Underground Injection Science and Technology (eBook)

Cover 1
Contents 6
Contributing Authors 18
Preface 26
History, Regulation, and Risk Assessment 28
An Overview of Injection Well History in the United States of America 30
Introduction 30
Prior to EPA UIC Regulations 31
EPA UIC Regulations 32
Class I Hazardous Well Regulations 34
Risk Analysis 35
Summary 37
References 38
Deep Injection Disposal of Liquid Radioactive Waste in Russia, 1963–2002: Results and Consequences 40
Introduction 40
Characteristics of Deep-Well Injection Sites and Preliminary Investigation 41
Tomsk-7 and Krasnojarsk-26 in 1963–2003 41
Dimitrovgrad in 1966–2003 42
Conclusions of Preliminary Investigation 42
Investigations of Waste Behavior and New Data Received while Operating Deep-Well Injection Sites 43
Safety Requirements and Criteria while Performing Site Injection for Liquid Radioactive Waste at the Present Time 44
Conclusion 45
References 46
Applications of Deep-Well Injection of Industrial and Municipal Wastewater in Texas 48
Introduction 48
Regulatory Jurisdiction and Federal Program Authorization 48
Definition of Terms 49
Well Numbers and Locations 49
Technical Requirements of Rules 49
General Characteristics of Injected Waste Streams 50
Industries with Current or Historical use of Class I Injection Wells 51
Petroleum Refining and Chemical Manufacturing 51
Metals Refining 51
In Situ Uranium Mining 52
Electric Power Generation 52
Animal and Food Processing 52
Commercial Waste Management and Disposal 52
Environmental Remediation (Site Cleanup) 52
Proposed uses of Class I Injection Wells 53
Carbon Dioxide Sequestration 53
Desalination of Produced Water 53
Salt Cavern Disposal of Industrial Solid Waste 53
Conclusion 54
References 55
Why Current Regulations Protect Florida’s Subsurface Environment 56
Introduction 56
Current Raw Water Supply 57
Effluent Disposal Alternatives 58
Risk Issues 61
Environmental Regulations 61
Injection Well Construction and Testing 62
Summary 65
References 65
An Interpretation of the Safe Drinking Water Acts Non-EndangermentŽ Standard for the Underground Injection Contro 66
Introduction 66
Statutory and Regulatory Authority 66
Approaches for Preventing Endangerment 67
Conclusions 69
Acknowledgments and Disclaimer 70
References 70
The Appropriate Methodology for Determining the use of a Fixed-Radius Area of Review or Zone of Endangering Influence, When Conducting an Area-of-Review Analysis for Underground Injection Control Operations 72
Introduction 72
Methodologies 73
Conclusion 76
Analysis of Injectate Location at Dupont Beaumont Works 78
Introduction 78
Geology 81
Analysis 82
Input Data 83
Simulation Results 85
Verification 88
Conclusions 91
References 91
Aquifer Storage and Recovery Wells in Florida: How and When will Impact be Regulated? 92
Introduction 92
The Concept 93
Floridan Aquifer System 94
ASR Development in Florida 96
Everglades Restoration„ASR Component 97
Concerns about Aquifer Storage and Recovery on a Large Scale 99
Governing Regulations 102
Conclusions and Recommendations 103
References 104
Alaska-Sakhalin 2002 Symposium Discussion of Underground Injection Control in Arctic Oilfields* 106
Introduction 106
Background 107
Sakhalin I Consortium 107
Sakhalin II Consortium 109
Well Drilling and Operation 109
Piltun-Astokhskoye Field (PA-B Platform) 109
Lunskoye Field (LUN-A Platform) 109
Drilling Program 109
Drilling Fluids 109
Produced Water Treatment 110
Water Discharge Disposal Routes 110
Produced Water Disposal 110
Drain Water Disposal Offshore 110
Muds and Cuttings Disposal 111
Gray Water Disposal 111
The Underground Injection Control Presentation to Sakhalin 111
Regulations 112
Enforcement 113
Well Integrity Testing 114
Discussion of Specific Wells 115
Russian Questions 116
Conclusions 117
Acknowledgments 117
References 117
A Probabilistic Risk Assessment of Class I Hazardous Waste Injection Wells 120
Introduction 120
Background 121
Methodology 123
Class IH Injection Well System Definition 124
Failure Modes and Effects Analysis 128
