METHOD OF INHIBITING CROSSLINKING OF AQUEOUS XANTHAN GUMS IN THE PRESENCE OF FERRIC ACID

摘要

Aqueous xanthan gums normally crosslink at a pH greater than about 1.5 in the presence of ferric ions. This phenomenon is undesirable under many conditions of use, such as acidizing treatments of wells, and is inhibited or prevented by adding certain soluble alkanoic and/or alkenoic acids to the system. The alkanoic and alkenoic acids have at least 4 carbon atoms and bear at least 2 alcoholic hydroxyl groups per molecule and can be added as the organic acid per se or as a soluble salt or .gamma.-lactone. Ascorbic acid and erythorbic acid are examples.