Polyacrylamide Adsorption and Readsorption in Sandstone Porous Media

SPE Journal ◽  
2019 ◽  
Vol 25 (01) ◽  
pp. 497-514 ◽  
Author(s):  
Vitor H. S. Ferreira ◽  
Rosangela B. Z. L. Moreno
Keyword(s):  
Oil Recovery ◽  
Polymer Concentration ◽  
Polymer Adsorption ◽  
Mobility Control ◽  
Polymer Molecule ◽  
Type I ◽  
Type Iv ◽  
Polymer Retention ◽  
Successive Injection ◽  
Flowing Solution

Summary The term polymer retention describes all mechanisms that remove the polymer from the flowing solution, with adsorption being its primary cause. This phenomenon can lead to detrimental effects during polymer enhanced oil recovery (EOR). In this paper, we present an investigation of dynamic polymer adsorption in sandstone-outcrop cores using polymer solutions. We study the effects of permeability and polymer concentration on the adsorption under two conditions: on virgin cores (adsorption) and a previously polymer-flooded core (readsorption). According to the results, two concentration plateaus and two regions of concentration-dependent adsorption characterize the polymer adsorption in a virgin porous medium, following a proposed Type IV isotherm. The transition between the first plateau and the second adsorption region occurs near to the overlapping concentration from dilute to semidilute regimes (cp*). Polymer readsorption increases slightly with the successive injection of banks with a higher polymer concentration, following a Type I (Langmuir) isotherm. For that case, we propose a readsorption mechanism on the basis of the desorption of a polymer molecule section and the adsorption of a new free polymer molecule. The adsorption and readsorption isotherms are similar until cp*, while the adsorption is much higher than readsorption for concentrations higher than cp*. Therefore, if the polymer concentration of the mobility control bank is greater than cp*, the total polymer loss during field applications can be reduced by preinjecting a polymer bank of lower concentration.

scholarly journals Effect of Polymer Adsorption on Permeability Reduction in Enhanced Oil Recovery

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Saurabh Mishra ◽  
Achinta Bera ◽  
Ajay Mandal
Keyword(s):  
Oil Recovery ◽  
Polymer Concentration ◽  
Polymer Adsorption ◽  
Mobility Control ◽  
Special Focus ◽  
Permeability Reduction ◽  
Solution Ph ◽  
Residual Resistance ◽  
Polymer Injection ◽  
Hydrolyzed Polyacrylamide

In order to reduce the permeability to water or brine, there is a possibility of polymer injection into the reservoir. In the present work, special focus has been paid in polymer [partially hydrolyzed polyacrylamide (PHPA)] injection as a part of chemical method. Tests were conducted in the laboratory at the ambient temperature to examine the reduction in permeability to water or brine in the well-prepared sand packed after the polymer injection. The experiments were performed to study the effect of polymer adsorption on permeability reduction by analyzing residual resistance factor values with different concentrations of polymer solutions. The rheological behavior of the polymer has also been examined. The experimental results also indicate that the adsorption behavior of polymer is strongly affected by salinity, solution pH, and polymer concentration. To investigate the effect of polymer adsorption and mobility control on additional oil recovery, polymer flooding experiments were conducted with different polymer concentrations. It has been obtained that with the increase in polymer concentrations, oil recovery increases.

Some Aspects of Polymer Retention in Porous Media Using a C14-Tagged Hydrolyzed Polyacrylamide

1975 ◽  
Vol 15 (04) ◽  
pp. 323-337 ◽  
Author(s):  
M.T. Szabo
Keyword(s):  
Porous Media ◽  
Oil Recovery ◽  
Pore Volume ◽  
Produced Water ◽  
Polymer Concentration ◽  
Oil Saturation ◽  
Polymer Flow ◽  
Hydrolyzed Polyacrylamide ◽  
Polymer Retention ◽  
Inaccessible Pore Volume

