Effect of Water Dissolution on Oil Viscosity

Abstract

Summary At temperatures above 150 degrees C water dissolution in crude oil becomes significant. Water solubilities in heavy crudes am about 40 mole percent at 250degrees C. Dissolved water acts as a low viscosity solvent reducing the oilphase viscosity. This phenomenon has been considered in thermal recovery simulations but has never been substance in this work the effect of water on viscosity was measured for four crude samples with API gravities ranging from14.2 to 5.3. At the highest experimental temperature of 286 degrees Cviscosities of water saturated samples were about one half of the water-free counterparts. The viscosity reduction, although quite significant, was not as pronounced as the drop estimated by viscosity miles used for hydrocarbon systems. While a log mixing rule or a 1/4 power mixing rule overestimated the viscosity effects, a mole fraction weighted average of the oil and water viscosities was found to match the experimental data. One possible explanation for the failure of the log mixing rule is that the water dissolved in the oil exists not as monomers but as hydrogen bonded dusters. When the mole fraction of water clusters, calculated from a statistical mechanics based theory, isused in the log mixing rule, we find good agreement with experiment. SUMMARY AND CONCLUSIONS At temperatures above 150 degrees C water dissolution in crude oils become significant. Water solubilities in heavy crudes are about 40 mole percent at250 degrees C. Dissolved water acts as a low viscosity solvent reducing the oil phase viscosity. This phenomenon has been considered in thermal recovery simulations but has never been substantiated. In this work the effect of water on viscosity was measured for two heavy oils, Huntington Beach (API gravity = 14.2) and Cloalinga Etchegoin (APIgravity = 10.5), and two tars, West Cat Canyon (API gravity = 5.3) and PeaceRiver (API gravity 6.7). At the highest experimental temperature of 286 degrees C viscosities of water-saturated samples were about one half of the water-free counterparts. The viscosity reduction, although quite significant, is not as pronounced as the drop estimated by viscosity mixing rules used in simulation work in the past. A mole-fraction weighted average of the oil and water viscosity was found to match the experimental data. Dissolved water exists on average as hydrogen bonded clusters. The log mixing rule matches the experimental data when the mole fraction of water clusters is used. Introduction Water dissolution in an oleic phase has been reported. The effect is negligible in crude oils at temperatures below 150 degrees C and becomes very pronounced (more than 60% mole fraction) as the temperature riser, above 280degrees C. The effect of dissolved water on the oleic phase viscosity has never been reported. Its potential impact has been estimated based on viscosity mixing rules typically used in hydrocarbon systems which predict very significant viscosity reductions due to water dissolution at high temperature. These predictions lack experimental support, however.

A Mechanistic Study of Ultrasonically‐Enhanced Transdermal Drug Delivery

“…The parameter, @, is a function that expresses the hindrance of ionic motion as the ions pass through the confined regions between the head groups of the lipid bilayers of the SC. The value of @ can be estimated with the analytical results of Faxen et ~1 .~~ and Glandt,34 which describe, respectively, the transport and partitioning of spheres through a narrow rectilinear channel bounded by parallel walls. For unaltered configurations of the SC lipids, the lipid head groups from adjacent bilayers have been observed to be in extremely close proximity (the average bilayer separation is -7 A35).…”

Prediction of water solubility in petroleum fractions and heavy crudes using cubic-plus-association equation of state (CPA-EoS)

“…To evaluate the CPA-EoS, experimental data for water solubility in decane, petroleum fractions (naphtha, kerosene and lubricating oil), heavy oil, and bitumen was gathered from the literature [1,[23][24][25]. The molecular weight of these crudes varies from 140 to 678 g/mol.…”

“…In fact, most of the thermal recovery processes including Steam Assisted Gravity Drainage (SAGD), Cyclic Steam Stimulation (CSS), and Expanded Solvent-Steam Assisted Gravity Drainage (ES-SAGD) are based on injecting saturated steam into bitumen and heavy oil reservoirs. Glandt and Chapman [1] reported that water dissolution in heavy oils and bitumens becomes significant at high temperatures (T > 150°C). The water mole fraction in heavy crudes can reach 40 mole% at 250°C [1].…”

“…Glandt and Chapman [1] reported that water dissolution in heavy oils and bitumens becomes significant at high temperatures (T > 150°C). The water mole fraction in heavy crudes can reach 40 mole% at 250°C [1]. Water that is dissolved in oil acts as a low viscosity component in the system and reduces the viscosity of the oleic phase.…”

“…Water that is dissolved in oil acts as a low viscosity component in the system and reduces the viscosity of the oleic phase. At high temperatures, this reduction in viscosity can be significant ($100% at 280°C) [1] and have considerable effect on the performance of thermal recovery processes where the governing production mechanism is viscosity reduction. Luo and Barrufet [2] showed that water solubility in the oil phase has a remarkable effect on simulation results.…”