Laurier L. Schramm
Dalhousie University
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Clays and Clay Minerals | 1982
Laurier L. Schramm; Jan C. T. Kwak
Viscosity and light-transmission measurements of dilute suspensions of montmorillonites having different exchangeable cations were used to calculate relative particle sizes as a function of cation composition, where particle size is expressed as the number of clay plates per tactoid relative to the number of plates per tactoid for Li-montmorillonite, after exchange of Li, Na, K, Cs, and Mg by Ca. Tactoid sizes increased in the order Li < Na < K < Mg < Ca, with the number of plates per tactoid relative to Li-montmorillonite varying from 1.5 for Na- to 6.1 for Ca-montmorillonite. The results for tactoid sizes derived from light transmission and those derived from viscosity data are in reasonable agreement with each other and with literature data for similar systems. Upon exchange of Ca-counterions for Li-, Na-, or K-coun-terions, a sharp initial decrease in tactoid size was observed over approximately the first 30% of cation exchange. Upon further exchange, tactoid sizes changed only slightly, but when Ca was exchanged for Cs or Mg, a much more gradual decrease in particle size was observed.РезюмеИсследовались измерения вязкости и трансмиссии света растворенных суспензии монтмориллонитов с разными обменными катионами для вычисления относительных размеров частиц как функции катионного состава. Размер частиц выражается как число глинистых пластинок на тактоид по отношениж к числу пластинок на тактоид для Li-монтмориллонита после обмена Li, Nа, K, Сs, и Мg ионом Са. Размеры тактоидов увеличивались в порядке Li < Na < K < Мg < Са, с числом пластинок на тактоид относительно к Li-монтмориллониту, изменяющимся от 1,5 для Иа- до 6,1 для Са-монтмориллонита. Результаты для размеров тактоидов, полученные из трансмиссии света и из данных по вязкости, находятся в довольно хорошем согласии между собой, а также с лиитературными данными для похожих систем. Во время обмена Са-противоионов на Li-, Na-, или K-противоионы, наблюдалось сильное начальное уменьшение размеров тактоидов, приблизительно, во время первых 30% катионного обмена. Во время следующего обмена размеры тактоидов изменялись незначительно, но наблюдалось более постепенное уменьшение в размерах частиц когда ион Са обменялся на Сз или Мg. [Е.С.]ResümeeEs wurden Viskositäts- und Lichtdurchlässigkeitsmessungen an verdünnten Suspensionen von Montmorilloniten mit unterschiedlichen austauschbaren Kationen verwendet, um die relativen Teilchengrößen als die Funktion der Kationenzusammensetzung zu berechnen. Dabei wird die Teilchengröße als die Zahl der Tonblättchen pro Taktoid im Verhältnis zur Blättchenzahl pro Taktoid für Li-Montmorillonit nach dem Austausch von Li, Na, K, Cs, und Mg durch Ca ausgedrückt. Die Taktoidgrößen nahmen in der Reihenfolge Li < Na < K < Mg < Ca zu, wobei die Blättchenzahl pro Taktoid im Verhältnis zu Li-mont-morillonit von 1,5 für Na-Montmorillonit bis 6,1 für Ca-Montmorillonit variierte. Die Ergebnisse für die Taktoidgrößen aus den Lichtdurchlässigkeitsmessungen stimmen sowohl mit denen aus den Viskositätsmessungen als auch mit Ergebnissen aus der Literatur für ähnliche Systeme recht gut überein. Nach dem Austausch von Ca-Gegenkationen für Li-, Na- oder K-Gegenkationen wurde eine schnelle anfängliche Abnahme der Taktoidgröße beobachtet, die etwa die ersten 30% des Kationenaustausches betraf. Nach weiterem Austausch veränderte sich die Taktoidgröße nur wenig. Wenn aber Ca für Cs oder Mg ausgetauscht wurde, war eine kontinuierlichere Abnahme der Teilchengröße zu beobachten. [U.W.]RésuméDes mesures de viscosité et de transmission lumineuse de suspensions diluées de montmorillo-nites ayant différents cations échangeables ont été utilisées pour calculer les tailles de particules relatives en fonction de composition de