Interfacial Tension at Elevated Pressures and Temperatures. I. A. New and Improved Apparatus for Boundary- Tension Measurements by the Pendent Drop Method

1948 ◽  
Vol 52 (7) ◽  
pp. 1157-1165 ◽  
Author(s):  
E. A. Hauser ◽  
A. S. Michaels
Keyword(s):  
Interfacial Tension ◽  
Drop Method ◽  
Elevated Pressures ◽  
Pendent Drop

A Study of Caustic Solution-Crude Oil Interfacial Tensions

1975 ◽  
Vol 15 (03) ◽  
pp. 197-202 ◽  
Author(s):  
Harley Y. Jenning
Keyword(s):  
Interfacial Tension ◽  
Crude Oil ◽  
Sodium Hydroxide ◽  
Surface Activity ◽  
Acid Number ◽  
Caustic Solution ◽  
Crude Oils ◽  
Interfacial Tensions ◽  
Drop Method ◽  
Pendent Drop

Abstract This paper presents the results of a study of caustic solution-crude oil interfacial tension measurements on 164 crude oils from 78 fields. Of these crude oils 131 showed marked surface activity against caustic solutions. Surface activity of crude oil against caustic solution correlates with the acid number, gravity, and viscosity. Almost all crude oils with gravities of 20 degrees API or lower produced a caustic solution-crude oil interfacial produced a caustic solution-crude oil interfacial tension less than 0.01 dyne/cm. Of the interfacially active samples, 90 percent reached maximum measurable surface activity at a caustic concentration of close to 0.1 percent by weight. The dissolved solids content of the water bas a marked influence on the surface activity. Sodium chloride in solution reduces the caustic concentration required to give maximum surface activity. Conversely, calcium chloride in solution suppresses surface activity. Introduction The oil-production technology literature contains a number of papers that indicate that the addition of sodium hydroxide to the flood water beneficially affects oil recovery. Although the proposed recovery mechanisms differ in detail, a variable common to almost all is the interfacial tension between caustic solutions and crude oil. A study of the factors influencing caustic solution-crude oil interfacial tensions is fundamental to an understanding of the proposed mechanisms and their optimum utilization. proposed mechanisms and their optimum utilization. We have obtained interfacial tensions against caustic solutions of 164 crudes. These crudes come from all major oil-producing areas in the free world. In addition to determining the correlation of interfacial tension with crude oil properties of acid number, gravity, and viscosity, we have also determined the effect of certain dissolved solids in the water. We define acid number as the number of milligrams of potassium hydroxide required to neutralize the acid in one gram of sample. The interfacial tension data were obtained by the pendent-drop method. pendent-drop method. EXPERIMENTAL PROCEDURE The caustic solutions used in this study were prepared by adding reagent-grade sodium hydroxide prepared by adding reagent-grade sodium hydroxide to laboratory distilled water. Our standard solutions were made from a 50 percent by weight reagent-grade sodium hydroxide solution. For convenience in relating our laboratory data to possible field application, the data were recorded and plotted in terms of weight percent sodium hydroxide. The pH of the caustic solutions was determined experimentally using a Coming expanded-scale pH meter; and the densities of the caustic solutions were measured experimentally using a Chainomatic Westphal balance. CRUDE OILS The crude oils were protected from the atmosphere and were collected in carefully cleaned glass or, when practicable, in plastic-lined containers. The crude oil samples were free of chemical additives, such as emulsion breakers and corrosion inhibitors. If the oil contained suspended solid material it was dehydrated and filtered. The densities were determined by the Westphal balance; and the viscosities were determined as a function of temperature using a glass capillary viscometer. APPARATUS AND EXPERIMENTAL PROCEDURE The interfacial tension measurements described in this study were made by the pendent-drop method. The pendent-drop method is based on the formation of a drop of liquid on a tip, the drop being slightly smaller than that which will spontaneously detach itself from the tip. The profile of this drop is magnified by projection and can be recorded on a photosensitive emulsion. The interfacial tension is photosensitive emulsion. The interfacial tension is calculated from the dimensions of the drop profile, a knowledge of be densities of the liquid forming. the drop, and the bulk phase surrounding the drop. All interfacial tensions described in this paper were recorded at a temperature of 74 degrees F and at an interface age of 10 seconds. Most systems were studied as a function of temperature; but temperature was found to be a second-order effect, so we selected 74 degrees F in order that all correlations would be at constant temperature. We selected 10 seconds because a study of the time variable showed that most of the decay of interfacial tension with time in these systems had occurred by the end of 10 seconds. SPEJ P. 197

The Effect of Temperature and Pressure on the Interfacial Tension of Water Against Methane-Normal Decane Mixtures

1971 ◽  
Vol 11 (02) ◽  
pp. 171-175 ◽  
Author(s):  
Harley Y. Jennings ◽  
George H. Newman
Keyword(s):  
Stainless Steel ◽  
Interfacial Tension ◽  
Water System ◽  
Visual Cell ◽  
Density Data ◽  
Interfacial Tensions ◽  
Drop Method ◽  
Temperature And Pressure ◽  
Live Oil ◽  
Pendent Drop