Event and Fault Tree Development 128
Event-Frequency-Distribution Development 129
Quantitative Analysis of Event Trees 129
Probabilistic Risk Assessment (PRA) Results 129
Packer Leak 133
Major Packer Failure 133
Injection Tube Leak 139
Major Injection Tube Failure 139
Cement Microannulus Failure 139
Confining Zone Breach 143
Inadvertent Injection Zone Extraction 145
Incompatible Waste Injection 145
Overall Loss of Waste Isolation Results 145
Conclusions and Recommendations 147
References 149
Well Testing and Hydrologic Studies 8
Replacing Annual Shut-In Well Tests by Analysis of Regular Injection Data: Field-Case Feasibility Study 166
Introduction 166
Description of the Method 167
Analysis of Field Data 168
Conclusions 175
Acknowledgments 176
References 176
Experimental Study of Injection-Interval Hydraulic Isolation from Overlying Formation at the Disposal Site of the Siberian Chemical Complex, Using High-Accuracy Hydraulic Head Measurements 178
Introduction 178
Monitoring Equipment and Measurements 179
Monitoring Data Processing 180
Results 181
Acknowledgments 182
References 182
Gulf Coast Borehole-Closure-Test Well Near Orange, Texas 184
Introduction and Background 184
Test Interval Selection 185
Borehole-Closure Testing 186
Conditioning Hole, Mud Displacement, and Transducer Tests 187
Mud Displacement and Shut In 187
Injection Testing 189
Summary 193
References 193
Interpretation of Transient Permeability Tests to analyze the evolution of a Brine-Filled Salt Cavern 194
Introduction 194
Experimental Design 194
Code Pate for Test Evaluation 195
Test Evaluation Procedure 197
Evaluation Results 198
Test No. 7 (Fig. 14.4) 198
Test No. 13 (Fig. 14.5) 200
Test No. 17 (Figs. 14.6 and 14.7) 201
Relationship between Permeability and Stress State 201
Conclusions 203
References 203
Potential Corrosion and Microbiological Mechanisms and Detection Techniques in Solution Mining and Hydrocarbon Storage Wells 204
Introduction 204
The Corrosion Process 205
The Oxygen Corrosion Process 205
Effect of Salt on Corrosion 207
Oxygen Corrosion Rates in Brine 207
Oxygen Solubility in Brine 207
Oxygen Concentration Cell 208
Carbon Dioxide Corrosion 209
Hydrogen Sulfide Corrosion 210
Effect of Flow Velocity 211
Microbiologically Influenced Corrosion (MIC) 213
The Microbiological Environment 214
Halophilic Bacteria 215
Halophilic bacteria in mined brine and storage brine 216
Testing for halophilic bacteria 217
Corrosive Bacteria 217
Conclusions and Recommendations 218
References 219
Characterization of Subsurface Heterogeneity: Integration of Soft and Hard Information using Multidimensional Coupled Markov Chain Approach 220
Introduction 220
Theoretical Background 221
The 3-D Coupled Markov Chain Model 221
Algorithm of 3-D CMC Model 223
Application of the 2-D And 3-D CMC Model 223
2-D Application 223
3-D Application 225
Summary and Conclusions 226
Acknowledgments 228
References 229
Modeling of Waste Injection in Heterogeneous Sandy Clay Formations 230
Introduction 230
Development of a 3-D Model for Heterogeneity 231
Flow and Transport Model Calibration 237
Analysis of Effective Hydraulic and Transport Properties 239
Modeling of the Injection History 242
Conclusions 244
Acknowledgments 245
References 245
Non-Darcy Flow Behavior Near High-Flux Injection Wells in Porous and Fractured Formations 248
Introduction 248
Mathematical Model and Numerical Formulation 249
Dimensionless Variables and Analytical Solutions 251
Type Curves of Non-Darcy Flow 252
Pressure Drawdown and Buildup 253
Effects of Finite Reservoir Boundaries 255
Non-Darcy Flow in Fractured Media 255
Non-Darcy Flow with Partial Penetrating Wells 255
Summary and Conclusions 259
Acknowledgments 260
References 260
Modeling Density Changes in Hazardous Disposal Well Plumes 262
Introduction 262
Generic Model Description 263
Generic Model Inputs 264
Modeling Results„Variation of Rate Schedule, Runs 1 and 2 264
Modeling Results„Variation of Injectate Density 265
Results„Model Run 3 266
Results„Model Run 4 266
