scholarly journals Rheology-based method for calculating polymer inaccessible pore volume in core flooding experiments

2019 ◽  
Vol 89 ◽  
pp. 04001 ◽  
Author(s):  
V. H. S. Ferreira ◽  
R. B. Z. L. Moreno
Keyword(s):  
Shear Rate ◽  
Pore Volume ◽  
Single Phase ◽  
Relative Difference ◽  
Core Flooding ◽  
Two Phase ◽  
Shear Rates ◽  
The Core ◽  
Inaccessible Pore Volume

Polymer flooding is an enhanced oil recovery (EOR) method that reduces the mobility ratio between the displaced oil and the displacing injected water. The flow of polymer solutions through porous media is subject to some process-specific phenomena, such as the inaccessible pore volume (IAPV). Due to IAPV, polymer molecules move faster through the porous medium than smaller ones. Thus the IAPV value needs to be accounted for in experiments and field projects. Recent reports found that polymer in-situ rheology correlates with the IAPV. The objective of this paper is to develop a method for estimating IAPV based on the in-situ rheology of polymers. The methodology proposed here can be used in both single- and two-phase experiments. The technique requires measurement of polymer resistance factor (RF) and residual resistance factor (RRF) at steady state conditions. Core permeability, porosity, and residual oil saturation, as well as water and polymer bulk viscosities, also need to be taken into account. Correlations for polymer in-situ viscosity and shear rate are solved simultaneously, to wield an estimative for the IAPV. Aiming at to prove the method, we report 16 core-flooding experiments, eight single- and eight two-phase experiments. We used a flexible polymer and sandstone cores. All the tests were run using similar rock samples. In the single-phase experiments, we compare the alternative method with the classic tracer method to estimate IAPV. The results show an average relative difference of 11.5% between the methods. The two-phase results display, on average, an 18% relative difference to the IAPV measured in the single-phase experiments. The difference between single- and two-phase results can be an effect of the higher shear rates experienced in the two-phase floodings since, in these cases, the aqueous phase shear rate is also dependent on the phase saturation. Additionally, temperature, core length, pore pressure, and iron presence on the core did not show any influence on the IAPV for our two-phase experiments. The method proposed in this paper is limited by the accuracy of the pressure drop measurements across the core. For flexible polymers, the method is valid only for low and mid shear rates, but, accoording to literature, for rigid polymers the method should be accurate for a broad range of shear rates. The method proposed here allows the measurement of polymer IAPV on two- and single- phase core-flooding experiments when a tracer is not used.

scholarly journals Shear-Induced and Nanofiber-Nucleated Crystallization of Novel Aliphatic–Aromatic Copolyesters Delineated for In Situ Generation of Biodegradable Nanocomposites

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2315
Author(s):  
Ramin Hosseinnezhad
Keyword(s):  
Shear Rate ◽  
Cooling Rate ◽  
Isothermal Crystallization ◽  
Cellulose Nanofibers ◽  
Crystallization Time ◽  
Nucleation Density ◽  
Shear Rates ◽  
Biodegradable Nanocomposites ◽  
In Situ Generation

The shear-induced and cellulose-nanofiber nucleated crystallization of two novel aliphatic–aromatic copolyesters is outlined due to its significance for the in situ generation of biodegradable nanocomposites, which require the crystallization of nanofibrous sheared inclusions at higher temperatures. The shear-induced non-isothermal crystallization of two copolyesters, namely, poly(butylene adipate-co-succinate-co-glutarate-co-terephthalate) (PBASGT) and poly(butylene adipate-co-terephthalate) (PBAT), was studied following a light depolarization technique. To have a deep insight into the process, the effects of the shear rate, shear time, shearing temperature and cooling rate on the initiation, kinetics, growth and termination of crystals were investigated. Films of 60 μm were subjected to various shear rates (100–800 s−1) for different time intervals during cooling. The effects of the shearing time and increasing the shear rate were found to be an elevated crystallization temperature, increased nucleation density, reduced growth size of lamella stacks and decreased crystallization time. Due to the boosted nucleation sites, the nuclei impinged with each other quickly and growth was hindered. The effect of the cooling rate was more significant at lower shear rates. Shearing the samples at lower temperatures, but still above the nominal melting point, further shifted the non-isothermal crystallization to higher temperatures. As a result of cellulose nanofibers’ presence, the crystallization of PBAT, analyzed by DSC, was shifted to higher temperatures.

