Partially hydrophobized hyperbranched polyglycerols as non-ionic reactive shale inhibitors for water-based drilling fluids

• Published in: Applied clay science 2016-11, Vol.132-133, p.122-132
• Main Authors: Ferreira, Conny Cerai, Teixeira, Gleber Tacio, Lachter, Elizabeth Roditi, Nascimento, Regina Sandra Veiga
• Format: Article
• Language: English
• Subjects: Hyperbranched polymer; Polyglycerol hydrophobization; Shale interaction and inhibition; Water-based drilling fluid
• ISSN: 0169-1317; 1872-9053
• DOI: 10.1016/j.clay.2016.05.025

The oil and gas industry demands drilling fluids that would be able to minimize the wellbore instability faced during the drilling of reactive shales. In this work we describe the synthesis of hydrophobized hyperbranched polyglycerols (HPG) with unique design and properties to be used as non-ionic reactive shale inhibitors. In association with KCl, HPG showed a superior performance in comparison with unmodified hyperbranched polyglycerol and with the commercial clay reactivity inhibitors PEG400 and PDADMAC. Intact cuttings recoveries were around 80%. The proposed inhibition mechanism suggests the formation of a complex between HPGs and K+ ions and its penetration into the clay interlayer spacing to minimize the shale-water interactions and remove water molecules present in the clay galleries. In addition, these aggregates formed by the amphiphilic structures would cause obstruction of the clay minerals pore throats, thereby making it even more difficult for the penetration of water molecules. [Display omitted] •Partially hydrophobized hyperbranched polyglycerols are excellent shale inhibitors.•Tests with different shales have shown recovery percentages higher than 90%.•Amphiphilic HPG strongly interacts with the clay minimizing shale swelling.•HPG structures did form aggregates that could beneficially seal clay pore throats.•HPG showed a shale inhibition performance superior to commercial additives.