A review of synergistic and antagonistic effects between oilwell cement additives

J. Plank, C. Tiemeyer, D. Buelichen, N. Recalde Lummer

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

8 Scopus citations

Abstract

Oil well cement slurries commonly incorporate several admixtures such as e.g. retarder, dispersant, fluid loss additive, anti-free water agent, defoamer etc. Between them, additive-additive interactions may occur which can result in incompatibilities and reduced performances (the most frequent case) or, oppositely, in improved effectiveness. Here, an overview of some synergistic and antagonistic effects between selected cement additives is presented. Four combinations of additives were tested and studied. At first, interaction between CaATBS-co-NNDMA fluid loss additive (FLA) and a NaATBS-co-itaconic acid retarder as well as welan gum, an anionic biopolymer applied as anti-free water additive, was investigated. It was found that the retarder which possesses a particularly high anionic charge reduces the effectiveness of the CaATBS-co-NNDMA FLA by decreasing its amount adsorbed on cement. Similarly, the anionic biopolymer can also negatively impact effectiveness of the FLA through competitive adsorption, whereby the biopolymer hinders sufficient adsorption of the FLA on cement. Incorporation of stronger anchor groups (e.g. dicarboxylates or phosphonates) into the CaATBS-co-NNDMA FLA enhance its affinity for the surface of cement and thus render it more robust against the negative impact from other admixtures. Second, compatibility between a Na+ lignosulfonate retarder and the CaATBS-co-NNDMA FLA was investigated. Here, surprisingly a dual synergistic effect was found. Na+ lignosulfonate improves the fluid loss performance of CaATBS-co-NNDMA while the latter greatly enhances the retarding effectiveness of lignosulfonate. The experiments demonstrate exceptionally high compatibility of both admixtures. The positive effect is based on coprecipitation of both polymers which enhances FLA adsorption on cement. At the same time, because of the thick adsorbed polymer layer the dissolution of the clinker phases is hindered which results in retardation of cement hydration. Finally, it was found that hydroxyethyl cellulose (HEC) and sulfonated formaldehyde polycondensate-based dispersants such as e.g. poly melamine sulfonate (PMS) or acetone formaldehyde sulfite (AFS) act synergistically whereby the fluid loss control provided by HEC is considerably improved. Dynamic light-scattering measurements revealed that in the presence of those dispersants, association of HEC molecules into large hydrocolloidal assemblies was greatly enhanced. Obviously, the increased ionic strength resulting from the polycondensate dispersants renders the nonionic HEC molecules less water-soluble less water-soluble and initiates their aggregation at an earlier stage. The larger hydrocolloidal polymer associates can plug filtercake pores more effectively which reduces cement fluid loss. The study suggests that multiple additive-additive interactions can occur in oil well cement. Understanding the underlying mechanisms can help to avoid unwanted incompatibilities and to develop mitigation strategies.

Original languageEnglish
Title of host publicationSociety of Petroleum Engineers - International Symposium on Oilfield Chemistry 2013
Pages690-702
Number of pages13
StatePublished - 2013
Externally publishedYes
EventInternational Symposium on Oilfield Chemistry 2013 - The Woodlands, TX, United States
Duration: 8 Apr 201310 Apr 2013

Publication series

NameProceedings - SPE International Symposium on Oilfield Chemistry
Volume2
ISSN (Print)1046-1779

Conference

ConferenceInternational Symposium on Oilfield Chemistry 2013
Country/TerritoryUnited States
CityThe Woodlands, TX
Period8/04/1310/04/13

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