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The past decades have witnessed a rapid development of enhanced oil recovery techniques, among which the effect of salinity has become a very attractive topic due to its significant advantages on environmental protection and economical benefits. Numerous studies have been reported focusing on analysis of the mechanisms behind low salinity waterfloo...
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... and a mass conservation restriction is added. In particular, the scaled species will be removed from the fluid mixture and no slip boundary condition is set on the scaled structure. Paraffin wax and asphalt are considered as the main species with scaling tendency in the injection fluid, and represented by the green droplets visualized in Fig.4, Fig.5 and Fig.6. The average density of scaling species is set as 0.9×10 3 kg/m 3 , while the density for injected water is set as 1.0 × 10 3 kg/m 3 . At the beginning, two droplets of scaling species are placed near the left inlet, as shown in Fig.4, and the injection is from left to right. A scaled structure is placed near the right outlet and ...
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Low-salinity (LS) waterflooding has been a topic of substantial recent interest in the petroleum industry. Studies have shown that LS brine injection can increase oil production relative to high-salinity (HS) brine injection, but contradictory results have also been reported and a mechanistic explanation of these findings remains elusive. We have r...
While the “low salinity waterflooding” (LSWF) has been praised for enhancing oil recovery from different core rocks, the performance of the technique in different wettability environments remains unclear. The consensus is that LSWF does not work well in water-wet carbonate oil reservoirs. The main research objective was to determine the effect of L...
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... Inappropriate temperature variations inevitably lead to variations in oil viscosity and density, directly affecting flow rate. Effective thermal insulation becomes crucial to maintain stable production conditions, thereby optimizing the yield of the offshore well [6]. The first models for interpreting temperature variations in oil wells were developed by researchers such as Ramey Jr [7]. ...
... Smart water can be divided into two main categories: low salinity water (salinity ranging from 1000 to 5000 ppm) and high salinity water (seawater salinity range) with changes in the composition of its main constituents [1,6]. These studies have proposed various mechanisms, including fines migration [7][8][9], mineral dissolution [10][11][12], pH increase [13][14][15][16], double-layer expansion [17][18][19], Multicomponent Ion Exchange (MIE) [20,21], salinity effect [22], wettability alteration [21,[23][24][25], mobilization of oil in solid [26,27], and micro-dispersion [28][29][30][31][32][33] for the versatility of using smart water. Despite extensive research on the subject of smart water and numerous mechanisms proposed in the literature, several open questions still need to be addressed. ...
... Smart water can be divided into two main categories: low salinity water (salinity ranging from 1000 to 5000 ppm) and high salinity water (seawater salinity range) with changes in the composition of its main constituents [1,6]. These studies have proposed various mechanisms, including fines migration [7][8][9], mineral dissolution [10][11][12], pH increase [13][14][15][16], double-layer expansion [17][18][19], Multicomponent Ion Exchange (MIE) [20,21], salinity effect [22], wettability alteration [21,[23][24][25], mobilization of oil in solid [26,27], and micro-dispersion [28][29][30][31][32][33] for the versatility of using smart water. Despite extensive research on the subject of smart water and numerous mechanisms proposed in the literature, several open questions still need to be addressed. ...
The utilization of smart water in EOR (enhanced oil recovery) operations has drawn increased attention in recent years. Nevertheless, the variety and complexity of mechanisms during smart water injection require more research endeavors. In this study, interfacial tension (IFT) for the smart water/crude oil interacting system has been investigated. The investigated parameters included various salts with different salinity, pH, asphaltene type, and aged smart water with two crude oil samples. The results showed that the hydration of ions in smart water would play a key role to discern the primary mechanism of smart water. The interaction of acidic and basic asphaltene with hydration shell of different ions can be considered as primary mechanism for efficacy of smart water. Acidic and basic asphaltenes serve as intrinsic surfactants due to their interaction with OH − in the anion hydration shell and H + in the cation hydration shell, respectively. The propensity of acidic asphaltene to interact with anions with high hydration energy and the tendency of basic asphaltene to interact with cations with high hydration energy led to an IFT of 0.2 mN/m and 11.3 mN/m for acidic and basic oils, respectively. The impact of pH also revealed that acidic and basic asphaltenes would have lower IFT in alkaline and acidic environments. Finally, it was found that changes in IFT for the aged smart water with crude oil depend on the asphaltene type as well as salt and salinity.
... Zhang et al. [89] from their chromatographic wettability test speculated that there is a certain pH level that can trigger a strong water-wet state due to the H þ ion adsorption at the interface. Gomari and Hamouda [90] carried on contact angle measurements to examine the effect of LSWF on calcite. ...
