Study of the polymer concentration and polymer/crosslinker ratio effect on gelation time of a novel grafted polymer gel for water shutoff using a central composite design method

Abstract

In this research article, a hydrogel was prepared by crosslinking of carboxymethyl cellulose-g-polyacrylamide copolymer aqueous solution with chromium(III) acetate for the purpose of a water shutoff job in the oil reservoir. The experiments were conducted to investigate the main effects of copolymer concentration and crosslinker/copolymer ratio on gelation time of the hydrogel system. Then the effects of these two factors and their interactions on the gelation time were determined by using a central composite design (CCD) of the response surface method. CCD was used to generate the quadratic mathematical model for the gelation time response as a function of copolymer concentration, crosslinker/copolymer ratio, and their interaction. Furthermore, the analysis of variance (ANOVA) was used to evaluate the quality of the quadratic model. The ANOVA result of the developed model showed that the model was highly significant. The result also showed that the crosslinker/polymer ratio had more effects on the gelation time than did the polymer concentration and their interaction. A response surface method provides an optimum gel formulation. Core flooding experiments reveal that a significant permeability reduction on the sand pack cores can be achieved at reservoir conditions, when it is treated with an optimum gel formulation. Hence, this gel system may be suitable in the water shutoff job required for enhanced oil recovery from the oil fields. Copyright

Synthesis, characterization and evaluation of polyacrylamide graft starch/clay nanocomposite hydrogel system for enhanced oil recovery

“…Graft copolymerization of natural polymers with functional synthetic polymers gives modified products having a wide range of applications due to combining in one molecule the desired properties of both the natural polymer and the synthetic polymer (Behari et al 2001;Biswal and Singh 2004;Maia et al 2012;Pandey and Mishra 2011). Graft copolymerization is an easy method to modify the structure of natural polymers and thus makes them suitable for various applications such as flocculants (Ghorai et al 2013;Sen et al 2011), controlled drug release (Namazi and Belali 2015) and petroleum recovery treatments (Singh and Mahto 2016b;Song and Zhang 2007) of mature reservoirs. The graft polymers have the advantage of associating common properties such as high thermal and shear stability because of the attachment of polyacrylamide chains onto the rigid polysaccharide backbone.…”

The Thermal Gelation Behavior and Performance Evaluation of High Molecular Weight Nonionic Polyacrylamide and Polyethyleneimine Mixtures for Indepth Water Control in Mature Oilfields

“…All experiments were carried out as designed scheme, and the obtained data of gelation time were fed into the "datafit" software. A mathematical model was obtained by using this approach, which could be utilized to express the comprehensive relationship between the gelation time and NPAM and PEI concentration by the following second-order polynomial equation [28,29]:…”

The Thermal Gelation Behavior and Performance Evaluation of High Molecular Weight Nonionic Polyacrylamide and Polyethyleneimine Mixtures for In-Depth Water Control in Mature Oilfields

“…All experiments were carried out as a designed scheme, and the obtained data of gelation time were fed into the “datafit” software. A mathematical model was obtained by using this approach, which could be utilized to express the comprehensive relationship between the gelation time and NPAM and PEI concentration by the following second-order polynomial equation [ 28 , 29 ]: where GT is gelation time; and are the NPAM and PEI concentrations, respectively; and , , , , and are intercept, linear, quadratic, and interaction constant coefficients, and the statistical random error term, respectively.…”