The effects of reservoir brine compositions on interfacial tension and reservoir wettability under reservoir conditions

2010 ◽  
Vol 50 (2) ◽  
pp. 735

The average primary oil recovery worldwide is around 35% of the original oil in place (OOIP). Various enhanced oil recovery (EOR) approaches are generally required to recover the remaining OOIP. Apart from the reservoir properties, the capillary pressure that governs fluid distribution and displacement behavior in the reservoir is also affected by the interfacial tension and wettability. Both IFT and wettability are considered to be key effective factors that affect EOR. This study investigated the effect of reservoir brine compositions on the interfacial tension (IFT) between synthetic formation brines and an Australian crude oil with pressures and temperatures up to 4000 psi and 140 °F, respectively. A series of measurements on the density, viscosity and IFT have been conducted. The brines, with total dissolved solids ranging from 3,820 to 38,200 ppm, consist of a diverse range of ions including sodium, lithium, magnesium, calcium, bromide, chloride, sulfate, bicarbonate and carbonate. The experimental results indicate that with all the synthetic brines investigated, the IFT declines with increasing temperature and pressure. Furthermore, it was observed that the IFT reduction with temperature was dependent on the pH values of the brine. Bicarbonate, carbonate, sulfate, and magnesium ions significantly decreased the IFT by up to 40% through either lowering the free surface energy or increasing the surface area. Coreflooding experiments using low salinity water have yielded an incremental EOR of 5.4% OOIP, suggesting that wettability alteration caused by the change of ion balance in the residual water may be responsible for the observed EOR.

2012 ◽  
Vol 1473 ◽  
Author(s):  
Ernesto Lopez-Chavez ◽  
Luis Silvestre Zamudio-Rivera ◽  
Jose Manuel Martinez-Magadan ◽  
Eduardo Buenrostro-Gonzalez ◽  
Raúl Hernández-Altamirano

ABSTRACTZwitterionic liquid (ZL) molecules are considered among the surfactant molecular species used in enhanced oil recovery (EOR). The surface activity of asphaltenes (ASP) is crucial for establishing reservoir rock wettability, which impacts enhanced oil recovery (EOR) process. The key to a successful EOR formulation is to carefully select the components that provide ultra-low interfacial tension (IFT) under reservoir conditions. Achieving ultra-low IFT greatly reduces capillary forces that trap oil. The objective of this work is the theoretical study of the influence of a class of germinal zwitterionic liquid on interfacial tension or changes on wettability of the oil-rock system under reservoir conditions. The ZL molecule used in this study was designed by Zamudio et al; while the asphaltene model was originally proposed by Buenrostro-González. Methods of molecular mechanics and dynamics were used in order to calculate interaction energies of all systems. The results indicate that the ZL molecule adheres more strongly to the limestone-rock than the asphaltene molecule does. In addition, our results suggest that the ion-pair formation is the dominant wettability alteration mechanism.


Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5360
Author(s):  
Samira Mohammadkhani ◽  
Benaiah U. Anabaraonye ◽  
Armin Afrough ◽  
Rasoul Mokhtari ◽  
Karen Louise Feilberg

We present a systematic study of crude oil–brine–rock interactions in tight chalk cores at reservoir conditions. Flooding experiments are performed on outcrops (Stevns Klint) as well as on reservoir core plugs from Dan field, the Ekofisk and Tor formations. These studies are carried out in core plugs with reduced pore volumes, i.e., short core samples and aged with a dynamic ageing method. The method was evaluated by three different oil compositions. A series of synthetic multicomponent brines and designed fluid injection scenarios are investigated; injection flow rates are optimized to ensure that a capillary-dominant regime is maintained. Changes in brine compositions and fluid distribution in the core plugs are characterized using ion chromatography and X-ray computed tomography, respectively. First, we show that polar components in the oil phase play a major role in wettability alteration during ageing; this controls the oil production behavior. We also show that, compared to seawater, both formation water and ten-times-diluted seawater are better candidates for enhanced oil recovery in the Dan field. Finally, we show that the modified flow zone indicator, a measure of rock quality, is likely the main variable responsible for the higher oil recoveries observed in Tor core samples.