Inaccessible Pore Volume in Polymer Flooding

1972 ◽  
Vol 12 (05) ◽  
pp. 448-452 ◽  
Author(s):  
Rapier Dawson ◽  
Ronald B. Lantz
Keyword(s):  
Porous Media ◽  
Mathematical Models ◽  
Pore Volume ◽  
Polymer Solutions ◽  
Polymer Flooding ◽  
Reservoir Rock ◽  
Front Edge ◽  
Polymer Molecules ◽  
The Core ◽  
Inaccessible Pore Volume

Abstract We have found that solutions of typical waterflooding polymers do not occupy all of the connected pore volume in porous media. The remainder of the pore volume is inaccessible to polymer. This inaccessible pore volume is occupied polymer. This inaccessible pore volume is occupied by water that contains no polymer, but is otherwise in equilibrium with the polymer solution. This allows changes in polymer concentration to be propagated through porous media more rapidly than propagated through porous media more rapidly than similar changes in salt concentration. At the front edge of a polymer bank the effect of inaccessible pore volume opposes the effect of adsorption and pore volume opposes the effect of adsorption and may completely remove it in some cases. This paper presents three experimental polymer floods showing the effect of inaccessible pore volume in the presence of varying amounts of adsorption. Results of these floods clearly show that about 30 percent of the connected pore volume in the rock samples used was not accessible to The polymer solutions. The changes required to include polymer solutions. The changes required to include inaccessible pore volume in mathematical models of polymer flow and in held prediction methods are discussed. Introduction One way o improving the mobility ratio during waterflooding operations is by addition of a water-soluble polymer to the flood water. Several different polymers have been proposed and a number of investigators have presented results on the behavior of these polymer solutions in porous media. In addition, mathematical models have been developed for predicting the field behavior of polymer flooding. In all these studies movement polymer flooding. In all these studies movement of the polymer bank through the reservoir rock is of great importance. One phenomenon that has been repeatedly observed in polymer flooding is the removal of polymer from solution by adsorption on the reservoir rock. As a polymer bank propagates through porous media, the polymer bank propagates through porous media, the front edge is gradually denuded of polymer. The amount of polymer lost from a bank may be large or small, depending on the nature of the polymer and rock surface. This loss of polymer must be measured and included in any realistic mathematical model of polymer behavior. It has been widely assumed that polymer behavior. It has been widely assumed that adsorption is the most significant factor causing polymer to propagate through porous media at a polymer to propagate through porous media at a velocity different from that of water. In this paper we present data that demonstrate that all of the pores may not be accessible to polymer molecules and that this "inaccessible polymer molecules and that this "inaccessible pore volume" can affect polymer propagation pore volume" can affect polymer propagation significantly. In addition to the experimental results, we discuss the changes in interpretation and in mathematical models that are required to include this phenomenon. EXPERIMENTAL The experiments described in this paper were single-phase displacement of polymer solutions through consolidated sandstone. All the cores were prepared by evacuating and saturating with brine; prepared by evacuating and saturating with brine; the pore volumes of the cores were measured at this time. The experimental floods reported here were then done in three steps.An "initial solution" was injected until the core was at complete equilibrium with that solution.A bank of a different solution was injected into the core.Injection of the initial solution was resumed and continued until the end of the experiment. During each experiment the effluent from the core was collected in small samples; the analyses of these samples for polymer and salt content gave the basic data which is presented here. In plotting the results we used a "concentration fraction" defined as (Ce -Ci)/(Cb -Ci), where C is concentration and the subscripts e, i and b refer to the effluent, initial inlet and bank inlet values, respectively. All the solutions used were mixed in distilled water; concentrations are given in weight percent or in ppm by weight. Two polymers were used; one was a polyacrylamide (Pusher 700, The Dow Chemical Co.); the other a polysaccharide (XC biopolymer, Xanco, Div. of Kelco Co.). SPEJ P. 448

