Prediction of Viscosity for Partially Hydrolyzed Polyacrylamide Solutions in the Presence of Calcium and Magnesium Ions

1981 ◽  
Vol 21 (05) ◽  
pp. 623-631 ◽  
Author(s):  
J.S. Ward ◽  
F. David Martin
Keyword(s):  
Ionic Strength ◽  
Oil Recovery ◽  
Divalent Cations ◽  
Polymer Concentration ◽  
Solution Viscosity ◽  
Shear Rates ◽  
Partially Hydrolyzed Polyacrylamide ◽  
Lower Shear ◽  
Total Ionic Strength ◽  
Hydrolyzed Polyacrylamide

Abstract Loss of solution viscosity in water of increasing ionic strength is a major problem encountered in the use of the partially hydrolyzed polyacrylamide polymers for improved oil recovery. It is recognized widely that the viscosity loss is more drastic in the presence of multivalent cations than is observed for sodium ions. There is, however, little information available on the relationships between total ionic strength, concentrations of multivalent cations, and solution viscosities.The purpose of this study is to establish relationships between total ionic strength, concentration of calcium or magnesium ions, polymer concentration, and the resulting viscosity for partially hydrolyzed polyacrylamides with varying degrees of hydrolysis. Solutions at constant ionic strength with varying ratios of calcium or magnesium to sodium ions are compared, and the loss of viscosity as a function of the fraction of divalent cations in the system is determined. For shear rates in the power-law region, the fractional loss in viscosity is a function of the fraction of multivalent cations and, in the range studied, is independent of the total ionic strength. A more complicated relationship is found at lower shear rates where the fractional viscosity loss does vary with total ionic strength.The relationship in the power-law region should prove valuable in predicting viscosities on the basis of the dependence of viscosity on ionic strength and on multivalent cation concentration at a single ionic strength, eliminating the need for many individual measurements of viscosity. More work is needed before useful predictions will be possible at lower shear rates. Introduction Partially hydrolyzed polyacrylamide (HPAM) polymers are currently the most widely used mobility control polymers for secondary and tertiary oil recovery. Small quantities of HPAM can increase the viscosity of water by two or more orders of magnitude in the absence of added electrolytes. This phenomenal increase in viscosity results from the extremely high molecular weight of these polymers and repulsion between the negative charges along the polymer chain, resulting in maximum chain extension. The latter mechanism leads to one of the greater disadvantages of using HPAM in an oil reservoir. In the presence of the electrolyte molecules in typical oilfield brines, negative charges along the polymer chain are screened from each other by association with cations from the solution. The polymer chains no longer are extended fully, and solution viscosity decreases. Mungan observed that divalent cations have a more pronounced effect on viscosity than univalent cations when compared on the basis of equal weights of the chloride salts.Viscosities have been reported for HPAM solutions in sodium chloride brines of varying strength as well as for solutions in brines containing CaCl2 or MgCl2. Some viscosities also have been reported for solutions in brines containing both sodium and calcium ions, but no systematic study of the viscosity trends in brines with more than one type of cation has been reported.The purpose of this study is to investigate HPAM solutions with varying ratios of univalent to divalent cations and to establish trends of the solution viscosities for different values of degree of polymer hydrolysis, polymer concentration, and total ionic strength. Such trends are useful for predicting a wide range of viscosities from a few basic measurements. SPEJ P. 623^

Temperature Dependence of the Shear-Thinning Behavior o Partially Hydrolyzed Polyacrylamide Solution for Enhanced Oil Recovery

2020 ◽  
Vol 143 (6) ◽  
Author(s):  
Pan-Sang Kang ◽  
Jong-Se Lim ◽  
Chun Huh
Keyword(s):  
Temperature Dependence ◽  
Polymer Solution ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Polymer Concentration ◽  
Shear Thinning ◽  
Temperature Model ◽  
Polyacrylamide Solution ◽  
Partially Hydrolyzed Polyacrylamide ◽  
Hydrolyzed Polyacrylamide

Abstract The viscosity of injection fluid is a critical parameter that should be considered for the design and evaluation of polymer flood, which is an effective and popular technique for enhanced oil recovery (EOR). It is known that the shear-thinning behavior of EOR polymer solutions is affected by temperature. In this study, temperature dependence (25–70 °C) of the viscosity of a partially hydrolyzed polyacrylamide solution, the most widely used EOR polymer for oil field applications, was measured under varying conditions of the polymer solution (polymer concentration: 500–3000 ppm, NaCl salinity: 1000–10,000 ppm). Under all conditions of the polymer solution, it was observed that the viscosity decreases with increasing temperature. The degree of temperature dependence, however, varies with the conditions of the polymer solution. Martin model and Lee correlations were used to estimate the dependence of the viscosity of the polymer solution on the polymer concentration and salinity. In this study, we proposed a new empirical model to better elucidate the temperature dependence of intrinsic viscosity. Analysis of the measured viscosities shows that the accuracy of the proposed temperature model is higher than that of the existing temperature model.