Results„Model Run 5 267
Results„Model Run 6 267
Conclusion 268
References 269
Leakoff Modeling of Fluid Injected in Gas Reservoir at Fracture Stimulation 270
Introduction 270
Reconstruction of Fracture Propagation 272
Estimation of the Leakoff Coefficient 273
Identification of Exponent . 273
Hypothetical Study 274
Case Study 276
Conclusions 278
Nomenclature 279
Acknowledgments 280
References 280
Geochemistry 10
Predicting Trace Metal Fate in Aqueous Systems using a Coupled Equilibrium-Surface-Complexation Dynamic-Simulation Model 284
Introduction 284
OLI Software 285
Dynachem Model 285
Surface Complexation Model Calibration 287
Definition of Case Studies 287
Results and Discussion 289
References 296
Review of the Studies of Radionuclide Adsorption/Desorption with Application to Radioactive Waste Disposal Sites in the Russian Federation 298
Introduction 298
Radon Site 300
Groundwater Contamination Specifics 300
Experimental Tasks 300
Batch and Column Experiments 301
Spatial Variability of the Freundlich Adsorption and Desorption Constants 304
Description of experimental work 304
Isotherms and estimated parameters 304
Statistical distribution of the parameters (histograms) 308
Spatial variability of the adsorption constants 308
Geostatistical Interpolation of the Adsorption Constants 312
Variability of the Desorption Constants 312
EUR Site 315
Geological Environment 315
Results of Diffusion Experiments 315
Tomsk-7 Site 317
General Information 317
Laboratory Series 318
Experiments under Room Conditions 318
Experiments at Elevated Temperature and Pressure 321
Krasnoyarsk-26 Site 324
General Information 324
Experimental Setup and Analysis of the Major Results 324
Lake Karachai Site 328
General Description of the Migration Process 328
Samples and Experimental Setup 328
Adsorption Parameters 329
Hysteresis in Adsorption 331
Conclusions 331
Acknowledgments 333
References 333
Appendix A. A Non-Equilibrium Model of Dual-Site, One-Component Adsorption 335
Appendix B. Sorption Coefficients (kfs, ns , and kd ) from batch Sorption Experiments with Lomonosovsky Sand (The Radon Site) 336
Appendix C. A Kinetic Model of Adsorption with Concomitant Mineral Dissolution 337
Chemical Interactions between Waste Fluid, Formation Water, and Host Rock During Deep-Well Injection 340
Introduction 340
Chemical Characterization of Formation Waters Prior to Waste Injection 340
Simulation of Chemical Interaction between Native Fluid, Waste, and Host Rock 343
Initial Speciation and Reaction-Path Simulations 344
Reactive-Transport Simulation 348
Discussion and Conclusions 351
Acknowledgments 352
References 352
Water–Rock Geochemical Considerations for Aquifer Storage and Recovery: Florida Case Studies 354
Introduction 354
Historical Overview 355
Research Goals 355
Hydrogeologic Setting 356
Water-Quality Changes 356
The Aquifer System Matrix 358
Discussion 361
Conclusions 364
Acknowledgments 364
References 365
Grouting with Mineral-Forming Solutions„A New Technique for Sealing Porous and Fractured Rock by Directed Crystallization Processes 368
Introduction 368
Fundamentals 369
Sealing of Porous or Fractured Rock Formation by Induced Crystallization 374
In Situ Immobilization by Crystallization Processes 378
Conclusions 384
Acknowledgments 385
References 385
Liquid Waste Injection 11
Injecting Brine and Inducing Seismicity at the World’s Deepest Injection Well, Paradox Valley, Southwest Colorado 388
Introduction 388
The Project 388
Local Geology 389
Injection Well and Operations 390
Paradox Valley Seismic Network 391
PVSN Recording Sensitivity 392
Seismicity and Injection 393
Preinjection 393
Injection Tests 394
Continuous Injection 394
Seismicity and Local Geology 396
Porosity and Reservoir Lifetime 400
Findings 400
Retrospective 401
Acknowledgments 401
References 401
Evaluation of Reservoir Information in Relation to Earthquakes in Ashtabula, Ohio 404
Introduction 404
Historical Overview 404
Regional Geology and Tectonics 405
Chardon Earthquakes 406