Abstract Numerous single-phase flow and oil-recovery tests were carried out in unconsolidated sands and Berea sandstone cores using C14-tagged, hydrolyzed polyacrylamide solutions. The polymer-retention polyacrylamide solutions. The polymer-retention data from these flow tests are compared with data obtained from static adsorption tests. Polymer concentrations in produced water in Polymer-flooding tests were studied using various Polymer-flooding tests were studied using various polymer concentrations, slug sizes, salt polymer concentrations, slug sizes, salt concentrations, and different permeability sands. Results show that polymer retention by mechanical entrapment had a dominant role in determining the total polymer retention in short sand packs. However, the role of mechanical entrapment was less in the large-surface-area Berea cores. In oil-recovery tests, high polymer concentrations were noted at water breakthrough in sand-pack experiments, an indication that the irreducible water was not displaced effectively ahead of the polymer slug. However, in similar tests with Berea cores, a denuded zone developed at the leading edge of the polymer slug. polymer slug. The existence of inaccessible pore volume to polymer flow is shown both in sand packs and in polymer flow is shown both in sand packs and in sandstone cores. Absolute polymer-retention values show an almost linear dependency on polymer concentration. The effect of polymer slug size on absolute polymer retention is also discussed. Distribution of retained polymer in sand packs showed an exponential decline with distance. The "dynamic polymer-retention" values in short sand packs showed much higher vales than the ‘static packs showed much higher vales than the’ static polymer-adsorption" values caused by mechanical polymer-adsorption" values caused by mechanical entrapment. The mechanism of polymer retention in silica sands and sandstones is described, based on the observed phenomenon. Introduction It is widely recognized that, as polymer solution flows in a porous medium, a portion of the polymer is retained. It is evident that both physical adsorption and mechanical entrapment contribute to polymer retention. The question of the relative importance of these retention mechanisms has not been studied adequately. The effect of residual oil saturation on polymer retention and the polymer retention during the displacement of oil from porous media has also been studied inadequately. Mungen et al. have reported a few data on polymer concentration in produced water in oil-recovery tests. However, no produced water in oil-recovery tests. However, no comparison was made between polymer retention at 100-percent water saturation and at partial oil saturation. It has been shown that the actual size of the flowing polymer molecules, with the associated water, can approach the dimensions of certain smaller pores found in porous media. Therefore, an inaccessible pore volume exists in which no polymer flow occurs. In this study, the existence polymer flow occurs. In this study, the existence of inaccessible pore volume is shown clearly, both in sand and sandstone. Although polymer-retention values have been reported for various conditions, correlation is difficult because of the differing conditions of measurements. The effect of slug size, polymer concentration, salinity, and type of porous media on polymer retention has not been systematically studied. The purpose of this study was to develop answers to these questions, rather than to provide adsorption data for actual field core samples. For this reason, unconsolidated silica sands were used in most of the experiments reported. This permitted identical, uniform single-layer and multilayer porous media to be constructed for repeated experiments under varying test conditions. Some experiments were also carried out in Berea sandstone cores to determine whether sand-pack results can be extrapolated to consolidated sandstones. Using a C 14-tagged polymer provided a very rapid, simple, and accurate polymer-concentration determination technique. SPEJ P. 323

Laboratory Investigations of Factors Influencing Polymer Flood Performance

1975 ◽  
Vol 15 (04) ◽  
pp. 338-346 ◽  
Author(s):  
M.T. Szabo
Keyword(s):  
Oil Recovery ◽  
Polymer Solutions ◽  
Polymer Concentration ◽  
Polymer Flooding ◽  
Mobility Control ◽  
Sweep Efficiency ◽  
Experimental Conditions ◽  
Polymer Injection ◽  
Polymer Flood