scholarly journals A New Empirical Model for Viscosity of Sulfonated Polyacrylamide Polymers

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1046 ◽  
Author(s):  
Saeed Akbari ◽  
Syed Mohammad Mahmood ◽  
Hosein Ghaedi ◽  
Sameer Al-Hajri
Keyword(s):  
Polymer Solution ◽  
Oil Recovery ◽  
Empirical Model ◽  
Linear Regression Analysis ◽  
Polymer Concentration ◽  
Polymer Flooding ◽  
Solution Viscosity ◽  
Operational Variables ◽  
Reservoir Conditions ◽  
Sulfonated Polyacrylamide

Copolymers of acrylamide with the sodium salt of 2-acrylamido-2-methylpropane sulfonic acid—known as sulfonated polyacrylamide polymers—had been shown to produce very promising results in the enhancement of oil recovery, particularly in polymer flooding. The aim of this work is to develop an empirical model through the use of a design of experiments (DOE) approach for bulk viscosity of these copolymers as a function of polymer characteristics (i.e., sulfonation degree and molecular weight), oil reservoir conditions (i.e., temperature, formation brine salinity and hardness) and field operational variables (i.e., polymer concentration, shear rate and aging time). The data required for the non-linear regression analysis were generated from 120 planned experimental runs, which had used the Box-Behnken construct from the typical Response Surface Methodology (RSM) design. The data were collected during rheological experiments and the model that was constructed had been proven to be acceptable with the Adjusted R-Squared value of 0.9624. Apart from showing the polymer concentration as being the most important factor in the determination of polymer solution viscosity, the evaluation of the model terms as well as the Sobol sensitivity analysis had also shown a considerable interaction between the process parameters. As such, the proposed viscosity model can be suitably applied to the optimization of the polymer solution properties for the polymer flooding process and the prediction of the rheological data required for polymer flood simulators.

Flow Behavior and Viscous-Oil-Microdisplacement Characteristics of Hydrophobically Modified Partially Hydrolyzed Polyacrylamide in a Repeatable Quantitative Visualization Micromodel

SPE Journal ◽  
2017 ◽  
Vol 22 (05) ◽  
pp. 1448-1466 ◽  
Author(s):  
Yongjun Guo ◽  
Yan Liang ◽  
Miao Cao ◽  
Rusen Feng ◽  
Xinmin Zhang ◽  
...  
Keyword(s):  
Oil Recovery ◽  
Flow Behavior ◽  
Resistance Factors ◽  
Partially Hydrolyzed Polyacrylamide ◽  
Viscous Oil ◽  
Hydrophobically Modified ◽  
Quantitative Visualization ◽  
Monomer Content ◽  
Hydrolyzed Polyacrylamide ◽  
Flow Experiments

Summary To profoundly investigate the flow behavior and viscous-oil-microdisplacement characteristics of hydrophobically modified partially hydrolyzed polyacrylamides (HMHPAMs) as well as the effect of associating monomer content on those behaviors and characteristics, compared with partially hydrolyzed polyacrylamide (HPAM), the flow experiments through three serial mounted flat-sand-inclusion micromodels and the viscous-oil-microdisplacement experiments in both homogeneous and interstratified connected heterogeneous repeatable quantitative visualization micromodels were conducted by use of a series of polymers with varied associating monomer content (0–1.0 mol%) at similar viscosity within all shear rates concerned. The results obtained from flow experiments show that the resistance factors (RFs) and residual resistance factors (RRFs) generated by HMHPAMs were noticeably higher than those of HPAM, and the RFs and RRFs exhibited significant permeability dependence and increased with associating monomer content. The greater RFs and RRFs for associative polymer might not be mainly caused by polymer adsorption or retention but mostly caused by increasing aggregate sizes. At concerned permeabilities (1.1–6.1 µm2), all injections of HMHPAMs could tend to be stable, which indicates that all HMHPAMs could propagate deep into the porous media. The viscous-oil-microdisplacement experiments regarding the visualization micromodels with varied permeabilities (and permeability contrasts) provide new insights into the viscous-oil-microdisplacement characteristics of HMHPAMs, such as the piston-like displacement and profile modification. In homogeneous models, under different permeabilities (1.1–6.1 µm2), the variations of final viscous-oil recovery first increased and then decreased as a function of increasing hydrophobe content, and the hydrophobe content of the polymer to obtain maximum oil recovery enhanced with increasing permeability. This might qualitatively indicate that a constant permeability matches an optimal content of hydrophobic groups. At permeability contrast of approximately three, the HMHPAM with lower hydrophobe content (0.2 mol%) could obtain the maximum viscous-oil recovery. In contrast, the maximum viscous-oil recovery was achieved by the HMHPAM with higher hydrophobe content (1.0 mol%) at a contrast of approximately five. The HMHPAM with higher content of hydrophobic groups is suitable for the significant heterogeneity.

