A Technical Limits Weight Control Tool for Integrity Management of Aging Offshore Structures

Abstract

This paper presents a digitized Technical Limits Weight Control (TLWC) tool for integrity management of existing fixed offshore structures. The tool is currently integrated into PETRONAS's Structural Integrity Compliance System (SICS), which is a web-based application for Structural Integrity Management (SIM) of fixed offshore structures. The main capability of the TLWC tool is to allow a user (engineer/ manager) to determine the fitness for purpose of an offshore facility quickly and efficiently for the inclusion of additional topsides loading at various locations on the platform decks. The tool makes use of global ultimate strength analyses results which considers the acceptance criteria for each operating region in Malaysian Waters. The limits of these criteria are used to create contour boundaries, which depending on Centre of Gravity (CoG) shifts due to topsides loading patterns. The tool can provide a high-level check on platform suitability for such increase in loading to cater for further development or operational needs. This quick check enables decision making at early engineering stage without the use of further elaborate and costly analyses. The contour plot shown in the results indicates the limiting acceptable Reserved Strength Ratio (RSR) for that platform. The TLWC decision-making tool is ideal for practicing offshore structural integrity engineers in operations to make a quick decision with regards to addition of topside loading for platforms with marginal reserved strength. Detailed assessment is required to address potential local member overstress for the topside structural members.