The nature of carbonate reservoirs promotes the adsorption of oil onto the rock surface hence making oil recovery a challenge even with the interventions of varied chemical EOR methods. Recently, low salinity water flooding has become of great interest since it is cost-effective and environmentally friendly. Although low salinity waterflooding has been highly investigated in sandstone reservoirs, it is not the same for carbonate reservoirs due to its complexities. Nonetheless, it has been proposed as a favourable technique to mobilise the trapped oil in carbonate reservoirs. Wettability alteration is regarded as the most accepted mechanism for low salinity flooding but has not been well understood making field scale applications doubtful. In this paper, we present a detailed review of the wettability alteration mechanisms in carbonate reservoirs during low salinity waterflooding. Parameters influencing wettability alteration in carbonates and the interactions that occur at the rock/brine/oil interface are also presented. The different methods utilised for wettability measurements during low salinity waterflooding are also reviewed including their drawbacks and advantages and recommendations. This will provide an improved understanding of the low salinity flooding application in carbonate reservoirs.
... Small-diameter thick-walled steel pipes are widely used in power stations (including nuclear power stations) and other areas. The long-term operation of these pipelines under complex working conditions will lead to various types of defects on the internal walls of the pipes, which pose great potential risks to the reliability and safety of the structure [1][2][3]. The circumferential stress in the pipe wall is about twice the scale of the axial stress, and axial cracking is more dangerous than circumferential cracking under the influence of creep. ...
Special geometric features and complex working environments render the internal defects of small-diameter thick-walled steel pipes “easy to expand, difficult to detect”. In this paper, a magnetic permeability perturbation testing (MPPT) method is proposed to assess the internal axial cracks of small-diameter thick-walled steel pipes. The mechanism of the MPPT method and its corresponding probe and magnetizer are introduced, and its feasibility is verified through a series of simulations and experiments. Experiments conducted using different sizes of small-diameter thick-walled pipes show that this method offers good performance with respect to the detection of internal axial cracks. Additionally, both diameter and wall thickness significantly affect the MPPT signal. To a certain extent, a greater wall thickness or a smaller diameter brings about a weaker signal. This method does not benefit from the lift-off effect, nor is it limited by the skin effect, which has great practical value as a supplement to the evaluation of thick-walled steel pipes.
... Fines migration can reduce formation permeability significantly (Bedrikovetsky et al., 2011;Pang and Sharma, 1997;Hussain et al., 2013;Li, 2011;Yuan et al., 2015;Yuan and Shapiro, 2011;Al-Sarihi et al., 2018;Yu et al., 2018;Sazali et al., 2018Sazali et al., , 2020. Generally, fines migration is not considered to be a key mechanism in carbonate rocks (Hao et al., 2019;Tetteh et al., 2020;Zhang et al., 2020;Nande and Patwardhan, 2022). Wang et al. (2022a) injected water into carbonate rock samples and observed dislodgement of fines due to mineral reactions. ...
... Temperature affects both dependent zeta potential (Khilar and Fogler, 1984;Musharova et al., 2012b;You et al., 2019) and mineral reactions (Zhang et al., 2020;Wang et al., 2021;Mokhtari et al., 2022) that leads to fines migration. Khilar and Fogler (1998) injected NaCl brine at salinities from 0.512 moL/l to 0.068 moL/l at 0 • C, 30 • C, and 60 • C, they concluded that fines migration began at higher salinity when high temperature was applied. ...
... Such permeability increase was not observed in any of the lower-temperature experimental runs. Higher temperature promotes mineral dissolution (Zhang et al., 2020;Musharova et al., 2012a), which caused more pore opening compared to seawater injection at lower temperature (Fig. 9b) and therefore permeability increase (Fig. 9c). More grain redistribution that causes pore opening can be observed at higher temperature, which can account for the permeability Fig. 9. Results for the two seawater experimental runs: (a) average permeability change, (b) percentage of pore changes on inlet and outlet faces, (c) composition of produced fines during distilled water injection stage, and (d) percentage decrease in rock sample dry mass after experimental run. ...
