Subsea System Architecture for Coral South FLNG Francesco Rossi Gastech 2017 Eni Mozambique Engineering
Subsea System Architecture for Coral South FLNG
Francesco Rossi
Gastech 2017
Eni Mozambique
Engineering
2
Eni Overview
Saipemengineering & construction
Versalischemicals
30.5% 100%
Italian Government 30% Market70%
exploration & production gas & power refining & marketing
exploration upstreammidstreamgas & power
Equity holding
Retail market gas & power
Development operations & technology
Revenues 55.8 bln €
Operating profit Adj. 2.3 bln €
Capital Expenditures 9.2 bln €
2016 Highlights
Production 1.76 Mboe/d
Proved reserves 7.5 bln boe
Organic RRR 193 %
Eni Mozambique Engineering
More than 34.000 employees in 69 countries of activity
LNG Experience
Eni's LNG Business
Eni's Track Record in LNG
Global LNG presence, with significant expertise throughout the value chain.
In 2015 Eni supplied 4.2 BSCM of feedgas to LNG plants, held 10.9 BSCM of liquefaction capacity, 15.6 BSCM of regassificationcapacity and sold 13.6 BSCM equivalent of LNG.
Eni intends to significantly strengthen its position along the whole LNG chain. This growth will be driven by Mozambique and new projects in Nigeria and Indonesia, where Eni is a significant player.
3
Eni Floaters Experience
4 Eni Mozambique Engineering
Floaters in Eni Operated Fields
In Operation 5 FPSO (Angola, Italy, Nigeria, Norway 2 FSO (UK, Lybia) 1 Construction Support Jack up (UK)
Under Construction 1 FPSO (Ghana) 1 FPU (Indonesia) 1 FSO (Lybia)
Under Development 1 FPSO (Nigeria) 1 FLNG (Mozambique)
Recently Decommissioned 1 FPSO (Timor Leste)
5
Area 4 Location: deep offshore Mozambique @ 200 km
from Pemba
Water depth: 1,500-3,000 m
Block Awarded: December 20th 2006 to JV Partners (Eni
East Africa SpA: Operator)
Exploration and Appraisal Wells: 15 of which 4 in Coral
Development & Production Phase: 30 years from
effectiveness of Plan of Development Hydrocarbon
Type: Gas + Condensate
Mozambique Area 4 Summary
Area 4 Location
IT00537VMozambique Coast
Palma
Pemba
TANZANIA
MOZAMBIQUE
Area 4
Maputo50 km
Area 4 Overview
Area 1 Area 4
Mamba N-1
Mamba NE-2
Mamba NE-1Mamba NE-3Mamba S-3
Mamba S-1Mamba S-2
Coral-2
Coral-1
Coral-3
Coral-4DIR
Agulha-1 dir.
Agulha-2
Area 4
* Eni & CNPC hold an indirect W.I. through their participation in EEA
*
50%
20%
70%
10%
10%
10%
*
JV Partners
Eni Mozambique Engineering
6
Coral South Development
FLNG Facilities
Liquefaction capacity in excess of 3.3 MTPA;
APCI Dual Mixed Refrigerant (DMR);
MEG Hydrate Inhibition;
Internal Turret Mooring System, non disconnectable;
Side-by-Side Offloading;
LNG Tanks: total storage >230,000 m3
Condensate Tanks: total storage ≈ 50,000 m3
Hull Dim.: 404m L x 66m B x 39m D;
Living Quarters: 350 POB;
25 Year Design Life without Dry Dock;
Subsea Facilities
6x Subsea wells;
7” subsea X-trees;
3x cluster manifolds;
6x 10” ND flexible flowlines;
6x 9” ID flexible risers;
3x pigging loops;
3x Umbilicals.
Eni Mozambique Engineering
7
Geophysical & Geotechnical Site Characterization
Site characterization completed;
A site-specific PSHA* has been performed;
Design Basis are a result of Geotechnical/Geophysical Campaigns;
Final geotechnical data are available for EPCIC;
Subsea components (e.g. Wellheads, Manifolds, Flowlines, Moorings)
are located in an area not subject to Geohazard.
