PRELIMINARY DESIGN OF A FLOATING PRODUCTION STORAGE AND OFFLOADING VESSEL

0
14

ABSTRACT
This project presents the ways and means of the preliminary design of an FPSO to be installed in the AKPO field, offshore Nigeria with a close attention to its hull form. The design and modeling of a FPSO vessel is divided into two parts: one for the hull system and the other for the topside, but this study focuses on the hull form of the vessel. In other to achieve this, the principal dimension of the vessel is gotten through the use of linear regression to compare the dimensions of 10 similar vessels. Also the effects of the environmental loads which involves waves, wind and current on the vessel have been evaluated using the 100 years return period. The hydrodynamic motion roll, heave and pitch movement of the vessel was also analyzed . The different types of mooring system is also discussed in this study, although not included in the design

TABLE OF CONTENTS
Declaration i
Dedication ii
Acknowledgement iii
Certification iv
Abstract v
List of figures vi
List of tables vii
CHAPTER ONE: INTRODUCTION
1.1 Background of study 1
1.2 Aim of study 2
1.3 Objectives of study 2
1.4 Statement of problem 3
1.5 Scope of research 3
CHAPTER TWO: LITERATURE REVIEW
2.1 Design method 4
2.2 FPSO mooring systems 5
2.3 Major Processing Systems of an FPSO 12
2.4 Sub-sea Production Systems (SPS) 12
2.5 UFR (Umbilicals, Flow lines, and Risers) 13
2.6 Accommodation 13
2.7 Ship Principal Dimensions Regression 13

CHAPTHER THREE: METHODOLOGY
3.1 Owner’s requirement 16
3.2 FPSO principal Dimension 17
3.2.1 Linear regression 17
3.3 Environmental factors 18
3.3.1 Wind 18
3.3.2 Waves 18
3.3.3 Current speed 19
3.4 Hydrodynamics 19
3.4.1 Added mass and moment of Inertia 19
3.4.2 Operating condition of the vessel 20
3.4.2.1 Roll Response amplitude operator 20
3.4.2.2Heave Response amplitude operator 22
3.4.2.3Pitch Response amplitude operator 22
3.5 Hydrostatics 22
3.5.1 Restoring spring 23
3.6 Algorithm for the equation 24
3.7 Mooring 25
CHAPTER FOUR: RESULTS AND DISCUSSION
4.1 FPSO principal dimension 28
4.2 Design Environmental factors 32
4.3 Analysis of Result 34
CHAPTER FIVE: CONCLUSION AND RECOMMENDATIONS
5.1 Conclusion 40
5.2 Recommendation 41
REFERENCE
APPENDIX
LIST OF FIGURES
FIGURE TITLE PAGE
1 Typical FPSO vessel 12
2 ship design spiral 16
3 System based design 17
4 Graph of Length against deadweight 39
5 Graph of width against deadweight 39
6 Graph of depth against deadweight 40
7 Graph of draft against deadweight 40
8 Graph of Storage against deadweight 41
9 Scatter plot of Heave RAO against wave frequency 46
10 Scatter plot of Pitch RAO against wave frequency 46
11 Scatter plot of Roll RAO against wave frequency 47
12 Scatter plot of Heave MRS against wave frequency 48
13 Scatter plot of Pitch MRS against wave frequency 48
14 Scatter plot of Roll MRS against wave frequency 49

LIST OF TABLES
Tables Title page
1 Data of 10 similar vessels 39
2 Principal parameters for new FPSO vessel 43
3 wind velocity 43
4 Surface current Velocity 44
5 Wave data 44
6 Obtained results from roll motion MRS 45
7 Obtained results from heave and pitch MRS 46

CHAPTER ONE
INTRODUCTION
1.1 Background of the Study
A floating production storage and offloading vessel (FPSO) is a vessel employed by oil and gas companies to both process and store hydrocarbons in offshore fields. They are made up of two parts: the topside and the hull. The topside produces and off-loads crude oil and gas, and the hull, like a big tank, stores the produced oil. (John et al., 2009)
FPSO vessels, a transportable platform, are popular because they can be easily moved and installed to nearby platforms and also allow for easy transportation of oil to tankers or pipelines. Once an existing field has been depleted, FPSO can then be moved to other locations. This makes them suitable for smaller fields which can be depleted quickly and avoids the need for installing permanent expensive pipelines. The vessels often take the form of traditional tankers. In addition to dedicated vessels that are designed for FPSO, oil and gas tankers can be converted to an FPSO vessel which also makes them an economical and flexible option.
The vessels are moored in place either via a central weathervane or by spread mooring which involves the vessel being anchored via multiple points on the sea floor (Figure 1.1). This allows them to operate in both deep water and ultra-deep water environments which are designed to take into account local weather situations and can even be detached from moorings which make them ideal in extreme weather conditions (Terpstra, 2001).
The basic design of most FPSOs encompasses a ship-shaped vessel, with processing equipment, or topsides, aboard the vessel’s deck and hydrocarbon storage below in the double hull. After processing, an FPSO stores oil or gas before offloading periodically to shuttle tankers or transmitting processed petroleum via pipelines. However, the FPSO alone cannot produce oil and gas in the oil field. It requires many offshore production systems such as the SPS (Sub-sea Production Systems), UFR (Umbilicals, Flow lines, and Risers), mooring lines, a shuttle tanker, an off-loading buoy, etc. Thus, the design and construction of an FPSO includes many other offshore production systems.
1.2 Aim of the Study
The aim of this study is to carry out a preliminary design of an FPSO capable of withstanding its environmental conditions.
1.3 Objectives of the Study
The following objectives are to be considered in order to achieve the above stated aim;
Obtain the principal dimensions of the designed FPSO by regressing data of similar FPSOs.
Investigates the impact of environmental forces on the FPSO.
1.4 Statement of the Problem
Floating Production, Storage, and Offloading (FPSO) systems comprise a new branch in offshore technology in which new discoveries and innovations are being made constantly. Literature review conducted has shown that these new discoveries in technology are not being fully utilized. Also, FPSO design is very broad and requires the aid of experts on different fields.
I also learnt that oil companies (The intended customers of FPSO) are highly interested in improving the safety of the crew and environment, increasing the uptime and reducing the probability of oil spills. This, of course, is in addition to the main objective of reducing the costs and satisfying the production requirement.
1.5 Scope of Research
The preliminary design and modeling of a FPSO vessel involves the study of the following activities.
The principal dimension of the vessel through regression
Analyzing the environmental factors which include wind speed, wave depth and current speed
Hydrodynamic calculations involving the roll pitch and heave movement of the vessel.
Hydrostatic calculations

PRELIMINARY DESIGN OF A FLOATING PRODUCTION STORAGE AND OFFLOADING VESSEL