cations, où la taille de particule est exprimée comme le nombre de plaques d’argile par tactoide relativement au nombre de plaques par tactoide pour la montmorillonite-Li, après échange de Li, Na, K, Cs, et Mg par Ca. Les tailles tactoides ont augmenté dans l’ordre: Li < Na < K < Mg < Ca, avec le nombre de plaques par tactoide relatif à la montmorillonite-Li variant de 1,5 pour la montmorillonite-Na, et 6,1 pour la montmorillonite-Ca. Les résultats pour les tailles tactoides dérivés de la transmission lumineuse et ceux dérivés de données de viscosité sont en accord raisonnable, et sont aussi en accord raisonnable avec les données de la littérature pour des systèmes semblables. Lors de l’échange de contre-ions Ca pour des contre-ions Li, Na, ou K, une forte diminution initiale de la taille tactoide a été observée pendant approximativement les premiers 30% d’échange de cations. Lors d’échange supplémentaire, les tailles tactoides n’ont changé que modérément, mais lorsque Ca a été échangé pour Cs ou Mg, une diminution de taille de particule beaucoup plus graduée a été observée. [D.J.]
Colloids and Surfaces | 1990
Laurier L. Schramm; Jerry J. Novosad
Abstract In enhanced oil recovery methods using gas flooding, foam injection is one of the ways used to reduce fluid mobilities in a reservoir. This improves the overall sweep efficiency causing increased oil recovery by the gas. Foam stability in the presence of crude oil is thus an important factor affecting process performance. It is known that crude oil has a destabilising effect on many foams but little has been known about what factors most influence the degree of stability when foams are in contact with oil. This is the subject of this paper. Thermodynamic model predictions suggested three types, or degrees, of foam-oil interaction. Direct micro-visual observations of foam—oil interactions in an etched glass micromodel confirmed the three types of behavior. However, the model parameters, based on measured interfacial properties, did not correlate well with either the types of behavior, or the trend in foam stability (lamellae breakage frequencies). A phenomenological addition to the theory is advanced, which yields a more satisfactory correlation with foam lamellae breakage frequencies. In the systems studied, the operative mechanism of foam—oil interaction appears not to involve spreading of oil. Rather, foam stability in the presence of oil seems to depend upon the degree to which oil becomes emulsified and imbibed into foam lamellae. Both emulsification of oil into small drops and extensive imbibition of the drops are associated with an increased tendency toward thinning of lamellar (pseudoemulsion) films, leading to rupture. In the glass micromodel used here, the most oil-resistant foams were those which allowed the smallest degrees of emulsification and imbibition.
Journal of Petroleum Science and Engineering | 1991
Laurier L. Schramm; Jerry J. Novosad
Abstract This paper describes an investigation into the effects of four different oils on the stability of foams that could be used in enhanced oil recovery (EOR). There can be strong interactions between foams and oils. Model predictions and microvisual observations indicate that degrees of oil sensitivity occur, ranging from quite stable foams, with little oil interaction, through quite unstable foams, due to oil penetration into the foam. The stability of these foams was found to correlate with the lamella number, an indicator of the forces favouring oil emulsification and imbibition into foams in porous media. Among three crude oils, foam stability in the presence of oil decreased as the “heaviness” of the crude oil decreased. Since the oil sensitivity of foams can be described in terms of surface properties, the present results can be used to set foam-oil stability criteria for the selection of foam flooding surfactant candidates.
