scholarly journals Experimental investigation of asphaltene phase behavior for live crude oil-Precipitation, re-dissolution and molecular weight characteristics-

2009 ◽  
Vol 74 (3) ◽  
pp. 225-233
Author(s):  
Yoshihisa Hayashi ◽  
Hajime Asayama ◽  
Komei Okatsu
Keyword(s):  
Molecular Weight ◽  
Experimental Investigation ◽  
Crude Oil ◽  
Phase Behavior ◽  
Molecular Weight Characteristics

Interfacial Tension and Phase Behavior of Surfactant Systems

1978 ◽  
Vol 18 (04) ◽  
pp. 242-252 ◽  
Author(s):  
W.H. Wade ◽  
James C. Morgan ◽  
R.S. Schechter ◽  
J.K. Jacobson ◽  
J.L. Salager
Keyword(s):  
Molecular Weight ◽  
Interfacial Tension ◽  
Crude Oil ◽  
Phase Behavior ◽  
Oil Recovery ◽  
Surfactant Concentration ◽  
Low Molecular Weight ◽  
Middle Phase ◽  
Surfactant Systems ◽  
Low Tension

Abstract The conditions necessary for optimum low tension and phase behavior at high surfactant concentrations are compared with those required at low surfactant concentrations, where solubilization effects are not usually visible. Major differences in tension behavior between the high and low concentration systems may be observed when the surfactant used contains a broad spectrum of molecular species, or if a higher molecular weight alcohol is present, but not otherwise in the systems studied. We compared the effects of a number of aliphatic alcohols on tension with phase behavior. An explanation of these results, and also of other observed parameter dependences, is proposed in terms of changes in surfactant chemical potential. Surfactant partitioning data is presented that supports this concept. Introduction Taber and Melrose and Brandner established that tertiary oil recovery by an immiscible flooding process should be possible at low capillary process should be possible at low capillary numbers. In practice, the required capillary number, which is a measure of the ratio of viscous to capillary forces governing displacement of trapped oil, may be achieved by lowering the oil/water interfacial tension to about 10(-3) dyne/cm, or less. Subsequent research has identified a number of surfactants that give tensions of this order with crude oils and hydrocarbon equivalents. Interfacial tension studies tended to fall into two groups. Work at low surfactant concentrations, typically 0.7 to 2 g/L, has established that a crude oil may be assigned an equivalent alkane carbon number. Using pure alkanes instead of crude oil has helped the study of system parameters affecting low tension behavior. Important parameters examined include surfactant molecular structure, and electrolyte concentration, surfactant concentration, surfactant molecular weight, and temperature. At higher surfactant concentrations, interfacial tension has been linked to the phase behavior of equilibrated systems. When an aqueous phase containing surfactant (typically 30 g/L), electrolyte, and low molecular weight alcohol is equilibrated with a hydrocarbon, the surfactant may partition largely into the oil phase, into the aqueous phase, or it may be included in a third (middle) phase containing both water and hydrocarbon. Low interfacial tensions occur when the solubilization of the surfactant-free phase (or phases) into the surfactant-containing phase is maximized. Maximum solubilization and minimum tensions have been shown to be associated with the formation of a middle phase. Both the high and low surfactant concentration studies have practical importance because even though a chemical flood starts at high concentration, degradation of the injected surfactant slug will move the system toward lower concentrations. This study investigates the relationship between tension minima found with low concentration systems, and low tensions found with equivalent systems at higher surfactants concentrations, particularly those in which third-phase formation occurs. Many of the systems studied here contain a low molecular weight alcohol, as do most surfactant systems described in the literature or proposed for actual oil recovery. Alcohol originally was added to surfactant systems to help surfactant solubility, but can affect tensions obtained with alkanes, and with refined oil. Few systematic studies of the influence of alcohol on tension behavior exist. Puerto and Gale noted that increasing the alcohol Puerto and Gale noted that increasing the alcohol molecular weight decreases the optimum salinity for maximum solubilization and lowest tensions. The same conclusions were reached by Hsieh and Shah, who also noted that branched alcohols had higher optimum salinities than straight-chain alcohols of the same molecular weight. Jones and Dreher reported equivalent solubilization results with various straight- and branched-chain alcohols. In this study, we fix the salinity of each system and instead vary the molecule; weight of the hydrocarbon phase. SPEJ P. 242

Synthesis and molecular-weight characteristics of n-vinylpyrrolidone and 2-methyl-5-vinylpyridine copolymers

2012 ◽  
Vol 46 (8) ◽  
pp. 478-481 ◽  
Author(s):  
S. A. Kedik ◽  
A. V. Panov ◽  
I. V. Sakaeva ◽  
Yu. V. Kochkina(Cherta) ◽  
D. V. Eremin ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Characteristics

scholarly journals Evaporation of Heavy Crude Oil in Soil

2021 ◽  
pp. 59-62
Author(s):  
Etini Etefia ◽  
L. O. Odokuma
Keyword(s):  
Molecular Weight ◽  
Crude Oil ◽  
Pour Point ◽  
Terrestrial Ecosystem ◽  
Heavy Crude Oil ◽  
Percentage Reduction ◽  
Oil Spillage ◽  
Heavy Crude ◽  
Rate Of Evaporation ◽  
Oil Density