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

Flow Behavior Through Porous Media and Microdisplacement Performances of Hydrophobically Modified Partially Hydrolyzed Polyacrylamide

SPE Journal ◽  
2016 ◽  
Vol 21 (03) ◽  
pp. 688-705 ◽  
Author(s):  
Yongjun Guo ◽  
Jun Hu ◽  
Xinmin Zhang ◽  
Rusen Feng ◽  
Huabing Li
Keyword(s):  
Pore Size ◽  
Flow Behavior ◽  
Polymer Concentration ◽  
Molecular Structures ◽  
Microporous Membranes ◽  
Series Connection ◽  
Partially Hydrolyzed Polyacrylamide ◽  
Hydrophobically Modified ◽  
Monomer Content ◽  
Hydrolyzed Polyacrylamide

Summary To investigate the relationship between the flow behavior and microdisplacement performance and the molecular structures, especially associating monomer content, of hydrophobically modified partially hydrolyzed polyacrylamides (HMHPAMs) with varied associating monomer content, compared with that of partially hydrolyzed polyacrylamide (HPAM), a series of experiments were conducted that involved the filtration through screen viscometer, nucleopore membrane, and series-connection microporous membranes; the flow through three serial mounted artificial cores; and the displacement in the microetching model. The screen factors and the hydrodynamic sizes of polymers were obtained by screen viscometer and nucleopore membrane, respectively. The results show that the screen factors and hydrodynamic sizes of HMHPAMs were much-more sensitive to the polymer concentration, filtration pressure, and associating monomer content than HPAM. Moreover, the filtration experiment through series-connection microporous membranes indicates that there were moderate associating monomer content or greater flow pressure or pore size for HMHPAMs to easily pass and obtain equivalent differential pressure between membranes, which implies that the compatibility between the pore size and the hydrodynamic sizes of the microstructures is the most-important factor for the injectivity of HMHPAMs. The resistance factor (RF) established by HMHPAMs through three serial mounted artificial cores notably tended to be higher than HPAMs, and the HMHPAMs with higher associating monomer content could generate a greater RF. In contrast, when the associating monomer content was low enough and the permeability was high enough, the flow could obtain equilibrium easily and the RFs were almost in accordance, which indicate there was moderate associating monomer content for HMHPAMs to propagate deep into the cores. At the same viscosity, HMHPAMs had better microdisplacement efficiency than glycerol (no effect) and HPAM (a small portion) for displacing the residual oil trapped in the “dead” ends of flow channel. The pilot tests of the associative polymer AP-P4, which was developed for Bohai oil fields, have demonstrated the great application potential of HMHPAMs for enhanced oil recovery (EOR).

Retention and Flow Characteristics of Polymer Solutions in Porous Media

1977 ◽  
Vol 17 (02) ◽  
pp. 111-121 ◽  
Author(s):  
J.G. Dominguez ◽  
G.P. Willhite
Keyword(s):  
Porous Media ◽  
Flow Rate ◽  
Polymer Solutions ◽  
Polymer Concentration ◽  
Flow Characteristics ◽  
Porous Matrix ◽  
Polymer Molecules ◽  
Partially Hydrolyzed Polyacrylamide ◽  
Hydrolyzed Polyacrylamide ◽  
Polymer Retention

