Effect of Temperature, Oil Asphaltene Content, and Water Salinity on Wettability Alteration

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractIt is well known that thermal enhanced oil recovery (EOR) improves recovery by lowering the oil viscosity and so is usually performed in heavy oil reservoirs. Wettability alteration may also occur during thermal EOR in which case it may also affect production rates in light oil reservoirs.The interaction between crude oil-brine on different rock surfaces as a function of temperature is not well defined. For example, for silicate surfaces some authors reported a complete reversal of wettability, from a predominantly water-wet system at lower temperature to a predominantly oil-wet system at higher temperature, while others found that the degree of water wetness increased with temperature.In this study, the microscopic behavior, by direct observation, of oil and brine on silicate surfaces at different temperatures up to 60°C was studied. Wetting preference of silica as a function of brine salinity, oil type and temperature has been studied during long time interaction (aging) tests. Four light crude oils of different asphaltene contents and brines of different composition have been used in this work.The study shows that as the temperature increases, the silicate wettability becomes more oil-wet as the asphaltene content of the crude oil decreases. When asphaltene is removed from a crude oil, the degree of oil-wetness is reduced. Regarding the brine effect, in acidic-lower salinity (NaCl brine) where oil adhesion occurs readily, hysteresis between advancing-receding contact angles is larger than for a neutral pH with high salinity brine. The consequence of these observations in flat surfaces is validated by flowing oil and water through glass micromodels, which provide wettability alteration evidence for lower salinity brine and as temperatures increases.

Mobilization and micellar solubilization of NAPL contaminants in aquifer rocks

“…16 The extent of wettability alteration depends on their colloidal stability in NAPL and is enhanced with aging (i.e., contact time), 17 especially at high temperatures. 18 The objective of this study was to investigate the remediation of oil-contaminated aquifers using Winsor Type III surfactant systems. Several surfactant candidates were selected based on prior studies.…”

Wettability Alteration of the Quartz Surface in the Presence of Metal Cations

“…There is always brine in the reservoir whether because of the natural aquifer around the reservoir or during the water flooding to increase oil recovery. The brine salinity and pH are very important factors in determining wettability . As a result, extensive research was conducted on the system of brine, crude oil, and rock, and it was proven that the brine composition of injected water can alter the wettability of the oil reservoir during water flooding to improve oil recovery. − Therefore, injection of modified water with a suitable salinity and brine composition, including low-salinity water flooding and seawater flooding, has been applied as an enhanced oil recovery (EOR) method, which aimed at wettability alteration by proper design of the brine composition. , …”

“…Wettability has been studied on mineral surfaces, such as quartz, mica, calcite, or kaolinite. − The advantage of using single mineral flat surfaces is to study the factors that can impact the wettability in a more controllable way without the additional complexity caused by pore geometry of porous media . Quartz is typically used as the model substrate of sandstone.…”

Investigating the Effect of the Temperature and Pressure on Wettability in Crude Oil–Brine–Rock Systems

“…Wettability is defined as “the tendency of one fluid to adhere to a solid surface in the presence of other immiscible fluids”. , The knowledge of wettability is very important for many aspects in the petroleum industry, including estimation of oil reserves, prediction of production performance, and implementation of enhanced oil recovery (EOR) methods. , Under oil reservoir conditions, studies of wettability have focused on a crude oil–brine–rock (COBR) system. Changes in the wettability of the rock surface affect the microscopic distribution of formation liquid at the pore scale, which, in turn, affects the displacement process and relative permeability characteristics. − It has been clearly shown that the wettability characteristics of reservoirs depend upon several factors, including oil composition, brine composition, pH, temperature, and pressure. − …”

“…After 3 h, the images of the static contact angle are captured and recorded. The captured images are analyzed to obtain the contact angle values using ADVANCE software by fitting the oil drop profile to the Young− Laplace equation (7). The substrate is held within the cell, and the measurement temperature is increased incrementally.…”