بە دڕێژایی کارو چالاکی یەکەی دلنیای جوری و بە هاوکاری یەکەی راگەیاندن ئەمڕۆ پێنچ شەممە ڕێکەوتی٢٠١٨/١١/٢٩، بە ئامادەبوونی بەڕێز ڕاگری فاکەڵتیی و مامۆستایانی فاکەڵتییەکەمان سیمینارێک پيشکەش کرا لە لایەن مامۆستای بەشی ئەندازیاری نەوت بەڕێز(د. عباس خاکسار) بە ناونیشانی: Experimental and Theoretical Study of CoreScale Spontaneous Imbibition
Interfacial tension and wettability are among factors
affecting forces in an oil reservoir. Both of these factors are influenced by
chemical mechanisms. For example, the interactions between ions, the rock
surface and fatty acids can alter the wettability. Moreover, the competitive
effects of salting-out and salting-in on increasing and decreasing the salinity
of injected water can lead the water-oil interfacial tension (IFT) to another
direction where adding carbon dioxide to the injected water can create factors
that change the properties of the oil droplet and consequently change the
interfacial tension value. The dissolution of carbon dioxide in smart water
(low salinity water) results in a chemical reaction and reduces the density as
well, and its diffusion into the oil droplet adjacent to the smart water
increases the volume of the droplet and affects its viscosity and other
properties. The acid formed by the dissolution of CO2 in the injected water may
dissolve some minerals in carbonate rock surface and change the surface
properties. The goal in enhanced oil recovery (EOR) process through water
injection is to minimize interfacial tension, and moderate rock wettability to
exhibit hydrophilic characteristics. Ions in injection water in a certain density
cause the interfacial tension to reach relative minimum, and alter oil-wet
characteristics of carbonate rocks towards more water-wet characteristics. The
effect of CO2 dissolution in injection water, forming carbonated water
containing dissolved ions, on these two parameters is obvious and improves
them. In this communication, K2SO4 , KI, MgSO4 , Na2SO4 , CaCl2 , MgCl2 , KCl,
and NaCl salts, as binary ionic compounds, were used for producing smart water
with concentrations of 1000 + 1000, 2000 + 2000, 5000 + 5000, and 10,000 +
10,000 ppm. Then, the effects of dissolution of these salts on interfacial
tension and contact angle between water, oil, and carbonate rock were studied.
In addition, CO2 was added to the ionic solution with optimal compositions and
densities in terms of minimum interfacial tension under the pressures of
6894.7, 10,342.1, and 13,789.5 kPa, and its effects on the latter two
parameters were investigated. After that, the effects of ions dissolved in
seawater (10 times diluted seawater) on water-oil interfacial tension,
wettability of carbonate rock and contact angle under the pressure of 101.4 kPa
in the absence of CO2 , and under the pressures of 6894.7, 10,342.1, and
13,789.5 kPa in the presence of CO2 were studied. All tests were conducted at
constant temperature of the reservoir (75 °C). The minimum interfacial tension
was obtained for MgCl2 + K2SO4 composition (6.73 mN/m), which was lower than
the interfacial tension between the initial amount of fresh water and oil
(24.145 mN/m) by 72%. This reduction reached 83% after carbonating the solution
under 2000 ppm and 75 °C conditions. The minimum contact angle in the aged
segment for KCl + MgCl2 composition with concentration of 2000 + 2000 ppm was
recorded as 39.80°, which decreased by 49.62% and reached 20.05° by adding CO2
under 13,789.5 kPa condition. The interfacial tension between seawater (initial
density) and crude oil, under 101.4 kPa and 75 °C conditions, was obtained as
27.464 mN/m. The interfacial tension values under 6894.7, 10,342.1, and
13,789.5 kPa conditions were obtained as 25.315 mN/ m, 25.146 mN/m, and 21.464
mN/m, respectively. These results reveal a decreasing trend after each dilution
stage. In addition to trend, reduction of the initial contact angle in the aged
segment in the solution after each dilution step indicates better performance
of ionized seawater relative to normal seawater.
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