Tandem Mooring and Offloading Guidelines for Conventional Tankers at F(P)SO Facilities.
These guidelines address tandem mooring and cargo transfer operations of crude oil and other petroleum products between Floating (Production) Storage and Offloading facilities (F(P)SOs) and Conventional Tankers (CTs). F(P)SOs are increasingly being designed to accommodate CTs, as this permits increased flexibility in trading patterns for CTs and optimises field export freight economics without requiring dedicated or specialised shuttle tankers. These guidelines are intended to assist in improving equipment and procedures for CT tandem activities. These guidelines are primarily intended to familiarise Masters, ship operators, F(P)SO Operators and project development teams with the general principles and equipment involved in F(P)SO – CT operations. Transfer of crude oil and petroleum products between an F(P)SO and a tandem moored Conventional Tanker (CT) has become commonplace in the shipping industry as Operators increasingly develop offshore fields without recourse to shore based export terminals. Experience gained from existing operations has proven that cargo transfer operations in a tandem mooring configuration may be undertaken safely and reliably. In order to address site-specific aspects in particular locations, the recommendations contained within this publication may be supplemented by additional requirements from development project teams, individual ship owners (or ship managers) and individual F(P)SO Operators.
These Guidelines are intended to provide an understanding of the issues - including design, equipment, operations and environmental limitations in operation – contributing to a successful and safe tandem mooring and cargo transfer between an F(P)SO and a CT. Such issues should be taken into consideration by Project teams in the design / construction stage and by Operators at the execution stage, in order to provide an F(P)SO facility that maintains operational risk as low as reasonably practical, utilising risk reduction processes including, but not limited to, HAZOP, HAZID, Quantitative and Qualitative Risk Assessment and Failure Modes and Effect Analysis (FMEA), as appropriate.
This OCIMF document addresses the inter-relation between the F(P)SO and unmodified, Conventional Tankers operating in tandem mooring configuration. The guidance includes recommendations for mooring equipment, considers mooring loads and operations, motions of the F(P)SO and CT, station keeping, cargo transfer equipment and cargo transfer operations. Risk management of F(P)SO operations is addressed in detail within the: • OGP ‘Guideline for Managing Marine Risk Associated with F(P)SOs’ • UKOOA ‘Tandem Loading Guidelines’ • OCIMF ‘Offshore Safety Guidelines with Special Relevance to Harsh Weather Zones’. These documents primarily address dedicated Dynamic Positioning capable shuttle tanker operations. The relevant principles of Risk Management when operating with CTs in a tandem configuration are considered within this document.