Impact of Natural Hazards on Oil and Gas Extraction: The South Caspian Basin

363 Pages·1999·9.494 MB·English

by  E. Bagirov, I. Lerche (auth.)

IMPACT OF NATURAL
HAZARDS ON OIL AND
GAS EXTRACTION:
THE SOUTH CASPIAN BASIN
IMPACT OF NATURAL
HAZARDS ON OIL AND
GAS EXTRACTION:
THE SOUTH CASPIAN BASIN
E. 8agirov
Conoco Inc.
P.O. Box 2197
Houston, Texas
and
I. Lerche
Department of Geological Sciences
University of South Carolina
Columbia, South Carolina
Springer Science+Business Media, LLC
Library of Congress Cataloging-in-Publication Data
Lerche. I. (Ian)
Impact of natural hazards on oil and gas extraction: the South Caspian Basin / Ian
Lerche and Elchin Bagirov
p. em.
Includes bibliographical references and index.
1. Petroleum--Geology--Caspian Sea region. 2. Hazardous geographic
environments--Caspian Sea Region. 3. Natural disasters--Caspian Sea Region. I.
Bagirov, Elchin. II. Title
TN875 .L47 2000
6221.33810947S--dc21 99-047693
ISBN 978-1-4419-3329-4 ISBN 978-1-4757-3019-7 (eBook)
DOI 10.1007/978-1-4757-3019-7
©1999 Springer Science+Business Media New York
Originally published by Kluwer AcademiclPlenum Publishers, New York in 1999.
Softcover reprint of the hardcover 1st edition 1999
http://www.wkap.com
10 9 8 7 6 5 4 3 2 1
All rights reserved
No part of this book may be reproduced, stored in a retrieval system, or transmitted in any
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otherwise, without written permission from the Publisher
PREFACE
Since the dissolution of the Soviet Union almost a decade ago, there has been
rapid evolution of interactions between the Western nations and individual
countries of the former Soviet Union. As part of that interaction, the
autonomous independent Republic of Azerbaijan through its scientific arm, the
Geological Institute of the Azerbaijan Academy of Sciences under the
Directorship of Academician Akif Ali-Zadeh and Deputy Director Ibrahim
Guliev, arranged for personnel to be seconded to the University of South
Carolina. The idea here was to see to what extent a quantitative understanding
could be achieved of the evolution of the Azerbaijan part of the South Caspian
Basin from dynamical, thermal and hydrocarbon perspectives. The Azeris
brought with them copious amounts of data collected over decades which,
together with the quantitative numerical codes available at USC, enabled a
concerted effort to be put forward, culminating in two large books (Evolution
of the South Caspian Basin: Geological Risks and Probable Hazards, 675 pps;
and The South Caspian Basin: Stratigraphy, Geochemistry, and Risk Analysis,
472 pps.) both of which were published by the Azerbaijan Academy of
Sciences, and also many scientific papers. Thus, over the last four to five years
an integrated comprehensive start has been made to understand the hydrocarbon
proneness of the South Caspian Basin.
In the course of the endeavor to understand the basinal evolution, it
became clear that a variety of natural hazards occur in the Basin. These
hazards are important for their potential impact on rigs, sub-sea completion
equipment, pipelines, and for drilling hazards. Over the time of the basin
evaluation study, we have also been compiling different hazard assessments
based both on historical data bases and on quantitative hazard techniques
constrained by geological, chemical and physical conditions appropriate for the
onshore and offshore components of the South Caspian Basin.
The purpose of this monograph is to provide technical details of the
hazards so that some appreciation is available of the likely worst case
conditions for each hazard and their frequencies of occurrence. In each case we
tried not just to estimate the possibility of the event, but to answer the question
"what will happen if the event does indeed occur?" In this way one can plan
strategies and tactics for rig-siting, pipelines, sub-sea completions, and for
drilling. While not necessarily eliminating potential hazards, the ideas and
estimates presented here may at least minimize the influence of particular
hazards. All examples are taken from one single basin -the South Caspian -to
show the variation of natural hazards in one geological setting, in order to
compare the scales of possible damages caused by such phenomena within a
consistent geological framework.