The Effect of Deposition and Annealing Conditions on the Microstructure of Al-Cu and Al-Cu-Si Thin Films

1991 ◽  
Vol 229 ◽  
Author(s):  
M. Park ◽  
S. J. Krause ◽  
S. R. Wilson
Keyword(s):  
Single Phase ◽  
Alloy Composition ◽  
Phase Region ◽  
Annealed Condition ◽  
Two Phase ◽  
Annealing Conditions ◽  
Transmission Electron ◽  
Sputter Deposited ◽  
Cu Thin Film

AbstractThe effect of deposition temperature and the addition of Si to sputter deposited Al-Cu thin-film microstructure was studied with transmission electron microscopy. Films were studied in the as-deposited and annealed condition. The effects of thermal treatment were studied with in-situ hot stage microscopy. Al2Cu (θ) precipitated at the grain boundaries and the sublayer interface. At higher deposition temperatures, with alloy composition in single phase region (Al-1.5 wt.%Cu), Al2Cu precipitated during cooldown. At lower temperatures, in the two phase Al-0 region, Al2Cu precipitated during deposition. The addition of Si caused formation of Si precipitates and retarded Al2Cu precipitation during deposition or cooldown.

scholarly journals In-Situ Epoxidation of Waste Cooking Oil and Its Methyl Esters for Lubricant Applications: Characterization and Rheology

Lubricants ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 27
Author(s):  
Atanu Kumar Paul ◽  
Venu Babu Borugadda ◽  
Vaibhav V. Goud
Keyword(s):  
Shear Rate ◽  
Methyl Ester ◽  
Flow Behavior ◽  
Methyl Esters ◽  
Waste Cooking Oil ◽  
Critical Parameters ◽  
Shear Rates ◽  
Cooking Oil ◽  
In Situ Epoxidation

In the present investigation, in-situ epoxidation of waste cooking oil and its methyl esters was prepared, and the rheological behavior was analyzed for biolubricant applications. Rheological properties of the prepared epoxides were measured at a temperature of 25–100 °C, at a shear rate ranging from 5 to 300 s−1. As viscosity is one of the critical parameters for potential biolubricant applications, in the present study, the power-law model was used to investigate the flow behavior of the epoxides. The viscosity of epoxidized waste cooking oil and its methyl ester epoxides showed Newtonian flow behavior in the studied temperature range. Different shear rates (5–100, 5–300, 100–300 s−1) were studied to determine the shear rate dependency of the epoxidized waste cooking oil and its methyl ester epoxides at different temperatures. From the average viscosity values, it was shown that the epoxides show identical results at all shear rates. The dynamic viscosities of the epoxidized waste cooking oil and its methyl ester epoxides were found to be dependent on fatty acid chain length, unsaturation, and temperature. Detailed physicochemical characterization for epoxide waste cooking oil (EWCO) and epoxide waste cooking oil methyl esters (EWCOME) were carried out to evaluate the properties for suitable biolubricant applications using standard American Society for Testing and Materials (ASTM) and American Oil Chemists’ Society (AOCS) methods. Based on the viscosity for EWCO (278.9 mm2/s) and EWCOME (12.15 mm2/s) and viscosity index for EWCO (164.94) and EWCOME (151.97) of the prepared epoxides, they could complement the standard ISO vegetable grade (VG) lubricants in the market.

