Preface 1. Basic tools 2. Elasticity and Hooke's law 3. Seismic wave propagation 4. Effective media 5. Granular media 6. Fluid effects on wave propagation 7. Empirical relations 8. Flow and diffusion 9. Electrical properties Appendices.

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The Rock Physics Handbook: Tools for Seismic Analysis of Porous Media

Intermolecular And Surface Forces

Responding to the latest developments in rock physics research, this popular reference book has been thoroughly updated while retaining its comprehensive coverage of the fundamental theory, concepts, and laboratory results. It brings together the vast literature from the field to address the relationships between geophysical observations and the underlying physical properties of Earth materials - including water, hydrocarbons, gases, minerals, rocks, ice, magma and methane hydrates. This third edition includes expanded coverage of topics such as effective medium models, viscoelasticity, attenuation, anisotropy, electrical-elastic cross relations, and highlights applications in unconventional reservoirs. Appendices have been enhanced with new materials and properties, while worked examples (supplemented by online datasets and MATLAB® codes) enable readers to implement the workflows and models in practice. This significantly revised edition will continue to be the go-to reference for students and researchers interested in rock physics, near-surface geophysics, seismology, and professionals in the oil and gas industries.

The Rock Physics Handbook

Geological atlas of western and central Europe

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The mobility and degradation of pesticides in soils and the pollution of groundwater resources

The fate of pesticides in aquifers is influenced by the small but not insignificant adsorption of pesticides to mineral surfaces. Batch experiments with five pesticides and four minerals were conducted to quantify the contributions to adsorption from different mineral surfaces and compare adsorption characteristics of selected pesticides. Investigated mineral phases included quartz, calcite, kaolinite, and alpha-alumina. Selected pesticides comprised atrazine (6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine), isoproturon [3-(4-isopropylphenyl)-1,1-dimethylurea)], mecoprop [(RS)-2-(4-chloro-2-methylphenoxy)propionic acid], 2,4-D (2,4-dichlorophenoxyacetic acid), and bentazone [3-isopropyl-1H-2,1,3-benzothiadiazin-4-(3H)-one 2,2-dioxide]. Specific surface area and mineral surface charge proved to be important for the adsorption of these pesticides. Detectable adsorption of the anionic pesticides (mecoprop, 2,4-D, and bentazone) was only measured when positive sites were present on the mineral surface. However, when CaCl2 was added as an electrolyte, a detectable adsorption of mecoprop and 2,4-D was also measured on kaolinite (which exhibits a negative surface charge), probably due to formation of Ca-pesticide--surface complexes. Adsorption of the uncharged pesticides (atrazine and isoproturon) was detected only on kaolinite. The lack of adsorption on alpha-alumina indicates that the uncharged pesticides have a greater affinity for the silanol surface sites (=SiOH) than for the aluminol surface sites (=AlOH) in kaolinite. No measurable effect of ionic strength was found for the uncharged pesticides. The results indicate that quartz and calcite play a smaller role than clay minerals.

Adsorption of Pesticides onto Quartz, Calcite, Kaolinite, and α-Alumina

Iron oxides are important components influencing the adsorption of various inorganic and organic compounds in soils and sediments. In this study the adsorption on iron oxides of nonionic and ionic pesticides was determined as a function of solution pH, ionic strength, and pesticide concentration. The investigated iron oxides included two-line ferrihydrite, goethite, and lepidocrocite. Selected pesticides comprised atrazine (6-chloro-N 2 -ethyl-N 4 -isopropyl-1,3,5-triazine-2,4-diamine), isoproturon [3-(4-isopropylphenyl)-1,1-dimethylurea)], mecoprop [(RS)-2-(4-chloro-2-methylphenoxy)propionic acid], 2,4-D (2,4-dichlorophenoxyacetic acid), and bentazone [3-isopropyl-1H-2,1,3-benzothiadiazin-4-(3H)-one 2,2-dioxide]. The adsorption of the nonionic pesticides (atrazine and isoproturon) was insignificant, whereas the adsorption of the acidic pesticides (mecoprop, 2,4-D, and bentazone) was significant on all investigated iron oxides. The adsorption capacity increased with decreasing pH, with maximum adsorption reached close to the pK a values. The addition of CaCl 2 in concentrations from 0.0025 to 0.01 M caused the adsorption capacity to diminish. The adsorption of bentazone was significantly lower than the adsorption of mecoprop and 2,4-D, illustrating the importance of a carboxyl group in the pesticide structure. The adsorption capacity on the iron oxides increased in the order: lepidocrocite < goethite < two-line ferrihydrite. The maximum adsorption capacities of mecoprop and 2,4-D on goethite were found to be equivalent to the site density of singly coordinated hydroxyl groups on the faces of the dominant [110] form, suggesting that singly coordinated hydroxyl groups are responsible for adsorption. Differences in adsorption capacities between iron oxides can be explained by differences in the surface site density of singly coordinated hydroxyl groups. The maximum measured adsorption capacity of mecoprop on two-line ferrihydrite was equivalent to 0.2 mol/mol Fe.

Atrazine, isoproturon, mecoprop, 2,4-D, and bentazone adsorption onto iron oxides.

