Polymer Adsorption/Retention in Porous Media: Effects of Core Wettability and Residual Oil

Broseta, Daniel; Medjahed, Fatiha; Lecourtier, J.; Robin, Michel

doi:10.2118/24149-pa

Cited by 86 publications

(47 citation statements)

References 11 publications

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“…In a different study by Broseta et al [1995] the silanization technique increased the adsorption of neutral polymer (∼0% hydrolysis) and reduced the adsorption of hydrolyzed polyacrylamides (27% and 45% hydrolysis) on silanized sand. The adsorption behavior of 10% hydrolyzed polyacrylamide used in this work on silanized silica sand was similar to the behavior of neutral polyacrylamides.…”

Section: Resultsmentioning

confidence: 99%

Development of Polymer Gel Systems to Improve Volumetric Sweep and Reduce Producing Water/Oil Ratios

Willhite¹,

McCool²,

Green³

et al. 2005

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Gelled polymer treatments are applied to oil reservoirs to increase oil production and to reduce water production by altering the fluid movement within the reservoir. This report describes the results of a 42-month research program that focused on the understanding of gelation chemistry and the fundamental mechanisms that alter the flows of oil and water in reservoir rocks after a gel treatment. Work was conducted on a widely applied system in the field, the partially hydrolyzed polyacrylamide-chromium acetate gel. Gelation occurs by network formation through the crosslinking of polyacrylamide molecules as a result of reaction with chromium acetate. Pre-gel aggregates form and grow as reactions between chromium acetate and polyacrylamide proceed. A rate equation that describes the reaction between chromium acetate and polymer molecules was regressed from experimental data. A mathematical model that describes the crosslinking reaction between two polymer molecules as a function of time was derived. The model was based on probability concepts and provides molecular-weight averages and molecular-weight distributions of the pre-gel aggregates as a function of time and initial system conditions. Average molecular weights of pre-gel aggregates were measured as a function of time and were comparable to model simulations. Experimental methods to determine molecular weight distributions of pre-gel aggregates were unsuccessful. Dissolution of carbonate minerals during the injection of gelants causes the pH of the gelant to increase. Chromium precipitates from solution at the higher pH values robbing the gelant of crosslinker. Experimental data on the transport of chromium acetate solutions through dolomite cores were obtained. A mathematical model that describes the transport of brine and chromium acetate solutions through rocks containing carbonate minerals was used to simulate the experimental results and data from literature. Gel treatments usually reduce the permeability to water to a greater extent than the permeability to oil is reduced. This phenomenon is referred to as disproportionate permeability reduction (DPR). Flow experiments were conducted in sandpacks to determine the effect of polymer and chromium concentrations on DPR. All gels studied reduced the permeability to water by a greater factor than the factor by which the oil permeability was reduced. Greater DPR was observed as the concentrations of polymer and chromium were increased. A conceptual model of the mechanisms responsible for DPR is presented. Primary features of the model are (1) the development of flow channels through the gel by dehydration and displacement of the gel and by re-connection of pre-treatment, residual oil volume and (2) high flow resistance in the channels during water flow is caused by significant saturations of oil remaining in the channels. A similar study of DPR was conducted in Berea sandstone cores. Both oil and water permeabilities were reduced by much smaller factors in Berea sandstone cores than in similar treatm...

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Section: Resultsmentioning

confidence: 99%

Development of Polymer Gel Systems to Improve Volumetric Sweep and Reduce Producing Water/Oil Ratios

Willhite¹,

McCool²,

Green³

et al. 2005

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“…The oil film limited the polymer adsorption in the rock surface [29]. The polymer solution with a concentration of 1750 mg/L was used for polymer flooding and the method of measuring retention was used in the experiment.…”

Section: Dynamic Adsorption Of the Polymermentioning

confidence: 99%

Distribution and Presence of Polymers in Porous Media

et al. 2017

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Abstract:In order to better utilize the residual polymers formed after polymer flooding, the distribution and the presence of the polymers after polymer flooding were studied. This paper studied the vertical and plane distribution of the hydrophobically-associating polymer in addition to measuring the parameters after polymer flooding, which is important for numerical reservoir simulation. The results showed that the polymers mainly enter into the high permeability zone and distribute in the mainstream line area with only a small portion in the wing area. Based on the comparison of various experimental methods, double-slug experiments were chosen to measure the inaccessible pore volume and retention, which is considered to be the most accurate, most time-consuming and most complex method. Following this, we improved the processing method of experimental data by reducing it to one experiment with two parameters. At the same time, we further enhanced the accuracy of the experimental results. The results show that at 1750 mg/L, the inaccessible pore volume of the polymer is 25.8%. When the detention is 68.2 µg/g, the inaccessible pore volume constituted 22% of the total polymer, with the other 77.7% being the dissolved polymer. Moreover, the static adsorption and dynamic detention were measured, with the results showing that the static adsorption is larger than dynamic detention. Therefore, in the numerical reservoir simulation, using the static adsorption capacity instead of the dynamic detention is unreasonable. The double-slug method was chosen since it is more accurate for the determination of various parameters. Meanwhile, in order to enhance the accuracy of results, we improved the treatment of data.

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“…Sohrabi et al 36 have also studied water alternating gas injection using high pressure micromodels in both oil-wet and mixed-wet systems. Polymer flooding in glass micromodels 37,38 has been studied as well, and Meybodi et al, 39 Jamaloei and Kharrat [40][41][42] have performed detailed investigations of displacement behaviors in this context. Perrin et al 43 have even investigated the quantitative information of the velocity field inside such pore network micromodels using micro-PIV (particle image velocimetry).…”

Section: Introductionmentioning

confidence: 99%