Low Salinity Water Flooding Experiments and Interpretation by Simulations

Fjelde, Ingebret; Asen, Siv Marie; Omekeh, Aruoture Voke

doi:10.2118/154142-ms

Cited by 83 publications

(51 citation statements)

References 9 publications

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“…Skrettingland et al (2010) reported no/very low additional oil recovery during LSWF. Slightly higher recovery in LSWF core flooding experiments was reported by Fjelde et al (2012), but the oil was produced during much longer production period in LSWF than in high salinity flood. Since one mechanism can not explain all the reported observations, the mechanisms for the improved oil recovery in LSWF are still discussed.…”

Section: Introductionmentioning

confidence: 70%

Secondary and Tertiary Low Salinity Water Floods: Experiments and Modeling

et al. 2013

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Change of injection brine composition from high to low salinity has been reported to improve the oil recovery in some field pilots and core flooding studies. In other studies low salinity water flooding (LSWF) has not been successful. It has also been reported that LSWF can be successful in secondary floods but not in tertiary floods. The main objective for the reported study has been to investigate the oil recovery and cation concentrations in effluent samples during secondary and tertiary LSWF experiments using brines of different compositions. These results have been combined with evaluation of cation exchange during these floods by simulations and history matching to estimate the saturation functions. When diluted formation water (LSW2) was injected in secondary floods, the oil production was only slightly higher than the total oil production during secondary flooding with formation water (FW) followed by tertiary flooding with LSW2. In the secondary flood with LSW2 the oil was produced during a long period, and wettability alteration appeared to occur during the flood. LSW2 was also found to give less water-wet conditions than FW. When LSW2 was injected to a core aged with LSW2, the oil production was slow and rather low remaining oil saturation was obtained. In a secondary flood with optimized low salinity water composition selected based on evaluation of cation exchange on clay surfaces, the oil recovery was found to be faster than in the secondary LSWF with LSW2 (diluted FW). By modeling of the cation exchange in the flooding experiments, it was found that the change in oil recovery profile can be explained with the change in the concentrations of divalent cations on the clay surfaces. It is concluded that the potential for secondary and tertiary LSWF, will strongly depend on the compositions of rock, FW and LSW. The potential for tertiary LSWF will also strongly depend on the composition of the high salinity brine injected in the secondary flood. Modeling of cation exchange during the reservoir history can be used to evaluate the potential for LSWF of the oil reservoirs and to optimize the LSW compositions.

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Section: Introductionmentioning

confidence: 70%

Secondary and Tertiary Low Salinity Water Floods: Experiments and Modeling

et al. 2013

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“…The desired final wettability is also matter of debate. Some researchers reported that low salinity water flooding change the wettability into neutral state rather than water-wet state [8], [9]. Ashraf et al [4] pointed out same result.…”

Section: Wettability Effects and Its Alterationmentioning

confidence: 87%

“…Furthermore, there is direct evidence that wettability altered to more water-wet during low salinity water flooding [9], [10]. Accordingly, initial and final wettability's are key indices which have been evaluated.…”

Section: Wettability Effects and Its Alterationmentioning

confidence: 99%

Low Salinity as New Technique of Enhanced Oil Recovery

Abdalla¹,

Sun²,

Tang³

et al. 2017

IJCEA

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Abstract-Low salinity water flooding is a very promising EOR method in recent years in which chemistry play major role in improving oil recovery. Several studies shown that oil recovery significantly increase by low salinity water flooding (LSWF) in sandstone. However, the mechanisms of oil recovery improvement are still controversial, its considered to be decrease of residual oil saturation and alteration of rock wettability, the solution and surface chemistry as well as rock/fluid interactions have important roles that can be attributed to reservoir minerals being sensitive to small changes in solution properties. This paper provides a comprehensive review of low salinity water flooding. Attempt is made to cover all aspects and features of low salinity water flooding to shed light on critical and challengeable features and clear the gaps and deficiencies of conducted studies. The proposed mechanisms are discussed and their success and failure are explained. Analytical and numerical modeling of low salinity water flooding is presented. Secondary and tertiary low salinity water flooding are compared in the term of additional oil recovered. Surfaces forces and rock/fluid/brine interaction and its relationship to wettability are discussed. Results of combined low salinity and EOR methods are described which includes simultaneous use of low salinity with polymer flooding, surfactant flooding. Accordingly, low salinity water flooding EOR methods have great potential for enhanced oil recovery in the future.Index Terms-Low salinity water flooding, oil recovery, secondary recovery, tertiary recovery.