Abstract The interfacial tension of water against mixtures of methane and normal decane bas been measured in the interval 74 to 350 degrees F and 14.7 to 12,000 psia. These measurements show the range of interfacial-tension values obtained with water against an ideal "live-oil" system under reservoir conditions of temperature and pressure. The interfacial-tension data were obtained by the pendent drop method. The density data used for pendent drop method. The density data used for the pendent drop calculations were based on visual cell pressure volume measurements of the mutually saturated phases. Seven systems covering the methane-decane composition range from 100 percent decane to 100 percent methane were studied at three temperatures and 11 pressure intervals in the single-phase, hydrocarbon region. A minimum in the interfacial-tension vs methane-decane composition curve was observed. The minimum occurred at about the same composition in each isotherm, namely, with a mixture containing nearly equal weights of methane and decane. Both temperature and pressure affected the interfacial tension. For some compositions at constant pressure the interfacial tension increased with increased temperature. Introduction Although crude oil usually occurs in the formation saturated to some degree with methane, interfacial-tension data for methane-oil mixtures against water have not been published. These data are fundamental to an understanding of the role of interfacial forces in oil recovery and provide a basis for interpreting the interfacial tensions against water obtained with "live" crude-oil systems. We obtained interfacial tensions against water for an ideal "live-oil" composed of mixtures of methane and normal decane. Portions of this three-component (water, methane, normal decane) system have been studied and reported and these data serve as limits for our results. Hough et al. presented data for the methane-water system at presented data for the methane-water system at temperatures to 280 degrees F and pressures to 15,000 psia. Stegemeier studied the two-phase methane-decane system to 183 degrees F and 5,100 psia, and Jennings published results for the normal psia, and Jennings published results for the normal decane-water system to 350 degrees F and 12,000 psia. In this study we have obtained data for water-oil interfacial tension as a function of temperature to 350 degrees F. and pressure to 12,000 psia, using a series of live oils of known composition. The interfacial-tension data were obtained by the pendent drop method. EXPERIMENTAL MATERIALS Laboratory distilled water was redistilled into a steam-cleaned pyrex receiver connected to the atmosphere through an ascarite tower. The hydrocarbons used in this study were pure-grade normal decane and instrument-grade methane, both obtained from the Phillips Petroleum Co. The decane was further purified by fractional chromatography. APPARATUS The interfacial-tension measurements were made by the pendent drop method utilizing an apparatus designed to permit measurement of interfacial-tension values as low as 0.001 dynes/cm under high temperature and pressure. A novel feature of this apparatus is a pendent drop tip-holding turret designed to permit five tips to be rotated into position under operating conditions. The visual cell containing the turret is made of stainless steel, 4.5 in. in diameter and 7.5 in. long. The windows are glass discs 1.5 in. in diameter and 0.75 in. thick. All valves and connecting lines are of stainless steel and teflon seals are used throughout the apparatus. SPEJ P. 171

Physical Characteristics of Natural Films Formed at Crude Oil-Water Interfaces

1966 ◽  
Vol 6 (02) ◽  
pp. 153-165 ◽  
Author(s):  
O.K. Kimbler ◽  
R.L. Reed ◽  
I.H. Silberberg
Keyword(s):  
Interfacial Tension ◽  
Crude Oil ◽  
Oil Recovery ◽  
Interfacial Area ◽  
Physical Characteristics ◽  
Petroleum Production ◽  
Drop Method ◽  
Oil Water ◽  
Interfacial Films ◽  
Pendent Drop

Abstract Interfacial films have frequently been observed at interfaces between certain crude oils and water. Several investigators have postulated that the presence of these films should influence the efficiency of oil recovery in water drive or waterflood operations. They may also influence the stability of emulsions which are sometimes a problem in petroleum production, and may be a factor in the formation of paraffin deposits in oil well tubing and flow lines. This paper presents a technique with which a modified Langmuir film balance may be used to study the compressibility and collapse pressure of these natural interfacial films. Experimental data are presented for several crude oil-water systems. Data developed are used to infer the phase state of the film as a function of such variables as rate of reduction of interfacial area, ionic composition of the subtrate and pH of the subtrate. A film of known physical characteristics is shown to have a significant effect on oil recovery from an unconsolidated sand pack. Possible applications of these results to petroleum production are discussed. INTRODUCTION The use of water to displace petroleum from reservoir rocks is of major importance both as a primary and a secondary recovery process. As water invades the rock, oil is completely displaced from some pores and left as a discontinuous phase in other pores. The manner in which water moves from pore to pore is strongly influenced by capillary forces. In view of the complexity of reservoir fluid systems, there can be little doubt that complicated interactions take place at both the liquid-solid and oil-water interfaces. One of the more interesting, and least understood, of the phenomena which take place at the oil-water interface is the formation of interfacial films. These films are believed to result from the adsorption of high molecular weight polar molecules at the interface.1,2 Presence of such molecules may cause a striking alteration in interfacial tension. When the oil-water interfacial area of certain crudes is rapidly reduced, a thin region (film) about the interface assumes the appearance of a solid membrane, and striations, wrinkles and gross distortions may occur. If such a film is solid, it should greatly alter the interfacial tension normally assumed to exist between the oil and water phases. If the membrane is continuous, a solid phase would separate the oil and water. Interfacial films between crude oil and water were observed in 1949 by Bartell and Niederhauser3 who commented upon the apparent rigidity of the films and their possible importance in the petroleum industry. Morrell and Egloff4 had earlier attributed the extreme stability of emulsions of sea water in fuel oil to very stable asphaltic films. Numerous investigators have observed rigid films in the course of crude oil-water interfacial tension determinations by the pendent drop method. Several investigators5,6,2 have separated interfacially active materials from crudes and attempted to characterize them chemically. Reisberg and Doscher,2 using Ventura crude, showed the interfacial tension against water (as measured by the pendent drop method) to be affected by aging, contraction and expansion of the interface, and the pH of the water. These investigators attributed the adhesion of oil to a water-wetted surface and the distortions of flow paths in glass capillaries to the presence of rigid films. Dodd7 has studied the interfacial viscosity of adsorbed films and found them to be non-Newtonian in behavior. Craighead and Harvey8 reported a series of displacements in tubes packed with 60 mesh glass beads. They interpreted the results as indicating an effect of stearic acid films on waterflood recovery and imply that natural films may produce similar results.

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