Gumbo shale

The formation may be reactive and swell. It may be unconsolidated and collapse on the tool joints or drill collars. We may have mobile formations such as gumbo shales or salt beds in a plastic condition. 

M. A. Alonso-Debolt and M. A. Jarrett. New polymer/surfactant systems for stabilizing troublesome gumbo shale. In Proceedings Volume, pages 699-708. SPE Int Petrol Conf of Mex (Veracruz, Mexico, 10/10-10/13), 1994. 

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