Abstract Numerous polymer floods were performed in unconsolidated sand packs using a C14-tagged, cross-linked, partially hydrolyzed ployacrylamide, and the data are compared with brine-flood performance in the same sands. performance in the same sands. The amount of "polymer oil" was linearly proportional to polymer concentration up to a proportional to polymer concentration up to a limiting value. The upper limit of polymer concentration yielding additional polymer oil was considerably higher for a high-permeability sand than for a low-permeability sand. It is shown that a minimum polymer concentration exists, below which no appreciable polymer oil can be produced in high-permeability sands. The effect of polymer slug size on oil recovery is shown for various polymer concentrations, and the results from these tests are used to determine the optimum slug size and polymer concentration for different sands. The effect of salinity was studied by using brine and tap water during polymer floods under similar conditions. Decreased salinity resulted in improved oil recovery at low, polymer concentrations, but it had little effect at higher polymer concentrations. Polymer injection that was started at an advanced stage of brine flood also improved the oil recovery in single-layered sand packs. Experimental data are presented showing the effect of polymer concentration and salinity on polymer-flood performance in stratified reservoir polymer-flood performance in stratified reservoir models. Polymer concentrations in the produced water were measured by analyzing the radioactivity of effluent samples, and the amounts of retained polymer in the stratified models are given for each polymer in the stratified models are given for each experiment. Introduction In the early 1960's, a new technique using dilute polymer solutions to increase oil recovery was polymer solutions to increase oil recovery was introduced in secondary oil-recovery operations. Since then, this new technique has attained wide-spread commercial application. The success and the complexity of this new technology has induced many authors to investigate many aspects of this flooding technique. Laboratory and field studies, along with numerical simulation of polymer flooding, clearly demonstrated that polymer additives increase oil recovery. polymer additives increase oil recovery. Some of the laboratory results have shown that applying polymers in waterflooding reduces the residual oil saturation through an improvement in microscopic sweep efficiency. Other laboratory studies have shown that applying polymer solutions improves the sweep efficiency in polymer solutions improves the sweep efficiency in heterogeneous systems. Numerical simulation of polymer flooding, and a summary of 56 field applications, clearly showed that polymer injection initiated at an early stage of waterflooding is more efficient than when initiated at an advanced stage. Although much useful information has been presented, the experimental conditions were so presented, the experimental conditions were so variable that difficulties arose in correlating the numerical data. So, despite this good data, a systematic laboratory study of the factors influencing the performance of polymer flooding was still lacking in the literature. The purpose of this study was to investigate the effect of polymer concentration, polymer slug size, salinity in the polymer bank, initial water saturation, and permeability on the performance of polymer floods. The role of oil viscosity did not constitute a subject of this investigation. However, some of the data indicated that the applied polymer resulted in added recovery when displacing more viscous oil. The linear polymer-flood tests were coupled with tests in stratified systems, consisting of the same sand materials used in linear flood tests. Thus, it was possible to differentiate between the role of polymer in mobility control behind the flood front in each layer and its role in mobility control in the entire stratified system through improvement in vertical sweep efficiency. A radioactive, C14-tagged hydrolyzed polyacrylamide was used in all oil-recovery tests. polyacrylamide was used in all oil-recovery tests. SPEJ P. 338

scholarly journals Less-Concentrated HPAM Solutions as a Polymer Retention Reduction Method in CEOR

2020 ◽  
Vol 18 (1) ◽  
pp. 75-92
Author(s):  
Lizcano Nino J.C ◽  
Ferreira Vitor Hugo de Sousa ◽  
Moreno Rosangela B. Z. L
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Polymer Concentration ◽  
Polymer Flooding ◽  
Resistance Factor ◽  
Mobility Control ◽  
Absolute Permeability ◽  
Low Molecular Weight ◽  
Molecular Weight Polymer ◽  
Polymer Retention