FEED
2014 2015 2016
Geophysical Campaign
Geotechnical - shallow
Geotechnical
Shallow Geotechnical
Reports Geohazard Reports
Preliminary Reports
Geotechnical Campaign - Deep
2013
Deep Geotechnical Reports
Ground Survey for Geohazard, Geotechnical (Deep), Slope stability;
Geotechnical Survey for Mooring Lines, Risers and Flowlines.
Coral South Development Area
*Probabilistic Seismic Hazard Assessment
Eni Mozambique Engineering
8
Geophysical & Geotechnical Investigations Area
Eni Mozambique Engineering
9
Area 4 Subsea
Eni Mozambique Engineering
10
Area 4 Subsea
Eni Mozambique Engineering
11
Area 4 Subsea
Eni Mozambique Engineering
12
The Subsea System
Design Life: 30 years service + wet storage
period;
Design Water Depth : 2,300m;
Seabed Temperature : 2.5°C;
Production Rate: 150 MMscf/d, per well;
6 wells clustered in pairs;
3 manifolds with integrated SDU;
3 umbilicals, one for each cluster;
6 flowlines and riser systems;
Maximum Wellhead Shut-in Pressure: 415 bar.
Eni Mozambique Engineering
13
Subsea Production System Architecture
Advantages: Reduced type of subsea structures;
Looped pigging of intrafield lines;
Reasonable level equipment modularization;
Redundancy in case of line damage;
Flexibility in production management;
Balanced distribution of risers across the mooring sectors;
Sound performance in terms of interferences between risers;
HR flexible jumper diameters within present manufacturing
capabilities;
Minimum expected liquid handling issues;
Maximum spare transport capacity.
Eni Mozambique Engineering
14
Umbilical System Configuration
Umbilical system design water depth ~ 2300m, design life ~ 30 years;
Location Metocean condition – Harsh, up to 10000yr cyclonic environmental condition;
Topside FLNG motion – large vessel offset ~ 230m (10% of water depth);
Other nearby adjacent structures such as flexible riser and moorings – Congested adjacent structures (6x
flexible risers and 20 mooring lines);
Six subsea wells controlled by three independent umbilical (two wells per cluster), each cluster is controlled
by one independent umbilical;
Umbilical departures from FLNG via pliant wave configuration, terminating at manifold;
Coral South Umbilical consist upper dynamic section and lower dynamic section;
Umbilical total lengths ranging from 5000m to 8000m.
Eni Mozambique Engineering
15
Control System Architecture Advantages
SDU not required if a large 4-way UTA is used;
Dedicated electrical cables to each cluster (reduced conductor
sections);
Dedicated hydraulic lines to each cluster (reduced line diameters);
Fast update rate and response both in commanded actuations and
uncontrolled ESD;
Good overall system availability (maximum of redundancy
capabilities);
Maximum level of achievable standardisation of equipment;
Minimum subsea equipment;
No infield umbilicals.
Eni Mozambique Engineering
16
The Selection of the Risers and Flowlines Solution
Two options were considered. The flexible riser coupled with flexible flowlines solution has been identified as the best;
All fundamental analyses have been performed – flow assurance analysis, global dynamic analyses, cross section
design/analyses, packing, transportation, installation analyses etc.;
In addition, three qualification tests have been identified.
Eni Mozambique Engineering
17
Advantages of the Risers and Flowlines Adopted Solution
Significant CAPEX saving;
De-Risking of the Installation Campaign schedule;
Production improvement at late field life;
No slugging issue;
Free spans on the flexible flowlines sections derisked;
No sand erosion and no flow induced vibration are
expected.
Eni Mozambique Engineering
18
Conclusions
Coral South Development Project started in 2012 with the Coral reservoir discovery in late 2011;
The whole Project area of operation has been interested by an extensive G&G survey;
The data acquired for the design of the subsea facilities minimised the relevant risks;
The design of the subsea facilities has been carried out with the target to optimise the FLNG
production in all the operating conditions and to have redundancy to maximise the availability of
the whole production system (FLNG, R&F, SPS and Wells).
Eni Mozambique Engineering
19
THANK YOU!
Eni Mozambique Engineering