1、 Guidance Notes on Conversion of Mobile Offshore Drilling Units to Floating Production Installations GUIDANCE NOTES ON CONVERSION OF MOBILE OFFSHORE DRILLING UNITS TO FLOATING PRODUCTION INSTALLATIONS MAY 2017 American Bureau of Shipping Incorporated by Act of Legislature of the State of New York 18
2、62 2017 American Bureau of Shipping. All rights reserved. ABS Plaza 16855 Northchase Drive Houston, TX 77060 USA Foreword Foreword Converting a mobile drilling unit to a production installation can be a cost effective approach for the development of offshore fields. The classification requirements o
3、f the existing drilling unit are to be changed to those for a site-specific floating offshore installation. The design of conversion is based on the site-specific conditions for the site where the unit is to be installed and operated through the intended period of operation. These Guidance Notes are
4、 intended to provide information on the items that need to be considered for the conversion, and give specific criteria that should be applied for classification in accordance with the ABS Rules and Guides. Two types of conversions are covered in these Guidance Notes: column-stabilized drilling unit
5、s to column-stabilized production installations, and drillships to ship-type floating production installations. It is not the intention of these Guidance Notes to alter the technical criteria of the ABS Rules and Guides referenced herein. The main focus of these Guidance Notes is to aid in the appli
6、cation of these criteria to the converted installations. The Guidance Notes contained herein should be used in conjunction with the ABS Rules for Building and Classing Floating Production Installations and the ABS Rules for Building and Classing Mobile Offshore Drilling Units. These Guidance Notes b
7、ecome effective on the first day of the month of publication. Users are advised to check periodically on the ABS website www.eagle.org to verify that this version of these Guidance Notes is the most current. We welcome your feedback. Comments or suggestions can be sent electronically by email to rsd
8、eagle.org. Terms of Use The information presented herein is intended solely to assist the reader in the methodologies and/or techniques discussed. These Guidance Notes do not and cannot replace the analysis and/or advice of a qualified professional. It is the responsibility of the reader to perform
9、their own assessment and obtain professional advice. Information contained herein is considered to be pertinent at the time of publication, but may be invalidated as a result of subsequent legislations, regulations, standards, methods, and/or more updated information and the reader assumes full resp
10、onsibility for compliance. This publication may not be copied or redistributed in part or in whole without prior written consent from ABS. ii ABSGUIDANCE NOTES ON CONVERSION OF MODUs TO FPIs .2017 Table of Contents GUIDANCE NOTES ON CONVERSION OF MOBILE OFFSHORE DRILLING UNITS TO FLOATING PRODUCTION
11、 INSTALLATIONS CONTENTS CHAPTER 1 Introduction 1 Section 1 General 2 Section 2 Application of Referenced Rules . 3 Section 3 Abbreviations . 4 CHAPTER 2 Conversion of Column-Stabilized Drilling Units to Column-Stabilized Installations 6 Section 1 Introduction 8 Section 2 Conversion Consideration . 9
12、 Section 3 Assessments 12 Section 4 Surveys 20 CHAPTER 3 Conversion of Drillships to Floating Production Installations . 21 Section 1 Introduction 23 Section 2 Conversion Consideration . 24 Section 3 Assessments 26 Section 4 Surveys 33 APPENDIX 1 References 35 ABSGUIDANCE NOTES ON CONVERSION OF MODU
13、s TO FPIs .2017 iii This Page Intentionally Left Blank Chapter 1: Introduction CHAPTER 1 Introduction CONTENTS SECTION 1 General 2 SECTION 2 Application of Referenced Rules 3 SECTION 3 Abbreviations . 4 ABSGUIDANCE NOTES ON CONVERSION OF MODUs TO FPIs .2017 1 Section 1: General CHAPTER 1 Introductio
14、n SECTION 1 General Converting a mobile drilling unit to a production installation can be a cost effective approach for the development of offshore fields. Two of these types of conversions are covered in these Guidance Notes: column-stabilized drilling units (CSDUs) to column-stabilized production
15、installations, and drillships to ship-type floating production installations (FPIs). The classification requirements involve changing an existing mobile drilling unit to a site specific floating offshore installation. The requirements for the converted unit are based on the site-specific conditions
16、for the operating site where the unit is to be installed and operated through the intended period of operation, and the transit conditions. These Guidance Notes are intended to provide information on the items that need to be considered resulting from the conversion, and give specific criteria that
17、should be applied for classification in accordance with the ABS Rules and Guides. The Guidance Notes are to be used in conjunction with the ABS Rules for Building and Classing Floating Production Installations (FPI Rules) and other applicable ABS Rules and Guides. Chapter 2 provides the requirements