Polymer Flooding has become one of the most implemented EOR techniques, due to three factors: First, Polymer flooding has expanded the range of the screening criteria parameters. Second, this EOR method is more effective than water injection, while handling water management issues in high water-cut reservoirs. Nevertheless, polymer retention can turn a viable technical project into an uneconomical one. Polymer loss due to retention is an inevitable phenomenon, which happens during injection processes. The development of experimental analysis aiming to minimize or reduce polymer loss from the displacing fluid bank is beneficial to broaden the application of this CEOR method. This experimental work evaluated the injection schemes aiming to reduce polymer retention in porous media. The approach consisted of injecting less-concentrated polymer banks followed for the main polymer bank designed for mobility control. An experimental methodology to quantify polymer retention due to each injected polymer bank, cumulative polymer retention, resistance factor, residual resistance factor and inaccessible pore volume (IPV) was developed. The measurement process was based on the injection of 20 PV polymer banks at a constant flow rate of 1ml/min at 25°C, separated by 30 PV brine banks. Two HPAM with molecular weights of 6-8 million and 20 million Daltons using 350mD and 5000 mD sandstone cores were tested, respectively. The HPAM solutions considering a Colombian field (0.7% NaCl) and seawater (3.5% TDS) salinities were prepared. All rock samples were previously submitted to the injection of 50 PV for preventing fines migration. Two injection schemes with variable polymer concentrations were performed: The first one in which the polymer concentration increased in each successive bank, and the second one in which the concentration decreased. HPAM concentration solutions from 50 ppm to 2000 ppm were sequentially used in both injection schemes. By comparing the results of these two schemes, the effect of the injection of the less-concentrated polymer solutions was evaluated. For the increasing concentration experiments, cumulative retention values of 175.7 μg/g and 58.9 μg/g were calculated for the low-molecular weight polymer and the high-molecular weight polymer, respectively. While comparing with decreasing concentration experiments, for the high-molecular weight HPAM a 19% of retention reduction was evidenced, but no retention reduction was observed for the low-molecular weight one. The results indicate that different retention mechanisms are strongly dependents on the absolute permeability of the samples. Additionally, IPV values of 0.5 PV and 0.25 PV were calculated using low and high permeability samples, respectively. There was no linear relation between the absolute permeability reduction and the polymer concentration of the first bank injected into the sample. The novelty of this work is to use sacrificial banks of less-concentrated HPAM solutions as a reducing retention agent for the polymer bank designed for mobility control.

scholarly journals Effects of Polymer Adsorption and Desorption on Polymer Flooding in Waterflooded Reservoir

2017 ◽  
Vol 3 (3) ◽  
pp. 1
Author(s):  
Sukruthai Sapniwat ◽  
Falan Srisuriyachai
Keyword(s):  
Oil Recovery ◽  
Polymer Concentration ◽  
Polymer Adsorption ◽  
Injection Rate ◽  
Polymer Flooding ◽  
Absolute Permeability ◽  
Rock Surface ◽  
Sweep Efficiency ◽  
Desorption Process ◽  
Adsorption And Desorption

Polymer Flooding is one of the most well-known methods in Enhanced Oil Recovery (EOR) technology, resulting in favorable conditions for displacement mechanism to lower residual oil in the reservoir. Polymers can lower mobility ratio by increasing the viscosity of injected water, hereby increasing volumetric sweep efficiency. Moreover, polymer adsorption onto the rock surface can help decrease reservoir permeability contrast. Due to absolute permeability reduction, the effective permeability to water is also reduced. Once the polymer is adsorbed onto the rock surface, polymer molecules can be desorbed with a chaser. This study is performed to further evaluate the effects of the adsorption and desorption process of polymer solutions to yield benefits on the oil recovery mechanism. A reservoir model is constructed by the reservoir simulation program called STAR® from Computer Modeling Group (CMG). Various polymer concentrations, starting times of polymer flooding process and polymer injection rates were evaluated with selected degrees of polymer desorption including 0, 50 and 100%. According to the results, polymer desorption lowers polymer consumption, especially at low concentrations. Polymer desorption causes polymer re-employment that is previously adsorbed onto rock surface, resulting in an increase of sweep efficiency in the further period of polymer flooding process. Furthermore, the results show that waterflooding followed by earlier polymer flooding can increase the oil recovery factor whereas the higher injection rate also enhances the recovery. Polymer concentration has relationship with polymer consumption due to the two main benefits described above. Therefore, polymer slug size should be optimized based on polymer concentration.

