Salt and Sediment Dynamics presents a thorough treatment of salt and sediment interactions and the implications of such interactions for sub-salt exploration. The book emphasizes and utilizes recent discoveries on many aspects of salt and sediment interactions, provides the theoretical framework for interpreting the increasing amount of available data on salt and sediments, and develops a self-consistent dynamical evolution model of salt structures and their interaction with surrounding sediments.
The model developed in the text consists of an evolving salt structure that influences sediment motion with self-consistent evolution of sediments and salt shape. The resulting stress and strain in the sediments and the thermal focusing effects of the salt are evaluated. The salt and sediments in the model are consistent with observed geometries, a result of having freely adjustable, observation-controlled model parameters.
In addition, the book describes case histories in a variety of geological settings, thus explaining aspects of the genesis and development of salt structures, of their impact on sedimentary structural evolution, and of the impact of sediments on salt masses.
The techniques developed by the authors expand the current state of knowledge regarding the evolution and dynamics of salt structures and increase the potential for effective sub-salt hydrocarbon exploration.
SECTION A: FACETS OF SALT AND SEDIMENT INTERACTIONS
Salt Velocity from Temperature and Thermal Indicator Anomalies: Lulu-1, Danish North Sea
Introduction
Theory
The Lulu-1 Diapir, Danish North Sea
Discussion: Sensitivity Analysis. Dynamics.
Conclusion
Appendix A: Equations for Determining Relative Salt Speed
Appendix B: Quasi-Equilibrium Model of Diapirism
Salt Insertions in Sedimentary Sequences: Impacts on Temperature and Thermal Maturation
One-Dimensional Representations: Introduction. Description of the Model. Temperature Distribution. Influence on Thermal Maturation of Hydrocarbons. Sensitivity Tests of Two Salt Cases. Discussion and Conclusion.
Two-Dimensional Representations: Heat Flow Model. Temperature Distribution Around Salt Sills. Hydrocarbon Maturation. Semi-Infinite Salt Sheets. Finite Horizontal Salt Sill. Semi-Infinite Inclined Salt Sills. Conclusions.
Multiple Salt Bodies: Two Synthetic Tests. Salt in the Northern Gulf of Mexico. Temperature Anomalies in the Northern Gulf of Mexico. Discussion.
Temperature Dependence of Salt Thermal Conductivity: Introduction. Basic Equations and Solution. Numerical Illustrations. Discussion and Conclusions.
Salt Insertions in Sedimentary Sequences: Impacts on Sediment Distortion and Sediment Fracturing
Modeling Sediment Fracturing Around Rapidly Moving Lateral Salt Sheets: Introduction. Methods. Model Results. Discussion. Summary.
Erosion Estimate from Salt/Sediment Shapes: Barents Sea, Norway: Review of Methods. The Method Applied to a Mushroom Salt Diapir. A Synthetic Test. A Case History in Barents Sea, Norway. Discussion.
Hydrocarbon Migration Speed Estimates: Green Canyon Block, Gulf of Mexico: Introduction. Stratigraphic Evidence. Synthetic Tests. Model Resolution to d13Cmixed Measurements. Application. Duscussion and Implications. Conclusions.
Appendix: Mixing. HC Steady Flow/Microbial Degradation. Least Squares.
Simple Estimates of Dynamical, Thermal, and Hydrocarbon Maturity Factors
Formulae for Making Estimates: Dynamical Aspects. Thermal Maturity Aspects.
Applications to a Gulf of Mexico Salt Structure: Background Information. Dynamical Considerations. Miocene Uplift. Thermal Maturity Considerations. Hydrocarbon Migration. Conclusions.
Overpressure Build-Up in Formations Underlying Salt Sheets in the Gulf of Mexico: Physical Conditions in Formations Underlying Salt Sheets. Dynamical Models of Physical Properties of Sub-Salt Formations. Discussion and Conclusion.
Integrated Model Requirements
Rim Syncline
Diapiric Stem
Mushroom Cap Overhang
Salt Volume
Geometrical Anisotropy of Diapirs
Sedimentary Bed Distortions
Basinal Evolution
Thermal Anomalies and Thermal Maturation
Faulting and Fracturing
Consistency Arguments
SECTION B: SELF-CONSISTENT SALT AND SEDIMENT DYNAMICS
Modeling Present-Day Salt Shapes
Introduction. Experimental Model Studies. Mathematical Models. Logic Structure of the Model Procedure.
Present-Day Salt Shapes
Sensitivity Analysis
Examples of Present-Day Salt Shapes - North Louisiana Salt Basin
Summary
Appendix: Construction of a 2-D Salt Shape. Determination of the Best Parameter Values
Deposition and Deformation of Sedimentary Beds Around an Evolving Salt Shape
Introduction
Grid Construction: Primary Grid. Secondary Grid.
Evolving Salt Shapes, Deposition, and Motion of Sediments: Input Sediment Thicknesses in the Grid. Smoothing Bed Positions.
Summary
Appendix 1: Track Construction. Equal Spacing and Spline Interpolation.
Appendix 2: A Time-Evolving Salt Shape. Inverse Methods for Time-Dependent Parameters.
Appendix 3: Smoothing Procedure.
Modeling Stress-Strain Development Through Time
Introduction
Modeling Strain: Correction of the Grid. Calculation of Strain Through Time.
Modeling Evolution of Stress: Calculation of Stress Through Time. Approximations of Rock Properties With Depth.
Examples: Overhang Structure. Plug-Shaped Structure.
Summary
Thermal Focusing of Heat
Introduction
Calculation of Temperature Anomalies
Examples: Temperature Anomalies Around Different Shapes. Effects of Varying Temperature-Controlling Parameters. Thermal Histories Around a Moving Salt Sheet.
Conclusions
Summary
SECTION C: APPLICATIONS AND CASE HISTORIES
North Louisiana Salt Basin - Test Case 1
Introduction
Present-Day Shape
Combined Evolution of Salt and Sediments: Models 1-3. Sensitivity Analysis. Structural History - Summary.
Deformation History
Temperature Histories: Models 1 and 3.
Summary
Norwegian-Danish Basin - Test Case 2
Introduction
Present-Day Shape
Combined Evolution of Salt and Sediments: Models 1 and 2. Structural History - Summary.
Temperature Histories
Summary
Pseudo-3D Modeling of the Combined Evolution of Salt and Sediments: A Danish North Sea Example
Introduction
Present-Day Shapes
Combined Evolution of Salt and Sediments
Thermal History
Stress and Strain Development
Discussion
General Summary
References
Biography
Ian Lerche, Kenneth Petersen