Studies of phase transformation of Fe1-xS by in Situ TEM

1989 ◽  
Vol 47 ◽  
pp. 648-649
Author(s):  
Thao A. Nguyen ◽  
Linn W. Hobbs
Keyword(s):  
Phase Transformation ◽  
Single Phase ◽  
Nucleation And Growth ◽  
In Situ Tem ◽  
Two Phase ◽  
S Matrix ◽  
In Situ Heating ◽  
Phase Mixture ◽  
Lamellar Type

The transformation from Fe1-xS (IC) phase to a mixture of FeS (2C) and iron poor Fe1-xS (IC) phases has been investigated by a series of in-situ heating experiments. The purpose of this study is to resolve the controversy over the mechanism of phase transformation (spinodal decomposition versus nucleation and growth) and to explain the different microstructures observed in the two phase mixture of FeS and Fe1-xS (Figure 1).In-situ heating experiments were carried out using a JEOL JEM EM-SHTH double tilt heating holder. Synthetic “single” Fe0.97S crystals were cut into 3 mm disks, mechanically and ion thinned to electron transparency. In all cooling experiments, the sample was first held at 390 K, a temperature above the transition temperature in order to generate an initial single phase material; then, the temperature was quickly reduced to the temperature of interest.Figure 2a shows the development of a lamellar type microstructure after the sample's temperature was reduced from 390 K to 363 K and then held at this temperature for ten minutes. At 363 K, the undercooling is 27 K. The troilite FeS (2C) phase heterogeneously nucleates and grows along the edge of the sample. Diffraction analysis shows that the FeS (2C) phase is embedded in the iron-poor Fe1-x,S matrix with a rod-like structure.

Novel Method for Characterizing Single-Phase Polymer Flooding

SPE Journal ◽  
2013 ◽  
Vol 19 (04) ◽  
pp. 695-702 ◽  
Author(s):  
Kewen Li ◽  
Wenjie Sun ◽  
Fen Li ◽  
Yantao Qu ◽  
Yaozhong Yang
Keyword(s):  
Fluid Flow ◽  
Shear Rate ◽  
Polymer Solution ◽  
Relative Permeability ◽  
Single Phase ◽  
Polymer Solutions ◽  
Polymer Flooding ◽  
New Method ◽  
Absolute Permeability ◽  
Two Phase

Summary Polymer flooding has been used to enhance oil production and reduce water cut for a long time. However, there are still many fundamental challenges in characterizing the multiphase-fluid flow, even the single-phase-fluid flow, associated with polymer flooding. For example, it is difficult to measure and calculate two-phase polymer solution/oil relative permeability. One of the difficulties comes from the non-Newtonian and time-dependent properties of polymer solutions; another comes from the change in absolute permeability caused by the adsorption of polymer on rock surfaces. Almost all the methods for computing relative permeability are based on the assumption that the absolute permeability is constant. It may be helpful to further understand the mechanisms and develop more-reliable methods for calculating two-phase polymer solution/oil relative permeability by investigating single-phase polymer flooding more profoundly. In this study, a new method has been developed to calculate the pseudopermeability during single-phase polymer flooding. The non-Newtonian property of the polymer solutions was considered in the new method. Polymer-flooding experiments with different concentrations of polymers were designed and conducted to study the single-phase flow of polymer solution in rocks with different permeabilities. The values of the pseudopermeability of single-phase polymer flooding were then calculated with the method. It has been found that the relationships between the pseudopermeability and the reciprocal of shear rate were linear. The polymer-flooding pseudopermeability extrapolated at the infinite shear rate was close to the brine-flooding permeability after polymer injections in many cases.

scholarly journals Experimental Investigation and Performance Evaluation of Modified Viscoelastic Surfactant (VES) as a New Thickening Fracturing Fluid