Ashtabula Earthquakes 407
Possibility that Injection Triggered Earthquakes 408
An Alternative Source Mechanism for the Ashtabula Earthquakes 412
Description of the Injection Zone 416
Injection activity in the Ashtabula Area 417
Propagation of Injection-Induced Pressure Effects 418
Geological Framework for Seismicity 420
Sensitivity Analysis 422
Case 1„The 1987 Seismic Sequence 423
Case 2„The June 2001 Seismic Sequence 424
Discussion 424
Conclusions 425
Acknowledgments 425
References 425
Injection of Brine from Cavern Leaching into Deep Saline Aquifers: Long-Term Experiences in Modeling and Reservoir Survey 430
Introduction 430
Historical Overview 430
Geological Requirements for Brine Disposal in Porous Aquifers 431
Preliminary Investigations 432
Technical Solutions 433
Disposal-Well Completion 433
Surface Disposal Facilities 434
Monitoring and Simulation Program for Brine Disposal 434
Results and Experiences Gathered 439
Kraak Storage Project 439
Rüdersdorf Storage Project 439
Use of Deep Geologic Horizons for Liquid Waste Disposal at Power Complexes in Central Russia 440
Introduction 440
Geological Conditions for Waste Injection in the Central Part of Russia 440
Geology of the Kalinin Nuclear Power Plant 441
Characteristics of Waste and Site Injection 442
Waste Treatment for Deep-Well Injection 443
Estimation of Deep-Well Injection Consequences 443
Equipment for using a Natural Underground Solution in Moscow 444
Conclusion 444
Case Study: Evaluation of Oil Field and Water-Well Disposal-Well Designs for Oil Sands Facility in Northern Alberta, Canada 446
Introduction 446
General Setting 446
Geology 446
Hydrogeology 449
Aquifer confinement 449
Formation geochemistry 449
Siting of Disposal-Well Locations 449
Well Construction and Completion 450
Permitting 450
Well Completion 450
Oil field design 450
Water-well design 450
Test and Analysis Procedures 451
Test Procedures 451
Methods for Data Analysis 452
Test Results 454
Conclusions 455
References 456
Fluid Injection Near the Waste Isolation Pilot Plant 458
Introduction 458
Mechanics and Practice of Fluid Injection in the Area 459
Production-based Operations 460
Primary recovery 460
Hydraulic fracturing (hydrofracturing) 460
Secondary recovery 461
Disposal-based Operations 462
Saltwater disposal 462
Solution mining 462
Geology and Reservoir Characteristics 463
Mechanical Response and Environmental Effects of Fluid Injection 463
References 465
Injection of Organic Liquid Waste in a Basaltic Confined Coastal Aquifer, Reunion Island 468
Introduction 468
The Case of the Savanna Distillery 469
The Hydrogeological Setting of Bois Rouge„A Rare Asset 469
Experiments and Results 469
Hydrodynamic Characterization of the Deep Confined Aquifer 472
Waste Migration Investigations 473
Discussion 474
Conclusion 475
Acknowledgments 476
References 476
Demonstration of Presence and Size of A Co2 –Rich Fluid Phase after HCL Injection in Carbonate Rock 478
Introduction 478
Wireline Logging Data 478
Interference Testing and Pressure Calculations 483
Summary and Recommendations 485
References 485
Stability Analysis of a Solution Cavity Resulting from Underground Injection 486
Introduction 486
Methodology Overview 486
Stress Analysis 487
Cavity Shape and Size 487
Rock Elastic Properties 489
Perturbation Stresses 489
Preexisting Stresses 493
Failure Analysis 494
Failure Criteria 494
Test for Failure 495
Model Results and Conclusions 496
Acknowledgments 497
References 497
Liquid Radioactive Waste Injection 13
Liquid Radioactive Waste Disposal into Deep Geologic Formations by the Research Institute of Atomic Reactors (Russia) 500
Introduction 500
Geologic-Hydrogeological Substantiation of the Method 501
Physicochemical Investigations of Disposal Processes 502
LRW Disposal and Control Processes 503
Conclusion 505
Safety Assessment of Deep Liquid-Organic Radioactive Waste Disposal 508
Introduction 508
Mathematical Model 509
Results and Discussion 510
Conclusions 512
References 512