Based on P-wave velocity and density data, a new elastic model for chalk sediments is established. The model allows the construction of a series of isoframe (IF) curves, each representing a constant part of the mineral phase contributing to the solid frame.The IF curves can be related to the progress of burial diagenesis of chalk, which is revised as follows:Newly deposited carbonate ooze and mixed sediments range in porosity from 60 to 80%, depending on the prevalence of hollow microfossils. Despite the high porosity, these sediments are not in suspension, as reflected in IFs of 0.1 or higher.Upon burial, the sediments lose porosity by mechanical compaction, and concurrently, the calcite particles recrystallize into progressively more equant shapes. High compaction rates may keep the particles in relative motion, whereas low compaction rates allow the formation of contact cement, whereby IF increases and chalk forms. Rock mechanical tests show that when compaction requires more than in-situ stress, porosity reduction is arrested.During subsequent burial, crystals and pores grow in size as a consequence of the continuing recrystallization. The lack of porosity loss during this process testifies to the absence of chemical compaction by calcite-calcite pressure dissolution, as well as to the porosity-preserving effect of contact cementation.At sufficient burial stress, the presence of stylolites indicates that pressure dissolution takes place between calcite and silicates, and depending on pore-water chemistry and temperature, pore-filling cementation may occur over a relatively short depth interval. Limestone and mixed sedimentary rock form, and porosity may be reduced to less than 20%. Isoframe increases to more than 0.6.In hydrocarbon reservoirs in North Sea chalk, relatively high porosity and high IFs are found. The reason may be that recrystallization and porosity-preserving contact cementation progress, whereas pore-filling cementation is small, probably because pressure dissolution along stylolites is arrested. Pressure dissolution may be arrested for two reasons: (1) the introduction of hydrocarbons causes a fall in effective burial stress, and (2) adsorption of polar hydrocarbons on the silicates may shield calcite from the silicates.

How burial diagenesis of chalk sediments controls sonic velocity and porosity

The complex conductivity of soils remains poorly known despite the growing importance of this method in hydrogeophysics. In order to fill this gap of knowledge, we investigate the complex conductivity of 71 soils samples (including four peat samples) and one clean sand in the frequency range 0.1 Hz to 45 kHz. The soil samples are saturated with six different NaCl brines with conductivities (0.031, 0.53, 1.15, 5.7, 14.7, and 22 S m21, NaCl, 258C) in order to determine their intrinsic formation factor and surface conductivity. This data set is used to test the predictions of the dynamic Stern polarization model of porous media in terms of relationship between the quadrature conductivity and the surface conductivity. We also investigate the relationship between the normalized chargeability (the difference of in-phase conductivity between two frequencies) and the quadrature conductivity at the geometric mean frequency. This data set confirms the relationships between the surface conductivity, the quadrature conductivity, and the normalized chargeability. The normalized chargeability depends linearly on the cation exchange capacity and specific surface area while the chargeability shows no dependence on these parameters. These new data and the dynamic Stern layer polarization model are observed to be mutually consistent. Traditionally, in hydrogeophysics, surface conductivity is neglected in the analysis of resistivity data. The relationships we have developed can be used in field conditions to avoid neglecting surface conductivity in the interpretation of DC resistivity tomograms. We also investigate the effects of temperature and saturation and, here again, the dynamic Stern layer predictions and the experimental observations are mutually consistent.

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Complex conductivity of soils

, Vol. 55, pp. 97–128. © 2007 by Geological Society of Denmark. ISSN0011–6297.Chalk is a sedimentary rock of unusually high homogeneity on the scale where physical propertiesare measured, but the properties fall in wide ranges. Chalk may thus be seen as the ideal startingpoint for a physical understanding of rocks in general. Properties as porosity, permeability, capil-lary entry pressure, and elastic moduli are consequences of primary sediment composition and ofsubsequent diagenetic history as caused by microbial action, burial stress, temperature, and porepressure. Porosity is a main determining factor for other properties. For a given porosity, the specif-ic surface of the sediment controls permeability and capillary entry pressure. As diagenesis progress-es, the specific surface is less and less due to the calcite component and more and more due to thefine-grained silicates, as a reflection of the coarsening and cementation of the calcite crystals. Theelastic moduli, which define sonic velocity, are for a given porosity mainly controlled be the degreeof pore-stiffening cementation, which may be quantified by effective medium modeling.Diagenetic processes include mechanical compaction, pore-stiffening cementation, dissolution,and pore-filling cementation. Processes involving clay, silica, and calcite are interlinked, but progressdifferently in different localities. This partly depends on primary sediment composition, includingorganic content, which may induce the formation of concretions by microbial action. The diageneticprocesses also depend on water depth, rate of burial, and over-pressuring. These factors cause thestress, temperature and pore-pressure to increase at different rates during burial in different local-ities.

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Ida Lykke Fabricius

Papers

Adsorption of Pesticides onto Quartz, Calcite, Kaolinite, and α-Alumina

Atrazine, isoproturon, mecoprop, 2,4-D, and bentazone adsorption onto iron oxides.

How burial diagenesis of chalk sediments controls sonic velocity and porosity

Complex conductivity of soils

Chalk: composition, diagenesis and physical properties