In our opinion, the work presented here should be readily understood
by the average graduate student, and should be of considerable use to those
individuals in the oil industry whose job it is to assess practical hazards as their
companies undertake hydrocarbon exploration and/or production efforts. We
believe the tools and techniques proposed in this book can be used by such
v
VI
individuals in their assessments of natural hazards. Companies working in the
South Caspian region can use directly the specific results presented in the book.
We are particularly grateful to Akif Ali-Zadeh, Ibrahim Guliev, and
their many colleagues at the Geological Institute of Azerbaijan for their
unending cooperation. We thank the Industrial Associates of the Basin
Modeling Group at USC for their financial support. And we are most
appreciative of families and friends who suffer the most during the many stages
of writing a book. This work would not have been possible without the
unfailing support of our secretary, Donna Black, who, once again, converted
hieroglyphic handwriting to legible English typescript.
To you all, and many others, we extend our thanks.
Elchin Bagirov
Ian Lerche
Columbia, SC
CONTENTS
LOCATION MAPS. . . . . . .. .............................. X111
1 INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
A. Introduction To The Quantitative Assessment of
Geological Hazards. . . . . . . . . . . .. ................ 1
B. Some Information on the South Caspian Basin. . . . . . . 2
1. Historical Oil Review. . . . . . . . . . . . . . . . . . . . 2
2. Tectonical Review. . . . . . . . . . . . . . . . . . . . . . 4
3. Sedimentation rates of the South Caspian Basin 8
4. Mud Volcanoes and Diapirs. . . . . . . . . . . . . . . 11
2 EARTHQUAKE HAZARDS. . . . . . . . . . . . . . . . . . . . . . .. 15
A. Seismicity Hazards. . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
1. Frequency and Strength Distributions of Major
Earthquakes. . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2. Directional Distribution of Longitudinal
Earthquakes. . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3. Occurrences of Seismic Dislocations, Causes,
and Spatial Onentations . . . . . . . . . . . . . . . . . .. 25
4. An Assessment Procedure for Seismic Hazards
to Installation Foundations. . . . . . . . . . . . . . .. 27
B. Conclusions............ . . . . . . . . . . . . . . . . . . . . . . . . .. 28
3 FAULT AND FRACTURE HAZARDS ........... '" 31
A. Deformation of Sedimentary Beds Around a Mud
Diapir ..................................... " 32
B. Interrelated Seismic and Mud Volcano Hazards .... " 37
C. Fracture Formations Associated with Mud Volcano
Eruptions ................................... " 40
D. Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 44
Appendix A: ........................................ 46
Modeling Strain. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 46
Modeling Stress ............................. " 47
Modeling fracturing of sediments. . . . . . . . . . . . . . . . .. 48
VB
Vlll
4 MUD VOLCANO ERUPTIONS AND FLAME
HAZARDS ........................................ 49
A. Statistical Hazard Assessment from the Historical
Record....................................... 49
1. Descriptive Information. . . . . . . . . . . . . . . . . .. 50
2. Onshore versus Offshore Statistics. . . . . . . . . . 51
3. Probability of a New Volcano Developing in the
Chirag Area ........................... . 62
4. Distance distribution of individual groups of
gryphons from a common eruptive center. . . .. 63
5. Waiting Time predictions and mud volcano
frequency of eruptions in the Chirag Field ... . 65
a. Determination of eruptive intensity .. . 66
b. Variability of observed eruptions with
time ........................... . 67
c. Evaluation of the average number of
eruptions per year ................ . 72
d. Expected number of yearly eruptions
at the Chirag area. . . . . . . . . . . . . . . . . 73
B. Flaming Eruptions. Historical Review. . . . . . . . . . . . .. 75
C. Factors Associated with Flaming Eruptions. . . . . . . . .. 81
1. Composition of mud volcano gases. . . . . . . . .. 81
2. Flame Ignition During Eruptions. . . . . . . . . . .. 84
3. Flame Height Distribution. . . . . . . . . . . . . . . .. 87