Colloids and Surfaces | 1991
Laurier L. Schramm; Karin Mannhardt; Jerry J. Novosad
Abstract The surface charge properties of Berea sandstone (and its major components), Indiana limestone and Baker dolomite in concentrated electrolyte solutions were investigated. This was accomplished by crushing the rocks into fine particles which were then suspended in aqueous solutions to permit electrokinetic measurements. The electrophoretic mobilities (zeta potentials) of the particles were determined as functions of pH, ionic strength and ionic composition in ranges that are of interest in enhanced oil recovery (EOR) processes. To achieve this, it was necessary to investigate electrokinetic behaviour at much higher ionic strengths than are normally reported in the literature. In general, the Berea sandstone and its constituent quartz and clay fractions adopted a negative charge in the aqueous solutions, the magnitude of which was significantly influenced by pH, the ionic strength and the degree of hardness in the electrolyte solution. Under some conditions severe charge reduction and charge reversal were observed. The limestone and dolomite were more dramatically influenced by both pH and the presence of multivalent cations. The magnitude of the surface charges varied considerably and could adopt positive or negative surface charges depending on the solution properties. The sensitivity of these reservoir minerals to small changes in solution properties carries potentially serious implications for any EOR process whose efficiency depends indirectly on the rock surface charge. Examples would include the adsorption of surfactants, particularly ionic and amphoteric surfactants, and the chemical mobilization of fines causing permeability damage.
Colloids and Surfaces | 1990
Kevin C. Taylor; Laurier L. Schramm
Abstract The conventional spinning drop technique does not always provide a clear representation of dynamic interfacial tension behavior because it places a lower limit on the interfacial ages that can be examined. A modification of the conventional technique is described which extends the accessible range to interfacial ages as short as two seconds. By injecting an oil drop into an already spinning tube and simultaneously recording the injected drop image with a video camera, measurements can be made much more quickly than usual. This modification allows the lower limit of interfacial age measurement to be reduced from 1–2 min to two seconds. Maintaining the same drop volume and spinning velocity allows results from the conventional and extended techniques to be combined into a single representation. The application of this modified technique is illustrated for crude oil/surfactant enhanced alkaline systems of interest in enhanced oil recovery research. Such systems exhibit complex dynamic interfacial tension behavior including minima which vary in both the magnitude and the interfacial age at which they occur. With the extended technique a more complete characterization was obtained than would have been possible previously.
Colloids and Surfaces | 1982
Laurier L. Schramm; Jan C. T. Kwak
Abstract Mean ionic activity and anion exclusion data based on membrane equilibria are reported for a series of alkali- and alkaline earth-forms of montmorillonite. Mean ionic activity coefficients can be described rather well by a simple additivity principle, from which counterion activity coefficients are estimated. These latter varied in a regular fashion from 0.1 for Li-form suspensions to as low as 0.01 for the Ca-form. The trend of low counterion activity coefficients for the more strongly preferred ions is reflected as well in the calculated anion exclusion volumes. The results are discussed in terms of the formation of clay tactoids which can be observed in such suspensions. It is demonstrated that tactoid formation model can describe the ionic distributions in suspension for the cases where diffuse double layer theory for single clay plates is inappropriate.
Spe Reservoir Engineering | 1993
Laurier L. Schramm; Alexandru T. Turta; Jerry J. Novosad
Foam stability in the presence of crude oil is important to foamflood performance. Microvisual observations were made to assess the degree of foam-lamella/oil interactions occurring between a light crude oil and foams being considered for foam flooding applications in Alta., Canada. Foam behaviors ranged from quite stable, with almost no foam/oil interactions, to quite unstable, where oil was extensively emulsified and imhibed into the foam. These behaviors matched phenomenological model predictions and also were consistent with coreflood mobility reduction factors and incremental oil recoveries obtained in foam flow experiments in Berea sandstone cores at ambient temperature, low pressure, and residual oil saturation (ROS)
Colloids and Surfaces | 1992
Karin Mannhardt; Laurier L. Schramm; Jerry J. Novosad
Abstract Surfactant adsorption studies carried out with surfactants suitable for mobility control by foams in gas-flooding enhanced oil recovery are described. The extent of adsorption of three surfactants (an anionic surfactant, a betaine, and a sulfobetaine) is measured on four types of rock representing reservoir materials (berea sandstone, Indiana limestone, Baker dolomite and quartz) from three brines (a sodium chloride solution and two synthetic reservoir brines with different concentrations of total dissolved solids). This allows the assessment of the effects of surfactant type, rock type, brine salinity and the presence of divalent cations on surfactant adsorption. In order to probe into adsorption mechanisms, an attempt is made to correlate adsorption levels with rock surface charges. Adsorption of the anionic surfactant on sandstone and dolomite is significantly lower than that of both amphoterics, while adsorption of the amphoterics on limestone is similar to or lower than adsorption of the anionic surfactant. The presence of divalent cations increases the adsorption of the anionic surfactant and the betaine on sandstone and limestone, but has very little effect on the adsorption of the sulfobetaine on all rocks, or on the adsorption of all three surfactants on dolomite. The effect of the total dissolved solids concentration in the brine on adsorption is different for different surfactant/rock combinations. A correlation of surfactant adsorption with rock surface charge shows that adsorption of the anionic surfactant is consistent with an electrostatic mechanism of adsorption. Adsorption of both amphoteric surfactants occurs through a complex interplay of mechanisms, some of which can be suggested from the observed trends.