Results of Long-Term Deep Liquid Radioactive Waste Injection Site Operation at the Siberian Chemical Combine 514
Introduction 514
Characteristics of the Injection Sites 514
Results and Discussion 515
Conclusion 517
Radionuclide Distribution in a Sandstone Injection Zone in the Course of Acidic Liquid Radioactive Waste Disposal 518
Introduction 518
Phenomenological Model 518
Mathematical Model 519
Results and Discussion of the Simulation 524
Conclusion 526
References 526
Deep-Well Injection Modeling of Radioactive and Nonradioactive Wastes from Russian Nuclear Industry Activities, with Examples from the Injection Disposal Sites of SSC RF-NIIAR and Chepetsk Mechanical Plants 528
Introduction 528
Model for Deep Injection Disposal of Industrial Waste at Glazov 529
Geological-Hydrological Schematic Presentation of Natural Conditions 529
Model of Deep Injection Disposal at Dimitrovgrad 534
Conclusion 535
References 536
Effect of Anthropogenic Transformations of Deep Liquid Radioactive Waste Repository-Containing Rocks on Radionuclide Migration 538
Introduction 538
Experiments 538
Results and Discussion 539
Behavior of Radionuclides in the Vicinity of the Injection Zone 539
Radionuclide Behavior in the Zone Farther from the Injection Borehole 542
Conclusions 547
References 547
Molecular Bacterial Diversity in Water at the Deep-Well Monitoring Site at Tomsk-7 548
Introduction 548
Materials and Methods 548
Water Sampling 548
DNA Extraction 549
Polyamerase Chain Reaction (PCR) Amplification 549
Construction of the 16S rDNA Libraries 549
Restriction Fragment Length Polymorphism (RFLP) Typing 549
Sequence Analysis 550
16S rDNA Sequence Accession Numbers 550
Results and Discussion 550
Estimation of Diversity of the Cloned 16S rDNA Fragments by RFLP Typing 550
Sequence Analysis of the Cloned Environmental 16S rDNA Fragments 550
Proteobacteria 550
Cytophaga/Flavobacterium/Bacterioides (CFB) group 555
Actinobacteria class 556
Conclusions 557
Acknowledgment 558
References 558
Injection of Solids 15
International Database for Slurry Injection of Drilling Wastes 566
Introduction 566
Slurry Injection Technology 566
Development of the Database 567
Number of Injection Jobs 568
Location of Slurry Injection Jobs 568
Who is doing the Injection? 569
Geological Information 569
Injection Depth 570
Duration of Injection 570
Injection Rate 570
Injection Pressure 571
Type and Volume of Material Injected 571
Slurry Properties 571
Pre-Injection Processing or Treatment 572
Problems Experienced 572
Economics 573
Acknowledgments 574
References 574
Regulatory Requirements and Practices Governing Slurry Injection of Drilling Wastes* 576
Introduction 576
Description of the Regulatory Compendium 577
Findings Presented in the Regulatory Compendium 577
Federal Framework for Injection Operations 577
Regulatory and Economic Challenges Confronting Slurry Injection 578
Regulatory Challenges 578
Economic Challenges 579
Results of the Survey on State Regulatory Requirements and Practices Governing Slurry Injection and Other Injection Technologies 579
Slurry injection 580
Subfracture injection 581
Annular injection 581
Plugging and abandonment 582
Salt cavern disposal 582
Disposal in coal mines 582
Conclusions 582
Acknowledgments 583
References 583
Alaskan underground Injection Control of Solid Waste Disposal* 584
Introduction 584
Regulatory Framework 585
Class I and Class V Wells 585
Underground Injection Reduces Surface Environmental Impacts 587
Aquifer Trends 588
Geological Limits to Injection 590
Construction, Operation, and Management 591
Conclusion 593
Acknowledgments 594
References 594
Disposal of Meat, Bonemeal, and Residual Ash by Injection into Deep Geological Formations 596
Introduction 596
Historical Overview 597
Geological and Physical Properties of the Benicanci Oil Field 597
Disposal of Meat and Bonemeal (MBM) 599
Disposal of Residual Ash 601
Transport Modeling and Risk Evaluation 603
Theory and Assumptions 603
Modeling 605
Conclusion 611
References 612
Thermal Treatment, Carbon Sequestration, and Methane Generation through Deep-Well Injection of Biosolids 614
