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.

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).

Flow of Hydrophobically Modified Water-Soluble-Polymer Solutions in Porous Media: New Experimental Insights in the Diluted Regime

SPE Journal ◽  
2010 ◽  
Vol 16 (01) ◽  
pp. 43-54 ◽  
Author(s):  
Guillaume Dupuis ◽  
David Rousseau ◽  
René Tabary ◽  
Bruno Grassl
Keyword(s):  
Oil Recovery ◽  
Polymer Concentration ◽  
Adsorbed Layer ◽  
Water Soluble ◽  
Water Soluble Polymer ◽  
Improved Oil Recovery ◽  
Water Soluble Polymers ◽  
Resistance Factors ◽  
Soluble Polymers ◽  
Hydrophobically Modified

Summary The specific molecular structure of hydrophobically modified water-soluble polymers (HMWSPs), also called hydrophobically associative polymers, gives them interesting thickening and surface-adsorption abilities compared with classical water-soluble polymers (WSPs), which could be useful in polymer-flooding and well-treatment operations. However, their strong adsorption obviously can impair their injectivity, and, conversely, the shear sensitivity of their gels can be detrimental to well treatments. Determining for which improved-oil-recovery (IOR) application HMWSPs are best suited, therefore, remains difficult. The aim of this work is to bring new insight regarding the interaction mechanisms between HMWSPs and rock matrix and the consequences concerning their propagation in reservoirs. A consistent set of HMWSPs with sulfonated polyacrylamide backbones and alkyl hydrophobic side chains together with an equivalent WSP was synthesized and fully characterized. HMWSP and WSP solutions were then injected in model granular packs. As expected, with HMWSPs, high resistance factors (or mobility reductions, Rm) were observed. Yet, within the limit of the injected volumes, the effluent showed the same viscosity and polymer concentration as the injected solutions. A first significant outcome concerns the specificities of the Rm curves during HMWSP injections. Rm increases took place in two steps. The first corresponded to the propagation of the viscous front, as observed with WSP, whereas the second was markedly delayed, occurring several pore volumes (PV) after the breakthrough. This result is not compatible with the classical picture of multilayer adsorption of HMWSPs but suggests that injectivity is controlled solely by the adsorption of minor polymeric species. This hypothesis was confirmed by reinjecting the collected effluents into fresh cores; no second-step Rm increases were observed. Brine injections in HMWSP-treated cores revealed high residual resistance factors (or irreversible permeability reductions, Rk), which can be attributed to the presence of thick polymer-adsorbed layers on the pore surface. Nevertheless, Rk values strongly decreased when increasing the brine-flow rate. This second significant outcome shows that the adsorbed-layer thickness is shear-controlled. These new results should lead to proposing new adapted filtration and injection procedures for HMWSPs, aimed, in particular, at improving their injectivity.

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.

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^

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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