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1470
Author(s):  
Z. H. Chieng ◽  
Mysara Eissa Mohyaldinn ◽  
Anas. M. Hassan ◽  
Hans Bruining
Keyword(s):  
Shear Rate ◽  
Hydraulic Fracturing ◽  
Shear Resistance ◽  
Core Flooding ◽  
Single Chain ◽  
Fracturing Fluid ◽  
The Core ◽  
Core Damage ◽  
Fracturing Fluids ◽  
Viscoelastic Surfactant

In hydraulic fracturing, fracturing fluids are used to create fractures in a hydrocarbon reservoir throughout transported proppant into the fractures. The application of many fields proves that conventional fracturing fluid has the disadvantages of residue(s), which causes serious clogging of the reservoir’s formations and, thus, leads to reduce the permeability in these hydrocarbon reservoirs. The development of clean (and cost-effective) fracturing fluid is a main driver of the hydraulic fracturing process. Presently, viscoelastic surfactant (VES)-fluid is one of the most widely used fracturing fluids in the hydraulic fracturing development of unconventional reservoirs, due to its non-residue(s) characteristics. However, conventional single-chain VES-fluid has a low temperature and shear resistance. In this study, two modified VES-fluid are developed as new thickening fracturing fluids, which consist of more single-chain coupled by hydrotropes (i.e., ionic organic salts) through non-covalent interaction. This new development is achieved by the formulation of mixing long chain cationic surfactant cetyltrimethylammonium bromide (CTAB) with organic acids, which are citric acid (CA) and maleic acid (MA) at a molar ratio of (3:1) and (2:1), respectively. As an innovative approach CTAB and CA are combined to obtain a solution (i.e., CTAB-based VES-fluid) with optimal properties for fracturing and this behaviour of the CTAB-based VES-fluid is experimentally corroborated. A rheometer was used to evaluate the visco-elasticity and shear rate & temperature resistance, while sand-carrying suspension capability was investigated by measuring the settling velocity of the transported proppant in the fluid. Moreover, the gel breaking capability was investigated by determining the viscosity of broken VES-fluid after mixing with ethanol, and the degree of core damage (i.e., permeability performance) caused by VES-fluid was evaluated while using core-flooding test. The experimental results show that, at pH-value ( 6.17 ), 30 (mM) VES-fluid (i.e., CTAB-CA) possesses the highest visco-elasticity as the apparent viscosity at zero shear-rate reached nearly to 10 6 (mPa·s). Moreover, the apparent viscosity of the 30 (mM) CTAB-CA VES-fluid remains 60 (mPa·s) at (90 ∘ C) and 170 (s − 1 ) after shearing for 2-h, indicating that CTAB-CA fluid has excellent temperature and shear resistance. Furthermore, excellent sand suspension and gel breaking ability of 30 (mM) CTAB-CA VES-fluid at 90 ( ∘ C) was shown; as the sand suspension velocity is 1.67 (mm/s) and complete gel breaking was achieved within 2 h after mixing with the ethanol at the ratio of 10:1. The core flooding experiments indicate that the core damage rate caused by the CTAB-CA VES-fluid is ( 7.99 % ), which indicate that it does not cause much damage. Based on the experimental results, it is expected that CTAB-CA VES-fluid under high-temperature will make the proposed new VES-fluid an attractive thickening fracturing fluid.

Understanding the Rheological Transitions in Semi-Solid Alloys by a Combined In Situ Imaging and Granular Micromechanics Modeling Approach

2022 ◽  
Vol 327 ◽  
pp. 127-132
Author(s):  
Te Cheng Su ◽  
Catherine O'Sullivan ◽  
Hideyuki Yasuda ◽  
Christopher M. Gourlay
Keyword(s):  
Shear Rate ◽  
Solid Fraction ◽  
Discrete Element ◽  
Quantitative Agreement ◽  
Micromechanical Modeling ◽  
Two Phase ◽  
Shear Cracking ◽  
Semi Solid ◽  
Boltzmann Method

