Correlation between clay type and performance of swelling inhibitors based on polyetherdiamine in aqueous fluids

• Published in: Journal of applied polymer science Vol. 136; no. 25
• Main Authors: Silva, Ítalo Guimarães Medeiros, Bertolino, Luiz Carlos, Lucas, Elizabete Fernandes
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 05.07.2019; Wiley Subscription Services, Inc
• Subjects: Cation exchanging; Clay; clay swelling; Drilling fluids; Inhibitors; Materials science; Microfracture; oil and gas; Polymers; Propylene; Rheological properties; Rheology; Scanning electron microscopy; Semiempirical equations; Swelling; swelling kinetics
• DOI: 10.1002/app.47661
• ISSN: 0021-8995

ABSTRACT In this work, the linear swelling of four samples of natural clays was evaluated, using poly(propylene glycol) bis(2‐aminopropyl ether) M¯n~230 g mol−1 (PEDA‐230) and M¯n~400 g mol−1 (PEDA‐400) as shale inhibitors for water‐based drilling fluids, in comparison to a commercial shale inhibitor. The swelling kinetics was described by a semiempirical equation. A correlation was found between the cation exchange capacity of the clays and the diffusion kinetic constant of the inhibitors. Increased molar mass of PEDA favored swelling inhibition. The swelling inhibition was also evaluated by rheology, and the results were in agreement with the linear swelling tests. Scanning electron microscopy demonstrated the occurrence of microfractures on the clay surface after water contact, as well as the adsorption of the different shale inhibitors on the clay surfaces after contact with the aqueous inhibited fluid. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47661. Representation of a drilling rig and different geological formations (left). Microscopy images of highly compacted clay before the contact with water (center). Clay swelling caused by water led to the occurrence of several microfractures (top right). PEDA effectively minimized the clay swelling (bottom right).