Laboratory Investigation of the Impact of Injection-Water Salinity and Ionic Content on Oil Recovery From Carbonate Reservoirs

Yousef, Ali; Al-Saleh, Salah; Al-Kaabi, Abdulaziz; Al-Jawfi, Mohammed Saleh

doi:10.2118/137634-pa

Cited by 505 publications

(370 citation statements)

References 16 publications

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“…Wettability alteration as an effect of LSF in carbonate rock is proven by Yousef et al (2011). Yousef et al (2011 conducted different laboratory studies to investigate the potential of LSF in carbonates.…”

Section: Wettability Alteration During Lsf In Carbonatementioning

confidence: 95%

Section: Wettability Alteration During Lsf In Carbonatementioning

confidence: 99%

“…From these observations Yousef et al (2011) concluded that the LSF in carbonate rock has a bigger impact on rock/fluid interactions (contact angle) than on fluid/fluid interaction (IFT). Yousef et al (2011). From the data matching, Aladasani et al (2012) concluded that the incremental oil recovery during LSF is caused by alteration of the wettability from oil wet to intermediate wet.…”

Section: Wettability Alteration During Lsf In Carbonatementioning

confidence: 99%

“…These clay particles are lacking in Carbonate porous media. The suggested recovery mechanism for carbonates is wettability alteration [Aladasani et al 2012;Yousef et al 2011], due to ion exchange [Al Shalabi et al 2013;Brady et al 2012], electric double layer expansion [Alotaibi et al 2011], Calcite dissolution [Hio 2008;Yousef et al 2011;Zhang and Sarma 2012] and pH increase. Other mechanisms are insitu surfactants generation, emulsion formation [Emadi and Sohrabi 2013;Mahzari and Sohrabi 2014], salting-in effect [RezaeiDoust et al 2009] and fines migration [Zahid et al 2012].…”

Section: Introductionmentioning

confidence: 99%

“…Calcite dissolution is claimed to have a positive effect on the incremental oil recovery by improving the connectivity [Yousef et al 2011] or exposing a fresh, more water wet surface [Hio 2008]. Both findings are theoretically supported, not experimentally.…”

Section: Introductionmentioning

confidence: 99%

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Calcite Dissolution Behaviour During Low Salinity Water Flooding in Carbonate Rock

Ouden¹,

Nasralla²,

Guo³

et al. 2015

Proceedings

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Master of ScienceCalcite dissolution behaviour during low salinity water flooding in carbonate rockby Liselotte den OudenLow salinity water flooding (LSF) has been proved to be a promising enhanced oil recovery method for sandstone reservoirs. The efficiency of LSF in carbonate reservoirs has not been proven completely yet, because there are still uncertainties about the LSF recovery mechanism in carbonate. From experimental studies, it was shown that wettability alteration, due to salinity reduction, is able to mobilize the remaining oil. Some studies attributed the wettability alteration by LSF to Calcite dissolution. Furthermore, Calcite dissolution can influence the salinity and pH of injected brines, and hence the oil recovery.However, there is a lack of experimental data on the Calcite dissolution effect of LSF in carbonate rock.The objective of this experimental study was to get a better understanding of the Calcite dissolution behaviour and how it might affect the oil recovery. Bulk and coreflood experiments have been performed; the experimental data was history matched with the use of PHREEQC. Calcite dissolution decreased with decreasing P CO2 and increased with decreasing pH and increasing NaCl salinity from 500-2000PPM.Increasing the injection rate reduced the interaction time and therefore Calcite dissolution did not reach equilibrium in coreflood at high rates. Calcite dissolution from chalk matched with the Calcite dissolution from pure Calcite, while Calcium concentration in effluent from limestone was higher. The two-phase coreflood experiment confirmed that Calcite dissolution occurs as well if oil is present in the porous media, but showed lower values than in single-phase coreflood experiment. pH increased from 5-6 to 9.5 due to Calcite dissolution, which might have an effect on the rock and oil surface charges, and hence oil recovery improvement. The effluent of the two-phase coreflood showed that an emulsion was formed, which suggested formation of in-situ surfactants. From CT scans, micro-CT scans and material mass balance calculations an increase in porosity around 1% was observed. The increase in the total dissolved species due to Calcite dissolution was not significant, which will not harm LSF effect.