scholarly journals Properties of Biodegradable Polymer from Terrestrial Mushroom for Potential Enhanced Oil Recovery

2020 ◽  
Vol 20 (6) ◽  
pp. 1382
Author(s):  
Tengku Amran Tengku Mohd ◽  
Shareena Fairuz Abdul Manaf ◽  
Munawirah Abd Naim ◽  
Muhammad Shafiq Mat Shayuti ◽  
Mohd Zaidi Jaafar
Keyword(s):  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Biodegradable Polymer ◽  
Polymer Concentration ◽  
Polymer Flooding ◽  
Mobility Control ◽  
Sweep Efficiency ◽  
Reservoir Conditions ◽  
Infrared Spectrometer ◽  
Original Oil In Place

Polymer flooding could enhance the oil recovery by increasing the viscosity of water, thus, improving the mobility control and sweep efficiency. It is essential to explore natural sources of polymer, which is biologically degradable and negligible to environmental risks. This research aims to produce a biodegradable polymer from terrestrial mushroom, analyze the properties of the polymer and investigate the oil recovery from polymer flooding. Polysaccharide biopolymer was extracted from mushroom and characterized using Fourier Transform Infrared Spectrometer (FTIR), while the polymer viscosity was investigated using an automated microviscometer. The oil recovery tests were conducted at room temperature using a sand pack model. It was found that polymer viscosity increases with increasing polymer concentration and decreases when increase in temperature, salinity, and concentration of divalent ions. The oil recovery tests showed that a higher polymer concentration of 3000 ppm had recovered more oil with an incremental recovery of 25.8% after waterflooding, while a polymer concentration of 1500 pm obtained incremental 22.2% recovery of original oil in place (OOIP). The oil recovery from waterflooding was approximately 25.4 and 24.2% of the OOIP, respectively. Therefore, an environmentally friendly biopolymer was successfully extracted, which is potential for enhanced oil recovery (EOR) application, but it will lose its viscosity performance at certain reservoir conditions.

Labelling of non-A, non-B hepatitis infected chimpanzee hepatocytes with nuclease-gold conjugates

1984 ◽  
Vol 42 ◽  
pp. 250-251
Author(s):  
G. D. Gagne ◽  
M. F. Miller ◽  
D. A. Peterson
Keyword(s):  
Endoplasmic Reticulum ◽  
Experimental Infection ◽  
Uranyl Acetate ◽  
Type I ◽  
Cellular Injury ◽  
Type Ii ◽  
Tubular Structures ◽  
Type Iii ◽  
Type Iv ◽  
Infected Chimpanzee

Experimental infection of chimpanzees with non-A, non-B hepatitis (NANB) or with delta agent hepatitis results in the appearance of characteristic cytoplasmic alterations in the hepatocytes. These alterations include spongelike inclusions (Type I), attached convoluted membranes (Type II), tubular structures (Type III), and microtubular aggregates (Type IV) (Fig. 1). Type I, II and III structures are, by association, believed to be derived from endoplasmic reticulum and may be morphogenetically related. Type IV structures are generally observed free in the cytoplasm but sometimes in the vicinity of type III structures. It is not known whether these structures are somehow involved in the replication and/or assembly of the putative NANB virus or whether they are simply nonspecific responses to cellular injury. When treated with uranyl acetate, type I, II and III structures stain intensely as if they might contain nucleic acids. If these structures do correspond to intermediates in the replication of a virus, one might expect them to contain DNA or RNA and the present study was undertaken to explore this possibility.

scholarly journals Virulence Factors Found in Nasal Colonization and Infection of Methicillin-Resistant Staphylococcus aureus (MRSA) Isolates and Their Ability to Form a Biofilm