To gain better understanding of rheological transitions from suspension flow to granular deformation and shear cracking, this research conducted shear-deformation on globular semi-solid Al-Cu alloys to study the rheological behavior of semi-solid as a function of solid fraction (38% - 85%) and shear rate (10-4 – 10-1 s-1) under real-time synchrotron radiography observation. By analyzing 17 X-ray imaging datasets, we define three rheological transitions: (i) the critical solid fraction from a suspension to a loosely percolating assembly; (ii) from the net contraction of a loose assembly to the net dilation of a densely packed assembly, and (iii) to shear cracking at high solid fraction and shear rate. Inspired by in-situ observations of semi-solid deformation showing a disordered assembly of percolating crystals in partially-cohesive contact with liquid flow, we reproduced a two-phase sample using the coupled lattice Boltzmann method-discrete element method (LBM-DEM) simulation approach for granular micromechanical modeling. In DEM, each globular Al grain is represented by a discrete element, and the flow of interstitial liquid is solved by LBM. The LBM-DEM simulations show quantitative agreement of semi-solid strain localization with the experiments and are used to explore the components involved in the shear rate dependence of the transitions, and the role of liquid pressure on the initiation of shear cracking.

Influence of Polymer-Molecule/Wall Interactions on Mobility Control

1981 ◽  
Vol 21 (05) ◽  
pp. 613-622 ◽  
Author(s):  
J.L. Duda ◽  
E.E. Klaus ◽  
S.K. Fan
Keyword(s):  
Porous Media ◽  
Shear Rate ◽  
Pore Volume ◽  
Xanthan Gum ◽  
Mobility Control ◽  
Permeability Reduction ◽  
Polymer Flow ◽  
Inaccessible Pore Volume ◽  
Wall Interactions ◽  
Low Shear

Abstract This paper presents the results of a study of molecule/wall interactions on permeability modification of consolidated porous media by polymer solutions. The experiments were conducted with a newly developed low-shear porous media viscometer. This is a simple-to-use, versatile instrument that is particularly useful for measurements at the low shear rates characteristic of reservoir flooding. The key for obtaining reproducible, steadystate results was to expose the porous medium to several hundred pore volumes of polymer solution to saturate it with polymer. The effective permeability during polymer flow and the residual permeability were determined for xanthan gum and polyacrylamide solutions in Berea sandstone, Bradford sandstone, filter papers, and Nuclepore filters. A mechanistic interpretation of the coupling of adsorption, mechanical entrapment, shear rate, and inaccessible pore volume effects on the effective and residual permeabilities was developed. This is the first study to show that inaccessible pore volume can influence the residual permeability significantly. Introduction Solutions of high-molecular-weight polymers are being used as modified waterfloods and to control the mobility of the waterflood that follows the chemical slug in enhanced oil recovery. Currently, two distinctly different polymers are used most commonly for this application. The most popular mobility-control polymer is partially hydrolyzed polyacrylamide. This polyelectrolyte is sensitive to electrolytes and is susceptible to mechanical degradation. The second most frequently used mobility-control polymer is a polysaccharide called xanthan gum. This biopolymer is produced by a fermentation process and is less sensitive to electrolytes and shear degradation than polyacrylamide. Polyacrylamide increases the viscosity of aqueous solutions and causes changes in the permeability of porous media by adsorption and mechanical entrapment in pores whose dimensions are the same order of magnitude as the dimensions of the polymer in solutions. Numerous investigators have shown that polyacrylamide reduces the permeability of porous media during flow and that some of this permeability reduction is permanent. It generally is considered that xanthan gum reduces the mobility of a solution in porous media mainly by increasing the viscosity of the solution and that the action of the xanthan gum on the permeability is insignificant.The purpose of this study is to investigate the influence of polymer-molecule/wall interactions on mobility control. This investigation uses studies on the flow of xanthan gum and polyacrylamide solutions in various kinds of porous media with a wide range of characteristics. Although the permeability modification caused by xanthan gum molecules is not as pronounced as that caused by polyacrylamide, the polymer/wall interactions with this biopolymer are significant. Results of permeability-reduction studies during polymer flow and the residual permeability reduction as functions of shear rate, initial permeability, hydrodynamic size of polymer molecule in solution, electrolyte (NaCl) concentration, polymer concentration, and porous media characteristics are reported. The experiments were conducted with a newly developed low-shear porous media viscometer. Permeability modifications during and after polymer flow can be determined accurately with this simple instrument that eliminates the need for pumps and pressure measuring devices. The results of this investigation have been used to develop a mechanistic interpretation for the influence of molecule/wall interactions on mobility, which incorporates adsorption, mechanical entrapment, shear rate, and inaccessible pore volume effects. SPEJ P. 613^