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“…(3) Expansion of the double layer to be as the dominant mechanism of oil recovery improvement (Nasralla and Nasr-El-Din 2012). The general agreement among researchers is that low salinity waterflooding cause reservoirs become more water-wet (Fjelde, Asen et al 2012, Nasralla and Nasr-El-Din 2012, Sohrabi and Emadi 2013, Shalabi, Sepehrnoori et al 2014.…”

Section: Introductionmentioning

confidence: 95%

Potential Evaluation of Ion Tuning Waterflooding for a Tight Oil Reservoir in Jiyuan OilField: Experiments and Reservoir Simulation Results

Xie

et al. 2015

Day 2 Wed, August 12, 2015

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Low salinity waterflood (LSF) is a promising improved oil recovery (IOR) technology. Although, it has been demonstrated that LSF is an efficient IOR method for many sandstone reservoirs, the potential of LSF in tight oil reservoir is not well-established. This paper presents a systematic evaluation of the potential of low salinity waterfloding for the tight reservoirs in Jiyuan Oilfield, China. This investigation pushes the application envelope of low salinity waterflooding towards the reservoir with low permeability (lower than 0.5mD), formation salinity of up to 45,180ppm, reservoir temperature of 70°C and in-situ oil viscosity of 0.6 cp.Our laboratory evaluation included zeta potential tests for interface of oil/brine and brine/rock, thermodynamic analysis through disjoining pressure calculation, corefloods using representative core samples.Thermodynamic analysis showed that decreasing divalent cations and salinity makes the electrical charges at both oil/brine and brine/rock interfaces become strongly negative, which enhanced the repulsive forces between oil and rock due to the double electric layer expansion. As a result, the rock turns more water-wet. Secondary corefloods were conducted with two different brines, which include shallow aquifer water and ion tuning water with consideration of field application. Coreflooding Experimental results were history matched to obtain the relative permeability curves. Results showed that compared to shallow aquifer water, low-salinity water exhibited a higher oil relative permeability and lower water relative permeability at the same water saturation and a lower residual oil saturation to water.Laboratory results were input into a reservoir simulator to investigate the potential of low-salinity water flood in Jiyuan oilfield. It showed that suitably formulated ion tuning water (ITW) has the potential to accelerate oil production and improve displacement efficiency, thus resulting in a higher recovery factor with only a fraction of pore volume of low-salinity water injected.To conclude, this paper demonstrates that ITWF has a good potential as an IOR/EOR technology in tight reservoirs, the key points are described as follows. Firstly, the mechanism of ITWF was interpreted by thermodynamics of wettability. Secondly, laboratory experiments have shown that ITWF could improve oil recovery by accelerating the oil production rate and decrease the residual oil production.Thirdly, the potential of ITWF in a tight oil reservoir in Jiyuan oilfield is investigated using a mechanistic model based on input data of laboratory experiments.

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Low Salinity Water Flooding Experiments and Interpretation by Simulations

Cited by 83 publications

References 9 publications

Secondary and Tertiary Low Salinity Water Floods: Experiments and Modeling

Secondary and Tertiary Low Salinity Water Floods: Experiments and Modeling

Low Salinity as New Technique of Enhanced Oil Recovery

Potential Evaluation of Ion Tuning Waterflooding for a Tight Oil Reservoir in Jiyuan OilField: Experiments and Reservoir Simulation Results

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