Role Of Clays Research Articles

Retention Of Foam-Forming Surfactants At Elevated Temperatures

Abstract There is considerable interest in the use of foam-forming surfactants for mobility control in steamfloods. To provide effective mobility control, the injected surfactant must propagate from the injection well toward the production well. One of the important parameters affecting foam propagation through the reservoir is the retention of surfactant due to its adsorption on reservoir rock. Because the foam encounters a range of temperatures and salinities between the injection and production wells, it is necessary to evaluate the temperature and salinity dependence of surfactant adsorption. This paper reports on the results of adsorption measurements an elevated temperatures for two typical commercially available surfactants currently in use for such applications an alpha olefin sulphonate and a synthetic alkyl toluene sulphonate. Adsorprion experiments were performed in unconsolidated sand cores of temperatures ranging from 50 °C to 150 °C The role of clays in surfactant adsorption was investigated by comparing the results obtained in clean sand with those obtained in cores containing known amounts of clays. Surfactant adsorption was de/ermined from surfactant concentration profiles at the core outlet. This analysis can be used for evaluating the whole adsorption isotherm provided a specific adsorption model (for example, the Langmuir isotherm) is assumed. Automatic history matching procedures for that purpose were tested and their efficiency evaluated. The results show that adsorption of both surfactants in clean sand is relatively low and decreases with increasing temperature. The alkyl toluene sulphonate was found to adsorb more than the alpha olefin sulphonate, and its adsorption was more strongly affected by salinity. The presence of clays in the core resulted in increased surfactant adsorption. Introduction The injection of foam-forming surface active agents in steamflooding applications has the potential for improving the performance of this enhanced oil recovery (EOR) process by two mechanisms. It can improve conformance by reducing steam mobility in the steam zone, and it can increase the oil displacement efficiency in the swept zone. Irrespective of which mechanism is dominant, for economic reasons it is desirable to inject the lowest surfactant concentration which is still effective in improving oil recovery. The rate of propagation of dilute surfactant solutions through the reservoir may be strongly affected by adsorption of the injected surfactant on reservoir rock surfaces. Thus the evaluation of surfactant adsorption should always be included when assessing the effectiveness of the surfactant in improving steamflood performance. As the injection of steam may result in large temperature and salinity gradients in the reservoir, a complete evaluation of surfactant adsorption requires its measurement over a wide range of temperatures and salinities. This paper describes the results of adsorption measurements for two types of commercially available foam-forming surfactants, an alpha olefin sulphonate and a synthetic alkyl toluene sulphonate. Adsorption of these two surfactants in unconsolidated cores saturated with either distilled water or a lowsalinity synthetic brine was evaluated at three temperatures. The solid used in the study was either a clean silica sand or a mixture of the sand and one of two types of pure clays montmorillonite and kaolinite.

Role of clays in the disposal of nuclear waste: A review

Applied and basic sciences of clay mineralogy have played significant roles in radioactive waste disposal practices. Clays and clay minerals as in situ lithologic components and engineered barriers are characterized by favorable properties from the viewpoint of radioactive-waste emplacement. Their high sorptivity, longevity, and low permeability make them promising candidates for retaining most natural and anthropogenic long-lived radionuclides within the contaminated and engineered disposal sites. In this review the following subjects are discussed: (1) source-term classification and current and proposed disposal methodology of low-level and high-level wastes: (2) selected physicochemical properties of clays pertinent to site characterization, grouting, and impermeable barrier components; (3) application of clays in current and future waste disposal practices.

Hydrous FE and MN oxides — scavengers of heavy metals in the aquatic environment

The behavior of heavy metals in a natural aqueous system is attracting researchers because of environmental issues. Man's activities have increased the quantity and distribution of heavy metals in the atmosphere, on the land, and in rivers, lakes, and seas. The extent of this widespread contamination has caused concern about its possible effects on plants, animals and human beings. One of the first steps in any systematic study of the aquatic chemistry of a potential contaminant is an elucidation of the principal modes of transport and sinks for the contaminant. It appears that a large proportion of the metallic substances discharged into water bodies is ultimately incorporated into sediments. (Warren, L. J.,112 and others). The sediment is a complex mixture with three main components: clays, organic matter, and oxides of iron and manganese. While the role of clays and biota in affecting the transport of heavy metals is commonly recognized, the significance of Fe and Mn among the factors that are involved...

Role of Clays in the Enhanced Recovery of Petroleum From Some California Sands

Summary Many oil-producing formations contain significant amounts of clay. Because of the large surface area and the high reactivity of such surfaces. the response of the formations to various recovery processes may be dominated by the reactions of the clays. Thus, the success or failure of enhanced oil recovery (EOR) methods may be controlled to a large extent by the amount and type of clays in the formations to which the methods are being applied. This paper evaluates the type and amounts of clays and clay minerals present in typical oil-producing formations that may be candidates for application of EOR methods. After identification of the clay minerals present, tests are run on the extracted clay fractions to determine cation-exchange capacities (CEC's), surface areas, and chemical-loss characteristics. Flood tests are run on core samples to evaluate the magnitude of chemical loss and to note the change in flow characteristics while different fluids, which might be used in EOR operations, are flowed through the core. This background material is used to test predictive equations developed for screening reservoirs for EOR applications and for optimizing process variables. Techniques to counter the effects of rock/fluid interactions are considered. Introduction Because of the large effective surface areas of clays contained in oil reservoir formations and because of the high degree of reactivity of such surfaces, clays may play a disproportionate role in the success or failure of EOR techniques. Clays adsorb many substances that may be injected into the reservoir to improve oil recovery. In many cases. surfactants and polymers adsorb on clay surfaces in sufficient amounts to make the recovery process uneconomical. The ion-exchange capacity of clay minerals may have two detrimental effects:release of divalent ions can cause surfactant precipitation, increased surfactant oil solubility, loss of ultralow interfacial tension, and polymer degradation;ion-exchange reactions with concomitant surface-charge effects may cause structural damage to the formation. Clay swelling and migration of fines also may result from causes other than changes in the system chemistry. For example, rate effects are important in fines migration. Rapid changes in flow rate, salinity, or temperature may cause plugging, whereas only negligible plugging may result if the rates of change are decreased. Many oil reservoir formations contain substantial amounts of fines including considerable amounts of clay minerals. Screening tests must be conducted on object formations to provide information on potential problems and to suggest means of minimizing their effects. There also are possibilities that certain clay mineral components can be used advantageously in mobility control. This is particularly important in heterogeneous formations containing viscous residual oils. Test Program The overall objectives of this research program are to evaluate the effects that clays present in typical oil-producing formations have on the failure or success of EOR operations. Methods of dealing with the detrimental effects of clays and enhancing the favorable characteristics of clays, if any, are explored. JPT P. 643^