18、 for conversion of column-stabilized drilling units to column-stabilized production installations, and Chapter 3 provides the requirements for conversion of drillships to ship-type floating offshore installations. It is not the intention of these Guidance Notes to alter the technical criteria of the
19、 ABS Rules and Guides referenced herein. The main focus of these Guidance Notes is to aid in the application of these criteria in the conversion process. Section 2: Application of Referenced Rules CHAPTER 1 Introduction SECTION 2 Application of Referenced Rules The application of referenced Rules in
20、 these Guidance Notes is based on the contract date for conversion between the shipbuilder and the prospective Owner. See also 1-1-4/3 of the ABS Rules for Conditions of Classification Offshore Units and Structures (Part 1). Structures other than hull structures (such as deckhouses), machinery equip
21、ment and/or marine systems which will remain unchanged will be considered on the basis of the original Rules used for the construction as well as the safety features of the converted unit. ABSGUIDANCE NOTES ON CONVERSION OF MODUs TO FPIs .2017 3 Section 3: Abbreviations CHAPTER 1 Introduction SECTIO
22、N 3 Abbreviations ABS American Bureau of Shipping API American Petroleum Institute ASME American Society of Mechanical Engineers AISC American Institute of Steel Construction CSDU Column-Stabilized Drilling Unit DEC Design Environmental Condition DISEC Disconnectable Environmental Condition DOC Desi
23、gn Operating Condition FEA Finite Element Analysis FOI Floating Offshore Installation FPS Floating Production (and Offloading) System FPSO Floating Production, Storage, and Offloading System FPI Floating Production Installation FSO Floating Storage and Offloading System GM Metacentric Height GOM Gul
24、f of Mexico ISIP In-Service Inspection Program ISE Initial Scantling Evaluation LCG Longitudinal Center of Gravity LSA IMO Code for Life Saving Appliances (such as lifeboat, life jackets, etc.) MARPOL International Convention for the Prevention of Pollution from Ships (Marine Pollution) MODU Mobile
25、Offshore Drilling Unit NACE National Association of Corrosion Engineers OCS Outer Continental Shelf OHCM Offshore Hull Construction Monitoring POB Person on Board SOLAS International Convention for the Safety of Life at Sea SFP Structural Fire Protection SPM Single Point Mooring SWBM Still Water Ben
26、ding Moment SWSF Still Water Shearing Force Chapter 1 Introduction Section 3 Abbreviations 1-3 TSA Total Strength Assessment TCG Transverse Center of Gravity VCG Vertical Center of Gravity ABSGUIDANCE NOTES ON CONVERSION OF MODUs TO FPIs .2017 5 Chapter 2: Conversion of Column-Stabilized Drilling Un
27、its to Column-Stabilized Installations CHAPTER 2 Conversion of Column-Stabilized Drilling Units to Column-Stabilized Installations CONTENTS SECTION 1 Introduction 8 1 Overview . 8 3 Classification Notations . 8 3.1 Class Symbols and Notations 8 3.3 Additional Notations . 8 5 Documentation 8 SECTION
28、2 Conversion Considerations . 9 1 General . 9 3 Potential Modifications for Conversion . 9 5 Considerations for Conversion 9 7 General Requirements 10 7.1 General 10 7.3 Lightweight data and Center of Gravity 10 7.5 Maximum Draft 11 7.7 Operating Manual 11 7.9 Stability 11 7.11 Engineering Analysis
29、. 11 7.13 Mooring Systems and Equipment 11 7.15 Onboard Computers for Stability Calculation . 11 SECTION 3 Assessments 12 1 Design Basis and Loads . 12 1.1 Design Basis 12 1.3 Environmental Conditions 12 1.5 Loads . 12 1.7 Directionality 13 1.9 Soil Conditions . 13 3 Structures and Global Performanc
30、e Analysis . 14 3.1 Structures Design 14 3.3 Materials and Welding . 14 3.5 Structural Strength Assessment 14 3.7 Structural Fatigue Assessment 15 3.9 Global Performance Analysis 15 6 ABSGUIDANCE NOTES ON CONVERSION OF MODUs TO FPIs .2017 5 Stability 17 5.1 Transit Voyage Stability . 17 5.3 On-Site
31、Stability . 17 5.5 Inclining Experiment 17 5.7 Watertight and Weathertight Integrity 18 5.9 Penetrations 18 7 Position Mooring Systems 18 7.1 Mooring System 18 7.3 Dynamic Positioning Systems . 18 7.5 Thruster Assisted Mooring Systems 19 9 Machinery and Systems 19 9.1 Marine Piping Systems 19 9.3 El
32、ectrical Systems . 19 9.5 Fire Fighting Systems and Equipment . 19 9.7 Machinery and Equipment . 19 9.9 Hydrocarbon Storage in Hull Tanks . 19 9.11 Additional Plans and Data to be Submitted . 19 11 Hydrocarbon Production and Process Systems . 19 11.1 Installations Classed as FPSO or FPS 19 11.3 Inst
33、allations Classed as FSO or FOI (Production Facilities not Classed) 19 11.5 Installations Classed as FSO or FOI (with Production Facilities Indicated in the Record) 19 SECTION 4 Surveys . 20 1 Surveys During Conversion 20 1.1 Surveys of the Existing Unit . 20 1.3 Surveys During Conversion or Modific