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Section: Wettability Alteration During Lsf In Carbonatementioning

confidence: 95%

Section: Wettability Alteration During Lsf In Carbonatementioning

confidence: 99%

Section: Wettability Alteration During Lsf In Carbonatementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Calcite Dissolution Behaviour During Low Salinity Water Flooding in Carbonate Rock

Ouden¹,

Nasralla²,

Guo³

et al. 2015

Proceedings

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Temperature dependence of the zeta potential in intact natural carbonates

Mahrouqi

Vinogradov

Jackson

2016

Geophysical Research Letters

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The zeta potential is a measure of the electrical charge on mineral surfaces and is an important control on subsurface geophysical monitoring, adsorption of polar species in aquifers, and rock wettability. We report the first measurements of zeta potential in intact, water‐saturated, natural carbonate samples at temperatures up to 120°C. The zeta potential is negative and decreases in magnitude with increasing temperature at low ionic strength (0.01 M NaCl, comparable to potable water) but is independent of temperature at high ionic strength (0.5 M NaCl, comparable to seawater). The equilibrium calcium concentration resulting from carbonate dissolution also increases with increasing temperature at low ionic strength but is independent of temperature at high ionic strength. The temperature dependence of the zeta potential is correlated with the temperature dependence of the equilibrium calcium concentration and shows a Nernstian linear relationship. Our findings are applicable to many subsurface carbonate rocks at elevated temperature.

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In situ characterization of wettability alteration and displacement mechanisms governing recovery enhancement due to low‐salinity waterflooding

Khishvand

Alizadeh

Kohshour

et al. 2017

Water Resources Research

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A series of micro‐scale core‐flooding experiments were performed on reservoir core samples at elevated temperature and pressure conditions to develop better insights into wettability alteration and pore‐scale displacement mechanisms taking place during low‐salinity waterflooding (LSWF). Two individual miniature core samples were cut from a preserved reservoir whole core, saturated to establish initial reservoir fluid saturation conditions, and subsequently waterflooded with low‐salinity and high‐salinity brines. A third miniature sister core sample was also cut, solvent‐cleaned, and subjected to a dynamic wettability restoration process (to reestablish native state wettability) and then a low‐salinity waterflood. All samples were imaged during the experiments using a micro‐CT scanner to obtain fluid occupancy maps and measure in situ oil‐water contact angles. The results of the experiments performed on the preserved core samples show a significantly improved performance of low‐salinity waterflooding compared to that of high‐salinity waterflooding (HSWF). Pore‐scale contact angle measurements provide direct evidence of wettability alteration from weakly oil‐wet toward weakly water‐wet conditions during LSWF, whereas contact angles measured during HSWF remain unchanged. We believe that the reduction in oil‐water contact angles toward increased water‐wetness lowers the threshold water pressure needed to displace oil from some medium‐sized pore elements. Contact angles measured during the dynamic wettability restoration process show an equilibrium wettability state very similar to the initial one observed in the preserved samples. This indicates that drilling fluid contaminants had a negligible effect on the reservoir rock wettability. The experimental results also reveal similarities between saturation trends for the preserved‐LSWF and restored‐LSWF tests.

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Laboratory Investigation of the Impact of Injection-Water Salinity and Ionic Content on Oil Recovery From Carbonate Reservoirs

Cited by 505 publications

References 16 publications

Calcite Dissolution Behaviour During Low Salinity Water Flooding in Carbonate Rock

Calcite Dissolution Behaviour During Low Salinity Water Flooding in Carbonate Rock

Temperature dependence of the zeta potential in intact natural carbonates

In situ characterization of wettability alteration and displacement mechanisms governing recovery enhancement due to low‐salinity waterflooding

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