2021 ◽  
Author(s):  
Xu-Guang Song ◽  
Ming-Wei Zhao ◽  
Cai-Li Dai ◽  
Xin-Ke Wang ◽  
Wen-Jiao Lv

AbstractThe ultra-low permeability reservoir is regarded as an important energy source for oil and gas resource development and is attracting more and more attention. In this work, the active silica nanofluids were prepared by modified active silica nanoparticles and surfactant BSSB-12. The dispersion stability tests showed that the hydraulic radius of nanofluids was 58.59 nm and the zeta potential was − 48.39 mV. The active nanofluids can simultaneously regulate liquid–liquid interface and solid–liquid interface. The nanofluids can reduce the oil/water interfacial tension (IFT) from 23.5 to 6.7 mN/m, and the oil/water/solid contact angle was altered from 42° to 145°. The spontaneous imbibition tests showed that the oil recovery of 0.1 wt% active nanofluids was 20.5% and 8.5% higher than that of 3 wt% NaCl solution and 0.1 wt% BSSB-12 solution. Finally, the effects of nanofluids on dynamic contact angle, dynamic interfacial tension and moduli were studied from the adsorption behavior of nanofluids at solid–liquid and liquid–liquid interface. The oil detaching and transporting are completed by synergistic effect of wettability alteration and interfacial tension reduction. The findings of this study can help in better understanding of active nanofluids for EOR in ultra-low permeability reservoirs.


SPE Journal ◽  
2022 ◽  
pp. 1-13
Author(s):  
Song Qing ◽  
Hong Chen ◽  
Li-juan Han ◽  
Zhongbin Ye ◽  
Yihao Liao ◽  
...  

Summary α-Zirconium phosphate (α-ZrP) nanocrystals were synthesized by refluxing method and subsequently exfoliated into extremely thin 2D nanosheets by tetrabutylammonium hydroxide (TBAOH) solution. Dynamic light scattering, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to characterize the size distribution and morphology of α-ZrP nanosheets. Interfacial tension (IFT) and contact angle measurement were conducted by different concentrations of α-ZrP nanosheets solutions. The results displayed that the wettability of porous media surface was altered from oleophilic to hydrophilic and the IFT decreased with the increasing of α-ZrP nanosheets concentrations. A new method was proposed to calculate the Hamaker constant for 2D α-ZrP nanosheets. The calculated results displayed that α-ZrP nanosheets were not easy to agglomerate under experimental environment and when the interaction energy barrier increased, the transport amount of α-ZrP nanosheets also increased. Coreflooding tests were also performed with various concentrations and the oil recovery efficiency increased from 33.59 to 51.26% when α-ZrP nanosheets concentrations increased from 50 to 1,000 ppm.


2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Xiaoxia Ren ◽  
Aifen Li ◽  
Asadullah Memon ◽  
Shuaishi Fu ◽  
Guijuan Wang ◽  
...  

Fracturing is a fundamental technique for enhancing oil recovery of tight sandstone reservoir. The pores in tight reservoirs generally have small radii and generate tremendous capillary force; accordingly, the imbibition effect can significantly affect retention and absorption of the fracturing fluid. In this study, the imbibition behaviors of the fracturing fluid were experimentally investigated, and the effects of interfacial tension, (IFT) permeability, oil viscosity, and the salinity of the imbibition fluid were determined. In addition, combining with nuclear magnetic resonance (NMR)-based core analysis, fluid distribution, and the related variations in imbibition and displacement processes were analyzed. Finally, some key influencing factors of imbibition of the residual fracturing fluid, the difference and correlation between imbibition and displacement, as well as the contribution of imbibition to displacement were explored so as to provide optimization suggestions for guiding the application of oil-displacing fracturing fluid in exploration. Results show that imbibition recovery increased with time, but the imbibition rate gradually dropped. There exists an optimal interfacial tension that corresponds to maximum imbibition recovery. In addition, imbibition recovery increased as permeability and salinity increases and oil viscosity decreases. Furthermore, it was found that extracted oil from the movable pore throat space was almost equal to that from the irreducible pore throat space during imbibition and their contribution in the irreducible pore throat space was greater than in the movable pore throat space in the displacement process. Hence, imbibition plays a more important role during the displacement process in the reservoirs with finer porous structure than previously thought.