4. Emitted Gas Volume Distribution. . . . . . . . . .. 88
5. Gas Volumes Emitted from Volcanic Mud. . .. 90
D. Flame Hazard Distances. . . . . . . . . . . . . . . . . . . . . . . .. 90
1. A Simple Model of Flame Column Distortion. 91
2. Heating Hazards. . . . . . . . . . . . . . . . . . . . . . . .. 94
3. Test Cases. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
a. The Eruption of Duvanny Island in
1961 .......................... . 96
b. Case History A: High Angle Flames .. 97
(i). Flames at 70° to the Horizontal 99
(ii). Flames at 80° to the Horizontal 100
c. Case History B: Low Angle Flames .. 103
E. Conclusions .................................. . 105
Appendix A. Solutions to Equations (4.15a) and (4.15b) under
the initial conditions of Equations (4.16) ...... . 110
A. Downward Flowing Wind (sinw>O) ........ . 110
B. Horizontal Flowing Wind (sinr-O) ......... . 112
C. Upward Flowing Wind (simJ1<O) ........... . 113
D. The Length of the Flame Column .......... . 114
Appendix B. Heating Effects .......................... . 114
A. Radiation ............................. . 115
B. Convection. ........................... . 116
IX
Appendix C. Summaries of Some Historical Flame
Observations. . . . . . . . . . . . . . . . . . . . . . . . . . . .. 117
5 MUD FLOW HAZARDS. . . . . . . . . . . . . . . . . . . . . . . . . .. 123
A. Distribution of Variables related to Mud Volcano
Flows ...................................... , 125
B. Dependence of Variables related to Mud Volcano
Eruptions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 129
C. Predicting the possible scales of mud flows based on
dynamical models. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 133
D. Conclusions ................................... 140
Appendix A. Mathematical Formulation ................. , 142
l. Gravity Current Flow. . . . . . . . . . . . . . . . . . . .. 142
2. Mud Transport. . . . . . . . . . . . . . . . . . . . . . . . .. 144
3. Mud Deposition. . . . . . . . . . . . . . . . . . . . . . . .. 145
4. Erosion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 146
6 HYDRATE HAZARDS ............................. 149
A. General Hydrate Dissociation Conditions. . . . . . . . . .. 149
B. Hydrate Properties. Pressure-Temperature Stability
Fields ........................................ 151
C. Phase Diagrams and Evolution Tracks ............ " 153
1. Evolutionary tracks under sediment deposition
redeposition conditions. . . . . . . . . . . . . . . . . .. 153
2. Evolutionary tracks under glacial-interglacial
conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 156
3. Evolutionary tracks under sea-level rise and/or
fall. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 158
4. Ethane enrichment in hydrates .............. 159
5. Aeolian effects: winter/summer and hydrate
evaporation/reformation ................. " 160
D. Hazard Factors for Hydrates ...................... 162
E. Seismic Effects and Mud Flows. . . . . . . . . . . . . . . . . .. 164
F. Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 167
Appendix: A Quantitative Procedure for Hydrate Composition
Determination from Seismic Data. . . . . . . . . . . . . . . . . . . .. .. 168
7 GAS HAZARDS ................................... 171
A. Geology and Input Parameters. . . . . . . . . . . . . . . . . . .. 173
B. Model Results. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 177
l. Water Flow. . . . . . . . . . . . . . . . . . . . . . . . . . .. 188
2. Gas Flow. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 195
C. Hazard Aspects .............................. " 209
D. Conclusions ................................... 210
Appendix A: Mathematical Considerations. . . . . . . . . . . . . . .. 211
1. Single Parameter Distributions. . . . . . . . . . . . . . . .. 212
2. Numerical Procedures. . . . . . . . . . . . . . . . . . . . . . .. 215
x
8 BRECCIA HAZARDS .............................. 217
A. General Observations. . . . . . . . . . . . . . . . . . . . . . . . . .. 217
B. Numerical Illustrations .......................... 218
1. Class 1. Onshore Ejecta. . . . . . . . . . . . . . . . .. 219
a. Planar Emission and Impact. . . . . . . .. 219
b. Raised Crater and Planar Impact. . . .. 222
c. Walled Crater Ejection and Planar
Impact .......................... 227