Abstract Retention and flow characteristics of a solution containing Pusher 700, a high-molecular-weight, partially hydrolyzed polyacrylamide, were studied partially hydrolyzed polyacrylamide, were studied in an 86-md core made by compacting Teflon powder. The quantity, of polymer retained during linear displacement experiments ranged from 10 to 21 mu gm/gm for polymer concentrations of 100 to 500 ppm in 2-percent NaCl solutions. Nearly all retention ppm in 2-percent NaCl solutions. Nearly all retention was attributed to mechanical entrapment because of low polymer adsorption on the Teflon surface. Flow rate affected polymer retention. In increase in velocity was accompanied by polymer retention. Polymer was expelled when the flow rate was Polymer was expelled when the flow rate was reduced. Inaccessible pore volume was about 19 percent of the total pore volume. percent of the total pore volume.Resistance factors in different sections of the core ranged Pam 2 to 10 /or solutions of 100 to 500 ppm polymer concentration in 2-percent NaCl. ppm polymer concentration in 2-percent NaCl. Permeability reduction resulting from polymer Permeability reduction resulting from polymer retention produces the resistance factor in most of the core at a velocity of 3.2 ft/D. Resistance factors in the Teflon cores were two to three times lower than those reported for natural porous media where polymer is also retained by adsorption. Introduction The search for a low-cost, effective mobility control agent is currently focused on dilute aqueous solutions containing partially hydrolyzed polyacrylamides or polysaccharides. Rheological polyacrylamides or polysaccharides. Rheological properties have been studied, including the properties have been studied, including the effects of polymer concentration, shear rate, electrolyte concentration, and type of electrolyte. Correlation of rheological data and models with the flow behavior of polymer solutions in porous media has been complicated by the many interactions that occur between the complex porous matrix and the polymer solutions. Some data have been correlated using non-Newtonian rheological models to describe the variation of fluid viscosity with the apparent shear rate that the fluid experiences as it flows through the tortuous paths in porous media. These correlations have adjustable parameters determined from the particular set of parameters determined from the particular set of data used to develop the correlation. Investigators studying partially hydrolyzed polyacrylamide solutions observed apparent polyacrylamide solutions observed apparent viscosities 5 to 20 times the values measured in a conventional viscometer at the shear rates believed to exist in the porous media. These viscosity increases were not anticipated from the rheological behavior of the fluids. Pye introduced the concept of the resistance factor to quantify this effect. Burcik observed a decrease in the mobility of brine in a Berea sandstone disk that had been previously contacted with partially hydrolyzed previously contacted with partially hydrolyzed polyacrylamide. The mobility reduction persisted polyacrylamide. The mobility reduction persisted even after 100 PV of brine had been flushed through the disk. Burcik concluded that polymer molecules retained in the pore structure by adsorption or mechanical entrapment were hydrophillic and restricted the flow of water. Gogarty made an extensive experimental study of partially hydrolyzed polyacrylamide solutions in porous media and concluded that these polymer porous media and concluded that these polymer solutions reduced the permeability of the porous media. He noosed that polymer retention in natural cores occurred by mechanical entrapment and adsorption. Both mechanisms contributed to the resistance and residual or flushed resistance factors observed with polyacrylamide solutions. Other evidence of interactions between the polymer solution and the porous matrix was found. polymer solution and the porous matrix was found. Adsorption of polymer molecules on the surface of materials present in the porous matrix has been demonstrated in batch adsorption experiments. Material-balance calculations made on the streams entering and leaving porous media following step changes in concentrations show retention of polymer molecules in the porous media. polymer molecules in the porous media. A dependence of polymer retention on flow rate has been reported. Szabo devised a set of static and flow experiments in which polymer adsorption was held to a low level by using silica sand with a small surface area. Mechanical entrapment was found to be the dominant retention mechanism in short sand packs. packs. SPEJ P. 111

Study on HPAM Biodegradation in the Wastewater of an Oilfield

2013 ◽  
Vol 364 ◽  
pp. 640-644 ◽  
Author(s):  
Qing Guo Chen ◽  
Mu Tai Bao ◽  
Mei Liu
Keyword(s):  
Waste Water ◽  
Oil Recovery ◽  
Growth Stage ◽  
Oil Field ◽  
Aerobic Bacteria ◽  
Synergetic Effects ◽  
Partially Hydrolyzed Polyacrylamide ◽  
Degradation Temperature ◽  
Hydrolyzed Polyacrylamide ◽  
Recovery Methods

The present paper studies the biodegradability of partially hydrolyzed polyacrylamide (HPAM) resulting from the waste water of an oil field after carrying out chemically based oil recovery methods. Three aerobic bacteria strains, PM-1, PM-2, PM-3 and PM-4 were isolated from the wastewater. The results indicated that PM-2, PM-3 and PM-4 had better degradability on HPAM. PM-4 showed antagonism to two other strains, whereas PM-2 and PM-3 showed synergetic effects. Primary optimized HPAM degradation conditions of mixed PM-2 and PM-3 were 35 °C ~ 45 °C of degradation temperature and 5.5~7.5 of pH. The mixed PM-2 and PM-3 showed alternative in different media and their different growth stage.

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