Geophysics ◽  
1998 ◽  
Vol 63 (5) ◽  
pp. 1507-1519 ◽  
Author(s):  
B. A. Hardage ◽  
J. L. Simmons ◽  
V. M. Pendleton ◽  
B. A. Stubbs ◽  
B. J. Uszynski

A study was done at Nash Draw field, Eddy County, New Mexico, to demonstrate how engineering, drilling, geologic, geophysical, and petrophysical technologies should be integrated to improve oil recovery from Brushy Canyon reservoirs at depths of approximately 6600 ft (2000 m) on the northwest slope of the Delaware basin. These thin‐bed reservoirs were deposited in a slope‐basin environment by a mechanism debated by researchers, a common model being turbidite deposition. In this paper, we describe how state‐of‐the‐art 3-D seismic data were acquired, interpreted, integrated with other reservoir data, and then used to improve the sitting of in‐field wells and to provide facies parameters for reservoir simulation across this complex depositional system. The 3-D seismic field program was an onshore subsalt imaging effort because the Ochoan Rustler/Salado, a high‐velocity salt/anhydrite section, extended from the surface to a depth of approximately 3000 ft (900 m) across the entire study area. The primary imaging targets were heterogenous siltstone and fine‐grained sandstone successions approximately 100 ft (30 m) thick and comprised of complex assemblages of thin lobe‐like deposits having individual thickness of 3 to 6 ft (1 to 2 m). The seismic acquisition was complicated further by (1) the presence of active potash mines around and beneath the 3-D grid that were being worked at depths of 500 to 600 ft (150 to 180 m), (2) shallow salt lakes, and (3) numerous archeological sites. We show that by careful presurvey wave testing and attention to detail during data processing, thin‐bed reservoirs in this portion of the Delaware basin can be imaged with a signal bandwidth of 10 to 100 Hz and that siltstone/sandstone successions 100 ft (30 m) thick in the basal Brushy Canyon interval can be individually detected and interpreted. Further, we show that amplitude attributes extracted from these 3-D data are valuable indicators of the amount of net pay and porosity‐feet in the major reservoir successions and of the variations in the fluid transmissivity observed in production wells across the field. Relationships between seismic reflection amplitude and reservoir properties determined at the initial calibration wells have been used to site and drill two production wells. The first well found excellent reservoir conditions; the second well was slightly mispositioned relative to the targeted reflection‐amplitude trend and penetrated reservoir facies typical of that at other producing wells. Relationships between seismic reflection amplitude and critical petrophysical properties of the thin‐bed reservoirs have also allowed a seismic‐driven simulation of reservoir performance to be initiated.


Fuel ◽  
2020 ◽  
Vol 263 ◽  
pp. 116599 ◽  
Author(s):  
Ghasem Zargar ◽  
Tooraj Arabpour ◽  
Abbas Khaksar Manshad ◽  
Jagar A. Ali ◽  
S. Mohammad Sajadi ◽  
...  

Author(s):  
Tao Zhang ◽  
Yiteng Li ◽  
Chenguang Li ◽  
Shuyu Sun

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 waterflooding in order to better design the injected salinity under various working conditions and reservoir properties. However, the effect of injection salinity on pipeline scaling has not been widely studied, but this mechanism is important to gathering, transportation and storage for petroleum industry. In this paper, an exhaustive literature review is conducted to summarize several well-recognized and widely accepted mechanisms, including fine migration, wettability alteration, double layer expansion, and multicomponent ion exchange. These mechanisms can be correlated with each other, and certain combined effects may be defined as other mechanisms. In order to mathematically model and numerically describe the fluid behaviors in injection pipelines considering injection salinity, an exploratory phase-field model is presented to simulate the multiphase flow in injection pipeline where scale formation may take place. The effect of injection salinity is represented by the scaling tendency to describe the possibility of scale formation when the scaling species are attached to the scaled structure. It can be easily referred from the simulation result that flow and scaling conditions are significantly affected if a salinity-dependent scaling tendency is considered. Thus, this mechanism should be taken into account in the design of injection process if a sustainable exploitation technique is applied by using purified production water as injection fluid. Finally, remarks and suggestions are provided based on our extensive review and preliminary investigation, to help inspire the future discussions.


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