ConocoPhillips Canada, Evraz Inc. NA, Husky Energy, Nexen Inc., Pengrowth, Shell Canada Energy, Statoil, Suncor Energy Inc., Tenaris, and Total.

TWCCEP ISO PAS 12835 can be purchased from: ISO web store.

We welcome your comments on the published TWCCEP PAS, and suggestions for its possible future enhancements.

Contact: Jarek Nowinka, Email:
Primary phone: +1.780.784.3522