Heavy crude oil spillage on soil threatens productivity and affects the natural biota of the ecosystem. Evaporation is an important parameter increases crude oil density, viscosity and fraction of lower molecular weight substances which reduce its infiltration into the soil and groundwater. The evaporation of heavy crude oil showed API of 21.5, viscosity of 15mm2/s, density 0.8952 g/cm3, pour point of 11.37. The crude oil was exposed to solar radiation for 35 days. The percentage reduction in mass of the crude oil and temperature on five day interval showed 8.22(38OC) on day 0, on day 5 was 8.13(34oC), on day 10 was 5.92(39oC), on day 15 was 5.38(39oC), on day 20 was 3.16(37oC), on day 25 was 2.94(31oC), on day 20 was 2.56 (41oC) and on day 35 was 1.79(38oC). The lighter molecules evaporated first leaving the heavier molecules behind causing a reduction in the rate of evaporation with time. This analysis will be provide insight to modelling oil spill in terrestrial ecosystem.

Surfactant Retention in Berea Sandstone- Effects of Phase Behavior and Temperature

1982 ◽  
Vol 22 (06) ◽  
pp. 962-970 ◽  
Author(s):  
J. Novosad
Keyword(s):  
Porous Media ◽  
Crude Oil ◽  
Phase Behavior ◽  
Oil Recovery ◽  
Liquid Interface ◽  
Divalent Ions ◽  
Surfactant Precipitation ◽  
Wide Range ◽  
Solid Liquid Interface ◽  
Solid Liquid

Novosad, J., SPE, Petroleum Recovery Inst. Abstract Experimental procedures designed to differentiate between surfactant retained in porous media because of adsorption and surfactant retained because Of unfavorable phase behavior are developed and tested with three types of surfactants. Several series of experiments with systematic changes in one variable such as surfactant/cosurfactant ratio, slug size, or temperature are performed, and overall surfactant retention then is interpreted in terms of adsorption and losses caused by unfavorable phase behavior. Introduction Adsorption of surfactants considered for enhanced oil recovery (EOR) applications has been studied extensively in the last few years since it has been shown that it is possible to develop surfactant systems that displace oil from porous media almost completely when used in large quantities. Effective oil recovery by surfactants is not a question of principle but rather a question of economics. Since surfactants are more expensive than crude oil, development of a practical EOR technology depends on how much surfactant can be sacrificed economically while recovering additional crude oil from a reservoir.It was recognized earlier that adsorption may be only one of a number of factors that contribute to total surfactant retention. Other mechanisms may include surfactant entrapment in an immobile oil phase surfactant precipitation by divalent ions, surfactant precipitation caused by a separation of the cosurfactant from the surfactant, and surfactant precipitation resulting from chromatographic separation of different surfactant specks. The principal objective of this work is to evaluate the experimental techniques that can be used for measuring surfactant adsorption and to study experimentally two mechanisms responsible for surfactant retention. Specifically, we try to differentiate between the adsorption of surfactants at the solid/liquid interface and the retention of the surfactants because of trapping in the immobile hydrocarbon phase that remains within the core following a surfactant flood. Measurement of Adsorption at the Solid/Liquid Interface Previous adsorption measurements of surfactants considered for EOR produced adsorption isotherms of unusual shapes and unexpected features. Primarily, an adsorption maximum was observed when total surfactant retention was plotted against the concentration of injected surfactant. Numerous explanations have been offered for these peaks, such as a formation of mixed micelles, the effects of structure-forming and structurebreaking cations, and the precipitation and consequent redissolution of divalent ions. It is difficult to assess which of these effects is responsible for the peaks in a particular situation and their relative importance. However, in view of the number of physicochemical processes taking place simultaneously and the large number of components present in most systems, it seems that we should not expect smooth monotonically increasing isotherms patterned after adsorption isothemes obtained with one pure component and a solvent. Also, it should be realized that most experimental procedures do not yield an amount of surfactant adsorbed but rather a measure of the surface excess.An adsorption isotherm, expressed in terms of the surface excess as a function of an equilibrium surfactant concentration, by definition must contain a maximum if the data are measured over a sufficiently wide range of concentrations. SPEJ P. 962^

CATIONIC COPOLYMERIZATION OF ISOBUTYLENE WITH ISOPRENE: KINETICS OF THE PROCESS AND DETERMINATION OF KINETIC CONSTANTS

2015 ◽  
Vol 88 (4) ◽  
pp. 574-583 ◽  
Author(s):  
N. V. Ulitin ◽  
K. A. Tereshchenco ◽  
D. A. Shiyan ◽  
G. E. Zaikov
Keyword(s):  
Experimental Data ◽  
Molecular Weight ◽  
Cationic Polymerization ◽  
Methyl Chloride ◽  
Theoretical Description ◽  
Kinetic Constants ◽  
Molecular Weight Characteristics ◽  
Cationic Copolymerization ◽  
Kinetics Of

ABSTRACT A theoretical description has been developed of the kinetics of isobutylene with isoprene (IIR) cationic polymerization in the environment of methyl chloride on aluminum trichloride as the catalyst. Based on experimental data on the kinetics of copolymerization (isobutylene conversion curve) and the molecular weight characteristics of the copolymer of IIR, kinetic constants for the process were found. Adequacy of the developed theoretical description of the kinetics of the IIR copolymerization process was confirmed by comparing the experimental molecular-weight characteristics calculated by this description, independent characteristics, and IIR unsaturation.

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