Introduction 614
Proposed Technology 615
Hyperion Anaerobic Mesophilic and Thermophilic Digestion Pilot Test 616
Description of Facilities 616
Test Results 617
Experimental Verification of Biodegradation and Methane Generation under Simulated Deep Subsurface Conditions 618
Phase I: Effect of Salinity, Temperature, and the Presence of Core Material on Methanogenesis at Ambient Pressure 618
Materials preparation 619
Core sample preparation 619
Test vial preparation and analysis of gas produced 619
Methods of evaluation 619
Effect of temperature 619
Effect of additional carbon sources on methanogenesis 619
Effect of salinity on methanogenesis 620
Effect of core material on methanogenesis 620
Effect of sample size 620
Results and Discussion 620
Phase 2: The Effect of Pressure on the Anaerobic Digestion of Biosolids in the Presence of Saline Fluid 626
Equipment used 627
Experimental procedures 628
Sample analysis 628
Experimental results 629
Summary and Conclusions 629
Acknowledgments 631
CO2 Injection 16
The Potential for Co2 Sequestration in large aquifer structures in Northeastern Germany 634
Introduction 634
Sequestration in Germany 635
Geological Conditions in Northeastern Germany 636
Evaluating the Structures 639
Parameter of Structures and Reservoirs 640
Case Study at Ketzin 643
Buildup of the Anticline 644
Reservoir Properties 645
Reservoir Seal 646
Reservoir Capacity 646
Well Construction 647
Material for Casings and Installations 647
Conclusions 647
References 648
Deep Injection of Acid Gas in Western Canada 650
Introduction 650
Surface Operations 651
Injection Well and Subsurface Requirements 654
Characteristics of Acid-Gas Injection 656
Conclusions 660
References 661
Underground Injection of Carbon Dioxide in Salt Beds 664
Introduction 664
Cavern Construction and Behavior 665
Salt Characteristics 665
Cavern Construction and Filling 667
Cavern Long-Term Behavior 669
Co2 Leakage and Monitoring 672
Conclusions 673
References 674
Coupled Hydromechanical Effects of Co2 Injection 676
Introduction 676
Fundamentals of Hydromechanical Interactions in Fractured Rock 677
Direct HM Coupling and the Theory of Poroelasticity 677
Indirect HM Couplings and Property Changes 679
Deformations in Pre-existing Fractures and the Creation of New Fractures 680
Fracture Fluid Flow 682
Fracture HM Behavior as a Function of Normal Stress 682
Fracture HM Behavior during Shear Slip 683
Summary of Indirect Couplings and Current State-of-the-Art 683
Natural and Industrial analogs related to study of Caprock Integrity and Reservoir Leakage 684
Correlation between Shear Stress and Permeability in Fractured Formations 684
Overpressured Sediments 684
Geological Storage of Natural Gas 685
EDZ in Tunnels through Argillaceous Rock Formations 685
The Tough-Flac THM Simulator 685
Application of the Tough-Flac Code to Co2 Injection 687
Material Properties 687
Initial and Boundary Conditions 690
CO2 Injection 691
Evolution of Fluid Pressure and Spread of CO2 691
Evolution of Injection-Induced (Poroelastic) Stress Changes 691
Potential for Shear Slip and Fracturing at Different Stress Regimes 692
Effect of a Vertical Weakness Zone in the Cap 696
Injection into a Reservoir/Caprock System Bounded by Two Sealing Faults 699
Discussion and Conclusions 702
Acknowledgments 703
References 704
Subsurface Property Rights: Implications for Geologic Co2 Sequestration* 708
Introduction 708
History of U.S. Property Rights 709
The Negative Rule of Capture and Secondary Recovery 710
Implications for GS 712
Injecting Industries 712
Hazardous Waste Injection Case Law 712
Curtailing Subsurface Ownership Rights: Chance v. BP Chemical, Inc. 713
Liability and Full Subsurface Property Rights: Mongrue v. Monsanto Co. 714
Implications for GS 715
Natural Gas Storage Case Law 715
Storage Space Property Rights 716
Ownership of Injected Gas 717
Access to Storage Rights 717
Implications for GS 718
Conclusions 719
Acknowledgments 720
Author Index 722
Subject Index 724