Long-term Applications in the ISO Standard for Site Specific Assessment of Mobile Jack-Up Units and the use of Skirted Spudcans

摘要

The requirements for the use of jack-up units in long term operations have been included in the ISO 19905-1 International Standard for the Site Specific Assessment of Mobile Jack-Up Units.rnThe paper will provide an overview of the verification, fatigue evaluation and the definition of the inspection programs associated with long-term operations of jack-ups as combined drilling and production units.rnThe paper will also address the interaction between the various stakeholders involved in defining conditions for acceptance of such operations in addition to the site specific assessment.rnTwo actual cases will be used to illustrate the level of analysis applied and what it took to obtain the necessary approvals. The cases are both pre-date the ISO but contain most of the same requirements in their assessment.rnThe cases will also provide details of the structural modifications and other operational requirements including underwater inspections that were deemed necessary to be able to operate the jack-ups for a period exceeding the five year Class inspection requirement.rnThe paper will further address the use of skirted spudcans on harsh environment jack-ups to enhance their operational capability and to permit operations with increased deck loads thereby facilitating the installation of the production modules on the jack-up.rnThe use of jack-ups in combined drilling and production mode is gaining increased interest in the offshore industry. In particular as they offer cost benefits solutions for development of marginal fields or second phase enhanced recovery.