Novel method for mitigating injectivity issues during polymer flooding at high salinity conditions

Julia Schmidt, Mohsen Mirzaie Yegane, Fatima Dugonjic-Bilic, Benjamin Gerlach, Pacelli Zitha

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

Abstract

Synthetic high molecular weight polymers have been utilized for enhanced oil recovery applications. Improving their injectivity remains an important issue for field applications. Large entangled polymer chains can clog pore throats, leading to injectivity decline. We investigated an emulsion polymer system and have developed a series of processing techniques to condition an acrylamide-based copolymer inverse emulsion system at a salinity of 50,000 ppm TDS before injection into porous media. The investigated polymer solution contained 4,000 ppm active emulsion polymer and 2,400 ppm inverter surfactant. The un-conditioned polymer system and test conditions were chosen to clearly demonstrate the impact of processing techniques on the injectivity behavior. The polymer solution was sheared with two agitators, a disperser and Ultra-Turrax, at different intensities and with a pressure-driven flow into a thin capillary to reduce the size of the largest polymer chains and disentangle the polymer chains while maintaining its viscosifying power. The injectivity of such differently sheared solutions was evaluated by performing filtration tests using a 1-micron membrane and sand-pack flooding tests. Our experiments have established a master curve showing viscosity and screen factor dependences on accumulated energy during pre-shearing, regardless of the mode of shearing. The un-sheared polymer solution had an unfavorable behavior in filtration test and sand-pack flooding experiment. After pre-shearing, the filtration behavior of polymer solution and the injectivity in sand-packs improved significantly. Polymer solutions sheared with a disperser at an energy input of 15 MJ/m3 improved the injectivity gradient (e.g. the ratio of the resistance factor over 30 pore volumes injected) from 3.7 to 1.6, while the viscosifying power was reduced by only 2%. To reach the same injectivity improvement with Ultra-Turrax, an energy input of 31 MJ/m3 were required, which reduced the viscosity by 11%. Shearing the solution using a capillary at an energy input of 50 MJ/m3, did not reduce the injectivity gradient while viscosity was reduced by 19%. This indicates that the injectivity performance is shear-origin dependent and the resulting polymer structure, when sheared through contractions, has a different alignment as compared to shearing with the agitators, the disperser and Ultra-Turrax.

Original languageEnglish
Title of host publicationSociety of Petroleum Engineers - SPE Europec Featured at 81st EAGE Conference and Exhibition 2019
PublisherSociety of Petroleum Engineers
Number of pages17
ISBN (Electronic)9781613996614
DOIs
Publication statusPublished - 2019
Event81st EAGE Conference and Exhibition 2019 - ExCeL Centre, London, United Kingdom
Duration: 3 Jun 20196 Jun 2019
https://eage.eventsair.com/81st-eage-annual-conference-and-exhibtion/

Conference

Conference81st EAGE Conference and Exhibition 2019
CountryUnited Kingdom
CityLondon
Period3/06/196/06/19
Internet address

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  • Cite this

    Schmidt, J., Yegane, M. M., Dugonjic-Bilic, F., Gerlach, B., & Zitha, P. (2019). Novel method for mitigating injectivity issues during polymer flooding at high salinity conditions. In Society of Petroleum Engineers - SPE Europec Featured at 81st EAGE Conference and Exhibition 2019 Society of Petroleum Engineers. https://doi.org/10.2118/195454-MS