The effect of sulphate and magnesium ions on oil recovery by low salinity waterflooding in dolomite rocks

2018 ◽  
Author(s):  
Andrés Fernando Peralta Sánchez
Keyword(s):  
Oil Recovery ◽  
Magnesium Ions ◽  
Low Salinity ◽  
Low Salinity Waterflooding

Continental-shelf freshwater water resources and improved oil recovery by low-salinity waterflooding

AAPG Bulletin ◽  
2017 ◽  
Vol 101 (01) ◽  
pp. 1-18 ◽  
Author(s):  
Mark Person ◽  
John L. Wilson ◽  
Norman Morrow ◽  
Vincent E.A. Post
Keyword(s):  
Water Resources ◽  
Continental Shelf ◽  
Oil Recovery ◽  
Improved Oil Recovery ◽  
Low Salinity ◽  
Low Salinity Waterflooding

Low-salinity waterflooding in non-polar oil

2018 ◽  
Vol 58 (2) ◽  
pp. 660
Author(s):  
A. Al-Sarihi ◽  
A. Zeinijahromi ◽  
P. Bedrikovetsky
Keyword(s):  
Oil Recovery ◽  
Water Volume ◽  
Fines Migration ◽  
Polar Components ◽  
Low Salinity ◽  
Reservoir Permeability ◽  
Low Salinity Waterflooding ◽  
Volume Production ◽  
Polar Oil ◽  
Positive Results

Enhanced oil recovery by low-salinity waterflooding is considered to have positive results only when polar components exist in oil. This study shows that low-salinity brine can result in incremental recovery for non-polar oil through fines-assisted waterflooding. Despite the traditional view of fines migration that it should be avoided because of its detrimental effect on reservoir permeability, this work shows that permeability decline is a main mechanism in the low-salinity effect on non-polar oil. Laboratory coreflood tests were performed on a clay-rich Berea outcrop core and a clean sand core to investigate the effect of clay migration when the core is saturated with non-polar oil. The results show that fines migration reduces residual saturation by 18%. In addition, a decrease in the water volume production was observed due to the decrease in water relative permeability.

scholarly journals Effect of salinity on oil production: review on low salinity waterflooding mechanisms and exploratory study on pipeline scaling

2020 ◽  
Vol 75 ◽  
pp. 50 ◽  
Author(s):  
Tao Zhang ◽  
Yiteng Li ◽  
Chenguang Li ◽  
Shuyu Sun
Keyword(s):  
Oil Recovery ◽  
Rapid Development ◽  
Preliminary Investigation ◽  
Petroleum Industry ◽  
Phase Field Model ◽  
Scale Formation ◽  
Wettability Alteration ◽  
Reservoir Properties ◽  
Low Salinity ◽  
Low Salinity Waterflooding

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.

A Robust Geochemical Simulator To Model Improved-Oil-Recovery Methods

SPE Journal ◽  
2016 ◽  
Vol 21 (01) ◽  
pp. 55-73 ◽  
Author(s):  
Haishan Luo ◽  
Emad W. Al-Shalabi ◽  
Mojdeh Delshad ◽  
Krishna Panthi ◽  
Kamy Sepehrnoori
Keyword(s):  
Oil Recovery ◽  
Magnesium Ions ◽  
Improved Oil Recovery ◽  
Low Salinity ◽  
Geochemical Reactions ◽  
Newton Raphson ◽  
Calcium And Magnesium ◽  
Sacrificial Agent ◽  
Raphson Method ◽  
Calcium And Magnesium Ions

