“DIMENSIONING OF AN OFFSHORE SYSTEM FOR TRANSSHIPMENT OPERATIONS” Diogo Pereira Costa Process Engineer – Petrobras Marcus Felipe Valle Pipeline Engineer – Transpetro

Introduction to TRANSPETRO Present in the majority of states in Brazil More than 14 thousand km of oil ducts and gas ducts 48 terminals 28 marine terminals 20 on-shore terminals 60 oil tankers Stores oil, oil byproducts and gas and transports them to different points in Brazil

Dimensioning of an offshore system for transshipment operations Presentation with focus in the process engineering Conceptual project Using the installations of an existing marine terminal

Marine terminal with potential for simultaneous operations of transshipment and transfer from oil tanker to the terminal The oil transfer system consists of 2 identical calm buoys linked together via two parallel subsea pipelines. Piggable pipeline The buoys are connected with 2 parallel flexible hoses to the subsea pipeline via a PipeLine End Manifold (PLEM). Distance between buoys MB2 and MB3: 2000 meters Water depth monobuoy MB2: 24 meters Water depth monobuoy MB3: 27 meters Floating hoses → 20” main hose / 16” tail hose Submarine hoses → 20” hoses

Proposed system

PLEM Each one with block valves of 34 inch and 20 inch

Operational requisites for the transshipment operation: → Minimum flow rate: 6500 m³/h → Oil tanker operating pressures: 7 kgf/cm² (minimum) 10 kgf/cm² (maximum) → Minimum fluid temperature: 20 °C → Maximum fluid temperature: 55 °C

Hydraulic simulation Product quality: density 885 kg/m³ and viscosity 12,3 cSt @ 55 °C Softwares: Stoner Pipeline Simulator 9.7 Pipeline Studio® 3.2.7.

SIMULATION RESULTS STEADY STATE

STEADY STATE TRANSFER RATE

Closure of tanker manifold valves RESULTS SURGE ANALYSIS Closure of tanker manifold valves Product at 40 ºC

Through the results of the surge analysis we can determine → All pressure rating classes (ASME) → The Maximum Allowable Operating Pressure (MAOP) of the pipeline → The rated working pressure of the marine hoses

Scenario 1 - Crossover valves closed

Scenario 1 – Crossover valves closed Flow rate 3711 m³/h per pipeline

Scenario 1 - Crossover valves closed The Maximum Allowable Operating Pressure (MAOP) of the pipeline has to be bigger than 20 kgf/cm² Pressure Rating Class: ASME 300 Marine hoses: rated working pressure → 21 bar The marine hoses have to support overpressures of up to 50% its rated working pressure (according to OCIMF 2009*) *Guide to Manufacturing and Purchasing Hoses for Offshore Moorings

Scenario 2 - Crossover valves opened

Scenario 2 - Crossover valves opened Flow rate 3711 m³/h

Scenario 2 - Crossover valves opened The transient waves have more area of propagation, for this reason the surge pressures are smaller Pressure rating class: ASME 150 The rated working pressure of the marine hoses can be of 15 bar and should be suitable for occasional pressure variations of up to 50% its rated working pressure (approximately 22,5 bar).

CONCLUSIONS The considered system fulfills the operational minimum requirements for the viability of the project In case that an operational procedure is created that leaves the crossover valves opened, the project it will have a lesser cost.

Thank you! Diogo Pereira Costa Marcus Felipe Valle diogo.pereira@petrobras.com.br Marcus Felipe Valle marcusvalle@petrobras.com.br