34、ation . 20 1.5 Mooring System Surveys During Construction/Conversion . 20 3 Surveys During Installation and Commissioning 20 5 Surveys After Construction . 20 ABSGUIDANCE NOTES ON CONVERSION OF MODUs TO FPIs .2017 7 Section 1: Introduction CHAPTER 2 Conversion of Column-Stabilized Drilling Units to
35、Column-Stabilized Installations SECTION 1 Introduction 1 Overview This chapter provides guidance for the conversion of CSDUs to column-stabilized production installations and addresses three major items: the installation, the position mooring system, and as applicable the production facilities if th
36、ey are requested to be classed. Sections 2 and 3 of the chapter addresses the items that may be considered for the conversion and specific criteria that should be applied for classification in accordance with the ABS Rules and Guides. 3 Classification Notations 3.1 Class Symbols and Notations For a
37、column-stabilized installation that is converted from a CSDU, the class symbols and notations are to be as indicated in 1-1-2/3.1, 1-1-2/3.3 and 1-1-2/3.5 of the FPI Rules as applicable. The class notation to be assigned depends on whether production and offloading systems are added, and whether sto
38、rage capability is available for the converted unit. 3.3 Additional Notations Additional notations can be assigned in accordance with 1-1-2/5 of the FPI Rules. For automatic or remote control and monitoring systems, class notations can be assigned in accordance with 1-1-2/9 of the FPI Rules. 5 Docum
39、entation The Owner or Designer is required to submit all applicable design documentation, such as reports, calculations, plans and other documentation necessary to verify the structural strength of the column-stabilized installation itself and adequacy of the mooring system, production and other uti
40、lity and riser system (if included in the classification) for the intended operations to ABS for review. The submitted design documentation is to be in accordance with Section 1-1-4 of the FPI Rules, and include the design environmental conditions (see Section 3-2-4 of the FPI Rules). 8 ABSGUIDANCE
41、NOTES ON CONVERSION OF MODUs TO FPIs .2017 Section 2: Conversion Considerations CHAPTER 2 Conversion of Column-Stabilized Drilling Units to Column-Stabilized Installations SECTION 2 Conversion Considerations 1 General The conversion of CSDUs to column-stabilized installations generally requires majo
42、r modifications in order to support the intended service at a specific site. This section outlines possible modifications and related considerations. 3 Potential Modifications for Conversion The following is a list of modifications that may be come out during conversion: Modification of upper hulls,
43、 lower hulls, decks, vertical columns, diagonal and horizontal braces Addition of production systems and supporting structures Addition of processing systems and supporting structures Addition of export systems and supporting structures Addition of fire and safety system design Addition of accommoda
44、tion space and lifesaving appliances Addition of mooring systems and supporting structures Modification of existing positioning systems and supporting structures Addition of power generation and distribution systems and equipment Modification of deck rearrangements and design Removal of thrusters an
45、d thruster compartment closures This list gives potential items to be addressed based on experience with similar conversion and should not be taken as being inclusive. 5 Considerations for Conversion The following items may be considered for conversion as applicable: Consideration of lifting capabil
46、ities, crane reach, access of welders to welding positions and ventilation, should be given to structural work related to reinforcements, deck extensions, moonpool closure, and thruster compartment closure. Care should be taken to survey the lower braces, especially if new brackets are added. New mo
47、oring loads in a FPI may be significantly higher than those when operating as a mobile offshore drilling unit (MODU). In such a case, additional mooring lines may be required. Structural reinforcement in way of mooring equipment may be needed. Fairleads, chain stopper and winch may need to be change
48、d, and may necessitate the installation of additional back-up structure. ABSGUIDANCE NOTES ON CONVERSION OF MODUs TO FPIs .2017 9 Chapter 2 Conversion of Column-Stabilized Drilling Units to Column-Stabilized Installations Section 2 Conversion Considerations 2-2 New processing equipment and risers ar
49、e typically heavier than drilling equipment. Sponsons and/or blisters may need to be installed to increase stability/payload. Location of the flare boom may affect the locations of helideck and hazardous areas. Similar consideration may be made for turbines and turbine exhausts. Location and loads applied to new riser porches may create a need for major structural reinforcements. Similar consideration may be needed for riser pull-in equipment. Care should be taken on the design of riser hard pipes from riser porches to process systems due to interfere
