Proceedings of the 25th Offshore Technology Conference, OTC'93, Houston, Texas, USA, Volume 2 (summary)

V O L U M E 2

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25th ANNUAL

OFFSHORE TECHNOLOGY

CONFERENCE

1993

PROCEEDINGS

1993 OFFSHORE TECHNOLOGY CONFERENCE

POLICY GOVERNING PUBLICATION OF PAPERS

PRESENTED AT THE OFFSHORE TECHNOLOGY CONFERENCE

The papers included in the four Proceedings for the 25th Annual Offshore Technology Conference will not be published in any other form. The sponsor organizations for the 1993 OTC are listed under the copyright statement below. No publication of papers presented at the 25th Annual Offshore Technology Conference is authorized without the express written permission of the Board of Directors for the Conference. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. Such use of an abstract should contain conspicuous acknowledgment of where and by whom the paper was presented.

Questions relating to publication of papers by individuals or organizations other than the sponsor organizations should be directed to the Program Deparmient, Offshore Technology Conference, P.O. Box 833868, Richardson, TX 75083-3868, U.S.A., or 222 Palisades Creek Drive, Richardson, T X 75080 U.S.A.

©Copyright 1993

OFFSHORE TECHNOLOGY CONFERENCE on behalf of the American Institute of Mining, Metallurgical, and Petroleum Engineers (Society of Petroleum Engineers, Society for Mining, Metallurgy, and Exploration, The Minerals, Metals, and Materials Society), The American Association of Petroleum Geologists, The American Institute of Chemical Engineers, The American Society of Civil Engineers, The American Society of Mechanical Engineers—Petroleum Division, The Institute of Electrical and Electronics Engineers—Oceanic Engineering Society, The Marine Technology Society, The Society of Exploration Geophysicists, and The Society of Naval Architects and Marine Engineers.

PROGRAM C O M M I T T E E

Bruce K. Ahrendsen, Chainnan

Fugro McClelland Marine Geosciences Inc. Houston, T X

Wolfgang Schollnberger (AAPG) Amoco Production Co.

Tulsa, OK

Gale L . Hubred (AIChE)

Chevron Petroleum Technology Co. La Habra, CA

David J . Hayes (ASCE) BP Exploration Inc. Houston, T X

Brian E . Schwind (ASME) Mobil E&P Technical Center Dallas, T X

William S. Manuel (IEEE) Manuel Designs Inc. Houston, T X

Doug Devoy (MTS) Matthews-Daniel Co. Houston, T X

Bill Dragoset (SEG) Western Atlas Intl. Inc. Houston, T X

J. Robert Woolsey (SME)

The Mississippi Minerals Resources Inst. University, MS

Rod Allan (SNAME)

Reading & Bates Drilling Co. Houston, T X

Matthew Noble Greer (SPE) Esso Norge A/S

Forus, Norway

Brian Laing (TMS)

CRC-Evans Automatic Welding Houston, T X

THE OFFSHORE TECHNOLOGY C O N F E R E N C E is the world's largest and most comprehensive technical conference and exhibition on of&hore resource development. The Conference is jointly sponsored by eleven major intemational engineering and scientific organizations that have a total membership of some 700,000 professionals.

The OTC technical program combines the expertise offered by the eleven engineering and scientific organizations. Authors from 27 nations will present practical applications, theory, and research findings on all facets of ocean resource development in the 1993 program. The papers have been placed in 47 sessions covering both state-of-the-art and new technology in every area of offshore resource development.

The four Proceedings volumes have been separated by major areas of interest, with sessions included in each volume listed below. Papers are listed by OTC number, and most are in numerical order.

V O L U M E 1 V O L U M E 3

Geology, Earth Sciences & Environment

Geophysical Technology

Ocean Drilling & Petroleum Geoscience Exclusive Economic Zone Programs Offshore Safety I Resource Economics Sequence Stratigraphy I Seafloor Surveying Offshore Safety II Sequence Stratigraphy II Environment

V O L U M E 2

Platform & Marine System Design

Platform Damage & Repair

API RP-2A : Background to the 20th Edition Offshore Production Systems

(CATS) Central Area Transmission System & Central Graben Development

Troll Oil Development

Design & Analysis of Floating Production Systems Cost Reduction Measures To Facilitate Economic

Hydrocarbon Production Analysis of Floating Systems Piled Foundations

Construction & Installation/Field Drilling

& Development Systems

General Instrumentation

Risers I—Marine Riser Design & Analysis Analysis of Mooring System Hardware

Subsea Production Systems Safety in Offshore Operations Control Rooms & New Technology

Risers II—Developments in Drilling & Production Riser Technology

Develoments in Materials Technology Recent Developments in Offshore Welding of

Marine Pipelines Snorre TLP Installation

Platform Construction & Installation

V O L U M E 4

Field Drilling & Development Systems

Cables, Hoses, & Umbilicals Pipelines. Materials, & Fatigue

Exxon USA's Zinc Subsea Developtnent Electrical Connectors & Subsea Maintenance Offshore Pipeline Installation

Analytical Considerations for Self-Elevating MODUS Innovative Pipeline Technology

Stainless Alloys, Downhole Pipelines, & Topsides Coiled Tubing Operations

Monobore/Slimhole Wells

High-Pressure & High-Temperature Technology Offshore Environmental Challenges

Completion Equipment & Technology Horizontal Wells

CONTENTS

OTC 7138 Developments in the Assessment and Requalification of Offshore

Platforms 9

OTC 7139 Platform Emmy Strengthening and Requalification 29

and M.L. Eskijian. Califomia Slate Lands Commission

OTC 7140 Loading and Capacity Effects on Platform Performance in Extreme Condition

Storm Waves and Earthquakes 45

OTC 7141 Ship Collision Analysis for the Kawasaki Island Steel Platforms 61

OTC 7142 Sea Loads on Floating Offshore Systems, 3rd Annual Honors Lecture,

Offshore Technology Research Center 73

OTC 7143 The Reduction of Low-Frequency Motions of Moored FPSO's 85

OTC 7145 Impact of Coupled Analysis on Global Performance of Deepwater TLP's 103

Jitendra Prasad, PMB Engineering Inc.