d. Depressed Crater Emission onto a Higher
Impact Plane. . . . . . . . . . . . . . . . . . . .. 231
2. Class 2. Ejecta under Offshore Conditions. . .. 233
a. Island Emission into the Ocean. . . . . .. 233
b. Submarine Emission. . . . . . . . . . . . . .. 238
C. Conclusions ................................. " 239
Appendix A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 239
A. Single Rock Fragment Motion in Air. . . . . . .. 239
B. Breccia Ejection in Air from a Walled Crater.. 241
C. Breccia Ejecta from a Depressed Crater. . . . .. 243
D. Submarine Breccia Ejecta. . . . . . . . . . . . . . . .. 244
E. Initial Distribution Considerations. . . . . . . . . . . 248
1. Initial Mass Distributions. . . . . . . . . .. 248
2. Initial Ejection Speeds. . . . . . . . . . . .. 248
9 OVERPRESSURE AND LATERAL STRESS IN
SEDIMENTARY FORMATIONS ................... 251
A. Overpressure Hazards. . . . . . . . . . . . . . . . . . . . . . . . . .. 251
1. Results of Modeling along W-E 12-second
cross-section. . . . . . . . . . . . . . . . . . . . . . . . . . . . 252
a. Present-day Fluid Pressures. . . . . . . .. 252
b. Present-day Excess Pressure ......... 254
2. Results ofN-S cross-section Modeling ....... 255
a. Present-day Fluid Pressures. . . . . . . .. 255
b. Present-day Excess Pressure ......... 256
3. Results of I-D Modeling .................. 257
a. Fixed depths, variable excess pressure
with time. . . . . . . . . . . . . . . . . . . .. .. 263
b. Isobaric pressures, variable depths
with time. . . . . . . . . . . . . . . . . . . . . . .. 264
B. Horizontal Stress. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 266
C. Conclusions ................................... 274
Appendix A ......................................... 275
1. The Governing Equations for Elastic Flexure
with Constant or Variable Plate Rigidity ...... 275
2. The Inverse Tomographic Procedure. . . . . . . . . 278
Xl
10 MUD ISLAND AND MUD DIAPIR MOTION
HAZARDS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 283
A. Historical Observation of Mud Island Occurrence ..... 283
B. Mud Diapirs and Semi-Permanent Islands. . . . . . . . . .. 287
1. Evanescent Mud Islands. . . . . . . . . . . . . . . . .. 287
2. Mud Islands formed due to mud diapir rise. . .. 288
3. Submarine/Aeolian Islands. . . . . . . . . . . . . . .. 289
4. Dry Push-Out Islands ..................... 289
5. Almost permanent islands ................. 290
6. Lateral Diapir Motion. . . . . . . . . . . . . . . . . . .. 290
C. Hazard Aspects ofIsland Motion .................. 291
11 HAZARDS OF VARIABILITY IN RESERVOIR
CHARACTERISTICS FOR SOUTH CASPIAN OIL
FIELDS ........................................... 293
A. Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 293
B. Specific Distributions of Reservoir Characteristics. . . .. 294
1. Geometrical Distributions. . . . . . . . . . . ... . . .. 294
a. Combined Onshore and Offshore
Fields. . . . . . . . . . . . . . . . . . . . . . . . .. 294
(i) Producing Thickness. . . . . . .. 294
(ii) Areal Distribution. .......... 296
(iii) Volumetric Distribution. . . .. 296
(iv) Reservoir Depth Distribution .. 297
b. Onshore or Offshore Geometric
Distributions. . . . . . . . . . . . . . . . . . . .. 297
2. Physical Parameter Distributions. . . . . . . . . . .. 298
a. Porosity. . . . . . . . . . . . . . . . . . . . . . . .. 299
b. Permeability . . . . . . . . . . . . . . . . . . . .. 299
c. Oil Viscosity . . . . . . . . . . . . . . . . . . . .. 299
d. Reserves, Recovery Factors, and Water
Content. . . . . . . . . . . . . . . . . . . . . . . .. 299
e. Reserves Versus Horizons and Depths. 310
f. Reserves Versus Reservoir Thicknesses
and Areas ....................... 311
g. Reserves and Production Versus Depth 311
C. Spatial Distribution of Economic Oil Field Horizons ... 320
D. Discussion and Conclusion. . . . . . . . . . . . . . . . . . . . . .. 322
Appendix A. List of Onshore and Offshore Oil Fields used
together with producing horizons/field. . . . . . . . . . . . . . . . . . .. 324
12 NATURAL HAZARDS IN HYDROCARBON
EXPLORATION AND PRODUCTION
ASSESSMENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 327
A. Catastrophic Loss in Exploration Assessments. . . . . .. 328
B. Catastrophic Loss after Oil is Found. . . . . . . . . . . . . .. 330