Handling Gas-In-Riser – Part I: Fundamental Concepts and Calculations Underlying 2023 IADC Riser Gas Guidelines

IADC published in 2023 new Deepwater Riser Gas Handling (RGH) Guidelines as well as a Riser Gas Tolerance (RGT) worksheet intended to make related calculations available to the industry. Both the Guidelines and the worksheet utilize terms and principles new to, or insufficiently documented within the industry. Aiming to fill the gaps in documentation, this paper provides definition of terms and specifically addresses two fundamental concepts that are either little known or inconsistently applied to field operations, Riser Equilibrium and Riser Unloading. These concepts underly both the Guidelines and the RGT worksheet. Furthermore, the significance of fluid compressibility is quantitatively illustrated to address common, significant calculation errors. Terms related to these concepts will be clearly defined and physically explained. The logic of related calculations (and derivation of formulae) will be clarified in order to provide the industry with a consistent basis for evaluation or further development of practical riser gas handling procedural issues.