Toxins ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 14
Author(s):  
Thamiris Santana Machado ◽  
Felipe Ramos Pinheiro ◽  
Lialyz Soares Pereira Andre ◽  
Renata Freire Alves Pereira ◽  
Reginaldo Fernandes Correa ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Sccmec Type ◽  
Protein A ◽  
Invasive Infection ◽  
Type I ◽  
Methicillin Resistant ◽  
Type Iv ◽  
Spa Gene ◽  
The City

Hospitalizations related to Methicillin-resistant Staphylococcus aureus (MRSA) are frequent, increasing mortality and health costs. In this way, this study aimed to compare the genotypic and phenotypic characteristics of MRSA isolates that colonize and infect patients seen at two hospitals in the city of Niterói—Rio de Janeiro, Brazil. A total of 147 samples collected between March 2013 and December 2015 were phenotyped and genotyped to identify the protein A (SPA) gene, the mec staphylococcal chromosomal cassette (SCCmec), mecA, Panton-Valentine Leucocidin (PVL), icaC, icaR, ACME, and hla virulence genes. The strength of biofilm formation has also been exploited. The prevalence of SCCmec type IV (77.1%) was observed in the colonization group; however, in the invasive infection group, SCCmec type II was prevalent (62.9%). The Multilocus Sequence Typing (MLST), ST5/ST30, and ST5/ST239 analyses were the most frequent clones in colonization, and invasive infection isolates, respectively. Among the isolates selected to assess the ability to form a biofilm, 51.06% were classified as strong biofilm builders. Surprisingly, we observed that isolates other than the Brazilian Epidemic Clone (BEC) have appeared in Brazilian hospitals. The virulence profile has changed among these isolates since the ACME type I and II genes were also identified in this collection.

scholarly journals Experimental investigation of the displacement flow mechanism and oil recovery in primary polymer flood operations

2021 ◽  
Vol 3 (5) ◽  
Author(s):  
Ruissein Mahon ◽  
Gbenga Oluyemi ◽  
Babs Oyeneyin ◽  
Yakubu Balogun
Keyword(s):  
Relative Permeability ◽  
Oil Recovery ◽  
Polymer Flooding ◽  
Mobility Control ◽  
List Type ◽  
Motor Oil ◽  
Flow Mechanism ◽  
Fractional Flow ◽  
Recovery Method ◽  
Polymer Flood

Abstract Polymer flooding is a mature chemical enhanced oil recovery method employed in oilfields at pilot testing and field scales. Although results from these applications empirically demonstrate the higher displacement efficiency of polymer flooding over waterflooding operations, the fact remains that not all the oil will be recovered. Thus, continued research attention is needed to further understand the displacement flow mechanism of the immiscible process and the rock–fluid interaction propagated by the multiphase flow during polymer flooding operations. In this study, displacement sequence experiments were conducted to investigate the viscosifying effect of polymer solutions on oil recovery in sandpack systems. The history matching technique was employed to estimate relative permeability, fractional flow and saturation profile through the implementation of a Corey-type function. Experimental results showed that in the case of the motor oil being the displaced fluid, the XG 2500 ppm polymer achieved a 47.0% increase in oil recovery compared with the waterflood case, while the XG 1000 ppm polymer achieved a 38.6% increase in oil recovery compared with the waterflood case. Testing with the motor oil being the displaced fluid, the viscosity ratio was 136 for the waterflood case, 18 for the polymer flood case with XG 1000 ppm polymer and 9 for the polymer flood case with XG 2500 ppm polymer. Findings also revealed that for the waterflood cases, the porous media exhibited oil-wet characteristics, while the polymer flood cases demonstrated water-wet characteristics. This paper provides theoretical support for the application of polymer to improve oil recovery by providing insights into the mechanism behind oil displacement. Graphic abstract Highlights The difference in shape of relative permeability curves are indicative of the effect of mobility control of each polymer concentration. The water-oil systems exhibited oil-wet characteristics, while the polymer-oil systems demonstrated water-wet characteristics. A large contrast in displacing and displaced fluid viscosities led to viscous fingering and early water breakthrough.

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