Journal of Petroleum Science and Engineering | 1996
Laurier L. Schramm; Karin Mannhardt
Abstract We evaluated foam-oil sensitivity in oleophilic (oil- or intermediate-wetting) media compared with hydrophilic (water-wetting) media. The porous media used were either Berea sandstone or glass microvisual cells with and without Quilon C coating (hydrophilic or oleophilic). Dynamic contact angle measurements on untreated and Quilon C-treated glass showed that the treatment makes the glass microvisual cells intermediately wet. Microvisual studies showed that foams tend to be more sensitive (less effective) to oil at residual oil saturation when the pores are intermediately wet as opposed to water-wet. These studies show that, at least for glass plates, the surfactants can adsorb and partially reverse the wettability, back towards water-wet. Coreflood tests using treated and untreated Berea sandstone rock show that the Quilon C treatment also changed the wettability of the rock away from water-wetting. In most cases the foam effectiveness was reduced in oleophilic rock over hydrophilic rock (oil-free). At residual oil saturation foam effectiveness for most foams was further reduced in oleophilic-treated rock over hydrophilic rock. This work confirms earlier suggestions that foam effectiveness may be reduced in porous media of intermediate or oleophilic wettability and that the foam effectiveness may be further reduced at residual oil saturation. Surfactant selection for field use should be made taking into account the actual reservoir conditions under which they will be used, including nature of the oil, Sor and wettability. The results of this research should provide some guidance for this purpose.
Journal of Surface Science and Technology | 1991
Ove Kvammen; Arne Skauge; Yan-Ru Zhou; Fang Wang; B. Y. Pu; Stanley Hartland; M. di Fruscio; A. K. Chattopadhyay; S. Acevedo; H. Rivas; S. K. Nanda; K. L. Goyal; Anil Bhardwaj; N. D. Sharma; Ramesh Kumar; V. N. Mathur; Karin Mannhardt; Laurier L. Schramm; Jerry J. Novosad; Trilok Chand; K. L. Patel; D. Datta; S. S. Marsden; J. M. Farrell; D. V. Mohan Rao; Y. Rambabu; K. V. Ram Prasad; Prabha R. Chatterji; R. C. Gaur; T. El Ouriaghli
The change in microemulsion phase behavior from contact with a laboratory crude oil (stock tank oil) to the contact by a live reservoir fluid is a combination of two effects. First the composition of the oil is different and there is also an effect of the change in pressure (Skauge and Fotland, SPE 14932) on the microemulsion phase behaviour. We have studied the effect of change in the molar volume of the oil on the phase behaviour of microemulsions. The experiments have been performed by changing the oil components with regard to both molecular weight and molecular structure. Static phase behaviour measurements have been performed at 22, 50 and 90°C. The changes in solubilization and optimal salinity are discussed in regard to the properties of the oleic phase. The effects of pressure (1–220 bar), and also the addition of gas (methane) have been determined. The change in phase behaviour with increase in pressure is found to be a function of the change in oil density versus pressure. Comparing the phase behaviour of alkanes or alkylbenzenes to that of a reservoir crude makes it possible to identify a synthetic oil having the same properties as the reservoir fluid.