Clay and the origin of life.

Research concerning the possible role of clay in chemical evolution is reviewed. The probable importance of clays in the origin of life is assessed.

Importance of Physical Properties of Clays in Oil Formation and Migration: ABSTRACT

Many source rocks have argillaceous matrixes. Until recently, only chemical interactions between clay minerals and organic matter (catalytic effect) have been given serious consideration. It appears now that the physical or physico-chemical properties of clays also play a key role in the processes of primary migration of oil. Among these properties are (1) microstructure of clays which influences the porosity and permeability in both the water and oil phase, (2) mechanical behavior of clays which may contribute to the microfracturing processes thus allowing the expulsion of oil from source rocks, and (3) physico-chemical properties of adsorption and wettability of clays which act strongly because of the high specific area of clay minerals. This property may influence the ermeability of clay shales. In addition, adsorption is selective toward various components generated by organic matter, thus explaining major differences observed between the composition of source rock extracts and reservoir oils. On a larger scale, such as anticlinal structures, clays are commonly the origin of fluid pressure anomalies. High pressures modify the flow system, since fluids are drained preferably by the tops of structures. The flow of water due to natural convection eventually may cause the alteration of clay minerals and enhance the permeability of the overpressured sections beneath the pressure seal. This process contributes to the modification of geothermal conditions in undercompleted rocks where poor thermal conductivity conditions exist. These combined effects influence both the nature and spatial distribution of hydrocarbons trapped in reservoirs. Therefore, a better knowledge of the physical properties of clays should lead to a better understanding of the role of clays in the formation and migration of oil and gas and thus lead to better exploration practices. End_of_Article - Last_Page 1447------------

Future of Clay and Clay Based Industries—A Review

The clay reserves of Kerala as well as of India as a whole and the world have been reviewed. Fine mapping charts of conventional and non-conventional uses of clay have been given. All uses have been indexed in consideration of their applicability and adaptation in India. A table giving the amount of various clays used in different Indian industries has been made. Certain new uses of clay as filler and reinforcement in metals, as a source of Al-Si alloys and as a material for making light weight insulating materials have been discussed. The imperative to develop new processes for some of the newer clay-based products have been listed. The role of clay in alleviating the energy crisis by acting as insulating materials and acting as a means of producing oxygen enriched air has been amplified. Research activities on clays in India have been discussed. The world-wide need to use materials based on abundant alumino-silicate materials in place of scarcer materials has been elaborated.

The role of clays in oil formation

(1976). The role of clays in oil formation. International Geology Review: Vol. 18, No. 2, pp. 125-136.

The possible role of clays in prebiotic peptide synthesis

Hypotheses of macromolecule formations during the prebiotic era are described. The presumed role of minerals and clays in these reactions are: concentration of monomers, proton release by ion exchange whenever the reaction demands it, scattering of the charges of the interacting substances, thus allowing such substances to interact, which in the absence of clays repel each other due to their charges. Because of these reasons the polymerization mechanism in the presence of clays is different from that in their absence. While in the absence of clays only free amino acids or peptides can interact with active amino acid anhydrides, giving thus peptides increased by only one unit, in the presence of clays two molecules of amino acid anhydrides can interact, giving a still active peptide anhydride which can interact with another active peptide. Clays catalyze polymerization only in these cases where the amino acid is small enough to enter between the sheets of the clay. Apparently most of the reactions also occur there and not on the surface of the clay. Copolymerization of different pairs of amino acids proceeds selectively in the presence of clay. The relationship between this selecitvity and prebiotic parent proteins is discussed.

LAKE KINNERET: THE NUTRIENT CHEMISTRY OF THE SEDIMENTS1

Lake Kinneret plays an important role in the water supply of Israel. Since the sediments may actively contribute to the nutrient supply causing the winter algal bloom, an extensive study of the mud‐water exchanges has been undertaken; the first results are reported here. The concentrations of Fe, Mn, P, N, organic‐C, and CaCO3 in recent sediments have been determined for the whole lake and the results discussed in the light of the chemical conditions of bottom waters, the detrital input, and the plankton composition. Only 4% of the total autotrophic carbon is withdrawn from the lake cycle by the sediments. The lake muds concentrate phosphorus in spite of the prevailing reducing conditions, which suggests an active physical adsorption. Conclusions are drawn concerning the role of clays as “nutrient fixer” and concerning lake management.

Chemical Studies on the Stability of Soil Aggregates (Part 1) : On the Role of Clay and Organic Matter in the Affregate Formation of Soils

Chemical Studies on the Stability of Soil Aggregates (Part 1) : On the Role of Clay and Organic Matter in the Affregate Formation of Soils

Role of Clay in Well-Log Interpretation

Role of Clay in Well-Log Interpretation