OTC 7146 FPSO Model Tests and Analytical Correlation I I 7

and Jian Xun Li, China Offshore Oil Nanhai Corp.; and Zi Guang IM, China State Shipbuilding Corp.

OTC 7147 Rehabüitation of a 96-Slot Platform I33

Hopper & Assocs.

OTC 7148 The Investigation and Repair of Defective Joints on the Kinsale Alpha Platform 143

OTC 7149 A New Repair and Strengthening Technique for Steel Offshore

Structures 255

OTC 7150 Design Provisions for Offshore Grouted Connections 165

OTC 7151 Grout Repair of Dent-Damaged Steel Tubular Bracing 181

Unocal Thailand Ltd.

OTC 7152 Impact Damage and Assessment of Offshore Tubulars I93

OTC 7153 Extreme Wave Force Calculation Procedure for 20th Edition of

APIRP-2A 201

Research Co.; and E.P. Berek, Mobil R&D Corp.

OTC 7157 Historical Development and Assessment of the Current API Design Methods

for Axially Loaded Piles 253

A.G. Young, Fugro-McClelland Marine Environmental Services Inc.

OTC 7158 Minimum Structures: New Recommended Practices in the 20th Edition

of API RP-2A 283

OTC 7159 Concrete Floating Central Facility 287

OTC 7160 Concrete GBS Platforms for Southeast Asia: Structural Concepts and Site

Considerations

^ 299

G.C. Hoff, Gary Reusswig, and O.G. Ugaz, Mobil R&D Corp.

OTC 7161 Compliant Tower Investigations for Larger Topsides and Shallower Water

Depths in the Gulf of Mexico 315

OTC 7162 The Casing Cage Concept for Deepwater Structures 327

OTC 7163 An Improved Lighweight Bottom-Founded Offshore Platform 335

OTC 7164 Long Buoyant Flexible Pile Frames for Support of Deepwater Offshore

Platforms 347

OTC 7165 The Central Area Transmission System (CATS) and Central Graben

Development 359

OTC 7166 Tower Jackets as Cost-Effective Design Solutions 369

Geoff Tate, R.W. Robinson, and E.O. Beer, Brown & Root

OTC 7167 Offshore Pipeline Welding for CATS Project 379

F. Hostler, Amoco Production Co.; and E.J. Hutchens, Brown & Root Vickers

OTC 7168 Central Graben Development/CATS Safety Management System 389

OTC 7169 The Approach to Passive Fire Protection Design for the North Everest and

Lomond Platforms '^^^

Sava Medonos, ABB Impell Ltd.; and Jacob Prager and S.F. Yasseri, Brown & Root Ltd.

OTC 7170 Approval and Restoration of the Environmentally Sensitive CATS Pipeline

Landfall 411

OTC 7171 Troll Oil Development Concept 421

OTC 7172 Production Geological Challenges of Characterizing the Thin Oil Rims m the

TroU Field 437

OTC 7173 Reservoir Management Aspects of Producing Oil From Thin Oil Rims m the

Troll Field 449

OTC 7175 Rapid Deployment CALM Buoy System 459

OTC 7176 Development of Shuttle Tanker Loading Systems in the Norwegian Sector

of the North Sea 469

OTC 7177 Design and Installation of a Cost-Effective Spar Buoy Flare System 4/9

OTC 7178 High-Pressure Gas SWivels for a New Generation of FPSO Systems 487

IMODCO Inc.

OTC 7179 Cadlao's Successful FPSO II Redeployed at the Deepwater West Linapacon

Field 497

OTC 7180 Cost Reduction Achieved by Convergence of Subsea Technology in Both

Shallow and Deep Water 505

OTC 7181 Flowline Bundles: The "End" Solution 515

OTC 7182 The Role of Information Technology (IT) in Reducing Offshore Operating

Costs 527

OTC 7183 Life-Cycle Cost Reduction Through Designing for Maintenance 537

OTC 7184 Minimum Visit Concept as Applied to Unmanned Platforms in the Southem

North Sea 547

OTC 7185 Economic Benefits of Subsea Flexible Flowlines 553

OTC 7186 Requalification Fatigue Assessment of Semisubmersibles Being Converted

for Floating Production Work 559

OTC 7187 The Effect of Corners on Diffraction/Radiation Forces and Wave Drift

Damping 571

OTC 7188 A Unified Structural Design Method for Floating Offshore Structures 583

Naval Architects

OTC 7189 Reliability-Based Fatigue Design Criteria for Offshore Structures Considering

the Effect of Inspection and Repair 591

OTC 7190 Hydrodynamic Aspects of Moored Semisubmersibles and TLP's 601

Delft U. of Technology

OTC 7191 Life-Cycle Design of Semisubmersible Platforms 615

Registro Italiano Navale; and Lutz Wittenberg, Germanischer Lloyd

OTC 7192 Friction Degradation and Set-Up Effects in Hard Clays Offshore Congo

and Angola ^27

OTC 7193 Improved Soil Characterization for Pipe Piles in Sand in API RP-2A 637

OTC 7194 Bearing Capacity of Driven Model Piles in Dense Sands From Calibration

Chamber Tests