Managed aquifer recharge is a water storage and recovery method. However, fines migration during water injection can significantly affect formation permeability. Several studies have analyzed fines migration in sandstone and soil samples, but few studies have investigated fines migration in carbonate rocks. In addition, the effect of neither temperature nor type of ion on fines migration has been investigated in carbonate rocks. Our experiments use filtered-deaired distilled water and pure salts to prepare the injection fluids. Rock samples are injected with 0.63 mol/L brine followed by four sequential injections of diluted brine: 0.21 mol/L, 0.1 mol/L, 0.05 mol/L, and 0 mol/L (distilled water). Pressure difference is recorded across the rock sample throughout each experimental run and used to calculate permeability. Effluent is collected to characterize produced fines and elements. pH and particle concentration measurements are collected frequently. Scanning electron microscope (SEM) images of inlet and outlet faces pre- and post-injection were taken to observe any changes. For the experimental runs performed at 25 °C, permeability decrease was 99.92% of the original permeability for seawater experimental run, 99.96% for NaCl brine experimental run, and nearly zero for CaCl2 brine experimental run. For CaCl2 brine experimental run, the only observed mineral reaction is mineral dissolution. For NaCl brine and seawater experimental runs, both mineral dissolution and cation exchange are observed, of which the latter appears to be the main mechanism for fines migration. Due to mineral dissolution, permeability increase is observed during 0.21 mol/L and 0.1 mol/L injection at high temperature. However, during distilled water injection, permeability decrease is found to be similar at both low and high temperatures.
... Fines migration and resulting enhanced 62 Almutairi, A., et al. Advances in Geo-Energy Research, 2023, 8(1): 61-70 oil recovery has also been attributed to cation exchange, which weakens the electrostatic force between fines and rock surface (RezaeiDoust et al., 2009;Zhang et al., 2020), and to the dissolution of carbonate minerals (Zahid et al., 2012;Hao et al., 2019). ...
... Many studies that listed recovery mechanisms in carbonates omitted fines migration (Yildiz and Morrow, 1996;Jerauld et al., 2008;Lager et al., 2008;Rivet et al., 2010;Katende and Sagala, 2019;Mohammadi and Mahani, 2020). And the studies that did mention fines migration in this context regarded it as insignificant (Zahid et al., 2012;Hao et al., 2019;Tetteh et al., 2020;Zhang et al., 2020;Nande and Patwardhan, 2022). Zahid et al. (2012) performed water injection on carbonate and chalk samples at room temperature and high temperature. ...
We perform single-phase and two-phase flooding on Edwards Brown rock samples. The single-phase injection was of seawater or CaCl2 brine, at successive salinities 0.63, 0.21, 0.07, 0.05, and 0 mol/L (distilled water). For CaCl2 brine experimental run, no significant fines migration or permeability decrease is observed. For seawater experimental run, distilled water injection is found to bring about the highest concentration of produced fines and most of the permeability decrease, with the ultimate permeability decrease being 99.94%. Therefore, distilled water injection is used to stimulate fines migration in the following two-phase experimental runs. Two-phase experiments are performed on four Edwards Brown rock samples using seawater or CaCl2 brine as the aqueous phase, and Soltrol® 130 or crude oil as the oleic phase. Rock samples are initially fully saturated with 0.63 mol/L of the selected aqueous solution. This is followed by injecting the selected oil at a constant rate for at least 20 pore volumes to displace brine. Next, selected brine is injected to displace oil, and finally distilled water. For CaCl2 brine, distilled water injection is found to recover no additional oil of either type of oil. However, for seawater, the fines production observed during distilled water injection is found to reduce water relative permeability by two orders of magnitude when Soltrol® 130 is used and by three orders of magnitude when crude oil is used. The seawater experimental runs also brought about additional oil recovery during distilled water injection: 18% when Soltrol® 130 is used and 3.4% when crude oil is used. This last result can be attributed to the plugging of pores due to fines migration, which can divert further injected water into previously unswept pores.
... However, the applicability as a recovery method in reservoirs is still not widely observed, which is justified by Hao et al. (2019) [12] due to the existing gaps related to understanding the SWF mechanisms in this type of mineralogy. There is still much discussion about the exact mechanisms that lead to improving recovery, especially when carbonate rocks are involved [2,[13][14][15][16]. Egbe et al. (2021) [3] and Awolayo and Sarma (2017) [17] highlight that the carbonate's heterogeneous nature makes it more difficult to understand the oil recovery mechanisms. ...
Smart water flooding (SWF) is a promising enhanced oil recovery (EOR) technique due to its economic advantages. For this process, wettability alteration is the most accepted controlling effect that leads to increased recovery factors (RFs). The main objective of this work is to investigate how the relative permeability curves’ interpolant affects the SWF mechanisms’ assessment. Wettability alteration is described by shifting these curves in simulations. Numerical simulations of core flooding tests are applied to carbonate at 114.4 °C. A comparison of oil recovery factor (RF), pH and effluent composition is performed for different injection approaches. Mg2+ and SO42− are the interpolant ions and the salinity levels range from 30 to 1 kppm. A simulation of 24 scenarios, 12 for each type of interpolant, is presented. Results show that RF changes significantly, due to salinity and composition, for each interpolant. This has a relevant influence on the interpolant. The greater the dilution, the smaller the effect of the interpolant and brine composition on the recovery estimates. When considering SO42− as an interpolant, the trend is that divalent rich brine (DV) has a higher recovery factor. In contrast, when Mg2+ is the interpolant, DV tends to have a lower recovery. The analysis of ionic exchange and pH variation corroborate the wettability alteration behavior. A pH increase was observed in all scenarios, regardless of the salinity, ion composition or interpolant variation. Also, monitoring the CH3COO-X reduction and SO4-X2 increase equivalent fractions indicated the ion exchange mechanism as being well represented in all simulations. In addition, the results emphasize that even at very low concentrations, SO42− plays a fundamental role in initiating the ion exchange process that culminates in the wettability alteration as a consequence of smart water injection.