scholarly journals Experimental evaluation of low concentration scleroglucan biopolymer solution for enhanced oil recovery in carbonate

2020 ◽  
Vol 75 ◽  
pp. 61
Author(s):  
Vitor H.S. Ferreira ◽  
Rosangela B.Z.L. Moreno
Keyword(s):  
Polymer Solution ◽  
Oil Recovery ◽  
Polymer Flooding ◽  
Permeability Reduction ◽  
Core Flooding ◽  
Low Concentration ◽  
Water Cut ◽  
Polymer Retention ◽  
Inaccessible Pore Volume

Injection of polymers is beneficial for Enhanced Oil Recovery (EOR) because it improves the mobility ratio between the displaced oil and the displacing injected water. Because of that benefit, polymer flooding improves sweep and displacing efficiencies when compared to waterflooding. Due to these advantages, polymer flooding has many successful applications in sandstone reservoirs. However, polymer flooding through carbonatic rock formations is challenging because of heterogeneity, high anionic polymer retention, low matrix permeability, and hardness of the formation water. The scleroglucan is a nonionic biopolymer with the potential to overcome some of those challenges, albeit its elevated price. Thus, the objective of this work is to characterize low concentration scleroglucan solutions focusing on EOR for offshore carbonate reservoirs. The laboratory evaluation consisted of rheology, filtration, and core flooding studies, using high salinity multi-ionic brines and light mineral oil. The tests were run at 60 °C, and Indiana limestone was used as a surrogate reservoir rock. A rheological evaluation was done in a rotational rheometer aiming to select a target polymer concentration for the injection fluid. Different filtration procedures were performed using membrane filters to prepare the polymer solution for the displacement process. Core flooding studies were done to characterize the polymer solution and evaluate its oil recovery relative to waterflooding. The polymer was characterized for its retention, inaccessible pore volume, resistance factor, in-situ viscosity, and permeability reduction. Rheology studies for various polymer concentrations indicated a target scleroglucan concentration of 500 ppm for the injection solution. Among the tested filtration methods, the best results were achieved when a multi-stage filtration was performed after an aging period of 24 h at 90 °C temperature. The single-phase core flooding experiment resulted in low polymer retention (20.8 μg/g), inaccessible pore volume (4.4%), and permeability reduction (between 1.7 and 2.4). The polymer solution in-situ viscosity was slightly lower and less shear-thinning than the bulk one. The tested polymer solution was able to enhance the oil recovery relative to waterflooding, even with a small reduction of the mobility ratio (38% relative reduction). The observed advantages consisted of water phase breakthrough delay (172% relative delay), oil recovery anticipation (159% and 10% relative increase at displacing fluid breakthrough and 95% water cut, respectively), ultimate oil recovery increase (6.3%), and water-oil ratio reduction (38% relative decrease at 95% water cut). Our results indicate that the usage of low concentration scleroglucan solutions is promising for EOR in offshore carbonate reservoirs. That was supported mainly by the low polymer retention, injected solution viscosity maintenance under harsh conditions, and oil recovery anticipation.

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