Summary The interest in modeling geochemical reactions has increased significantly for different improved-oil-recovery processes such as alkali/surfactant/polymer (ASP) flood, low-salinity waterflood, and ethylenediaminetetraacetic acid (EDTA) injection as a sacrificial agent in hard brine. Numerical simulation of multiphase flow coupled with geochemical reactions is challenging because of complex and coupled aqueous, aqueous/solid, and aqueous/oleic reactions. These reactions have significant impact upon oil recovery, and hence a robust geochemical simulator is important. UTCHEM (2000) is a chemical-flooding reservoir simulator with geochemical-modeling capability. Nevertheless, one major limitation in the geochemical-reactive engine of UTCHEM is assuming the activities of reactive species is equal to unity. In fact, the activity coefficients are strongly nonlinear functions of the ionic strength of solution. One approach to tackle this deficiency was to couple UTCHEM (flow and transport) with IPhreeqc (a geochemical reactive engine) (Kazemi Nia Korrani et al. 2013). However, the simulator proved to be computationally expensive. Therefore, it is desirable to improve the geochemical- reactive engine within UTCHEM. This paper presents the improvement of the geochemical-reactive engine in UTCHEM including implementing different activity-coefficient models for different reactive species, cation-exchange reactions, and numerical convergence. Certain unknown concentrations are eliminated from the elemental mass-balance equations and the reaction equations to reduce the computational burden. The Jacobian matrix and right-hand side of the linear-system equation in the Newton-Raphson method are updated accordingly in the Newton-Raphson method for performing the batch-reaction calculation. A low-salinity-waterflood case is presented to validate the updated UTCHEM against PHREEQC (Parkhurst and Appelo 1999) and UTCHEM-IPhreeqc. The simulation studies indicated that the updated geochemical simulator succeeds in tackling the inaccuracy concerned in the original UTCHEM. Also, the updated version is more efficient compared with PHREEQC and UTCHEM-IPhreeqc with the same degree of accuracy. The updated geochemical simulator is then applied to model an ASP coreflood in which EDTA is used as a sacrificial agent to chelate calcium and magnesium ions. The experimental data of pH, oil recovery, and pressure drop were successfully history matched with predictions of the effluent concentrations of calcium and magnesium ions. A synthetic 3D ASP pilot case is successfully simulated considering effects of acid equilibrium reaction constant on oil recovery.

scholarly journals Enhanced oil recovery efficiency of low-salinity water flooding in oil reservoirs including Fe2+ ions

2018 ◽  
Vol 37 (1) ◽  
pp. 355-374 ◽  
Author(s):  
Yeonkyeong Lee ◽  
Hyemin Park ◽  
Jeonghwan Lee ◽  
Wonmo Sung
Keyword(s):  
Oil Recovery ◽  
Oil Production ◽  
Water Flooding ◽  
Sulfate Ion ◽  
Low Salinity ◽  
Low Salinity Water ◽  
Low Salinity Waterflooding ◽  
Injection Water ◽  
Salinity Water ◽  
Reservoir Simulator

The low-salinity waterflooding is an attractive eco-friendly producing method, recently, for carbonate reservoirs. When ferrous ion is present in the formation water, that is, acidic water, the injection of low-salinity water generally with neutral pH can yield precipitation or dissolution of Fe-minerals by pH mixing effect. FeSO4 and pyrite can be precipitated and re-dissolved, or vice versa, while siderite and Fe(OH)2 are insoluble which are precipitated, causing permeability reduction. Particularly, pyrite chemically reacts with low-salinity water and release sulfate ion, altering the wettability, favorably, to water-wet. In this aspect, we analyzed oil production focusing on dissolution of Fe-minerals and Fe-precipitation using a commercial compositional reservoir simulator. From the simulation results, the quantities of precipitation and dissolution were enormously large regardless of the type of Fe-minerals and there was almost no difference in terms of total volume in this system. However, among Fe-minerals, Fe(OH)2 precipitation and pyrite dissolution were noticeably large compared to troilite, FeSO4, and siderite. Therefore, it is essential to analyze precipitation or dissolution for each Fe-mineral, individually. Meanwhile, in dissolving process of pyrite, sulfate ions were released differently depending on the content of pyrite. Here, the magnitude of the generated sulfate ion was limited at certain level of pyrite content. Thus, it is necessary to pay attention for determining the concentration of sulfate ion in designing the composition of injection water. Ultimately, in the investigation of the efficiency of oil production, it was found that the oil production was enhanced due to an additional sulfate ion generated from FeS2 dissolution.

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