... The limited availability of fresh water often limits social development. For example, the high salinity of seawater can cause problems, such as the scaling of pipelines and corrosion of equipment, making it more difficult to extract oil in the Middle East [1]. Desalination can use a wide range of seawater resources to alleviate water pressure and scarcity. ...
Recently, solar-driven seawater desalination has received extensive attention since it can obtain considerable freshwater by accelerating water evaporation at the air–water interface through solar evaporators. However, the high air–water interface temperature can cause volatile organic compounds (VOCs) to enter condensed freshwater and result in water quality safety risk. In this work, an antioxidative solar evaporator, which was composed of MoS2 as the photothermal material, expandable polyethylene (EPE) foam as the insulation material, polytetrafluoroethylene (PTFE) plate as the corrosion resistant material, and fiberglass membrane (FB) as the seawater delivery material, was fabricated for the first time. The activated persulfate (PS) methods, including peroxymonosulfate (PMS) and peroxodisulfate (PDS), were applied to inhibit phenol from entering condensed freshwater during desalination. The distillation concentration ratio of phenol (RD) was reduced from 76.5% to 0% with the addition of sufficient PMS or PDS, which means that there was no phenol in condensed freshwater. It was found that the Cl− is the main factor in activating PMS, while for PDS, light, and heat are the dominant. Compared with PDS, PMS can make full utilization of the light, heat, Cl− at the evaporator’s surface, resulting in more effective inhibition of the phenol from entering condensed freshwater. Finally, though phenol was efficiently removed by the addition of PMS or PDS, the problem of the formation of the halogenated distillation by-products in condensed freshwater should be given more attention in the future.
... As shown in the photos, the oil-water two-phase fluid gathered from production will be injected from the upper-left inlet of this separator, and a collection pipeline will be connected from the lower-right outlet to collect the separated water for further utilization. For instance, the water can be further purified and injected back into the reservoir to enhance oil recovery, which is highly preferred by our industrial partners in the desert areas of Iraq [26]. Considering the difference in density, the oil pipeline is connected with the upper-right outlet to collect the purified oil for further storage and transportation. ...
The effect of temperature on oil–water separations is studied in this paper, focusing on the changed penetration velocities of water droplets on the separation membrane in a horizontal separator. A compact numerical scheme is developed based on the phase-field model, and the temperature effect is first theoretically analyzed regarding the key thermodynamic properties that may affect the separation performance. The computational scenario is designed based on practical horizontal separators in the oil field, and the droplet motions in the oil–water two-phase flow are simulated using our scheme under various operation conditions. It was found that a higher temperature may result in a faster penetration of the water droplets, and a larger density difference in the oil–water system is also preferred to accelerate the separation using membranes. Furthermore, increasing the operation temperature is proved to benefit the separation of water and heavy oil.
... Zhang et al. [89] from their chromatographic wettability test speculated that there is a certain pH level that can trigger a strong water-wet state due to the H þ ion adsorption at the interface. Gomari and Hamouda [90] carried on contact angle measurements to examine the effect of LSWF on calcite. ...
The nature of carbonate reservoirs promotes the adsorption of oil onto the rock surface hence making oil recovery a challenge even with the interventions of varied chemical EOR methods. Recently, low salinity water flooding has become of great interest since it is cost-effective and environmentally friendly. Although low salinity waterflooding has been highly investigated in sandstone reservoirs, it is not the same for carbonate reservoirs due to its complexities. Nonetheless, it has been proposed as a favourable technique to mobilise the trapped oil in carbonate reservoirs. Wettability alteration is regarded as the most accepted mechanism for low salinity flooding but has not been well understood making field scale applications doubtful. In this paper, we present a detailed review of the wettability alteration mechanisms in carbonate reservoirs during low salinity waterflooding. Parameters influencing wettability alteration in carbonates and the interactions that occur at the rock/brine/oil interface are also presented. The different methods utilised for wettability measurements during low salinity waterflooding are also reviewed including their drawbacks and advantages and recommendations. This will provide an improved understanding of the low salinity flooding application in carbonate reservoirs.
